Citation
Experimental analysis of behavioral isolation among four sibling species of nemobiine crickets

Material Information

Title:
Experimental analysis of behavioral isolation among four sibling species of nemobiine crickets
Creator:
Mays, David Lee, 1941- ( Dissertant )
Walker, Thomas J. ( Thesis advisor )
Huettel, Milton D. ( Reviewer )
Johnson, F. C. ( Reviewer )
Nation, James L. ( Reviewer )
Kerr, S. H. ( Reviewer )
Place of Publication:
Gainesville, Fla.
Publisher:
University of Florida
Publication Date:
Copyright Date:
1975
Language:
English
Physical Description:
xii, 111 leaves : ill. ; 28 cm.

Subjects

Subjects / Keywords:
Crickets -- Behavior ( lcsh )
Dissertations, Academic -- Entomology and Nematology -- UF
Entomology and Nematology thesis Ph. D
City of Gainesville ( local )
Chirp ( jstor )
Heart rate ( jstor )
Mating behavior ( jstor )
Genre:
bibliography ( marcgt )
non-fiction ( marcgt )

Notes

Abstract:
Pictonemobius ambitiosus (sendder)," formerly considered a single species, is four closely related species, separable by male song, color pattern,intersterility, and female phonotaxis. these species occur sympatrically and yet are separated by the closest series of species specific calling song pulse rates known for any complex of sympatric cricket species: approximately 37, 47, 55, and 60 p/s at 25° C. The geographic and ecological ranges of the four species are delineated from more than 700 laboratory recordings of crickets from more than 100 localities. The 37 p/s and 55 p/s species overlap broadly through much of the xeric sand ridge of Florida. The 55 p/s species often occurs in the central ridge scrub association and in the east and west coastal dunes. The 37 p/s species ranges northward into the upland longleaf-pine and turkey-oak where the 55 p/s species is absent. The 47p/s species (the real ambitiosus) occurs in pastures, roadsides, and disturbed xeric and mesic hammocks. The 60 p/s species, occasionally intermixed with the 47 p/s species, lives in the pine flatwoods from east Gainesville to the Okefenokee Swamp of Georgia. Populations morphologically similar to the 60 p/s species, but with pulse rates of 50-55, occur from Lafayette and Taylor Counties west into the Florida panhandle sometimes in association with the 37 p/s species. Of 14 intraspecific allopatric crosses between distant populations, all mated normally and 11 produced progeny. the range of pulse rates from intraspecific allopatric populations throughout central Florida exceeding interspecific differences that occur between closely related species pairs in area of sympatry. Interspecific pulse rate overlap in areas of sympatry appealed likely on cold clear days because temperatures where these crickets lived ranged from 15-20°C int he shade to 30-35°C in the sun. Individual temperature determinations derived from 71 fields recorded male calling songs suggested that males locate in microhabitats which maintain and probably enhance differences between closely related species pairs. The identity and exact location of 1624 male Pictonemobius from 51 separate hourly sampling periods on a one-acre plot defined male calling song production as diurnal and bimodal with a distinct morning and late afternoon peak. Pictonemobius spp. are present in all stages throughout the year, even where Weather Service temperatures below -8°C occur yearly; however, eggs, nymphs and adults were killed by a controlled, simulated natural temperature regime of -8°C. synthetic signals, controlled in carrier frequency (7,000 Hz) sound level (75 db), pulse rate (varied with test), pulse duration, chirp length and interval, and pulse shape were used to test females in the laboratory. Females of each species, when presented with replicated series of seven randomly ordered, synthetic trills differing by 2.2 p/s responded to pulse rates corresponding to calling songs of their conspecific males. Both visual scoring and a motion detector coupled to an even recorder revealed the same peaks of female response. Sixty-four virgin females, 16 of each species, were tested to determine the extent of reproduction isolation under conditions of forced crossing. Females were pretested for responsiveness 24 hours prior to a 4-hour mating observation period. In 16 control pairings the mating sequence produced normally. In 48 heterospecific crosses 26 produced calling song; 12 courtship song; 10 the first, spermatophoreless mounting; 9 a spermatophore and an attempt at mounting; 4 a spermatophore transfer and its retention by the female for more than 5 minutes; and 1 hybrid progeny with a pulse rate intermediate between the parental types. approximately 90% of pinned specimens examined can be identified using a combination of locality, color pattern and stridulatory file characteristics.
Thesis:
Thesis (Ph. D.)--University of Florida, 1975.
Bibliography:
Bibliography: leaves 102-103.
General Note:
Typescript.
General Note:
Vita.
Statement of Responsibility:
by David Lee Mays.

Record Information

Source Institution:
University of Florida
Holding Location:
University of Florida
Rights Management:
Copyright [name of dissertation author]. Permission granted to the University of Florida to digitize, archive and distribute this item for non-profit research and educational purposes. Any reuse of this item in excess of fair use or other copyright exemptions requires permission of the copyright holder.
Resource Identifier:
022389378 ( AlephBibNum )
ACZ5875 ( NOTIS )
02273916 ( OCLC )

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Full Text












EXPERIMENTAL .ANALYSIS OF
FOUR SIBLING SPECIES


BEHAVIORAL ISO
OF NEMOBIINE


NATION AMONG
CRICKETS


David


Mays


A DISSERTATION
COUNCIL OF THE UNI
FULFILLMENT OF THE
DOCTO


PRE
VER
REQ
R 0


ENTED TO THE GRADUATE
ITY OF FLORIDA IN PARTIAL
IREMENTS FOR THE DEGREE OF
PHILOSOPHY













































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s oP -


C )


; -


;1 ,


S L


1 .:-


< I /, /


- -I


Iloricda in P .tidl Frilfi ^ -, nt of the


] "-1:


foir


. I I













dcl s C.-:h.ct x:ric- artd nr.sic i


, c1-


The 60 p/ ci,


oc:-r s ^- is ,.- i '
S


inte-rmW 1 >1cl "i


/' 7 p/S


i .11-' -


. i-i <'" .-1n


the p1-,


r i ?+^'/0Cn^
J.- C- ... O V) -

frou 0o0 t Cs -mc L

t 1*e O "l cr-


S-'' p Of


the O0 p/s


Gor:gia.


.1ie ,- -
a-Jr^ v- i 2_ ',~-i,_- '


fro.l L, s7'' &


Popul at i or ,


, :i' *'
1is; *t-O ^.*.-


v,- h pus 0
-t +,+


"T; l C.:


( 0 '


I--.-. !


I -a lly *, ,n.l


of 50-5<


o:..U r


ino tie: FlorJ da


panhbe lI,." s-ru"ti. ,


(-. '


Ci 'C''


- ta -


-4 ;I ^ 'o
.I-


S a -' ,fJ
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c' .


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d- -


p '111 ?


I I''


: p ; ot tn Fvop;


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A-- _


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*< -J 1
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h l .


occulJ. C r-' i
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c'I SE \;
$;9 L('' ':S '-2 1/^^ tJ7S 3 -fl


CE- t C'


SC :,]-,.


il i' c" VS Ci --(-1


p -


L+ '


c-- < ar


O] ,-


ar.as


no a'


" +V T .; p ) < i,7
c\ ;I
a)


* Itenp1-.- 1.u .', i


31 ""' y


(: TiC] < C,


c )1(I


_iJ. v e


s5adc-


r a,.d from 1.5-200 in


' -o C


tL 4. a


Indi.v3 Uci J.


teln.TeratUrE c1oi~^<
-. +, < I ~ ,


r1 co d C ,iH.le Ali,. .


C102) 45


uiTLis *' -


,F 1 -C c r r


det :;Aved f C-.,:i


til"t inles .


i1 fiC ..


J oca. e


miC 'habi S hLl -
macl(2. nnb w La+. +.- uS Ufh/_CI.


i. ini c. in


pro.-.uly, LL c1ihlace di ffer-


e.DCOS. b..t e closely rolated


Csp ci t C -


pa:


She .dentJ ty


fil d +,A / ..- t+


location of


162^


fi: :.i-.


-1 ,-- i-, -r^- o +


from rr
T- y ^\-' ** t-


separate hourly saiuf.l ing perLodc on cie-acro plot de fir -,


in3. Ie calling


SOi, i


o
pro2C ,-'+ on
,+'O !CL IO+ t


Ec r; 2iurrnaL


S, "; -' m ++ -
kA ll.+/ k- *


V.X 1l


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ri-l ra .. dC ,,'i V. i, 13..


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rao L -.


-e ~


cd.v, *,














1 '4 .


cr-,5


nT 7 I 1 'f


Cad1. I tr


Wt:.~O i


5i1 ll.ed hi


1.1 CO. -^.


Sli '; C


:; .1


S -, ,
J.1.ffi A .


CO-iO Xro lle


t-e'ivtp2Dr i. :2


or<. ) I 2 :


7 jt( -I iat


f .- @ c I'


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Synt.!,. c


SOU :-i


]i ,' -Iv


(75 b)


ra'I-e


(V ;. c d


1.'.L [:


lu ji .c


t.-. ', l


di o'n,


C(11 g


1"
_-k<- -i -' T 1 .


@-7Gev^ lt ,,


p U il:


< -1 -
- n S.


-" r.t ,


tI .-


tuU


1a;1 E' atI ) -


Femi 1c.:'. of c.:- Ch


'po r1.p


1 li4 .


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- &,- ""


j.-r l -.- 1- ..


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C:,< ; t3


<- (^' *


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SCC" 3
(>2


S* -. -


.. t:J< :


Lt 'o'C-


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F.J


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i. .
t. -j it IL -


LC )'.


c YC-t&1,cv.


S.i-tv'-fur


p .0 ?
(, *: i 5. .


viAg i l


fm-.1n A C


c '. r -
S-S* V '- *


v' 1:-


3 Lo CLcL.u iJK 'h'" ECt.. t IO Lt


rc .' :c ? ....


so! ,TI" 10o


- oh.- -


ConcIiti lis


for,<-'<'


Cri ct., .
C ^ r ^--:' ^ ,, -3


A'C K I *' -


717 T3


I- ,4


-: ,:.puj\i v ti ss


C


ho ur:


I:. for


iV& 1 LD'1 0o1'..


Ji *t.. -


'.CV :i : 0


:.ijeC -'


:1r 0.3.


p, OC


10 6 C oT)trul


i-r.cria1


hoter-U5p 3 i. xc


Co lr'eS


'2 pio 'Cu,. "C caR] 1n (


S. .
*-* ~ I- -


COU 1't


sip
3_f iLj9


J.j i c


f-i. st, sporhoi jle


spcrraLtp1. ore


. X DSfli )'


a tIr'mot


and .ts retcl-inn by


at mouK t iiig;


feC:male for more1 t-.n


t-- ltl.." i


be tL;c:. i:


hybr:

L-1Z pac:n a.l


rrO.enyy


typ .


\it. th ; pulse rate


Approxir:a tely 90%


3 :rrcd late.


Sf pinned


( 7 000 z )


8;)?'


"a:l" a


:.:' ,iC


.- 4- our


'K I


In


r)u r;tinqg;


, PU r"


-. \ -


.0:^< -


r_ -":- .'0] .:" .


r n v^
*--\^ T J


.,- L-O :


'lA


11hc( ], :


]B h -2 : 1


t:Si






















Among


no &; t:


c. m
C^h O Lltxfl--A


i1:ur -lI


singing


Orthoptera


th ouI: Jo)i CI


(1- .


of pet -instutli
--1< -*'-- _.-* P- I -


Flo:da


somewhat


northward a


areL


. ,,' b .i -.


qrOund


rqi c c
'-J- './jft*'L*h


1iow


kniotn>


-s Pict.Oj mI.bius


ambi ti)..L-


rSc' r}


EBth


Exc


a- c


f iqht.e- L e -,,


possessing


only


forVwincf


case


f Co 1 V


th cCOe


1. j ra


arc


t re3 0: ^^c


c.:: r,


3]st


a "o-.:is al
aP'z o x a 1 -/Ji---- -< I


segOe9 t t


The


Ti~. i r. p
JL' L-^ t- S


, i- Tf-! li CE


dt K-


i1..: u? S !y'


clark


border


v w. q


tri xL,


St.-COated


appearance.


Be th


sexes f .,


have


prnomiii rant:


eves.


!whZ u


-3 --.-? ;- r-^


fr"ot


T.


their


WT 1k 11


head


S;-1d


between


sop-tenmr or


1964


mioorph


, T.


Sh' b.i


olK.og


ambit iouOS


frowp


noted


c- )or ation


d'f fe.en..


found


t hatit


b-ctwECC 1i


ecol oqical


Flori da


differences


population ns


s itua ti ons.


that


-^.t n


calli ] jf_


song


r'l J i


rate


drained

st.dy (

wJ ng st


bet-coen


co11ections


C. '-n


Walt cr

rake
T"7- 1 I ,
\ t '" "{. "


Sjrea :


, 1962)


a L-t


.n .-


in Soi_-L


a tcmpc:rature


one


indiv idual


appro :i.rnma tely


areas


vs.


cricket


weI 1 --


wirngstroke

maintained


(p/s)


tl ani


Otiw-rY $


over


range


^eii'P^4-~ C- /-LLL


tested,


s r t -


ti 9c


CWa-< ]


e1 .


no te-


T: MT' Pfi1 -p3r1j Or\


w i tL


pulses/ S second










Gun Club,


near


the municipal


airport.


"Slow"


ambitious,


with


a calling


song pulse


rate of


at 25C,


was


given


University


of Florida


Depar tmen t


of Entomology


library


specimftenl


recording


code


number


528.


"Fast"


ambitious,


with


a pulse


rate


25C


was


given


code


number


531.


Thes


types


crickets


could


be distinguished


the muni


cipal


airport.


Crickets


pro-


during


weedy


songs


were most


tur key-oak


areas


conunonl v


whereas


found


crickets


the disturbed


producing


songs were


found


surrounding


hammock.


In another


locality


(Goldhead Branch


State


Park,


Clay


Co.)


both


crickets


were


again


collected


in close


n r.
CtL 0 )


ociation.


Field


collected


adult


females


taken


laboratory


isolated


gallon


jars


provisioned


with


food


water


ap proxi mately


inches


autoclaved


sifted


sand


soon


p1odo uced


progeny


that


were


either


100%


100%


531.


Genera lly


females


were


more


black


white


sp- ,ckled


above


anid wb Lte


whi 3.o


were


markncd


softer


tones of


brown


with


J nLters.


nymphs


types


were


distinctively


consistently marked


colored


about


accuracy


separating


them.


nurb er


teeth


and


length


sound


producing


wing


file


varied


between


531.


These data


suggested


4rQ nnA




r.- To /Ir nT. cv. ri


Is\N r


-7 r- -i


Sf /""\ S-


tape


-t


allowing


_____










turkey-oak,


sandhill


area


3/4 mi.


west of Archer,


Florida, on 5 April 1967,


discovered


females


of Picto


nemobius that


were


dark brown with bright


straw


colored


markings


well. 1


the more typical dull 1-brown females of


Pictonemnobius 531.


Their differences


were


quite striking.


One individual female of each


color


type


was


brought to


the laboratory and each gave rise to progeny which were true


and bred true to their parental color type.


Laboratory tape


recordings of the resulting male progeny fell into two

categories corresponding with the two parental female color


types. The

in Florida,


dull-brown type,


known


(previously designated


song pulse rate of


47 p/s at 25C.


from

as 5


many other


31)


had a ca


The new, dark-b


brightly marked P. ambitious had a calling song


localities

11 ing

rown,

approxi -


mately


55 p/s at


5C.


Recordings


field-collected


ambitious


from


Archer locality confirmed the new male


song


type in the


field.


Numerous recordings


h"-d


already


been made under the


531 number for the two types,


the notation 531--1) for


the Dull brown


(47 p/s)


and 531-B for the Brightly marked


p/s)


Type


ambiti


31-B


osus


was


was


instituted.


found to breed true wherever


was


found and could be separated from 531-D and


in central











531-D,


making


this


character


less


dependable


terms


separating


species.


Type


531-B


appeared


to be distinct


from


531-D and


A fourth


anmbi


taosus


song


type.


was


discover


author


February


1969


along


a grassy


road


surrounding


pine


flatwoods,


.3 mi.


east


Clay


line on


Florida


road


The male


calling


song


attracted


attention


because


resembled


t of


Miogryllus


saussurci


(' Scuc1 r
" Li -V!.^^ -- ^ -


(whi ch


was


singing


from


burrows


e same


having


ti: me)


lasting


differed


more


than


from M.


secon11ds


saussui.cxi


A 531-D


male


was


located


same


site


calling


song


provided


a contrasting


reference


newil


song


type,


designated


as Pi ctoneitobius


525.


The


calling


son


pulse


rate


was


about


250C.


Both


ma I e s


females


were darkly


marked,


eas


from


other


three


types.


Early


tis


stud


four


song


type s


represent


biological


entities,


possessing


charac teristics


species


with regard


to reproductive


isolation


ecological


geog


raphical .


distribution


wi 11


refer


them


species


, 531-D,


531--B


f rom


this


point


will


present


proof


their


separateness


appeared


this


distinguishable

















SONG ANALYSIS


Equipment: Recording and Analysis

Tape recordings of male crickets were made


in the


Department of Entomology


noise


room


(LNR)


crickets


were


caged


individually in 4


in.


screen-


cages.


Caged


singers


were


located by using an


ear-


phone monitor,


and recorded with


a dynamic microphone


Scotch 202 magnetic recording tape at 15


inches/sec.


on an


Ampex models


tape


recorder.


The


tape


record er


was


located


an adjoining laboratory and


was s


activated


remote controls from within the LNR.


Some


tape


recorded


sounds


were


analyzed with a Kay


Electric


Company


audio-


spectrograph


(Sona-Graph)


but calibration


procedures


were


leng thy and production


was


slow.


More


often I


used


oscilloscope with


"stora


sc reen.


" Several


different


complete chirps could be displayed


one


time on the


osciilosco


using a


sweep


rate of


sec/cm.


From


tota 1


30 pulses the pu


rat


wa s


determined by the


formula


^- 30


I .-3


sided










where D


-= mm required for


30 pulse display and


the sweep rate


(.05 sec/cm)


Calling song pulse rates


perature


are


the individual cricket


a function of the tern-


therefore can he


corrected to some temperature standard


comparative


purposes given the


slope


of the pulse-rate-vs.-temperature


plot,


Pulse rate


corrections


25C


were made with the


form la


p/s at 25.00C


(25. 0


- T)


2.232


+ p/s


where T


= temperature


time of recording


2.232


slope


of the pulse-rate-vs.-temperature plot


(Walker


1962)


Description of Cal ing Songs


The calling songs of Pictonemobius,


like the calling


songs


of other Gryllidae,


are p


reduced


itary adult


males and attract sexually


responsive


females.


songs


have been shown to be


species


speci fic with


respect


to the


females that are attracted


(Walker


1957


, Alexander


1967


Hill


et al.


1972,


Ulagaraj


1974).


On numerous


occasions


or more of the four Picto-


nemobius


species


have


been heard calling in the


same


area.


In such


areas


individuals with intermediate


sonCs


have not










pulses


of sound


("chirps")


as opposed


trilling


crickets


which


produce


long


sec.


seFries


of pulses


("thrills")


Each


pulse


created


a single


clos ie C


upheld


mesothoracic


wings,


during which


file


(ventral.,


right


wing)


in contact


with


scraper


(dorsal,


left


wing)


The


ses


are


discrete


bursts


sound


havLrng


fundamenLal


oscillations


5,000-7,000


range.


These


fundamental


oscillations


correspond


with


strikes


file


teeth


scraper.


Species


long


chirp


, appro.x.yimte..
\^- ^1~ J YU- n- .tEIN7-


sec.


in duration,


with


a pulse


ra te


at 2


(n=21)


municipal


airport,


Gai,-esville,


Florida.


0O -.il graphic


traces


of a 528


calling


song


are


in i.1


A.


10. O/


chirp


makes


pulse


rate


sound


even,


slowe r


listener,


compared


with


Species


531-D


a chirp


interm-d i iatr


length,


to 0


sec.,


with


a pulse


rate of


47.0


(n=9)


from


the municipal


airtportj
T) -


Gaime Jvi


l e,


Flor ida -


A complete


cbhirp,


pulses


, an d


spaced


chirps


are


shown


Fig.


Species


531-B


short


chir


! .. fl


S -e .


length,


with


a pulse


rate


54.9


(1n-21)


from


west


of Archer,


Florida


Some


individual


ctlisi


stently


yn\ ry ,-r A -i a


- ---_ : -


h an


1, less


I 1


long


regul.arly


^ ,^ ^


I


*


fw J h ^ -


II


'I












































































































.. Calling


song
r- ^ r


S
- -


4 sp
* 1


>ec


of Pi


- a .


ctonemobius


^-


..lla


% rl


-_-r-


f 'i


"*


A AII










Species


long


chirp,


long


longer


than


528,


usually


sec.


long,


fastest


Pictonemobius


pulse!


rate,


59.9


250C


(n=8)


.3 mi.


east


Clay


line


on SRI 6.


trend:


of decreasin


g pulse


rate


with


increase


chirp


length


from


31-B


makes


song


quite


unusual


to hear.


Adding


distinctness


a slow build-up


intensity


early


part


chirp


(Fig.


ID) .


PictoneInohius


song


individual


variation


exists


the number


of chirps


unit


time,


intensity


changes within


chirp,


the maximum


intensity


chirp.


These


differences


rem ra in


consistent


throughout


sample of


individual' s


calling


song.


Several


laboratory-


reared


pulses


531-D


within


were


a chirp


found


recorded


to have


shortly


irregularly


after


spaced


their


maturation


adult


stage.


field-collected


laboratory-reared


ec_, in e- 11 -


more


than


one


week


were


found


to be


irregul ar


this


mcinner. t


geographic


distribution


corn


pi nation


cal in n


song


pulse


rates


presented


later


this


section


will


serve


define


four


species


of Pi c tonemobius.


Description


of Cour


ship Songs


acoustical


s iqrials


associated


with mating


are











prin


cipal


courtship


song-


(with


or without


spermnatophore


characteristic cal


a long


seri s


soft


chirps


(often


irregularly


spaced)


in which


f irsi


pulses


pulse


are


rate,


produced


followed


at almost


exactly


resumption


calling


of the


typical


song


raLte,


increase


intensity


(Fig.


When


a male


loses


contact


with


female


court-


he often


produces


loud


extended


pulsed


chirp


Fig.


usually


beginning with


court tship-type


wide-spaced


pulses.


Prior


"backing


under"


both


"brief


spermatophoreless


mounting"


" lengthy


mountinigt


[sperma tophore ]


produced,


transfer"


entirely


(Mays


calling


1971)


a long


SOn l


trill


rate


(Fig.


Courtship chJ rps


are


than


calling


song


chirps.


Courtship


interruption


chirps


backing


under


trills


531-D


531--B


are


than


their


call in


song


chirps.


untrained


listener


would


likely


find


it difficult


to d.sLinquish


courtship


chirps of


four


species


easy


to di sti anguish


courtship


chirps


from


calling


chirps.


Geographic Dstribu tion


Crickets


orinciiallv


belonging


in Florida


genus


. ,,<.. . .


Pictonemobi


immed i 5te1 v


occur


.n1 *n


5-10


hiuchh


Singer


shorter


, --\-i t
a mJ












































I(f *
r- T .Q
C f-H 0)
.0 Mf A


a C










Cleburne Co., Alabama


I have been unsuccessful in locating


Pictonemobius


west


the Florida panhandle, and north


southern Alabama and central Georgia.


Collections and laboratory tape


record nrgs


of more than


700 Pictonemobius from


over


1.00 Florida localities fall into


the four


categories


of Pictoremobius


discovered


in the


Alachua


area.


The identity of field-collected specimens


was determined by


analysis


laboratory recordings of male


calling songs,


habitat specificity,


color


patterns.


areas


distribution overlap do not


indicate intimate sympathy.


Localities in which


necessarily


such


sympathy


was


evidence


are


listed


(Table 1)


and illustrated


(Figs.


& 6).


The ana


lysis


of calling songs from several


areas


sympathy defined the


species


numerous times.


Marler


(1962)


states "Judgments of degrees


species


speci ficity


are


relative and


arise


from


compari sons


between


signals


under


consideration


other


signals


wh ich


are


likely


to be


present at the


same


t ine a nd place"


After


several


areas of sympatry


were


understood,


widely separated popula-


tions


each of the four kinds could be related


over


a wide


geographic


area


including most


Florida.


A detailed


analysis of allopatric variation in


Pi Ctonemob i us


is not


I _


u
























































































































v r


I 0'




























































































Ob C


'a'






















0


U,
CC
o
rto
in
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Notes to Table 3


Alachua Co.


Municipal
R.20E., 'iT


airpo t,


. 9S.


Monteocha
Fairbanks


"Gun


Gaines vis Ie


Club"


10 rm.


(T J.


north


(NE.


Walker


of Sec. 24,
collections)


of Gainesville,


east


Gainesville


sever


inc.


39th


Ave.


15th


Mill Ihopp


Archer
Plan L


Di vi


block


Industry


of F.


campus


Alachua-Levy


1 i]_ c


Sr. 24


mi.


west


of Archer,


scou t


SR.24


cast


S2nOA0


from


jct..


w ith


US. 301


Baker Co.


.1 mi.


south
west


GeorTij. a


scate


line


SR 121


from


Bay Co.


Panama


City


Leac"h,


city


limits,


east


Highland


Clay Co.


Goldhead


Starke


Branch


ea st of
Country


State


Cl] a
Club


Park


line on


Walker


SR 16


collections)


vicinity


Collier Co.


sou-th


jct..


jct .


-1 r- I


i 4


I ___


vicini .











Flagler Co.


South


of Marineland


Franklin Co.


Carrabelle,


nr.


cemetery,


north


side


town


Gilchrjst Co.


Jenny


Springs


Hernondo Co.


south


Co.
Archbol d


Croom west


biolocrical


1-75


Station


Venus


Jefferson Co.


.5 mi.


north


on SR.


LaPayette Co.


north


Dixie


line,


S357


Lake Co.


LTesburg


city


limits ,


south


US.27


Leon Co.


Ta 11


Ti;ues


Research


Stai.tion/,


north


Lake


lamoni a


Levy Co.


west


of Otter


Creek,


then


4.5 mi.


nor th


north Bronson,


flatwoods


1.5 mi.


north


Ma r i on-Levy


line


on US.41


Manatee


Springs


"18.












Mar ion Co.


.7 mi.


north of


Sparr


Ocala,


city


limits


& S336


US.27


& 441


at Orangeblossom Hills


S484 at Dunellon


jet.


S200


S 484;


east


jct.


S200


S484


Pa Im Beach Co.


Jupiter


PuLnam Co.
-- -- -_- _


easi-


Me 1 rose


S iinole Co.


Sanford, nr.
northwest of


25th St.


"F or t-


Grand view,


1/2 mi.


Reed"


Sumter Co.


SumL to -Lake


line


SR.50


Tavlor Co.


Blue Sp-ings 1 mi.


north


of Cedar


Island


Forest


Capi tal


Statc


Park


south!


of Perry


Wackulla Co.


1/2 mr.


west


of jct.


SR.365 on


SR. 98


on "old"












Brooks Co.


Quitman


Decatur Co.


West


of Climax


_ _





















35.7


41.0


36.7


'. 38.3

38,3 1

35.9


37.5'

37.2k

38,5


35.9


33.1


S, .**' -


Fig. 3.
T-Tnn/ nr-^i ni-1nA-


Distribution o
1 nn~ml 4a1 4-,, ntw^ -


Pictonemobius


n -S. f a-


.L. -- I-----------


528
__ .1 -I


in Florida.


















47.3


46.5


43.7


45.8


46.7


46,3


47.2


46.4


48,7


e1.0***




























52.8


" 55,4


55,4-


54,9'

46.6"


53.3


51.2


, *0*


Fig. 5.


a.


distribution o


f Pictonemobius


531-B
*


in Florida.
a


52.9


J






















59.9


60.4


a 50,6


, .'.* '*"
















ECOLOGICAL DISTRIBUTION


General


Habitat


Crickets


genus


Picton


"ius


are


found


from


dry


sand dunes and


central


ridge


areas


margins


swamps


tidal


salt marshes.


They


are


rarely


found


in mature,


dense hammocks with


a closed


canopy where


fire


been


ex-


eluded


years


or more.


Most of


Florida


is maintained


fire


sub-climax


with


additional


removal.


of pine


from


the central


sand


ridge


area,


clearing


agriculture,


creation


of pasture


ran


ge grazing


land


road


dredge


fill.


these


disturbed


areas


found


largest


populations


of Pictonemobius.


Alexander


and


Thomas


(1959


their


studies. s


three


sibling


soecir es


the Allonrn.ob


.US


fasciatus


group


found


that


three


were


nmijxed


with


indication


of interbrcedi ng


areas


Vw;her


artif


icia


ci earina


taken


place.


Similar


occurrences


with


Picto-


nemrnobi. us


are


discussed


later


in this


chapter.


The


effect


burni


size


of Pictonemobiu s


poDulations


was


evident


in comipar


unburr


annually


biannually


burn ed


plots


Ta ll


Ti. be .rs


Resear ch


Station


(TTRS)


rnA c' t


T -.


-i


11 C, I 1-- I r -. .-. I


- f E .


T r f..-


*m /, -' --i


__


,-^lr^ J -


i










A plot


whi ch


fire excluded


past


years


not contain


Pic Lonemobius.


They


ware


scarce


from


mar-


gins


absent


from within


"woodyard


hammock k


which


appears


lightning


to have


fires


been


and


und isturb ed


a record


except


logging


localized


northeast


Gum Pond


area


1945.


A 26 January


1913


account


from


Beadel

tall p


Diary


ine,


records


live oak,


the "w

holly,


Joodyard"


magnolia,


being


etc.


"thick


" (Betty


wood,

Ashler,


Historian,


TTRS, Personal]


Communication, 10


March


1973) .


Habitat descriptions


four


song


types


Pictonemobius


follow the


classification


Laessle


(1942)


The


531--D


Habitat


Species


531-D


is most


COL'lmo1n


in xeric


hammocks


mesic and hydric

thereby opening


hammocks

the canopy


that

and


are


burned


thinning


or disturbed,


understory.


Many


of Florida's


ruderal


commruni ties


such


as old


fields


fire


lanes,


roadside


ditches,


sand


lC)mounds,


fall


into


this


category making


531-D


most


commonly


encountered


Pictonemobius.


Species


531-D occurs


ii ammock


communities


over most


of mid


-central


Florida


even


into


"the


sandhills"


longleaf-pine


turkey-oak


(Pinus


palustris


Quercus


laevis


association,


predominantly


beneath


live-oak


virginiana)


They


appear


in xeric


hammock


sandhill


lawns


. .











(Vitis


Virgini a


crceperr


Parthenoci.ssus


quinquefolia),


saw palmetto


(Serenoa


J__-s1r -_,' r


persirunon


Diospyros


virginiana),


are


prcsenti


an areas


where


large


populations


531-D are


encountered.


In Alachua


surrounding


counties,


gum


they


(Liquidambar


persimmon,


hackbe


abounded


under


styracifl uaa

rry (Celtis


several


species


hawthorn


of oaks,


(Crategus


nississippiensi.s)


and


sweet


sp.)


wax myrtle


(Cerothamnus


ceriferus)


growing


solitarily


small


clusters


in pasture


s and


along


g assy


roads


ides.


They


are


also common


in partially


shaded


lawns


with


soime


leaf


litter


in and


around


clumps
c].u_,4-


fallen


Spanish


moss


(Tillandsia


usneoides)


the well-drained


portions


of weedy-grassy


roadsides


grown-over


road


heaps.


typical


531-D


hammock


habitat,


kept


open


grazing


cattle,


shown


Fig.


The 531-B Habitat


Species


531-B


is associated


with


"scrub


" i.e.


sand-pine


Pinus


clausa-Qutrcus


spp.


association


longleaf-pine


turkey-oak


associa


tion


wi. th


some


tran-


sition


into


]onglea*-pine


bh uejack-oak


(Pinus


palustris-


Quercus


cinerca)


association.


In most


tnese.


situ:.t tons


rosemary


ericoides)


, sEnd-pine


(Pinus clausa)
I---


"vPr TV


.-4A A -1l- '' J A IUA ^.* > f- ..J.- \ V- ^- <' / t -J A .t *- -


nrhrr r


nlnnl


(Geobalanus


oblancifolius.


r ITm mon


(Ceratiola


are r


sp.),








27














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en
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years


ago.


East


west


coast


531-B


occur on


well-drained


dunes,


shell


mounds,


and


dry


sandy


hills


that.


contain


live-oak


Quercus


virginiana


var. .


geminata)


sandhill


plant


associations.


The more


northern


sandhills


are


more


heavily


forested


less


likely


to have


sandpine,


rosemary,


and


cricket


531-B.


531-B


habitat


a xeric


, open


habitat,


occupying


highest and


"scrubby


best drained


1latwoods"


chapmanii)


asso


soils


(Quercus


var.


which


entire


state.


gemninata


occurs


myrtifolia,

n places


I


where


general


there


level


is a slight


of the


rise


flatwoods"


one or


(Laessle


feet ab


1942)


ove


usually


sufficiently


open


or well


drained


531-B.


Species


-D and


531-B


were


plentiful


an area


where


hammock


woods


adjoin


a turkey-oak


sandhill, 3/4


west


Archer,


528 with


north


Florida


Figs.


531-B occurred

Bronson, Levy


S A


site


Co.,


Florida


similar


distribution


5 mi. west

(Figs. 10


The


Habitat


Specie


s 528


does


covers

occurs


much

in


same geographic


the more disturbed,


area

weedy


recently

spottily


burned


alonic


sections


field


of a site.


martin.


- ... -----


Commonly


a road margqi


occurs


the center


citation


isolates


- Q.


r


_








29









r4*
to
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CO
-O -
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4(1


































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ooft


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Hr4












z


S. ,










males


(Fig.


The


opposite


situation,


where


531-B


surrounded by


occurred


center


of a large


weedy


field


(Fig.


number s


have


been


found


recently


cultivated


fields


weedy,


grassy


pastures,


and


in young pine

now border, 1


plantations?


ongleaf-pine


which

and t


were


formerly part


urkey-oak


woods


and


containing


531-B


as shown


in Fig


northern


associated


Florida


with disturbed


p-in


counties

e forests


528 appears

that contai


closely

n some


turkey-oak.


Here


they


often


border


531-D


areas


with


predominating


underbrush


higher


fire


sandhills


or mechanical m


that are


cans.


kept


clear


A detailed


study


of a 528


, 531-D


habitat


presented


later


this


paper.


Habi tat


Species


paulustris


COcurs


association,


slash-pine


and


flatwoods


black-pine


Pinus


fetterbush


flatwoods


(Pi nus


seroti na


- Desmothamnus)


association.


These


assoc


river


ceriferus)


Ilex


atiorns


flood


wir


coriace .)


often


plains

e grass


and

(A


blackberry


border

contain

ristida


(Rubu


bayheads


or extend


wax myrtle

spiciformis)

s betulifolil


outward


(Cerothamnus

, gall-berry


sundew


(Drosera


capil laris


usually with


-A


Spec


packed


dark


sites

colored


have


rich


soils


pine needles,


mossy


_11_ _










herbage


often


grow


these depressions.


Alachua


sites


have


include


been


northeast


opened by


Gainesvil e' s


occas onal


wet


burning


flatwoods


clearing.


that


Simi-


sites


of south


occur


Georgia.


northward


The.


into


river


Okeefenokee


flood


Swamp


plains


region


ground


situations


where


further


Florida


occurs.


northward


panhandle


possible


throughout


are


that


pine


additional


species


flatwoods


areas


occurs


of Georgia


since


this


habitat


fragmen ted


in North


Florida


into


east


west


coast


areas


separated


central


sand


ridge.


528,


53J -D


Habitat, a Case_ Study


temrporal


spatial.


distribution


531-D


was


intensively


examined


.n an


area


near


the Gainesville


municipal


airport


of Sec.


R20E,


in August


1971)


study


area.


was


selected


because


contained


both


531-D


over


an ecologically


diverse


area.


Components


xeric,


mros


, andc


hydric


hamrmock


communities


plus


long leaf-pine


turkey


longJleaf--pine


and blue-


jack-oak


communities,


both.


disturbed


undisturbed,


occur


together


this


study


arac


The distribution


principal


types


vegetation


are


shoun


in Fig.


woods


area


was


a mixture of


turkey


'-oak


longleaf-pine


with


bluejack-oak,


water-oak,


wild


cherry


one0


zone.


y--a ,

























































** e


- -1


:I
.... :I



**. -^--
'* *., 4S


*. ~**


,* 5*


- I


*..... .-." *. :
*" : ^," I
* ** I
* af r tin.
<3 .- **. *.r..

S
i
*e
.0e
*e
C


(....,
S**


- S
*
S
*5
- -


.5
*
* S
5 0
*~*S I
S
S.. *~g.. *5
C


.S
*

S..
99 -*


.

*
*
S


** 2



-* -


a-o
0- Q

0 Cn
-I 0


I



I
I
"l



t*

'^3
8S


<1o


,w


***,.:










sumac


is overgrown


with


grape


(Vitis)


and


virginia


creeper


(Parthenicissus


quinque fol i.a)


area


where


tree


s and


brush had


been


close


ground


level


appeared


to have


been


periodically


treated


this


a U.S.


manner


Government


Jame s


Lloyd.


at least


(1955-1960)


The most


last


aerial


recent


years


photo


judging


loaned


clearing


was


from


to me by


about


months


beforehand


and resulted


in about


are


ground.


remainder


water-oak


was


brush,


littered


palmetto


with


fronds,


dead,


turkey-oak


and numerouS


heaps


bottles,


paper,


cans,


and


other


debris.


Daytime


high


temperatures


in the


shade


ft.


above


the ground


were


23rd


2C on


24th,


, 21 and


about


22 August


270C


5th.


Niqhttime


low temperature


s were


20-22C.


The midday


low


relative


humidity


was


-30%


first


days,


but


creased


50-60%


remaining


days.


Methods


irregular


plot


approximately


one


acre


was


mapped


with


respect


the major


physical


features and


vegetation


(Fig.


12 A)


Hourly


surveys


were


made


ong


a predetermined


route


(Figs.


August


over much


p.m.


25 August


period


1971.


from 1:00


Sampling


p.m.


continued


* S a


-1 *


, Smilax,


I


A










1624


locations


individual


singers


(528


531-D)


were


recorded


on separate


hourly maps.


S ong Per i od i c ity


Song production


was diurnal


bimodal.


number


calling males


increased


during


early portion


dropped


to about


0.2X


(528)


0.5Xv


(531-D)


the morning peak


y midday.


nurmbe r


of calling males


increased


agaa n


afternoon


(Fig.


dark


numbers


of calling males


of both


31-D


had


again


decreased.


This


bimodal


peak


number


calling


males


agrees


closely with


isolated


males


plot


under


calling


conditions


song


produced


constant


tempera-


ture


controlled


photoperiod


laboratory


(Fig.


Similar


singing


occurs


on sunny


days


(Figs.


A-C) ,


on cl


ou.cy


(Fig


D-F)


under


uniform


diurnal


light


intensity


laboratory


(Fig.


sug-


gestingc


internally


controlled


diurnal


cycle


song


production.


Alexander


(1960)


states


"Light


intensity


seems


to be


mo s t


import an t


single


factor


determining the


exactU


time on


each


day when


different


species


begin


song "


42)


This


seems


appropriate


nocturnal


crepuscular


singing


species,


does not


offer


suggestion


to how


Pictonemobius


spp.


"anticipate"


1 S


S *-


& .. LI 4. -.4 4---'- A-- --- ~ -1---- L


bimodality


universally


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Spatial Distribution


Calling males


of Pictonemobius


were


heard


in both


open


areas


wooded


areas -


Male


s of


in open


areas


decreased


their


calling


the approach


of midday more


than


compared


with


those


wooded


areas


which


decreased


by only


(Figs.


& E)


There


was


indication


any movement


individual


to or


males


from


woods


females


were


this


observed


time,


though


moving


just


after


rain,


on moist


ground.


Calling males of Pictonemobius


the woods,

areas. Th-

(Figs. 15


gers


following


cloudy


with


only


ie distribution


& C)


n cloudy

except


days


the open


The


(Fig.


approximate'


days,


on:


(Figs.


531-D


heard,


singers

d the d

5 D, E,


the morning


15 F)


there


appeared


were

locate


sunn


istribut


wi


after


to be mo


areas.


like] ihood


number


highest


occurs

are low

heard a


of hearing


calling


proportion


at night


yet


night


when

the

7 in


courtshi p


songs


courtship

relative n


relative


sampling


songs


given


songs


umbers


umbers of

periods)


tim


to ca

of ca


courts


approx


usually in

d in open

y days,

ion of

th the

oon on the

re singers



is independent

e. For 528,

lling songs

lling songs

hip songs

inmates





















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- -


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may have gone

slow pulsed c


field


unnoticed


ourtship


than


since


shorter


song


courtship


song


more-

of 5


[than

easily


cal

re


31-D.


Pulse Rate Overlap in Callina Songs


The

from one

calling


four sp

another

songs.


initially


detects t

involved,

singers h


ecies

in t

When


of Pictonemobius


he

one


difficult

differences


short


ieard.


species-specific


between

tected.


open

It


Once

song


sunny


this


to differences


prompted my


rates be

should o

example,

males.

made mea


var


twee

ccur


the


field

first


are


basis


arrives


identify the


between


time


m


at a new sit


singers


songs


can


listener


differences


shady

e in


in microhabitat


postulating

n species s


the existence


singing


heterospecific


,


attraction


find


isurements


iety


crickets


of cool


such


identify


"tuned


variation


sites


can


individual

temperature


together.

attraction


531-D

overla


on clear winter


ambient

located.


temperatures

Recordings


all

in"


in pul

often


pulse


thi


overlapping


If

could]


females


days


such


ov'


occur


to warm


pulse

in ho


at ground


rate


level


temperatures


f-

wa

a


42



ling]

cognized







ishable

ale

e it may

soon one

ecies

he

the

se rate

be de-

rates,

at

g pulse

erlap

--for

28 singing

occurs, I

finding

here

t various


sites


difference


g


distingu


O<


t


_


___



















































































































































































































































































































H Hm











Pulse


overlap


was


iinves ticated


three different


sites


Pictonemobl us


species.


were


known


to occur


sympatrically.


Calling


songs


C. l--r- J-


ind] ividuals


slowestL


pul se


rate


s ec-' C 1-


slowest


individuals


fastest


corded


pulse


to establish


rate


whether


were


pulse


sought


rate overlap


out


exis ts


un der


these


conditions


area


approximately


square


yards.


studv


si te


was


orti


transitional.


habitat


airport,


used


son.g


Gainesville.


iodic


A cool,


study


clear


wJ th


te'm


municipal


peratures


15--200C


shade


30-350C


under


leaves


full


sun-


light


was


selected,


Songs


individuals


531-D


were


recorded


over


1-hour per


iod -


Whenev er


possible


specimens


were


captured


andi


location


ecC


h singer


noted.


Du r :i ng


survey


period


temp ecratre. Te


ground


funll


shadee


went


from


17.0


while


temperature


under


a leaf


ful 1


sunliqhtt


remained


.00C,


results


are


g i.ven!


in Table


A simi.


2-hour


study


was


conduct ted


a site


nta r


Croom,


Hernando Co.,


Florida,.


with


531-B


(n=9)


(n=30


that


were


found


together


in a disturb


partial


logged-over ,


longleaf-pine


area.


irl- *I --1 I


*


re-


wee(oy


race


Sere


species


1 -


trke'-uc.k


I.


m i^/^


_ I


-1


I







45



O- -
G) C 0.


jtfl in N
kLo to


.- C **




jwj
l on Ln r-


r1 ) l H Wi


(.LO'i ,-
Or-H > i*
Om *-
C) > )
-1 O < L
o -4 >cQ
QL) Lt) LY




O Q
0 i: V

40Jf 0 ) L






rU 0

O0
OrH

0)) !o
ed 0 0 tC
r 0 I I
*H p J



9 -14
U)0 Q)O
Cd r-









(A CO a>
* *H ( *


o -0 H

o 0 0 <





r-1 U) r<
rO cUQ ^








043


0 co .
01 0A O 0)








U) H V
*^ r 0 co o'

*r-t





^M U
004 0H )










study


period.


The


temperature


under


a leaf


full


sunlight


11:45


a.m


was


41.60C but


dropped


p.m.


shadows


from nearby


trees


shaded


results


are given


Table


A similar


3-hour


was


conducted


with


531-D


(n=16)


531-B


(n=21)


at a


site


west


of Archer,


Florida,


in an


ecotone


between


longleaf-pine


turkey-oak


sandhill


live-oak hammock


(Table


the Archer


site one


case


pulse


rate


overlap


occurred


between


specimens


identified by


chirp


length


531-B and


531-D.


This


531-D male


was


singing


open


a pul


rate of


66.6


which


was


faster


than


four


slowest


531-Bs


that hour.


There


is no correlation


between


pulse


rate and


degree


shading


where


song


was


heard:


however,


mos t


specimens


531-D


were


in more


shaded


situations


than


those


531-B.


assuming


temperature


linear


(Walker


relationship


1962)


between


using


pulse


the mean


rate


pulse


rate of


same


conspecific


locality


laboratory recorded


a reference,


individuals


temperature


from


of each


going


mal e


was


approximated.


The


results


indicate


that


calling males


are


areas


where


temperatures


are


25-35C


even


though


a wider


range


temperatures


are


available


r I I 1 1 i I-


invest nation







47


IO CM 0 0^


















I




uo
< n* *
.C C N N














C- I 1 I I
























O
Cd (N>.


tn
In



Q H In

X 4 CM CM
00
(1) 04
c: 0-It







4.3* 0 O it O
0 *
-- t Lo








*r^0 to^ n 0 ^

C-




















OO O
O 0 o
Cf C LM ( N CO 04 0-
c:a

HO










T^CO
0
C. C 0
Q) tO'.












-H SD I ol

0 ui 0) ^
-d0 Cn *s
'0$-I C I I I I














r-1 od r0 Ln L>
HO CU in **
4^ ^Din

0 0
4-i
0 Q2 10 I

03 E- IUC

0L! N 04 H-
0 0 4- 4

-H cC X< en o D O
HE SD 10> Sn in




0d 10 0HH '


N) Cl .
U) IT I.


tfWO .nQ)r4 -














































sUr-I


CtH
CD 4
0 0
4J
tP u)
CC,
-H H
s *
f0 *H
U


C)


r-














u)












04

HIQ
&^I


COO



HO
! 04
H,


(12 ^ IC NN e r-I 0 s-H en Sr C rHWWn d
U) IH CH Hoi i- i-
*-P0 -- OnO~

rr) U)tI04i40
Hrri r-i un cJ i^ OnOOl

r C u 0o 2Hm
S( ) 0 0) ** .. I t i















































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HQ
S03
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00
(U
oOi


54 I
O r-
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r4C
rttHG











(Table


may


actually


less


than


given.


Furthermore,


ecies


with


fastest


pulse


rate


appeared


to be


singing


the highest


temperature


at each


three


localities


studied.


This


would


tend


accentuate


calling


song


differences


that already


exist between


song


types


at each


three


study


sites.


primary


conclusion


from


this


study


that


calling


song pulse


rate


overlap


areas


sympathy


extremely


rare.


Coldhardiness


Study


life


stages


of Pictonemobius


have


been


found


during


seasons


the year,


during winter months


at drier


times


reasons


early


early


juveniles


juveniles


appear


become


scarce.


scarce


Possible


include


lack


female


wintering)


oviposition,


behavioral


delayed


adaptation


development


(i.e.


(egg


burrowing)


over-


or the


eggs


juveniles


being


unable


to survive


periods


severe


cold


or drought.


Laboratory


vs.


Field


531-D Coldhardiness


Test


Pictonemobius


spp.


breed


continuously


, all


stages


being


present


throughout


year,


even


in areas


of northern


Florida


where


weather


service winter


temperatures


below


-8C


occur


yearly.


Pictonemob ius


531-D


survives


winters


-I r 0 Xl IV fl rN r fl


fl Tk \ ,.-^ 4--


4- ,-v1nV,- 4 -% t.. r *


+-1- 0 F'I -1 l0CT


--* Y


~UI1










colonies


same


species,


which


life


stages


were


best adapted


any,


following


study


was


conducted.


From both


laboratory-rear


ed colonies


recent


field


col-


elections


(April),


individuals


five


classes--small


juveniles,


(large)


juvenile


males,


(lar


juvenile


females,


adult males,


and adult


females--were


placed


in rearing


jars


put


in an environmental


chamber


to be


subjected


series


successively


colder


night


temperatures,


approxi-


mately


10 hours


each


night,


until


crickets


had


died.


Each midday,


at approximately


20C


, mortality


counts


were


made.


In general


laboratory-reared


531-D


suffered


more


mortality


beginning


-40C


than


field-collected


individuals


(Table


appears


that


small


juveniles were


least


tolerant


temperatures.


This


experiment


was


in part


repeated


with


10 male


female


nymphs


from


same


field


laboratory


sources


days


later.


single


10-hour


cold


period


-80C was


given


first


night


to eliminate


effects


starvation


dessication


which


were


suspected


to have developed


previous


experiment.


test


crickets


were dead


the day


following


treatment


suggesting


that


a single


-hour


exposure


to -8C was


suf-


ficient


to kill


531-D collected


field.


Under


natural













































































)041
4m>0 -











528,


May


531-D,


1971,


531-B,


varying


were


numbers of


investigated.


field--collected


In early


individuals


each


species were


divided


into adult


male,


adult


female,


juvenile


groups,


placed


into


roaring


ars


containing


sand


that was moistened


on one


side


, and


a small


piece


of paper


toweling.


jars


were


placed


the environ-


mental


chamber,


which


was


to provide


midday


high


temperatures of 7 0C


followed by


successively


lower


night


time


temperatures.


successive


nights


temperature


declined


was


held


four


hours at


-80C.


Census ing


took


place during


following midday warm-up


periods.


The


stepwise decline


was


give


greatest


chance


acclimation


occur


as well


to provide more


than


one


period


where


temperature


might


enough


cause


mortality.


temperature


towel-sand


interface,


where most


crickets


congregated,


was


monitored


during


most


cooling-down


and


warming-uo


periods


showed


a 1-


to 2-hour


reaching


same


temperature


ambient


the environmental


chamber.


A pretest


census


census


following


first


cold


night


(+30C


were


identical;


no crickets


died.


The


results


successively


colder


ni.ahts


on adult


males,







54








a,

U 01
a M
4~ 0)
U

U
UU

0

a I
4 0)
















{~~~~~ ^io**5 P|*
*r4
6



'':. a0

0%I 4-I
C 0)
*
5-H
4* ,O
*0g





- doi 43 (
4':.C a)






L,-^pll^~~~U r-1- aoCa '
Oa 0
I t*I O
** 0

H -i-i
:. er*-r-4 a0



0 U. r-w










levels


one


after


adult


exposure


female


to -30C.


remained


Only


after


one


juvenile


an exposure


-80C.


additional


treatment


-80C


killed


remaining


crickets.


During


these


studies


laboratory


rearing


Pictonemobius


continued


normally.


Crickets


controls


these experiments


were


not


always


available,


but


surplus


crickets


that


were


collected


reared,


lived


weeks


under


laboratory


conditions.
















PHONOTAXTS


TO CALLING


SONGS


Introducti on


Species


specific


"calling


songs"


"pair


formation


songs"


are


produ


by male


Pictonemobius


(and most


other


crickets

females


female


as well) t

for mating.


toward


0o attract sexually

Phonotaxis is th


sound.


responsive

directed


strength


conspecific


movement


phonotaxi s


that


female


shows


toward


source


of a male


calling


song


or test


signal


difficult


to measure.


development


a consistent


reliable method


of quantifying


female


phonotaxis


to precede


attempts


evaluate


specifi-


city


of phonot


actic


response.


deve lopmen t


such


method


a maj


part


this


section.


assay


531-B,


virgin


their


female


response


Pictonemob i.us


to a wide


528,


range of


531-D,


natural


synthetic


sounds


further


defined


those


Pictonemobius


species.


Methods


Remote Event


Recording


EIqui. ment


Recordings


song


cycles


movement


crickets










Alton


Electronics


following


Company


transducers


were


Sensitive


used


Relay

trigger


(SR).

the


The

relay.


Micro


phone transducers:


A n um ber r


inexpensive


crystal


microphone


, such


The ro


Test


TRM-1A


"tape


recorder


microphone,


or dynamic microphones


such


Astatic


Corp.


model


level


DN-HZ


such


studiomike


a cricket


were


used.


singing


increase


caused


relay


sound


trigger.


Cadmium disulphide photoelectric cell:


This


photocell


was


used


to record


exac


t inme


that


LNR lights


were


switched


on or off.


Phonocartriidge:


A "sensitive


platform"


was


constructed


from nylon me


strung


tightly


across one end


inch hoop


and held


tight


small


spring


diameter


metal


pulling


disc,


downward


(Fig.


agci nst


The


a central


needle of


inch


an Astatic


type

disc


414-2


phonocartridge


Vibrations


applied


rested


lightly


anywhere on


this


platform


central

m were


transmitted


phonocartridge


resulted


triggering


relay-event recorder


system.


relay


could


acti-


vated


slight


stroking


a human


hair.


Whenever


crickets


walked


onto


or moved


slightly


while


upon


plat-


form,


relay


was


activated


several


times.


preserve


con


Lac ts


to eliminate


unnecessary


movement t


s of


event


recorder,


capacitors


I













































































































































































































































r










closed


longer


than


pulse


interval,


thereby


remaining


closed


for the entire


duration


of a chirp.


Further


capaci-


tance was often


applied


cause


relay


contacts


remain


closed during


chirp


intervals,


causing


recorder


remain


"on"


position


until.


singing


had


stopped.


Depending


transducer


signal,


various


resistors


with


values


100,000


range


were


applied


across


relay


input


to locate


relay


sensitivity


controls


some-


where


near


their mid


range.


Both


capacitors


and


resistors


effect


of preventing


spurious


noise


from


being


event on


ER chart


averaging


discontinuous


signa


into


continuous


positive


responses.


Photo-


cell required

output whereas


a 100

most


resistor


microphones


input

were


and

used


with


76,000


across


input


output


respectively,


Synthesis of Artificial Test Signals


Cricket

single


songs ge

frequency


nerally


between


ave

3,00


their

0 and


energy

8,000


concentrated


and


consequently


sounds


they


produce


are


often musical


"bell


like"


human


listener.


This


single


frequency


result


rapid


wing vibration


developed


wing


file


teeth


are


driven


over


scraper


during


a wing


-S










7,000


This


tone was


switched


a General


Radio

trill


type

with


1396--A T

an on-of


'one--burst


f ratio


Generator

1:2. Th


(TG)


to create


e AO output


was


monitored


a Monsanto model


100B


Counter


Timer which


gave


visual


readout


the AO


frequency


intervals.


A sine wave generator


used


(SWG)


vary


was


pulse


used


timing


rate.


inout


signal


thus


produced had


on-off


swi thing


noise


with


a harsh


on-off


contrast.


This


type


of signal


was


used


once


test


females


resp


onise


synthetic


signals


Further


refinements


involved


replacing


TG with


Alton


Electronics


Company


Field Effect


Transistor


Gate


Signal


Switch


(FET)


which


switched


7,000


AO signal


on and


off.


An externally


appi


drive


signal


produced


an Alton


switching


Electronics


rate.


Company


timer


rise-time


determined


fall-off


the FET


each


pulse


wa s


modified bv


second


drive


apple


ication


input


FET.


a .04


This


capacitor


equipment


across


made


possible


to shape


beginning


each


pulse


(Fig.


An example


an artificial


signal


illustrated


in Fi


D along with


a natural


pulse


(Fig.


19 C)


TG was


used


to chop


this


signal


into


chirps


various


pulses


long.


output


from


19).


numb






























END AND BEGINNING OF .5 MSEC/DIV
"SQUARE CUTr PULSE,
SYNTHETIC SIGNAL. 7000 CPS.


PAIR OF NATURAL PULSES.


5 MSEC/DIV


BEGINNING AND END OF .5 MSEC/DIV
"ROUND CUT' PULSE,
SYNTHETIC SIGNAL. 7000 CPS.


PAIR OF SYNTHETIC PULSES.


5 MSEC/DIV


7000 CP














COUNTER


(Mon


TIMER


santo model


TONE BURST
GENERATOR


(Gener
type


TIMING


Radio


1396-A)


INPUT


TIMER


(Alton


Electronics


Company


TAPE


RECORDER


(Ampex model


351)


100B)


1-IN
68f
/ -OUT

DRIVE
/I


WIDE


RANGE


(Hewlett


OSCILLATOR


Packard


-7


201C)


.004uf


47Th


OSCILLOSCOPE


(Tektronix


EXTERNAL.


type


564)


TRIGGER


AUDIO MONITOR


(Alton


Electronics


Company)


SPEAKER


(Sphericon


model


T-202)


Fig.
cun+^-i-hnF r


Schematic


equipment


used


in production


nrv r-lro- nal


r(* > II r











TG was displayed


the Tektronix where


final


adjustments


were made


upon


amplitude of


the AO output,


pulse


rate,


pulse


interval,


and


pulse


shape.


finished


signal


was


switched


input


the Ampex


and recorded


tape


ips.


A section


this


tape


was


then


removed and made


into


model


loop


T-202


for testing


(Sphericon)


females


or Realistic


phonotaxis.


40-2338


Sphericon


(Realistic)


exponential


horn


tweeters


(8n)


were


used


to broadcast


signals


(Fig.


Equipment


for Tests


of Phonota


xis


-foot-diameter,


sand-bottom arena


with a


6-inch-high


screen


side


lightweight nylon-mesh


was


test


enclosure


in which


female-responses


were


studied


(Fig.


21) .


Sitting .atop a


6-foot


step


ladder,


experimenter


looked


downward


arena,


recorded


data,


and by


remote


con-


trols


started


stopped


broadcast of


sound


arena


speaker.


arena


center were


two or


three


water vials with exposed


moist wicks


and a


small


dish


crushed. dogfood.


arena


experiments


took


place


low noise


room


(LNR)


under


16L:8D photoperiod.


All


experiments


were at


to 50%


The Ampex


was


used


to record


and


play


back


tapes


20).


































































































source


Fig. :
Ra ta


Test


arena


containing


-U


sens


* U


itive


- a r n n 4.. a a 9L 9 m.L-n I a


platforms


- .3 m- -


* 1


<


I










output


the Ampex was


tested,


and


sound


level


adjusted


sound


laboratory.


Experimental Designs


Controlled


experiments


demonstrating


female


response


to natural


for Oecanthus


synthetic

by Walker


male calling

(1957), for


songs


have been


Ephippiger


spp.


reported


Busnel


(1963)


, Teleogryllus


Hill


(1972)


Scapteriscus


by Ulagaraj


(1974)


It appeared


that


Pictonemobius


would


lend


itself


quite well


oassay


virgin


female


response


since


they


are


plentiful,


small,


wingless,


diurnal.


factors


controlled


several


equipment


test


pilot


that


will


investigations


were


into


necessary


be described


various


a reliable,


in detail,


some


these


findings will


given


preface


larger


and more


inclusive


tests


discussed


later.


Earl


response


y experiments


periodism,


were made with a


one of


single


speaker


female


"square


test


locations


response


cut"


speaker,


to sound


synthetic


located


surrounding


level,


trills


randomly

arena


(Fig.


with


"dummy"


speaker placed


opposite


con-


trol.


arena


Two wire


that


arcs


when


were


viewed


placed


from above


mesh


an arc with a


inch


radius


extended


outward


from


eac


speaker,


demarking










period


9 minutes.


Following


this


speaker positions


were


changed


a different


test


sound


was


presented


same crickets

females were


after

tested


another

each ti


m


9-minute

e. If t


silent


wo or more


period.


females


were within


either


zone of


attraction another


test


speaker


position


was


randomly


chosen before


test was


begun.


sound


period


was


divided


into


three,


3-minute


periods.


number of


females


each


zone of


attraction


test


control)


each


3-minute


period was


recorded.


Control,

tended t


or dummy,


.o respond


speaker

visually


counts were made


speaker


in case


or remain


females


beneath


wire


arc.


Later


experiments


female


response


"round


cut"


trills


chirps


was


evaluated by


using


three


test


speakers,


addition


of ER counts of


cricket activity.


The


random selection


speaker


locations


used


earlier


experiments


sometimes


resulted


in a


test


starting when


several


crickets were


concentrated


in an


adjoining


speaker


location.


To eliminate


this,


a sequential


presentation


test


control


signals


was


developed


which


three


speakers were


spaced


equidistant


the outer margin


arena


(Fig.


21).


A control


(natural


calling


song


instead


of the


previously


used


silent


control)


test broadcasts











change


the next


tape


loop


speaker


position,


and


adjust


signal


intensity.


It also


allowed


enough


silent


time


before


next


test


presentation


the experimenter


to return


room and


crickets


resume


normal


movements


around


the arena


after


the experiment


was


readied,


After


each


test


signal


presentation,


3-minute


silent


period


preceded


each


control


tape


loop


presentation.


Each


6-minute


control


broadcast had


effect


of clearing the


area


around


next


test


speaker


prevy


Ous


test


speaker


attracting


test


subjects


to one


location,


served


test


a before


presentation


could


after


control


be compared.


signal,


The


to which


6-minute


each


test


control


periods


allowed


enough


time


record


res


ponse


present


a number


different


signals


same day


without


loss


sensitivity


and


responsiveness


part


crickets.


The


sequence was


follows:


6-minute


control


3-minute


signal,


silence.


6-minute


This


silence,


sequence


6-minute


was


test


repeated


signal,


eac


different


test


signal,


and


ended


with


6-minute


control


broadcast.


this


manner


it was


possible


to present


series


order,


seven


different


to a group of


virgin


test


signals,


female


in a randomly


crickets


less


chosen


than


3 hours.


third


consecutive










early tests


phonotaxis,


age of virgin


females was


the only


standard


used


select


test


subjects.


Because


some


females


showed


a lack


responsiveness,


a new


method


of selection


virgin


females


was


developed


females


used


later


experiments


were


selected


only


they


began


a mating


sequence


(courtship


"spermatophore


formation"


stage


(Mays


1971)


with


a male


their


own


song


type


24-48


hours


prior


testing.


They were


selected


taking


stridulating male,


placing


him in


jar with


several


virgin


females,


observing


courtship


then


re-


moving


responding


female


soon


the male


formed


spermatoph


ore.


Differential


Response


Taped


Calling


Songs


Species


531-D virgin


females


were


tested


response


tape


recordings


their


own


(conspecific)


each


other


s (heterospecific)


calling


songs


three


reasons.


First,


such


test


would


determine whether virgin


females


would


res


pond


tape-recorded


songs of


their


con-


specific males.


Second,


it would


demonstrate


response


attracted


was


species


to each


specific


other'


s songs


or whether


Third,


they


could be


it would


give


some


indication


suitability


test


terms


signal


presentation,


sound


pressure


level,


response










females was


tested


three


replicates of


each


species.


numbers


that


responded by


entering


zone


attraction


test


speaker


are


shown


Fig.


There was


Such


indication


sharp discrimination


attraction


females


the dummy


favor


speaker.


calling


songs of


their


conspecific males


demonstrates one way that


531-D avoid


interbreeding.


The


test


signals


were


528-100,


35-1


s at


26.0C


-78,


44-8


25-80C.

Sound Level


test


to evaluate


more-intense-than-normal


response


male


calling


of virgin


song was


females


necessary


before


an appropriate


sound


level


future LNR arena


tests


could be


selected


The effect


a more


intense


signal


phonotactic


behavior


virgin


females


was


evaluated


compared


with a


tape


recorded


song


similar


that


produced


singing males


5-inch


distance.


A General


Radio Company


type


1551


B sound


level


meter


(SLM)


(scale A at


inches


from the


sneaker)


was


used


adjust a


tape


loop


copy


calling


song


levels


intensity,


75 db.


speed


female


response


sound


was


greater


during


db signal


broadcast


than


during










attraction.


test


signal


was


effective


in demon-


strating


a rapid


positive


response,


but


responding


females


moved


aro


much


more


rapidly


than


ever


observed


in response


living


males


(Fig.


23).


The distribution


sound


level.


arena


was


measured with


SLM.


The


zone of


attraction


close


approximated


area


to which


75 db extends


Fig.


Broadcast


sequent


sound


levels of


experiments


because


75 db were


adequate


chosen


response


sub-


occurred


a relatively


short


period


time


at sound


levels


approxi-


mating natural


Response


ones.


Perlodism


Daily


chan


female


response


were


suspected


view of


response


daily


ten,


rhythm of male


3-week-old,


song


virgin,


production.


laboratory-reared


females,


a pair


9-minute


broadcasts of


taped


calling


sured


song


four times


separated by


daily


minutes of


three


silence


consecutive days.


was mea-


Once


daily the


broadcasting


schedule


was


offset


two


hours


resulting


broadcasts


every


2-hour


period


(composite)


24-hour


day.


this


study


percent


those


entering


zone


attraction


during


initial


minute


of broadcast


24).























SONG


531-D


SONG


100-


FNOTESTED-

NO .TESTED-


531-D


531-D


Fig. 22.
Pictonemobius


spons
and


e to tape recorded
531-D females.


calling


songs


S* *.
* ** *
*g *
* "...
* a
.me:..*
*. *.
* *. C
*/ -*.
* *g *
**
genS
* S*
- **-
,,d *<.
.'.* .* i

! a *
* *. .
e* *


** I
49-<


Teste


_ _L T E S_ I__T Y


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F fl nt -


......


* n ^rW ^1 f- ^/I I


/ 2\


I


9 _
























































1 foot


Fig.


Distribution of sound level in test


arena.




















* t
* *


0


. ....



^~~~~~-


-4 ^
SN


4.1

0
O
-4-

0
4 -)


'-4


-r4 C


O3
-"-4
WH Cn
CC)











average


response


broadcast


dark


period


(1.25)


was


similar


that


the day


(1.31)


average


first


response was


average


2.11


response


compared


.88.


with


silent


a second


period


third


response


day


averaged


.05.


In general


crickets


responded


poorly


during


last


days


test.


One


cricket


died


on 10


February


the others


spent much


their


time


center


arena


around


the water vials


food


dish.


These data


demonstrate daily periodism


female


responsiveness


re-


corded male


calling


songs,


overall


level


response


was


so low that


such


periodism,


exists


could


have


been


missed.


results


tions


pointed


physiological


need


readiness


further


virgin


considera-


females.


Greater


response.


response


Rather


been


than


noted


repeating


other


this


test


tests


female


s-ubsequent


testing


virgin


female


Pictonemobius


was


the morning


hours


corresponding


first


daily


peak


in male


song


activity


noted


in both


field


and


labor


atory


Results


Analysis of Female Response

Square-cut trill s, 2 species


When


531-D


laboratory


reared


virai n


fPma 1 r


a ictI i n-m i i rmrc


f rnrn nr


I


1











the pulse rate was appropriate.


y varying


audio


oscillator


from


range


nr.


31-D


range


nr.


45 p/


experimenter


could


attract


one


direction


switching


speaker


pulse


rate)


attract


531-D


opposite


direction.


No differences


could


shown


cut,


in response


synthetic continuous


531-D


trills of


virgin


females


appropriate


square-


pulse


rate


their


tape-recorded


natural


calling


songs


(Fig.


Round-cut trills, 4 species tests.


Virgin


females


528,


531-D


531-B


that


were


exposed,


one


species


time,


a series


seven


synthetic


round-cut


trills


each


apart


range of


their


expected response


(30.0


67.5


p/s).


Tape


loops


of natural


calling


songs,


38.1,


47.2


3.8,


p/s,


res


pectively,


were


used


controls


throughout.


Sixteen


different


synthetic


trills


ranging


from


30.0


67.5


p/s,


were


used.


Portions of


three


such


trills,


, 32.5,


are


shown


(Fig.


Synthetic


trills


were


used


because


chirp


length


varied


between


four


song


types


would


likely


introduce


additional


variable.


Each


series


seven


test


signals


were


presented


once


each


day


between


8:00


12:00


a.m.


EST


to a group of


crickets


one


species.


randomly


chosen


sequence of


presentation


began


at a different broad-


27)















531-D


FEMALES


FEMALES


100-


-4


* ,-S
*:'
** >
f4 f S 44
* .45


*, .
**.
*
* **
So
*. *

* *
**
9 ** .
*
* a *
*
"* **
. 4-
C
*


* *
* S S
* a

-,


TESTED


BROADCAST

SIGNAL*


*The re


was


no difference between the broadcast periods and


the silent periods at the
of the arena).


"dummy"


speaker


(opposite


side



































SYNTHETIC TRILLS (TOP TO .10


BOTTOM)


30.0,


32.5 AND


SEC/DIV


NATURAL NEONEMOBIUS


SEC/DIV


aL.iaiA a A


*.1 ^^I


-.,,.\


-- =


-


A i I I ii, |


~IICLI










response


to each


test


broadcast


period was


evalu-


ated


following


four ways


data


compiled


each method


separately.


results


show


four


peaks


female


resp


onse


each of


four methods


corresponding


calling


song pulse


rates of


each


four


species.


Each of


four methods


analysis


was


attempt


measure


same


test


response


in different


ways.


Event recorder


counts.


As crickets moved


area


front


of a broadcast


speaker,


they walked


onto


sensitive


platform


(Fig.


triggered


phono-


cartridge-sensitive


"clicks"


relay


the event


system.


recorder pen


number


scribed


events


on a chart


each


6-minute broadcast


period


was


tallied.


Unavoidable


individual


ferences


between


eacn


sensitive


platform


system with respect


responsiveness


given


cricket


movement


were


averaged


having


each


test


signal


broad-


cast


once at


each


platform during


three


test


periods


each


species.


This


tally was


compared


with


average


number


of events


broadcast


the controls.


control


This wa


preceding


signal


following


expressed


an attempt


6-minute


a percent


to reflect


intensity


attraction


time


each broadcast


test


signal


to eliminate


effect


any


changes


in responsiveness










test


trill


pulse


rates


were


range


of +


appropriate


male


calling


song


(Fig.


Number


responding.


Any


female


which


turned


toward


direction


broadcast


sound


and moved more


than


body


lengths


toward


broadcast


speaker with


short


quick


steps


characteristic of


phonotaxis


was


given


a posit


response.


The number


responding was


expressed


a percent


the average number


responding


during


preceding


following


control


periods


(Fig.


thereb


y eliminating


effect


of different


proportions


females


being


ready to


respond


rate


produced by


conspec


ific


males


Number


moving.


Movement during


each


6-minute


experimental


period


whether


silent,


test


or control


was


quantified by


totaling


the number


individuals moving


during t

2-minute


he first-

segments


2-minute,


index of


second


2-minute


third


movement during each test


or control


period


maximum--10

subtracting


during


index was


was


cricke


preceding


arrived

ts during


total m

silent


to demonstrate


place during the


various


at by

q there


movementt


period.

change


test broad


taking the total mov

e, 2-minute periods)

30 maximum) that occ

The purpose of this

in activity that too

asts. The controls


ement



urred



k


29).


















fiaaa


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r
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greatest


appropr


activity


iate calling


occurred


t^ ci-Jt^L
r]an-
ew


four


song


spac e "


females


tested


. 31)


Weighted response i n d ex.


Ti- .


vre.asure


a ttmp nts


score


individual


femal


to how


strong lyi


they


respond


to a gi', en broadcast


siane 1


was


done


include


comparison


with


the event


recorder


counts. -


index


was


evaluated


total


number


cricket Ls


"zone


attraction"


(less


those


already


present.


during


pre-


ceding


plus

Some


6-minute


silent


3-4-minute


females


climbed


period)


count


0-2-minute


plus


screen


period


4-6-miniute


direct .y


front


count.

the


speaker


were given


sum of


these


previously


index


outlined


values.


at tractiveness


shown


Fig.


528,


531-D,


531-B,


525.


plot


this


index agrees


closely with


event


r ecor i


counts


and


describes


similar peaks


response


, orientation,


activity


already


described


(Fig.


32).


preceding plots


female


response:


showed


a wide


range of


peak


response


each


song


type


tasted.


This


lack


sharp discrimination


under


theE 2


test


conditions


may


have


resulted


from usina


fema les


with


low threshold


response


in a


"single


choice"


. e.


response


vs.













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similarly


deprived


virgin


females


of Teleogryllus


responded


two choice


about


cases


situations,


i.e.


to nonconsoecific


no response


songs.


. response


conspecific


sound


vs.


response


to nonconspecific


sound,


Hill


et al.


(197


noted


that


females


discriminated nearly


100%


time.


Artificial


trills


stimulated


females


to greater


response


than


control


calling


song,


suggesting


that


continuous


trills


present


above-normal


stimulus,


which


have


also


effect


lowering pulse


rate dis-


crimination.


Chirp


Length


effect


changing


chirp


length


while


maintaining


a constant


pulse


rate


chirp-to-interval


ratio,


was


evaluated


using


virgin


females.


Species


was


chosen


because


it had


longest chirp of


Pictonemobius


seemed


the most


likely


species


to be affected by


shortened


chirps.


test)


Round-cut


trills


were chopped by TG


used


into


chirps


previous


, 64,


pulses


long with


intervals


chirp


length,


that


each


test


signal


presented


same


number


pulses


minute


increase


28)


Plots


response


response


chirps


(Fig.


approached


show


typical





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It appears


that


a chirp of


some


length


important,


short


4-pulse-on,


2-pulse-time-off


chirp


received


some


response.


When


the number


pulses


per minute


kept


same,


short


pulse-number


chirps


are


close


together


and may


elicit


response


which


reflects


pulse


rate effect


rather


than


a chirp


rate


effect


(Fig.


The calling


song


of Neonemobius


cubensis


(Saussure


537-16,


which


a nearly


continuous


trill


similar


that


525,


was


added because


cubensis


occurs with


some


situations.


The N.


cubensis


test


signal


(Fig.


57.1


s received


lowest response of


despite


nearly


continuous


trill


close


pulse


rate


being within


range


expected


response


noted


pulse


rate experiment


(Figs.


33)














































128/64 64/32 32/16 16/8 8/4 4/2 537-16


COPY


128/64 64/32 32/16 16/8 8/4 4/2 537-16


PULSES ON


PULSES OFF


COPY


COPY


/




Full Text

PAGE 1

EXPERIMENTAL ANALYSIS OF BEHAVIORAL ISOLATION AMONG FOUR SIBLING SPECIES OF NEMOBIINE CRICKETS By David Lee Mavs A DISSERTATION PRESENTED TO THE GRADUATE COLT^CIL OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY UNIVERSITY OF FLORIDA 1975

PAGE 2

To Esthor

PAGE 3

ACKKO-i'LEDGMENTS I am d:jep].y gratefii.l to Dr. T. J. VJalksr, my major profeGsor, for his unsolfirih and unoqua'i.f-d advi.ce and aR.sistiince in all ncpocts of my do;^:toral research. Dr. Walker's drrect, honest and enthus.i.a.s'c'' c ai;'proach ho a iMir.nnderstand.lnc; or expcr.imr;ntal failu:':e Wz\::> alvays obje-tive, cloar and construe t.lvo and never failed, to Icj^jg rae inore knowledgable and encoai:aged. I am iRdcr)tcd to the; other mer.^l-rs of iny supervisory cojianittoe MiJicn D. Hocttcl, F. C. Johnsen, Jame.s L. Nai:ion, and S. II. Kerr, and. to Dr. K. G. Eden, Cliairrnan of the Department of Ent-o.aoj.oqy and Nonia -';.-! logy I wist to cxpxj^s lay than}:s to Da\ id A. Ilickle, Fj chard C. Vv'ilkor'^on, Bill Hunt and Jac]. C. Sehunter for their helpfiil sug'-at ions and a.5^:istance in th?. preparation of the figures, and to Pat Whiteharst for her assistance in the preparation of the tables. During t.'tis study s. M. Ulagaraj and J. vJ Khiteoell contributed ve^luaJjle suggest: ions regarding numerous experiir'.ent^:! procedures. Most of all I am grateful to my v/ife, Roxie, for her patience and understanding and her expert typing of this diasert.Jition

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tablj?; or co^vtehts ACK];;0';^-..:;DGMEl-iTS iii ABSTRACT X INTFUDliC-'lOV; 1 SONG AfUa^YSIS 5 EquJ.;:'~yrit ; Recording cutd Analynir^ ...... 5 Des^-j. iptio-,) of Collirifj Songs ......... 6 Description of Couji. :?hip Songs 9 GciOgrapii.lc I'ict.v ibnt.ion 10 ECOJ,0GTC/'/": DI^^lRlxJUTICiJ 24 Gener. 1 Eabiral 24 T";*^ b31"D Habitol ..,..,... 25 The 531-iiJobitat 26 The 52 8 TJcbitat 28 The 52 5 I-ibitM: 33 The S2o, 531-L' Kabitat, a Cas<-^ Study 34 I'uIl-.o Rato Overlap in Calling Songs 42 Cold; 'arc!. ii, ess Study 50 piiokot;.xts to C'alliijg so:>i('s 56 Intic'"'ict io:i 56 Methodr> 56 RestUta 74 HYBRIDIZATTCli STUDIES 89 Prclirvln'.iry Tests 89 Pinal Test of: Hyb-'^-'i di;.a tion with 4 Spoc:ic-;r: of PictorG';nobius 96 ].ITE.RA'j''UkE CITRD 102 APPF'.-gDIX A—Tvio uso of Stridulatory File Characteristics nn ldont.i f j.cation of Pictonemo biu s . 104 APPEMDIX B — A Key to tlie Adults of Pictoncn obius 108 BIOGRAPHICAL SKEI^CH Ill iv

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LIST OF TABLE? Table P?.ge Locality and pulse leite .ir. Lorr.ia tion on 4 13-19 spcoies of P icto nemob.i ur. Puli-.e rates of calling congs roin f ie.i d 45 recordi.ngs of Pi ctoi n-.obius 531--D and 52S liiuiiici.pal airport site, Gainesville, I'lorida. 4 May, 19 71. Pul '^e rates of Ccrlliiig songs from j ield 47 record:'. i^.gs C)i £i£;f'''nf"'i^iobir3 531-B ar.d 528, near Crooni, r.ervu.'.lo Co., Flori.dci, 8 March, 19 7] Pulse rP-te'. of calling Rong;:; from field 4 8 recoi'dings of Il-i_£l'''-f-'^i<2'''L'_'i>^--^ 5 31-B and 531-D, 3/4 mile west of Arc'her Alacli"a Co., Florida.. 5 March 19 71. Estinr-ited tf : ; :ratures (C) of fi.eld xe~ 49 corded male ri c tonernobius deueriirinod by assuming a 2.2 p/s incrc?oe in ulse rate for each deg^"ee rise in ter.'iperature Co.ldhardinc .o of field collected vr. 52 laboratory reaj-'t-.d Fi.ctoiic. -obius 531--D. Coldh.ardiness expressed as nun.be.. alive on day follov/ing treatment. Intraspeci f i.c allopatric creases from 90 selected F.lorid£i localities. An interspecific alloi'atric cross between 92 crickets from nepr thr^ type locality ("Fort Reed," Floridcx) and crickets (Pictonemobius 53.1-D) ruost like the Scudder type of P. amb it ios-us Interspecific sympatrie crosse-s of 94 Pic ton emobius 528 and 5 31-D, Alachua Co., Florida.

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Table Paqe 10 lute-specif 5 c sj'.npai.ric crost'-^.s of P^:.^^" neBK)Mu:.5 53] -D i 'o ^ .. 105

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LIST OF ]-'IGURES Fig-jr 1 10 11 12 13 Calling congs of 4 t-pr les of Picton era oblTV, at 25.0 to 26.3^C. Acour;tic al rept:::toije of }-'ictor)e)''.obius 5 31-r) iiic'ile in labo.ratory at T: '> !i T .5C. Distr ibiition of P jctoric Flo?:iaM. bius sp 523 in Dir,trihutUrn of rictono} ibius .sp. 5 31-D in Floricia DiF.tr 1 but ion of P i c t on enob i u s sp 53l~L! in Florida. Ill stribution of Pic t o .' i c v o b i u s sp. 525 in l-'lorjua. Hef.ic hi^romoc}-; ,so\ithwe5t Gainesville, typ'cal of 531~D habitat. Aerial vie.,-; of site 3/4 mi. west of Archer, Alachua Co,, Florida. 15 '^cb 1 75 1 j i s t X i b u t i on o f Pic tcnemobins 528, 531-D and 5 31~B at 5lte 3/4 mi. v/est of Aroher, Alacliua Co., F] or J. da. Atrial vic\7 of s.ite !< mi. east & .5 mi. north of Bronson, Levy Co., Florida. 15 Feb, 1975. Dif;tr ibvition of P i c ton omo b i. n s 528, 531 -B at site .5 mi. east & .5 thI. north of Bronson, Levy Co., Florida. Municipal airport site, Gainesville, Florida. Daily activity cycle of P i c t on emob i u s 528 and 5 31-D, municipal airport site, Gainesville, Florida. Page 8 11 20 21 22 23 27 29 30 31 32 35

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Figure Page 14 Daily activity cycle of 2 Pj:£^tojTe^iviobius^ 39 528 unde3: Daboratory conditions. 15 Spatial distribi'.ti.on of singj.ng Pictone41 iTiobius 528 >inrl 531--D, municipal e...'rport site~ Gs i nesvi 13 e Florida. 16 DaytiiiV3 tero.pe raturcs of varicr"^' nicj-oVu.bi4 3 tci.ts in close j>roxiinity, site 3/4 mi. west of Archer, Alacl'ja Co., Florida. 5 March 19 71. 17 Proportion c^f criclets a.livc f o] lov. trig eacli 54 of 4 Gucce^.si.vc cold trcLmeafs. 18 Sensitive platform. 58 19 Charact.eristicw of square cnt, rev 'id cut, Gl nai-ural and synthetic publics. 20 Schematic of eqairTaent used in production G2 of syiitliotic criclvct calls, 21 Test arena containing 3 sensitive platforms 54 connected to sensitive relays, v.'ith a speaker at each platforia. 22 Response to tape recorded calling song by 71 Pictciiieinohj u;:. 52 c and 5 3.1D females. 23 Respc-nse of Pi ctoriemob mis 528 virgin f emalr-.;;, 71 to 7 5 db and 9 db calling song sound IovcIl 24 Distribution c-f sound level in test a.rena 72 25 Female response in relation to tlie time of 73 day using Piclonemobius 52 8 n.atural calling song (528-100)". ^ ^^' 26 Respoise to a square cut syntlietic trill by 76 virgin f c m ; > 1 e Pic tone ro oIj J u s^ 528 and 53 1 JD 27 Oscilloscopic traces of natural (N eon omo77 bins cuboi:sis) and synthetic test signals.

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Figure lll^ 28 Osci lloncopic t;Laces of a synthetic trill ii() 62.5 p/s chopped into cliirps \7ith j^ chirpto-'iiitervalratio of '.' 1 and a conGta'U: nur.ilier of pulses pe?: : -inite 29 Feiiiole recponse to pulse rate expressed '-'O in event recordc-r cor^ntv as % of neighboring control. 30 Female rcaponf^e to pulse rate expressed 82 in nuF;hers respond ir-;j as % of neighboring control X. 31 Fevaale response to pulse rator n um] J e r rno v .1 n g I-',:. ring behavior arid progeny product ioji in crosses of Pi ctonerao bi i -3 528, 5 3] --D, 531-B, and 52 5. 8 3 32 Fcirale resp''. :;e to puIbo rate expressed as 84 weighted visual respon-.e index. 3 3 Effect of chirp length on or i. en ted v. '..we88 me:it and event recorder counts of P.ict r,ao.r.iob i u s c p 5 25. 100

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Abstract of Di Bscrtation Pro sen [•.'^ J to tlie Graauate Council of the. Uiiiversii-y of I'lorida in Pc.rtial Fu.lf i3 .luiant of the Heqi.ii;i:eniP.nt3 for the Dcgre;: of Doctor of Philosophy EXPJ:R1I1T•;^JT^L /^NALYSJB OF HEH7\VJ.0i-.A,L ISOLATION AMONG FOU:^ SIDLING SPECIES OF NHriOBIINE CRICKFTS By David Lee T'^'yo June 19 7 5 Chairn,: i-i : Dr. T. J. Walker h-:y:jy !)epa.rtji''int .* Entojuolcvgy v/^id F'eroatoloviy ''Pi^ lc>:.cn'Obivtc a'':i!:o tior^Li? (fcac^dcr) forii:' i:ly considf^'re'l a sinyli^ npecies, J .:. four cli:)sely 3 late'' species, soparcibla by r:\aJe sc/ng, colc:r iattein, i-,b3rnteri].i ty and fe".irile ph CHOtaT-^it Thesu. species occur sympatr j.cally and yet are i>eperatGd by the clo;ve..L SLiriec of :^pocies specific caJlMig sC'iig pulse rates known foi: any con^plex of Gympatric cricket f^y^'Cies: approxi.nt^.tcTy 37, 47, 53 and 60 p/s at 25*^1;. The c;eograi;.hic and ecolocrical ranges of the four specie^' are dcl;ineated from rt;jre tlian 700 labor-.-tory re-cordiries of crickets froin ni.ore than 100 loc-'i lities The 37 p/s and 55 p/s species overlap broadly through rrj'ch of the xeric sand ridge of Florida. The 55 p/s .species often occircc in tlie centr;.l ridge scrrb associaLion and in the cast a!'id v^est coastal durics. The 37 p/s species ranges northward ir-co the upland lo/igleaf --pine and turkey-oak V7he?:e, the 55 p/s species is absent. The 47 p/s species (the real arabitiosu s) occurs in pastures, roadsides, and X

PAGE 11

disturbed xeric and n'.esic he.n ;ock53 The 60 p/s ;i)3cies, occasionally inte.rmixnd v^itb the ^7 p/s f^pecies, livo^ in the piiiG flatvvoods froin. east Gainesville to the Okefeno]:ee Svaiap of Georgia. Populations laorph-";!'.ically S'nila.r to the GO p/s sp'-vcies, buv V-^ih pulse rate:: of 50-5;; occur frohi La rayetii.: a-id Taylor CoiDities v.'ei:t into the FlorJ.da panhai.dle someti.iv.es in a,sf.^cia; iron wit'i the 37 p/t. sp'-nics. Of 14 ini.raspeeif i c clJopat.ric cros!^..ei, betv;een di:--Liint popuj.atioiiS ; all raati^d norrioiLly and 11 pro''incod progeny. The ran-jc of pulfje rates from inLraspecj.f ic allopati'ic popvJ ati.ons throug}ioat cen,tral Frorida er/jeodathe interspecific dif fere, ees that occur betv,'een closely relat^-d species pairs j.n areaof syjiipaL-ry. Intersp'^cif ic pnlco rate overlap in areas rympatry appeared li'-.ely on cold clear da^^ s because teinperatures whexe tlie.-v cric]:ets lived ranged from la-20''C in t.]ie shade to 3C-J5'^C in tlic si;n. Individual temperature deberixiinationr. derived froin 71 fieldrecorded male calling songs suggested that males locate in microhabitats v/hicli lii'^intaii.n and probably enhance differences betv;een closely related species pairs. The identity and exact location of ]-C24 niale P i c to n e mob i u s from 51 separate hourly sampling periods on a one-acre plot defined male calling song production as diuirnal and bimodal v/ith a distinct morning and late afternoon peak. Pic ton eraobius spp. eire. present in all stages tliroughout thc-i year, even V7here Weather Service temperatures belov/ -SC occur yearly;

PAGE 12

hovce^-er, eggj, nyjaphs and adiiltf; v/ere killed by a control ]_.-d, simulr.ted nc.toi.al teH.psra tn?;e recjjrae of •-8'"'C. Synthetic sigiirils, controlled in carrior frequency (7,000ilz), sou.-'d lovel (75 db) pulG^^ rate (varied v/ith teyi:) pulse duxation, chirp lenotJi and inl:erval, and pulse .siiape 'or?, us^d to test ft; laler. in the la'.'Oratoj.y Females of each specie-;, v/hen prc'-ented \Mth 3.C:;plicatod sei ies of •;aven randoif.ly orderad, syntlietic trills differing by 2,2 p/s reai^cded to j-alj-.c ratea coxr^ a^Kindini;! to caliincj songa of ilioiv co;-..;jpecif ;! c malea Both v:',-;uc;] sc'oring and a moi.ion del f;ctor coi'i^'lod to an eveirL I'occ :dei reveai.led the f.-.a,iie peaj'.s of fenale respoi^ae. 5i>:ty--four virgin females, 3 6 of each specie-;, v:ere tested to detcj-iaine the extent of reirTodu.cf-i.ve isolatioii 'i.nder cond.itions of forced cros;jijjcj. Females v,'ere pretented for rcsponsJ.veness 2^. houra prioj: to a 4hoar mafing ob:v:r-rvation period. In 16 control pair: iiys the mating bciquence proce led ncrrnally. In 4 8 heteroapecif ic croeres 2G produced calling song; 1? courtship Eong; 10 the f iist, sperraatophoi elesc riounting; 9 a sperniatophore and an atteinpt at mounting; 4 a sp'.. aniatop]i-../;e transfer and its retention by the female for more tlian 5 lainutes; and 1 liybjrid firogeny v.rith a pulse rate i nl erraediate between the parenta]. typeij. Approximately 90% cf pinned, spec.'-nena examined ca:! be identified usiiig a combination of locality, color pattern and stridulatory file characteristics.

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INTRODUCTION Among the nost coiRmcn diuriial singing Orthoptera thxougliout ]T,o3t of peninf-uler Florida and somewhat northward are the neu'Obiine ground crickets now knovvn as Pictonen'.obiuG ainbi.tio;;us (Scudder) Both rexes are f lightle-.K'. possessing only forev/ings; in the case of the fcrr.ale these tegmj.na are Eomov7h.-'t reduced, expoBing the last ahdoiainal segi^^ent?:^ The male's tegmina arc u::urJ-lY dark with light l:)order5. giving him a trim, v;aist"Coated appearance. Both sexes have a prominant v^hife bar ori the froiit of their head betvveen the eyes. In a lett.er to Dr. T. J. Walker dated 23 September 1964, T. II. Hulbell noted that he had found differences in morphology and coloration between Florida populations of ambitiosus from different ecological situations. At that time Walker had noted differences in calling song pulse rate betvoen collections made in moist lov; areas and v/elldrained s.'M"id]iill areac In a temperature vs. v^ingstroke study (Kall'cr, 1962) one individual cricket maintained a v.'ing stro):e rate approiima tely 6-8 pulses/second (p/;; ) less than the others over the range of temperatures tested, and was designated as "slov/" ambi tiosus v;hile the remaining v,'ere termed "fast" am bit iosus Additional specimens of "slov;" amb itiosus were collected by John D. Spooner in an area known as the Gainesville 1

PAGE 14

Gun Club, near the municipal airport. "Slow" P. ambitiosus with a calling song pulse rate of 37 p/s at 25C, was given a University of Florida Department of Entomology tape library specimen recording code number of 528. "Fast" P. amb iti osus v/ith a pulse rate of 47 p/s at 25C v/as given code number 531. These two types of crickets could be distinguished at the municipal airport. Crickets producing 528 songs were most conunonly found in the disturbed and v^eedy turkey-oak areas whereas crickets producing 531 songs vrere found in i.he surrounding ham.mock. In anothcr locality (Goldhead Branch State Park, Clay Co.) both 523 and 531 crickets v/ere again collected in close association. Field collected adult females taken to the laboratory and isolated in gal]on jars provisi.oned with food and v/ater and approxim.ately 2 inches of autoclaved and sifted sand, soon produced progeny that v/ere either 100% 528 or 100% 531. Generally tlie 528 females were more black and white sp„-ckled above and white below, while the 531 were marked in softer tones of brown and tan with tan vt'nters. The nymphs of the two types v;ere distinct i.vely and consistently marked and colored allowing about 90% accuracy in separating them. The nui:il;-er of teeth and the length of the sound producirig v/i.ng fiie varied betv;een 528 and 531. These data suggested that 528 and 531 were two species based on behavioral and morphological grounds despite overlap in habitat, and the presence of some individuals with interm.ediate color patterns

PAGE 15

In a turkey-oak, sandhill area 3/4 mi. west of Archer, Florida, on 5 Apri] 1967, I discovered females of Picto nemobiu s that were dark brown with bright strav; colored marP.ings as \-7ell as the more typical dull-brown female;^ of Picton emobius 531. Their differences wore quite striking. One individual female of each color type vras brought to the laboratory and each gave rise to progeny which were true and bred true to their parental color type. Laboratory tape recordings of the resulting male progeny fell into two categories corresponding v;ith the tv;o parental female color types. The dull-brown type, known from many other localities in Florida, (previously designated as 531) had a calling song pulse rate of 47 p/s at 25 C. The new, dark-brown, brightly marked P. a mbitiosus had a calling song of approximately 55 p/s at 25C. Recordings of field -collected P. ambitiosus from the Archer locality confirmied the nev/ male song type in the field. Numerous recordings hr,d already been made under the 5 31 number for the two types, so the notation 5 31--I) for the Dull brown (4 7 p/s) and 5 31-B for the Brightly m.arked (55 p/s) P. a mbit J osus was instituted. Type 5 31-B v/as found to breed true v/herever it vjeis found and could be separated from 531-D and 528 in central Florida by pulse rate and color pattern 100% of the time. Some individual 531-B had stridulatory files that v/ere v/ithin the range of stridulatory file lengths of 528 or

PAGE 16

531-D, making this character less dependable in terms of separating species. Type 531-B appeared to be distinct from 531-D and 5 28. A fourth P. amb itiosiis song type was discovered by the author on 25 February 1969 along a grassy roadside and in the surrounding pine flatwoods, 3 mi east of -che Clay Co. line on Florida road S 16. The male calling song attracted my attention because it resembled that of Miog ryllus saussurei (Scudder) (v/hich was singing from burrows at tlie same time) but differed from M, saussurei by having chirps lasting more than 2 seconds. A 531-D male v/as located at the same site by its calling song and provided a contrasting reference to this new song type, designated as Pic tonenio}:' i u s sp. 525, The calling song pulse rate v;as about 60 p/s at 25"'C. Both males and females were darkly marked, and easily distinguishable from the other three types. Early in this study the four song types appeared to represent biological entities, possessing characteristics of species with regard to reproductive isolation and ecological and geographical distributi.on I will refer to them as sp?!cies 528, 531-D, 531-B and 525 from thispoint and will present proof of the;ir separateness in the remaining sections of this paper.

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SONG ANi'vLYEIS Equipment : Re cor din g and An a 1 y s i s Tape recordings of male crickets were made in the Depertraent of Entomology low noise room (LNR) The crickets were caged individually in 4 x 4 x 4 in. screensided cages. Caged singers v/ere located by using an earphone monitor, and recorded with a dynaraic m.icrophone or\ Scotch 202 magnetic recording tape at 15 inches/sec. on an Arnpex model 351 tape recorder. The tape recorder was located in an adjoining laboratory and was activated by remote controls from v-ithin the LNR. Some tape recorded sounds were analyzed with a Kay Electric Company audiospectrograph (Sona-Graph) but calibration procedures were lenguhy and production was slow. More often I used an oscilloscope with a "storage screen." Several different complete chirps could be displayed at one time on the oscilloscope using a sweep rate of .05 sec/cm. From, a total of 30 pulses the pulse rate v/as determined by the formula p/s ^3 .0 5D The mean A-V7eighted sound pressure level (SPL) v/as belov.30 dB (re. 0.0002 dynes/cm^) as determined by a General Radio Model 1551-B sound level meter.

PAGE 18

where D = mm required for a 30 pulse display and .05 is the sweep rate (.05 sec/'cm) Calling song pulse rates are a function of the temperature of the individual cricket and therefore can be corr-ected to some temperature stemdard for comparative purposes given the slope of the pu] se-rate-vs -temperature plot. Pulse rate corrections to 2 5''C were made with the formula p/s at 25.0C = (25-0 T) 2.232 + p/s at T where T = temperature at time of recordj.ng and 2.232 = slope of the pulse-rate-vs .-temperature plot (Walker 1962). Description of Ca lling S orgs The calling songs of Pictonemobius like the calling songs of other Gryllidao, are produced by solitar-y adult males and attract sexually' responsive females. Such songs have been shown to be species specific v.-ith respect to the females that are attracted (VJalker 1957, Alexander 1967, Hill et al. 1972, Ulagaraj 1974). On numerous occasions two or more of the four Picto n emobi us species have been heard calling in the same area. In such areas individuals with intermediate songs have not been found. Crickets of the genus Pictone mobius are chirping crickets, i.e. m.ales produce short (<5 sec.) series of

PAGE 19

pulses of sound ("chirps") as opposed to trilling crickets which produce long {>5 sec.) series of pulses ("trills"). Each pulse is created by a single closure of the upheld mesothoracic wings, during which the file (ventral, right wing) is in contact with the scraper (dorsal, left wing). The pulses are discrete bursts of sound having fundamental oscillations in the 5,000-7,000 Hz range. These fundamental oscillations correspond with strikes of file teeth on the scraper Species 528 has a long chirp, approximately 1-2 sec. in duration, with a pulse rate of 36.7 p/s at 25^C (n--21) municipal airport, Gainesville, Florida. Oecil.1 ographic traces of a 528 calling song are in Fig, 1?^. The long chirp makes the pulse rate sound even slower to the human listener, compared v/ith 531-D. Species 531-D has a chirp of inten-nediate leiigth, 0.3 to 0.8 sec, v/itli a pulse rateof 4 7.0 p/s at 2 5''C (n=9) from the municipal airport, Gainei-vil] e Florida. A complete chirp, 20 pulses long, and a seiies of regularly spaced chirps are shown in Fig. IB. Species 531-B has a short chirp, less th?n 0.5 sec. in length, with a pulse rate of 54.9 at 23 = C (ri-21) from 3/4 mi. west of Archer, Florida. Some individuals consistently produce 9 and 10 pulse chirps while others produce chirps up to 20 pulses long, overlapping in chirp length with 531-D. A typical series of 7 chirps, and one 14 pulsed chirp are shown in Fig. IC.

PAGE 20

528 Portion of chirp .05 sec/div B 531-D One complete chirp -^^ sec/div 528 Two chirps .5 sec/div 531-D Seven chrips .5 sec/div m 531-B One complete chirp .05 sec/div 531 -B Seven chirps .5 sec/div 525 Two chirps .5 sec/div Fig. 1. Calling songs of 4 species of Pictonemobius at 25.0 to 26.3C. A. 528, municipal airport, Gainesville, Florida, 25 Jan. 1967 (U. F. Tape No. 528-54). B. 531-D, municipal airport, Gainesville, Florida, 19 Oct. 1956 (531-60) C. 531-B, 3/4 mi. west Archer, 4 June 1969 (531-218). D. 525, .2 mi. east on S400A, 3.0 mi. north Orange Hts 29 May 1969 (525-9)

PAGE 21

Species 525 has a long chirp, as long or longer than 528, usually 1-2 sec. long, and the fastest Pict oneniobius pulse rate, 59.9 p/s at 25C: (n-8) at .3 mi. east of the Clay Co. line on SE16 The trend of decreasing pulse rate with increase in chirp length from 531-3 to 528 makes the 525 song quite unusual to hear. Adding to its distinctness is a slow build-up in intensity in the early part of the chirp (Fig. ID) • For all P ic toncriioh ius songs individual variation exists in the number of chirps per unit time, the intensity changes v;ithin the chirp, and the maximum in, tensity of the chirp. These differences remain consistent throughout a sample of an individual's calling song. Several laboratoryreared 528 and 5 31-D were found to have irregularly spaced pulses within a chirp if recorded shortly after their maturation to the adult stage. No field-collected or laboratory-reared specimens more than one vreek old were found to be irregular i.n this mianner. The geographic distribution and compilation of the calling song pulse rates presented later in this section will serve to defirie the four species of Pictonemobius Descrip tion of Cour t ship S ong s The acoustical signals associated v/ith mating are described and illustrated here to supplement my earlier (Mays 1971) paper on the mating behavior of Pictonem obius The pattern of courtship sound production is sim.ilar for the four species 528, 531-D, 531-B and 525.

PAGE 22

10 The principal courtship song (v?ith or v/ithout a spermatophore) is characteristically a long series of soft chirps (often irregularJ.y spaced) in which the first 5-10 pulses are produced, at almost exactly 1/2 the calling song pulse rate, followed by resumption of the typical rate, and an increase in intensity (Fig. 2, B & D) When a male loses contact v/ith the female he is courting he often produces a loud and extended pulsed chj.rp (Fig. 2C) usually beginning witli coui tship-type v/ide-spaced pulses. Prior to "bacJcing under" for both the "brief spermatophoreless mounting" and the "lengthy mourrting and [speriaatophore] transfer" (Mays 1971) a long trill is produced, entirely at the calling song pulse rate (Fig. 2E) Courtship chirps for 528 and 525 are shorter than calling song chirps. Courtship interruption chirps and backing under trills for 5 31-D and 531-B are much longer than their calling song chirps. The untrained listener would likely find it difficult to distinguish among the courtship chirps of the four species but easy tc> distinguish courtsriip chirps from cal] iirg chirps. Geograp h i c Di.stribut ion Crickets belonging to the genus Pictonemobi vis occur principally in Florida and in the iitinnodiately adjoining portions of Georgia and Alabama. T. J. V7alker has field recordings from. Decatur, Brooks, and Cobb Co., Georgia, and

PAGE 23

11 4-1

PAGE 24

12 Cleburne Co., Alabama. I have been unsuccessful in locating Pictonemobius west of the Florida panhandle, and north of southern Alabama and central Georgia. Collections and laboratory tape recordings of more than 700 Picto nemob ius from over 3.00 Florida localitj.es fall into the four categories of Picto nemo bius discovered in the Alachua Co. area. The identity of field-collected specimens was determined by analysis of laboratory recordings of ma]e calling songs, habitat specificity, and. color patterns. The areas of distribution overlap do not necessarily indicate intimate syrapatry. Localities in which such sympatry v/as in evidence are listed (Table 1) and illustratec (Figs. 3, 4, 5, & 6) The analysis of calling songs from several areas of sympatry defined the species numerous times. Marler (19 52) states "Judgments of degrees of species specificity are relative and arise from comparisons betv;een signals unde;r consideration and othersignals which are likely to be present at the same t.ime and place" (p. 538) After several areas of sympatry v/ere understood, v'idely separated populations of each of the four kinds could be related over a v/ide geograpliic area including most of Florida. A detailed analysis of allopatric variation in P ic tionem obi us is not presented here, and would not necessarily serve to further define the species already recognized. A discussion of inconsistencies in 52 5 from the Panhandle region (Table 1) is in the Appendix.

PAGE 25

13 ^ r* c* n r* vo r^ CD in 04 04 01

PAGE 26

14 r* m o T rCO m

PAGE 27

15 CM rH p^ o

PAGE 28

IG Notes to Table 1 A lachua C o. 1. Municipal airport, Gainesville (NE, 1/4 of Sec. lA R.20E., T.9S.) "Gun Club" {T.J. Walker collections) 2. Monteocha Rd 10 mi. north cf Gainesville, east of Fairbanks 3. Gainesville & vici.nii.y: sevei;al inc. N. 39th Ave. and NE. 15th SI..; S.W. Archer Rd. 37 block; Millhopper; Division of Plant Industry Bldg,, U. of F. carapu.s 4. Alachua-Levy Co. line fSR.2 4 5. 3/4 mi. west of Archer, south of SR.24 6. .2 mi. cast on S200A from jet. V7ith US. 301 Baker Co. 7. .1 mi. south of 'Georgia state line on SR.121 .2 mi. west on S23B frorr. SR.i21 Bay Co. 8. Panama City Beach, NE city limits, east of HiqhJand Dr. Clay Co. 9. Goldhead Branch State Park (T. J. tValker col].ections) 10. .3 mi. east of C]ay Co. line on GK,16 & vicinity of Starke Country Club Collier Co 11. 1/2 mi. south of jet. 84 & 29 & jet. 8 40 & 2 9 12. 2 mi. south of 865 on 8 6 5A, near beach Columbia Co 13. 3.0 mi. south of Suwannee Co. line off US. 27

PAGE 29

17 F lagler C o. 14. South of Marinelancl Franklin Co. 15. Carrabelle, nr. ccinete;cy, north side of tovn Gilchrist Co. 16. Jenny Springs Hern and o Co. 17. 2 mi. south of Croom west of 1-75 Hi q^/qwpis Co. 18. AFchbold Biological Station 19 Venus Jef ferson Co. 20. .5 xni. north US. 9 8 on SR.59 LaF ayet t e Co. 21. 4.0 mi. north of Dixie Co. line, S357 Lake Co. 22. Leesburg city limits, south on US. 27 Leon_ Co_^ 23. Tall Tiixbers Research Station, north of Lake lamonia Levy Co 24. 1.9 mi. v;est of Otter Creek, then 4.5 mi. north 25. 1 mi. north Bronson, flatwoods 26. 1.5 mi. north Marion-Levy Co. line on US. 41 27. Manatee Springs 28. Near Shell Mound, S326 north of Cedar Key 29. .5 mi. east, .5 mi. north of Bronson

PAGE 30

M'n_ion Co^ 30. .7 mi. north of Sparr on "old" 301 31. Ocala, east city limits 32. SE.40 & S336 33. US. 2 7 & 441 at Orangeblossom Hi.lls 34. S4 8 4 at Dune lion 35. Nr. jet. S200 & S484; 5 mi. east jet. S200 & S484 Palm> Bo ach Co 36. Jupiter Putnam. Co. 37. 2 mi, east Melrose Se l uinole Co. 38. Sanford, nr, E, 2 5th St. and Grandview, 1/2 mi. northwest of "Fort Reed" gvn nter Co 39. Sumtoi.-Lake Co. line & SR.50 Ta ylor Co 40. Blue Spi-incjs 1 mi, north of Cedar Island 41. Forer.t Capital State Park 42. 5 mi south of Perry W.;'.'sulla Co. 43. 1/2 r.-.i. west of jet, SR.365 on SR,98 Georgia CI inch _C o_^ 44. Mile post ^1 on Ga,17 7

PAGE 31

19 Brooks^ Co. 4 5. Quitman Deep t ur C o 4b. V7est of Climax

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20 35.7 ^^' Fig. 3. Distribution of Pictonemobius sp 528 in Florida, Hand printed locality numbers refer to numbered sites in Table 1. Additional localities are indicated by unnumbered dots. Mean pulse rates for localities with 3 or more individuals assayed (Table 1) are to the left and right of the Florida peninsula.

PAGE 33

21 47.3 46.5 ^^1* Fig. 4. Distribution of Pictonemobius sp. 531-D in Florida. Hand printed locality numbers refer to numbered sites in Table 1. Additional localities are indicated by unnumbered dots. Mean pulse rates for localities with 3 or more individuals assayed (Table 1) are to the left and right of the Florida peninsula.

PAGE 34

22 • >• •• Fig. Distribution of Pictonemobius sp. 531-B in Florida, Hand printed locality numlDers refer to numbered sites in Table 1. Additional localities are indicated by unnumbered dots. Mean pulse rates for localities with 3 or more individuals assayed (Table 1) are to the left and right of the Florida peninsula.

PAGE 35

23 50.6' ^^' Fig, Distribution of Pictonemobius sp. 525 in Florida, Hand printed locality numbers refer to numbered sites in Table 1. Additional localities are indicated by unnumbered dots. Mean pulse rates for localities with 3 or more individuals assayed (Table 1) are to the left and right of the Florida peninsula.

PAGE 36

ECOLOGICAL DISTRIBUTION General Habitat Crickets of the genus E' i c t o n e itiO j > i u s are found fron dry sand dunes and central ridge areas to the margins of sv:amps and tidal salt marshes. They are rarely found in mature, dense haroKiocks with a closed canopy where fire has been excluded for 50 years or more. Most of Florida is maintained as a fire sub-climax v/ith additional removal of pine from the central sand ridge area, clearing for agriculture, creation of pasture and range grazing land and road dredge and fill. In these disturbed areas I found the largest populations of Picto nem obi us Alexander and Thomas (1^59) in their studies oi three sibling species in the Allonei uobius f asc iatus group found that the three v/ere mixed with no indication of interbreeding in areas v?herf.' artificial clearing had taken place. Similar occurrences with rictonerao bius are discussed later in this chapter. The effect of burning on the size of Pictonem.obiu_s^ populations was evident in comparing the unbarred and the annually and biannually burned plots of the Tall Timbers Research Station (TTRS) near Tallahassee, Leon Co., Florida. Here Pictonerac b Jus wore abundant along fire trails, roadv^'ays, and in plots that were burned as recently as v/ithin t!ie last 6 months, 24

PAGE 37

25 A plot v/hJch had fire excliidecl for the past 16 years did not contain Pictonemobius They v/ore scarce frorr. the margins and absent from within the "v;oodyard hammock" v/hich appears to have been undistujrbed except for localized lightning fires and a record of logging in the northeast Gun\ Pond area in 1945. A 26 January 1915 account from the Beadel Diary records the "woodyard" as being "thick wood, tall pine, live oak, holly, magnolia, etc." (Betty Ashler, Historian, TTRS, Personal Coimminication, 10 March 1973). Habitat descriptions of the four song types of Pictonemobius follov/ the classification of Laessle (1942) The 531-D Habitat Species 531-D is most coj-iiaion in xeric hammocks and in mesic and hydric hammocks that are burned or disturbed, thereby opening the canopy and thinning the understory. Many of Florida's ruderal communities such as old fields, fire lanes, roadside ditcb.es, sand moun.ds, and lav;ns fall into this category making 531-D the m.ost commonly encountered Pictonemobius. Species 531-D occurs in hamm.ock communities over most of mid-central Florida even into "the sandhills" in the longleaf-pine and turkey -oak ( Pinu s paliistr is Querc us laevis) association, predoiainantly beneath live-oak (Q. vir ginian a) They eippear in xeric hammock to sandhill transitional zones where the forest thins out. Genera.lly wire grass ( Aristida stricta ) bluejack-ofxk (Q. cinerea ) laurel oak (0, laurifolia) v;ater~oak (Q. nigra), wild grape

PAGE 38

26 (Vitic sp.), Virginia creeper ( Parthenocissus guin guef olia ) saw palmetto ( Serenoa re pens ) and perf^inimon (Dios pyros virgin iana) are present in areas V;-here large populations of 531-D are encountered. Tn Alacliua and surrounding counties, they abound under several species of oaks, sweet gum ( Liquidambar styrac if lua) hav;thorn ( Crateg us sp.) persiminon, hackberry (Celtis niis sissippiensis ) and v/ax myrtle ( Cerotha mnus cer if erus ) growing solitarily or in small clusters in pastures and along grassy roadsides. They are also coimnon in partially shaded lawns v/ith some leaf litter and in and around clumps of fallen Spanish moss ( Tillands ia usneoide s) and on the welJ.-drained portions of weedy-grassy roadsides and grown-over road dredge he^5.ps A typical 531-D hamraock habitat, kept open by grazing cattle, is shown in Fig. 7. Th e 5 31-D Habj.tat Species 531~B is associated v;ith the "scrub," i.e. the sand-pine and oak ( Pj.n us clausa-Qu ercu s spp ) association and longleaf-pine and turkey-oalc. association v.'itli some transition into long lea-f -pine and blue jack-oak ( Pinus palustris Quercus cinerea) association. Tn most of tliese situations rosemary (C eratiola ericoides) se^nd-pine ( Pinus clausa) and gopher apple (Geobr.3 anus ob 1 o n g i f o 1 i u s. ) are very common and appear as the most consistent indicators of the presence of 531-B. The 531-B habitat is the central ridge sandhills on v/hich the original longleaf-pine forest was present until

PAGE 39

27 O •H >, 4->

PAGE 40

28 150 years ago. East and west coast isolates of 531-B occur on well-drained dunes ^ shell mounds, and dry sandy hills that contain live-oak (Qu ercus virg jniana var geminata ) and sandhill plant associations. The more northern sandhills are more heavily forested and less likely to have sandpine, rosemary, and the cricket 5 31-B. The 531-B habitat is a xeric open habitat, occupying the highest and best drained soils in the entire state. The "scrubby l"latv/oods" (Qu ercus var. gemina ta Q. myrti folia Q. chapma uii) association which occurs "... in places where there is a slight rise of one or two feet above the general level of the flatv.'oods" (Laessle 1942) is usually not sufficiently open or well drained for 531-B. Species 531-D and 531-B were plentiful in an area where hamraock Wv-ods adjoin a turkey-oak sandhill, 3/4 mi. west of Archer, F:iorida (Figs. 8 & 9) A similar distribution of 528 v;xth S31-B occurred at a site .5 mi. west and ,5 mi. north of Isronson, Levy Co., Florida (Figs. 10 & 11). Th e 52 8 Ha bitat Species 52 8 covers much the same geographic area as does 531-V^ but it occurs in the more disturbed, weedy, or recently burned sections of a site. Coromonly 52 8 occurs spottily :5loug a field margin, a road margin, the center strxp of a dirt road, or in a dump. In a few cases isolated groups of singing males have been heard in the open near white sanoy spots, surrounded completely by singing 5 31-B

PAGE 41

29 (d

PAGE 42

30

PAGE 43

31

PAGE 44

32 ^osNom

PAGE 45

33 males (FJ.g. 9) The opposite situation, where 531-B is surrounded by 528 occurred in the center of a large weedy field (Fig. 11). Large numbers of 528 have been found in recently cultivated fields, weedy and grassy pastures, and in young pine plantation'^; which were formerly part of, and nov7 border, longleaf-pine and turkey-oak v/oods containing 531-B as shown in Figs. 10 & 11. In the northern Florida counties 52 8 appears closely associated v/ith disturbed pine forests that contain some turkey-oak. Here they often border 531-D areas v/ith 528 predominating in the higher sandhills that are kept clear of underbrush by fire or mechanical means. A detailed study of a 528, 531-D habitat is presented later in this paper. The 52 5 Habitat Species 525 occurs in the slash-pine flatwoods ( Pinus p aulustris ) association, and in the black-pine and fetterbush flatv.'oods (Pi_nu_s_ serotina Des mothamnus ) association. These associations often border bayheads or extend outv/ard in river flood plains and contain wax m^yrtle (C erotham nus ceriferus) wire grass (Aristida spic i form is) gall-berry ( Ilex c oriace a) blackberry (Rubus betulif ol ius) and sundew ( Pro se ra capilla ri.s) Species 525 sites have rich soils usually v:ith a packed mat of dark colored pine needles, mossy patches, and openings in the wire grass v/ith occasional depressions (loft by uprooted trees) that often contain water during rainy peri.ods Fine grasses, sedges, and other

PAGE 46

34 low herbage often grow in these depressions. Alachua Co. sites include northeast Gainesville's v;et flatwoods that have been opened by occasional burning and clearing. Similar sites occur northvard into the Okeefenokee Swamp region of south Georgia. The river flood plains and low ground situations of the Florida panhandle are additional areas where 525 occurs. It is possible that species 525 occurs further northward throughout the pine flatwoods of Georgia, since this habitat is fragmented in North Florida into east and V7est coast areas separated by the central sand ridge. The temporal and spatial distribution of 52S and 531-D was intensively examined in an area near the Gainesville municipal airport (NE 1/4 of Sec. 24, R20E, T9S in August 1971) The study area was selected because it contained both 531-D and 528 over an ecologically diverse area. Components of xoric, mesic, and hydric hammock communities plus longlcaf-pine and turkey-oak, longleaf-pine and bluejack-oak communities, both disturbed and undisturbed, occur together in this study area. The distribution of the principal types of vegetation are shovm in Fig. 12, The woods area was a mixture of turkey-oak and longleaf-pine with blue jack-oak, vzater-oak, and v/ild cherry in one zone. Patches of palm.etto v/ere common throughout most of the woods and along the margin. Some lov/ brush sucli as blackberry and

PAGE 47

35 X to < "T oj oi i^ o o3 < < ' 5$ ct o to o i^ u< QQ I< I o < o IS >< i^ =J5Q:=5ZH3 o tQ:^i— pa— i:^^ <^ a. 3 -1 o o a, 175 FEET

PAGE 48

36 sumac is overgrown with grape (Vitis) Smilax, and Virginia creeper (P ar then ic is s us qui nquefo lia) The area where trees and brush had been cut close to ground level appeared to have been periodically treated in this manner for at least the last 10 years judging from a U.S. Government (1955-1960) aerial photo loaned to me by Dr. James E. Lloyd. The most recent clearing was about 6 months beforehand and resulted in about 30% bare ground. The remainder was littered with dead, cut turkey-oak and water-oak brush, palmetto fronds, and numerous heaps of bottles, paper, cans, and other debris. Daytime high temperatures in the shade at 1 ft. above the ground were 3 3 + 2C on 20, 21 and 22 August, 31 + 2C on the 23rd and the 24th, and about 27C on the 25th. Nighttime low tem.peratures v/ere 20-22 C. The midday low relative humidity was 2 5-3 0% on the first 2 days, but increased to 50-60% on the remaining days. Methods An irregular plot approximately one acre v/as m.apped v/ith respect to the major physical features and vegetation (Fig. 12 A) Hourly surveys were made along a predetermined route (Figs. 12 B) over much of the period from 1:00 p.m. 20 August to 9:00 p.m. 25 August 1S71. Sampling continued during periods without rain until 3 saiiiples were compiled for each hour from 6:00 a.m. to 8:00 p.m. and one hourly observation was made for each hour from 9:00 p.m. to 5:00 a.m.

PAGE 49

37 The 1624 locations of individual singers (528 and 531-D) were recorded on separate hourly maps. Son g Peri odicity Song production was diurnal and bimodal. The number of calling males increased during the early portion of the day but dropped to about 0.2X (528) and 5X (531-D} of the morning peak by midday. The number of calling males increased again in the afternoon (Fig. 13) but by dark the nuJTtbers of calling males of both 528 and 531-D had again decreased. This bimodal peak of the nui:iber of calling males agrees closely with a plot of the calling song produced by tv70 isolated 52 8 males under conditions of constant tem.perature and controlled photoperiod in the laboratory (Fig. 14) Sim.ilar bimodality of singing occurs on sunny days (Figs. 15 A-C) on cloudy days (Figs. 15 D-F) and under uniform diurnal light intensity in the laboratory (Fig. 14) suggesting an internally controlled diurnal cycle of song production. Alexander (1960) states "Light intensity seems to be the most universally important single factor in determining the exact time on each day when different species begin song" (p. 42) This seems appropriate for nocturnal and crepuscular singing species, but does not offer a suggestion as to how Pictonem.obius spp "anticipate" the late afternoon peak of song production under uniform light (Fig. 14)

PAGE 50

38 3 u I 3 u J 3 q ui n N d i e J 3 A y • 0) tn+J •H U h o u

PAGE 51

39 "3 00

PAGE 52

40 Spatial Distribution Calling males of rictonemobius 525 were heard in both open areas and v/ooded areas. Maler> of 528 in open areas decreased their calling at the approach of raidday more than lOX compared with those in the v;ooded areas Vv-hich decreased by only 2X (Figs, 15 A, B, D, & E) There v;as no indication of any movement to or from the v;oods at this time, though individual 528 males and females were observed moving just after rain, and on moist ground. Calling males of Pictone mobius 531-D were usually in the woods, with only 5 out of 33 9 heard, located in open areas. The distribution of 52 8 singers on sunny days, "(Figs. 15 A, B, & C) approximated the distribution of singers on cloudy days, (Figs. 15 D, E, & F) with the following exception: in the morning and afternoon, on the cloudy days (Fig, 15 F) there appeared to be m.ore singers in the open areas. The likelihood of hearing courtship songs' is independent of the number of calling songs at any given time. For 528, the higb.est proportion of courtship songs to calling songs occurs at night when the relative numbers of calling songs are low, and yet the relative numbers of courtship songs heard at night (7 in 9 sampling periods) approximates daytime counts (28 in 45 samipling periods) Courtship was recogni:-ed only once in 339 531-D songs as compared v/ith 34 times in 1285 528 songs. Other 531-D courtship songs

PAGE 53

41 -.1 —

PAGE 54

42 may have gone unnoticed since the shorter [than calling] slow pulsed courtship song of 528 is more easily recognized in the field than the courtship song of 531-D. Pulse Rate Ove rla p in Calling Songs The four species of Pictonemobius are distinguishable from one another in the field on the basis of the rr.ale calling songs. When one first arrives at a new site it may be initially difficult to identify the singers but soon one detects the differences between the songs of the species involved, and in a short time can identify all of the singers heard. Once the listener is "tuned in" to the species-specific song differences, variation in pulse rate betvv-een open sunny sites and shady sites can often be detected. It is this difference in individual pulse rates, due to differences in microhabitat temperatures, that prompted my postulating the existence of overlapping pulse rates betv;een species singing together. If such overlap should occur, heterospecif ic attraction could occur — for example, attraction of cool 531-D females to v/arm 528 singing males. To find out if such overlap in pulse rate occurs, I made measurem.ents on clear winter days in hopes of finding a variety of ambient temperatures at ground level whore crickets are located. Recordings of temperatures at various microhabitats during a cold clear winter day (Fig, 16) revealed a wide range of temperatures in places v;here crickets might be singing.

PAGE 55

43 \ 3 — 1— Ln — rCD >1 P •H -H X u Ck Q) 0) O H O • <-\ C r•H O^ iH (0 4J x; to o H (d n3 O O • •H (0 E XJ •H CO M 3 O OrH H fc > • O iH U O (0 tn 3 Q) Xi M U 13 (0 -P H u Q) & M B <0 axi P O u £ •P O !>i Q 03 0) ^ g E^ n
PAGE 56

44 Pulse rate overlap v/as inves ticated at three different. sites where two Pic t on eino b i u s species were known to occur sympatrically Calling songs cf the fastest individuals of the slowest, pulse rate species and the slovzest individual; of the fastest pulse rate species were sought out and recorded to establish vhetlier pulse rate overlap exists under these conditions in an area of ap'proxiraately 100 square yards. One study site was a portion of the transitional habitat used in the song periodicity study at the municipal airport, Gainesville. A cool, clear day wj th temperatures 15--20C in the shade and BO-BS^C under leaves in full sunlight was selected. Songs of 9 individuals of 52 8 and 6 of 531-D v;ere recorded over a l-liour period. V-Thenever possible the specimens were captured and the location of eacii singer noted. During the survey period the temperature on the ground in full sha'-^e went from 17.0 to 17. 2 ^C viiij.e Lne temperature under a loaf jn full sunlight remainod at 32.0C., Tlie i-esults are given in Table 2. A similar 2-hour study v/as conducted on a sj.te near Croom, Flernando Co., Florida, v/ith 531-B (n=^9) and 528 (n-10) that vrere found together in a disturbed, weedy, partially logged-over, longloaf-pine and tr;rkey-oak area. The temperature at 18" above the ground in complete shade ranged from 14.6 to 15.0C while the temperature in full sunlight at ground level ranged from BS.S^C to 40.4C during

PAGE 57

45 Q

PAGE 58

46 the study period. The temperature under a leaf in full sunlight at 11:45 a.m. was 41.6C but dropped to 25.2C by 2;00 p.m. as shadov;s from nearby trees shaded it. The results are given in Table 3. A similar 3-hour investigation v/as conducted with 531-D (n-16) and 531-B (n=21) at a site 3/4 mi. west of Archer, Florida, in an ecotone between longleaf-pine and turkey-oak sandhill and a live-oak hammock (Table 4) At the Archer site one case of pulse rate overlap occurred between specimens identified by chirp length as 531-B and 531-D. This 531-D male was singing in the open and had a pulse rate of 66.6 p/s v/hich was 1.4 to 7.2 p/s faster than the four slowest 531-Bs for that hour. There is no correlation betv;een pulse rate and degree of shading where the song was heard: however, most specimens of 531-D were in miore shaded situations than those of 5 31-B. By assuming a linear relationship betv^een pulse rate and temperature (Walker 1962) and by using the mean pulse rate of conspecific laboratory recorded individuals from the same locality as a reference, the temperature of each singing male was approxim.ated The results indicate that calling m;ales are in areas where temperatures are 25-35C even though a wider range of temperatures are available as broadcasting sites. Considering that individuals vary in calling song pulse rate at any given temperature, the range of temperature values derived from the field recordings

PAGE 59

47 CO 3

PAGE 60

48 o u tfi r-f
PAGE 61

49 1 (L) (D c a, H e (1) -H 0^ to m Xi

PAGE 62

50 (Table 5) may actually be less than given. Furthermore, the species with the fastest pulse rate appeared to be; singing at the highest temperature at each of the three localities studied. This would tend to accentuate the calling song differences that already exist betv/een the song types at each of the three study sites. The primary conclusion from this study is that calling song pulse rate overlap in areas of syrapatry is extremely rare, Coldhardiness Study All life stages of Pictoneraobius have been found during all seasons of the year, and yet during v.'inter months or at drier times early juveniles appear scarce. Possible reasons why early juveniles becom.e scarce include the lack of female oviposition, delayed egg development (egg overwintering) behavioral adaptation (i.e. burrov/irig) or the eggs or juveniles being unable to survive periods of severe cold or drought. Laboratory vs. Field 531-D Cold hardin ess Test Pictonemobius spp. breed continuously, all stages being present throughout the year, even in areas of northern Florida V7here weather service winter temperatures below --8C occur yearly. Pi ctonemiobius 531-D survives winters in the Gainesvili.e area, where ambient air temperatures below -8C are frequently recorded. To determine v/hether field-collected P ictonemobius 531-D were physiologically better adapted to survive cold than laboratory-reared

PAGE 63

51 colonies of the same species, and which life stages were the best adapted if any, the following study was conducted. From both laboratory-reared colonies and recent field collections (April) ten individuals of five classes — small juveniles, (large) juvenile males, (large) juvenile females, adult males, and adult females — v/ere placed in rearing jars and put in an environmental chamber to be subjected to a series of successively colder night temperatures, approximately 10 hours each night, until all the crickets had died. Each midday, at approximately 20 C, mortality counts v;ere made In general laboratory-reared 531-D suffered more mortality beginning at -4C than the field-collected individuals (Table 6). It appears that small juveniles v/ere the least tolerant of low temperatures. This experiment was in part repeated with 10 male and 10 female nymphs from the same field and laborcitory sources 2 days later. A single 10-hour cold period of -8C v;as given the first night to eliminate effects of starvation and dessication which were suspected to have developed in the previous experiment. All test crickets were dead the day follov/ing treatment suggesting that a single 5-hour exposure to -8C was sufficient to kill 5 31-D collected in the field. Under natural conditions 531-D would rarely have to contend with temperatures belov; freezing. Interspecific Coldh ardiness Test The difference in cold hardiness among field-collected

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52

PAGE 65

53 528, 531-D, 531-B, and 525 were investig^^.ted. In early May 1971, varying numlDcrs of field-collected individuals of each species were divided into adult male, adult female, and juvenile groups, placed into rearing jars containing sand that v/as moistened on one side of the jar, and a small piece of paper toweling. All jars were placed in the environmental chamber, which was set to provide midday high temperatures of 17C followed by successively lower nighttime temperatures. On successive nights the tem.perature declined and was held for four hours at +3, -3, and -8C. Census i.ng took place during the following midday warm-up periods The stepwise dec] ine Vv'as to give the greatest chance for acclimation to occur as v/ell as to provide more than one period where the temperature might be lov/ enough to cause mortality. The temperature at the towel-sand interface, where miost of the crickets congregated, was m.onitored durj.ng most of the cooling-dov/n and warming-up periods and shov/ed a 1to 2-hour lag in reacliing the sam.e temperature as the ambient air in the environmental chamber. A pretest census and the census following the first cold night ( + 3C) v/erc identical; no crickets died. The results of the successively colder nj.ghts on adult m.ales, adult females, and juveniles of the four species of Pictonemobius are in Figure 17. Species 531-D and 531-B appeared the least cold hardy with 52 5 and 520 holding near pretest

PAGE 66

54 Number of Survivors

PAGE 67

55 levels after exposure to -3C. Only one juvenile 528 and one adult female 525 remained after an exposure to -8C. One additional treatment of -8C killed the remaining crickets. During these studies laboratory rearing of Pictonemobiu s continued normally. Crickets for controls in these experim.ents were not always available, but surplus crickets that were collected or reared, lived for v/ecks under laboratory conditions.

PAGE 68

PHONOTAXTS TO CALLING SOIs^GS Introducti on Species specific "calling songs" or "pair formation songs" are produced by male Pictonemobius (and most other crickets as well) to attract sexually responsive conspocific females for mating. Phonotaxis is the directed movement of a female toward a sound. The strength of the phonotaxis that a female shov'/s toward the source of a male calling song or test signal is difficult to meatrure. The development of a consistent and reliable method of quantifying female phonotaxis had to precede attempts to evaluate the specificity of phonotactic response. The development of such a method is a major part of this section. The assay of virgin female Pictonemobius 528, 531-D, 531-B, and 525 for their response to a wide range of natural and synthetic sounds further defined these Pict onemobius as species Methods Remo te E vent Recording Equip me n t Recordings of song cycles and m.ovemenL of crickets v/ere made on an Esterline Angus model A620T multichannel event recorder (ER) On-off gating was accom.plished by an 56

PAGE 69

57 Alton Electronj.cs Company Sensitive Relay (SR) The following transducers were used to trigger the relay. (1) Microphone transd ucers: A number of inexpensive crystal microphones, such as the Thcro Test TRM-IA "tape recorder microphone," or dynamic raicrophones such as Astatic Corp, model DN-HZ studiomike were used. An increase in sound level such as a cricket singing caused the relay to trigger. (2) Cadmiumt disulphido photoelectric cell; This photocell was used to record the exact time that the LNR lights v/ere switched on or off. (3) Plion ocartri dge ; A "sensitive platform" v/as constructed frora nylon mesh strung tightly across one end of a 6 x 2 inch hoop and he3d tight by a small spring pulling downward against a central 1/2 inch diameter metal disc, (Fie. 18). The needle of an Astatic type 414-2 phonocartridge rested lightly on this central disc. Vibrations applied anywhere on the platform were transmitted to the phonocartridge and resulted in triggering the relay-event recorder system. The relay could be activated by the slight stro}:ing of a human hair. Whenever crickets v/alked onto or moved slightly while upon the platform, the relay v.'as activated several times. To preserve the relay contacts and to eliminate unnecessary pen movements of the event recorder, capacitors ranging from .94 to 50.0 iif were applied to the relay to reduce the on-off sv/itching rate. The capacitance was adjusted to cause the event recorder contacts to remain

PAGE 70

S8 u o > •H +> -H > H

PAGE 71

59 closed longer than the pulse interval, thereby remaining closed for the entire duration of a chirp. Further capacitance was often appli.ed to cause the relay contacts to remain closed during chirp intervals, causing the recorder pen to remain in the "on" position until singing had stopped. Depending on the transducer and signal, various resistors with values in the 100 to 100,000 Q range were applied across the relay input to locate relay sensitivity controls somewhere near their mid range. Both the capacitors and the resistors had the effect of preventing spurious noise from being an event on the ER chart and averaging discontinuous signals into continuous positi^'e responses. The CDS Photocell required a 100 Q. resistor at the input and 50 yf at the output whereas most of the microphones v/ere used with 76,000 n, 10 yf or 100,000 Q and 5 yf, across the input and output respectively. Synthesis of Artificial Test S ignals • Cricket songs generally have their energy concentrated at a single frequency between 3,000 and 8,000 Hz and consequently the sounds they produce are often musical or "bell like" to the human listener. This single frequency is the result of rapid wing vibration developed as the v/ing file teeth are driven over the scraper during a wing closure. The natural calling songs of Pictonemo bius are described in the previous section. In synthesizing cricket signals a Hewlett Packard 201C Audio Oscillator (AO) was used to generate a pure tone of

PAGE 72

60 7,000 Kz, This tone v/qg switched on and off by a General Radio type 1396-A Tone-burst Generator (TG) to create a trill v;ith an on-off ratio of 1:2. The AO output was monitored by a Monsanto model 10 OB Counter Timer v/hich gave a visual readout of the AO frequency at rapid intervals. A sine wave generator (SWG) was used as a timing input for the TG and used to vary the pulse rate. The signal thus produced had on-off svidtching noise v/ith a harsh on-off contrast. This type of signal was used once to test females for response to synthetic signals (Fig. 19). Further refinements involved replacing the TG with an Alton Electronics Company Field Effect Transistor Gate Signal Switch (FET) which sv^itched the 7,000 Hz AO signal on and off. An externally applied drive signal produced by an Alton Electronics Company timer determined the FET switching rate. The rise-time and fall-off of each pulse was modified by application of a .04 yf capacitor across a second drive input of the FET. This equipment raade it possible to shape the beginning and end of each pulse (Fig. 19 B) An example of an artificial signal is illustrated in Fig. 19 D along with a natural pulse (Fig. 19 C) The TG was used to chop this signal into chirps various numbers of pulses long. The output from the The Alton Electronics Company is presently out of business. Alton Higgins of Archer, Florida, developed and marketed the equipment sold by Alton Electronics Company.

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61 End and beginning of .5 msec/div "square cut" pulse, synthetic signal. 7000 cps. ..—" lUui^ Beginning and end of "round cut" PULSEy SYNTHETIC SIGNAL. 7000 CPS. 5 msec/div Pair of natural pulses. 5 msec/div Pair of synthetic pulses. 7000 CPS. 5 msec/div Fig. 19. Characteristics of square cut, round cut, natural and synthetic pulses.

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62 COUNTER TIMER (Mon-santo model 1003) TONE BURST GENERATOR (General Radio type 139S-A) TIMING INPUT TIMER (Alton Electronics Company) TAPE RECORDER (Ampex model 351) WIDE RANGE OSCILLATOR (Hewlett Packard 20 IC) FIELD EFFECT TRANSISTOR GATE (Alton Electronics Conipany) DRIVE.iL .004uf OSCILLOSCOPE (Tektronix type 564) EXTERNAL TRIGGER AUDIO MONITOR (Alton Electronics Company) SPEAKER 8/1 (Sphericon model T-202) Fig. 20. Schematic of equipment used in production of synthetic cricket calls.

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63 TG was displayed on the Tektronix where final adjustments were made upon the amplitude of the AO output, pulse rate, pulse interval, and pulse shape. The finished signal was switched to the input of the Ampex and recorded on tape at 15 ips A section of this tape was then removed and made into a loop for testing females for phonotaxis. Sphericon model T-202 (Sphericon) or Realistic 40-2338 (Realistic) exponential horn tweeters {8Q) were used to broadcast all signals (Fig. 20) Equipment for Tests of Phonotaxis A 2-foot-diameter sand-bottom arena with a 6-inch-high screen side and a lightweight nylon-mesh lid was the test enclosure in which female-responses were studied (Fig. 21). Sitting atop a 6-foot step ladder, the experimenter looked downvv'ard on the arena, recorded data, and by remote controls started or stopped the broadcast of sound to an arena speaker. In the arena center were two or three water vials with exposed moist wicks and a small dish of crushed dogf ood All arena experiments took place in the low noise room (LNR) under a 16L:8D photoperiod. All experiments were at 25 + 1C and 35 to 50% RH. The Ampex was used to record and play back all tapes for analysis and bioassay. Tape loops up to 20 feet in circumference were played on the Ampex by running the tape over additional idler pulleys. For each tape loop the

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64 DC Power source connected lo^nTtLTrTli^t'"' 3 sensitive platforms platform. The test sianJ?^^ '.''t^^ ^ speaker at each 75 db (re. 0.002 dyneVcm^rat."^' """ adjusted to tory. ynes/cm ) at 6 xnches in sound labora-

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65 output of the Arapex was tested, and the sound level adjusted in the sound laboratox-y. Experimental Designs Controlled experiments demonstrating female response to natural or synthetic male calling songs have been reported for Oecanthus by Walker (1957) for Ephippiger spp. by Busnel (1963) Teleogryllus by Hill et al. (1972) and Scapteriscus by Ulagaraj (1974) It appeared that Pictonemobius would lend itself quite well to the bioassay of virgin female response since they are plentiful, small, vjingless, and diurnal. The several pilot investigations into various factors and equipment that were necessary for a reliable, controlled test will not be described in detail, but some of these findings will be given to preface larger and m.ore inclusive tests discussed later. Early experiments of female response to sound level, response periodism, and to "square cut" synthetic trills were made with a single test speaker, located randomly in one of 16 speaker locations surrounding the arena (Fig. 21) v/ith a "duroray" speaker placed opposite as a control. Tv/o wire arcs V7ere placed on the mesh lid of the arena so that when viewed from above an arc with a 6.5 inch radius extended outv;ard from each speaker, demarking an area defined here as the "zone of attraction." Each zone included 10% of the area of the arena. Each test consisted of a 9-minute silent period follov;ed by a broadcast

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66 period of 9 minutes. Follov;ing this the speaker positions were changed and a different test sound was presented to the sarrie crickets after another 9-minute silent period. Ten females v/ere tested each time. If two or more females were within either zone of attraction another test speaker position was randomly chosen before the test was begun. The sound period was divided into three, 3-rainute periods. The number of females in each zone of attraction (test and control) at the end of each 3-minute period was recorded. Control, or dummy, speaker counts v/ere made in case females tended to respond visually to a speaker or remain beneath the wire arc. Later experiments of female response to "round cut" trills and chirps was evaluated by using three test speakers, and the addition of ER counts of cricket activity. The random selection of speaker locations used in earlier experiments sometimes resulted in a test starting v/hen several crickets were concentrated in an adjoining speaker location. To eliminate this, a sequential presentation of test and control signals v/as developed in which three speakers were spaced equidistant on the outer margin of the arena (Fig. 21) A control (natural calling song instead of the previously used silent control) and test broadcasts were presented alternately in a counter clockwise direction. A 6-m.inute silent period preceding each 6-minute test signal enabled the experimenter to leave the low noise room.

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67 change to the next tape loop and speaker position, and adjust the signal intensity. It also allov/ed enough silent time before the next test presentation for the experimenter to return to the room and for the crickets to resume normal movements around the arena after the experiment was readied After each test signal presentation, a 3-minutc silent period preceded each control tape loop presentation. Each 6-minute control broadcast had the effect of clearing the area around the next test speaker and the previous test speaker by attracting the test subjects to one location, and served as a before and after control signal, to which each test presentation could be compared. The 6-minute test and control periods allowed enough time to record response and yet present a number of different signals on the same day without loss of sensitivity and responsiveness on the part of the crickets. The sequence was as follows: 6-minute control signal, 6-minute silence, 6-minute test signal, and 3-minute si.lence. This sequence was repeated for each different test signal, and ended with a 6-minute control broadcast. In this manner it was possible to present a series of seven different test signals, in a randomly chosen order, to a group of virgin female crickets in less than 3 hours. By the end of the third consecutive day of testing, each test signal had been broadcast once on each of the three speakers, thereby eliminating speaker bias.

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68 For the early tests of phonotaxis, the age of virgin females was the only standard used to select test subjects. Because some females showed a lack of responsiveness, a nev/ method of selection of virgin females was developed. All females used in later experiments were selected only if they began a mating sequence (courtship to the "spermatophore formation" stage) (Mays 1971) with a male of their ov7n song type 24-48 hours prior to testing. They v/ere selected by taking a stridulating male, placing him in a jar v;ith several virgin females, observing courtship, and then removing any responding female as soon as the male formed a spermatophore Differential Response to Taped Calling Songs Species 528 and 531-D virgin females were tested for response to tape recordings of their ov;n (conspecif ic) and each other's (heterospecif ic) calling songs for three reasons. First, such a test would determine whether virgin females would respond to tape-recorded songs of their conspecific males. Second, it would demonstrate if this response was species specific or whether they could be attracted to each other's songs. Third, it would give some indication as to the suitability of the test in terms of signal presentation, sound pressure level, and response behavior of the females tested. Seven to ten virgin females of both 528 and 531-D were tested in the arena, one species at a time, A total of

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69 25 to 28 females was testPd in three replicates of each species. The numbers that responded by entering the zone of attraction of the test speaker are shown in Fig. 22. There was no indication of attraction to the dum.my speaker. Such sharp discrimination by females in favor of the calling songs of their conspecific males demonstrates one v/ay that 528 and 531-D avoid interbreeding. The two test signals were 528-100, 35-1 p/s at 26.0C and 531-78, 44-8 p/s at 25-8C. Sound Level A test to evaluate the response of virgin females to a more-intense-than-normal male calling song was necessary before an appropriate sound level for future LNR arena tests could be selected. The effect of a more intense signal on the phonotactic behavior of virgin females was evaluated and compared with a tape recorded 7 5 db song similar to that produced by singing males at 6.5-inch distance. A General Radio Company type 1551 B sound level meter (SLM) (scale A at 6.5 inches from the speaker), was used to adjust a tape loop copy of 528 calling song to tv70 levels of intensity, 90 and 75 db. The speed of female response to sound was greater during the 90 db signal broadcast than during the 75 db signal. The females would often jump with the first chirp of the 90 db test signal and run to the speaker, or move rapidly about, traveling in and out of the zone of

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70 attraction. The 90 db test signal was effective in demonstrating a rapid and positive response, but the responding females moved around much more rapidly than ever observed in response to living males (Fig. 23) The distribution of sound level in the arena was measured with the SLM. The zone of attraction closely approximated the area to which 75 db extends (Fig. 24) Broadcast sound levels of 7 5 db were chosen for all subsequent experiments because adequate response occurred in a relatively short period of time at sound levels approximating natural ones. Response Per iodism Daily changes in female response v;ere suspected in view of the daily rhythm of male song production. The response of ten, 3-week-old, virgin, laboratory-reared 528 females, to a pair of 9-minute broadcasts of taped calling song separated by 9 minutes of silence v;as m.ea-sured four times daily for three consecutive days. Once daily the broadcasting schedule was offset by two hours resulting in broadcasts every 2-hour period of a (composite) 2 4 -hour day. In this study the percent of those entering the zone of attraction during the initial 3 minutes of broadcast were weighted 3x, the second 3 minutes of broadcast were weighted 2x and the final 3 minutes of broadcast Ix. The

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71 10090 70^ 60528 SONG NO. Tested F_ 528 25 531-D 25 531-D SONG o 50-

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72 Fig. 24. Distribution of sound level in test arena.

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73 X 3 a lU 3 S f J d S 3 H

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74 average response to the broadcsist for the dark period (1,2 5) was similar to that for the day (1.31). The average first day response was 2.11 compared with a second and third day average response of .88. The silent period response averaged .05. In general the crickets responded poorly during the last days of the test. One cricket died on 10 February and the others spent much of their time in the center of the arena around the water vials and food dish. These data did not demonstrate daily periodism in female responsiveness to recorded male calling songs, but the overall level of response was so lov/ that such periodism, if it exists, could have been missed. ._ ^ The results pointed to the need for further considerations of the physiological readiness of virgin females. Greater response had been noted for other tests of female response. Rather than repeating this test all subsequent testing of virgin female Pictonemob ius was in the morning hours corresponding to the first daily peak in male song activity noted in both field and laboratory Results Analysis of Feraale R es ponse Square-c ut trills, 2 sp ecie s. When 52 8 and 5 31-D laboratory reared virgin females (distinguished from one another by dots of colored paint) v/ere placed together in the arena, it v;as found they would go to a speaker broadcasting a square-cut, synthetic, continuous trill providing

PAGE 87

75 the pulse rate was appropriate By varying the audio ' oscillator from the 528 range nr. 36 p/s to the 531-D range nr. 4 5 p/s, the experimenter could attract 52 8 in one direction and (by switching speaker and pulse rate) attract 531-D in the opposite direction. No differences could be shown in response by 528 and 531-D virgin feroales to squarecut, synthetic continuous trills of appropriate pulse rate and their tape-recorded natural calling songs (Fig. 26) R ound-cut trills, 4 species test s. Virgin females of 528, 531-D, 531-B and 525 that were exposed, one species at a time, to a series of seven synthetic round-cut trills each 2.5 p/s apart in the range of their expected response (30.0 to 67.5 p/s). Tape loops of natural calling songs, 38.1, 47.2, 53.8, and 6 0.4 p/s, respectively, were used as controls throughout. Sixteen different synthetic trills ranging from 30.0 to 67.5 p/s, were used. Portions of three such trills, 30, 32.5, and 35 p/s are shown (Fig. 27). Synthetic trills were used because chirp length varied betv/een t}ie four song types and v;ould likely introduce an additional variable. Each series of seven test signals were presented once each day between 8:00 and 12:00 a.m. EST to a group of 10 crickets of one species. The randomly chosen sequence of presentation began at a different broadcast speaker position each test day enabling each test sj.gnal to be broadcast from each speaker once during the three day test period (see previous section for more detailed discussion of methods)

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76 531-D FEMALES 528 FEMALES 100-

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77 iiiiiiiiiimiiiiiiiin'r tyiiijiiiiiiiiiiiiiiiiriiiiiiiiii Synthetic trills (top to jo sec/div. bottom) 30.0. 32.5 and yillljlllllllliyilllll^ Natural Nfqnemobius .05 sec/div. CUBENSIS (top) with synthetic PirTONEMOBIUS 525 TRILL. 62.5 p/s (bottom) Fig. 27. Oscilloscopic traces of natural ( Neonemo bius cubensis) and synthetic test signals.

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The response to each test broadcast period was evaluated in the following four ways and the data compiled for each method separately. The results show four peaks of female response for each of the four methods corresponding to the calling song pulse rates of each of the four species. Each of the four methods of analysis was an attempt to measure the same test i-esponse in different ways. :_ 1. Event re corder coun_ts. As crickets moved to the area in front of a broadcast speaker, they walked onto the sensitive platform (Fig. 18) and triggered the phonocartridge-sensitive relay system. The number of events or "clicks" of the event recorder pen scribed on a chart for each 6-minute broadcast period was tallied. Unavoidable individual differences between each sensitive platform system with respect to responsiveness to a given cricket movement V7ere averaged out by having each test signal broadcast once at each platform during the three test periods for each species. This tally was compared with the average number of events for the preceding and following 6-minute broadcast of control signal and expressed as a percent of the controls. This v/as an attempt to reflect the intensity of attraction at the time of each broadcast of test signal and to eliminate the effect of any changes in responsiveness that might have occurred during a test sequence. Female motor activity was the highest during the test and control broadcast periods. The greatest activity occurred when

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79 the test trill pulse rates were in the range of + 5 p/s of the appropriate male calling song (Fig. 29) ;_^ 2, Number res ponding. Any female which turned toward the direction of broadcast sound and moved more than 10 body lengths toward the broadcast speaker v/ith short quick steps characteristic of phonotaxis v/as given a positive response. The number responding v/as expressed as a percent of the average number responding during the preceding and following control periods {Fig. 30) (thereby eliminating the effect of different proportions of the fem.ales being ready to respond to the pulse rate produced by conspecific males. ) .... -3. Number moving Movement during each 6-minute experimental period whether silent, test, or control was quantified by totaling the number of individuals moving during the first 2-minute, the second 2-minute and the third 2-minute segments. An index of movement during each test or control period v/as arrived at by taking the total movement (30 maximum — 10 crickets during three, 2 -minute periods) and subtracting the total movem.ent (30 maximum.) that occurred during the preceding silent period. The purpose of this index v/as to demonstrate any change in activity that took place during the various test broadcasts. The controls are also plotted to illustrate the crickets' consistent responsiveness throughout the 3-hour test sequence. The results were very similar to the above two methods. The

PAGE 92

80 CO ........Hllllllllll s CO (((••i4lll|||||>,^ 9^ggS8^ ................4IIIIIIIIIII 00 CM in .4iiii7iiiii)iiiiiiK^ 0) 0) -p ( en o iH cn Cij cs^ u u -p -H-H„ CC CO (Uf^ (D (0 c n3 c, 0) rtiu 0) 0) O W • cnnJ Cn-H O H G-H OM dPVO

PAGE 93

greatest activity occurred in the range of + 5 p/s of the appropriate calling song for the four species of females tested (Fig. 31) 4. Weighte d re spon s e in dex. This n'.easure attt.mpts to score individual females as to how strongly they respond to a gi'^'en broadcast signal and was dona to include a comparison v/ith the event recorder counts. The index was evaluated as the total number of crickets in the "zone of attraction" (less those already present, during the preceding 6-minute silent period) of the 0-2-m.inute period plus 2x the 3-4-Tninute count plus 3x the 4-6-minuto count. Some f empties climbed the screen direct]. y in front of the speaker and were given ?.x the previously outlined values. The sum of all of these is an index of attractiveness stiown in Fig. 31 for 528, 531-D, 531~B, and 52 5. The plot of this index agrees closely with the event recorder counts and describes similar peaks of resi)onse, orientation, and activity already described (Fig. 32). The preceding plots of female response shov/ed a wide range of peak response for each song type tested. This lack of sharp discrimination under these test conditions may have resulted from using females v.'ith a low threshold for response in a "single choice" (i.e. no response vs. response to sound) situation. In the field, no female would likely fail for long to be inseminated after becoming responsive to male songs. Hill et a] (.1972) found that

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82 ^^^^-m^ CO U) ..-.-immiilllllilltlK^ -4iii
PAGE 95

83 CO IllllllllllllilllllK I— —4111111)1)1111 Q -Hlllllllllllllllflli^^^^ CO.— >-i!<||||{|{|{|{|{|{|{|llill|{|||||l1lk 10 __, _ee. ^ 0) 0) (A oNiAow aaawriN asuodsau aieuiaj c 03 (13 QJ cn tn (U M CQ a I OJ (C o Mm 0) iH Q, a^ O vc -p OJ '. W 0) C a O (U aj-l tn 0) m a) -H (G e +J QJ c fe QJ >^ QJ •H

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84 iBssm^mssk ga^ in in CO 10 CO in illllllfllllKIIIIIlK, mMlllllllllK, ••iiiiiiiiiiiiiiiifiiiiK^ ^^XfSBL (0 0) (0 3 Q. X3aNI 3SN0dS3a TVnSlA a3iH9I3N asuodsau aieuiaj t3 -P | 'O ^^ OJO CO 0) ^ tn QJ >^ -P u '^ c m Q) S-l nj Cm re!

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85 similarly deprived virgin females of Teleogr yllus sp. responded in about 50% of the cases to nonconspecif ic songs. In two choice situations, i.e. no response vs. response to conspecific sound vs. response to nonconspecif ic sound. Hill et al. (1972) noted that females discriminated nearly 100% of the time. Artificial trills stimulated the females to greater response than the control calling song, suggesting that continuous trills present an above-normal stimulus, which may have also had the effect of lowering pulse rate discrimination. Chirp Length The effect of changing chirp length while maintaining a constant pulse rate and chirp-to-interval ratio, was evaluated using 525 virgin females. Species 525 was chosen because it had the longest chirp of any Pictonemobius and seemed the most J.ikely species to be affected by shortened chirps. Round-cut trills 62.5 p/s (as used in the previous test) were chopped by TG into chirps 4, 8, 16, 32, 64, and 128 pulses long with intervals 1/2 the chirp length, so that each test signal presented the same number of pulses per minute (Fig. 28) Plots of response (Fig. 33) shov/ an increase in response as the chirps approached typical 525 length. Most event recorder and oriented movem.ent counts did not exceed the control average as they did with previous tests on trills, further indicating that a continuous trill provides an above-normal stimulus.

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86

PAGE 99

87 It appears that a^ chirp of some length is important, yet the short 4-pulse~on, 2-pulse-time-of f chirp received some response. When the number of pulses per minute is kept the same, the short pulse-number chirps are too close together and may elicit a response which reflects pulse rate effect rather than a chirp rate effect (Fig. 33) The calling song of Neonemobius cubensis tSaussure) 537-16, which has a nearly continuous trill similar to that of 525, was added because N. cubensis occurs with 525 in some situations. The N. cubensis test signal (Fig. 27) at 57.1 p/s received the lowest response of all despite its nearly continuous trill close to the 525 pulse rate and being v.'ithin the range of expected response noted in the pulse rate experiment (Figs. 29, 30, 31, & 32).

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88 537-15 COPY (0 Q) 2015122128/51) ei)/;2 537-16 PULSES ON / PULSES OFF Chirp Length Fig. 33. Effect of chirp length on oriented movement and event recorder counts of Pictonemobius sp. 52 5. Widths of each bar differentiate three component replicates.

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HYBRIDIZATION STUDIES Preliminary Tests 1 The mating behavior of Pictonemobius (Mays 1971) was studied initially in numerous, small-scale crossing experiments. As techniques improved, larger and more inclusive tests became possible. This section deals with the first replicated tests of Pictonemobius hybridization that I conducted. Intraspecif ic Allopatric Crosses Intraspecif ic crosses between widely separated populations of what appeared to be the same species of Picto nemobius were successful. In most cases, spermatophores were transferred normally and progeny were produced. No exhaustive series of crosses between distant populations for each of the four song types of Pictonemobius was attempted, but some such crosses were made v/ith the following results: allopatric populations of each song type were interfertile (Table 7) An Unintentional Interspecific Allopatric Cross The first Pictonemobius encountered in the vicinity of Gainesville was 531-D and it was assumed to be conspecific with the type of ambitiosus The subsequent discovery of 528 raised the question of which Pictonemobius (531-D or 528) was the real ambitiosus Two approaches were taken to answer this question. First Dr. T. J. V7alker and I went to the vicinity of the type locality described as "Fort Reed 89

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90 Table 7. Intraspecif ic allopatric crosses from selected Florida localities Song type

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91 Orange County 3 mi. S. Mellonville, at the head of navigation on the St. Johns" (Scudder 1877) to collect the "true" ambitiosus. "Fort Reed" had been about where the hangar now is at the Sanford Naval Air Station, and on 18 September 1967 we collected Pictonemobius from a nearby area (east 25th Street and Grandview Ave. in Sanford) The specimens collected were brought to Gainesville, reared one generation in the laboratory and crossed with laboratory colonies of 531-D from the Gainesville area to determine if these populations were genetically compatible and could therefore be considered conspecific. The second approach was to borrow from the Museum of Comparative Zoology, Harvard University the (Scudder) type of ambitiosus and compare it with 531-D and 528 from Gainesville and the Pictonemobius from near the type locality "Fort Reed." The results of the cross were unexpected. No progeny were produced in crosses between "Fort Reed" species and Gainesville 531-D (Table 8) However, I subsequently discovered that the 1967 specimens from "Fort Reed" were 531-B and I had unintentionally made an allopatric, interspecific cross. I identified the type specimen as 531-D; and on the basis of other recent records of 531-D (Fig. 1),, I suspect it as well as 531-B still live near "Fort Reed." Interspecific Sympatric Crosses Specimens of 528 and 531-D from north Gainesville were crossed to test whether they were genetically compatible.

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92 0)

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93 Adult females of both species were collected at two sites, the municipal airport and a site 5 miles north on Monteocha Road. The females were placed singly in gallon rearing jars to oviposit. The calling songs of five to ten adult progeny from each parent female were recorded and analyzed for pulse rate, to determine their identity. Forty-four crosses were set up in gallon jars like those used for the parental females. Only virgin females, obtained by separating nymphal females into separate "sorority" rearing jars, were used. All jars were kept on a 16L:8D photoperiod. Part of the sand in each jar was m.oistened about every five days. The close spacing of the shelves on which the jars were kept lead to mold formation within the jars. Widening the shelf spacing lead to conditions v/hich appeared to be too dry. This variation in rearing conditions probably caused some loss of egg hatch. Conspecific crosses {528 x 528 and 531-D x 531-D) resulted in progeny in 52.4% of the crosses attempted. Heterospecific crosses (528 x 531-D and 531-D x 528) never resulted in the production of progeny (Table 9) Another pair of song types, 5 31-D and 5 31-B from sympatric populations at 3/4 mi. west of Archer, Florida, were crossed to test v/hether they were genetically compatible. Individual pairs were observed until a complete mating sequence had elapsed terminating in the female mounting the male with genitalia coupled and spermatophore present. The

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94 -d

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:95 males were then removed from the jars and the females were maintained alive for at least 30 days. The results of the crosses are given in Table 10. Table 10. Interspecific sympatric crosses of Pictonemobius 531-D and 531-B, 3/4 mi. west of Archer, Alachua Co. Florida. Mating Behavior Spermatophore ' Retained by Progeny X Premount Mount Female Produced 531-D X 531-D + + '•"-. j; + 531-D X 531-B Mating not seen pair together for 17 days Jar 1 • r Jar 2 + + ": 531-B X 531-D ; y Jar 1 + + Jar 2 + + dropped 531-B X 531-B + + + .. + Despite spermatophore transfer (seen for 3 out of 4 test pairs) progeny developed in the control jars only. Test females that received spermatophores from males of song types different from their own did not actively deposit eggs, and appeared similar to unmated virgin femalesThe/ repeatedly inserted their ovipositors into the sand but only occasionally were eggs observed in these jars. The abdomens of these test females and those of virgin females became nearly twice

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96 normal size after about 3 weeks. Dissection of such females revealed the ovarioles and oviducts to be filled with 15 to 20 light-brown full-sized eggs with a larger number of white nearly full-sized eggs packed closely behind. These Pictonemobius females from inappropriate matings were similar to the females of Allonemobius ( Nemobius ) fasciatus of Fulton's 1933 (p. 371) study wherein he found that when the spermatheca was empty "The ovaries were packed with eggs . . Loher and Edson (1973) report that virgin females of Teleogryllus commodus Walker behaved similarly, depositing relatively few eggs and retaining large numbers of eggs in their oviducts. The receipt of some stimulatory factor derived from the testes and transferred by inclusion in the spermatophore, caused oviposition to return to normal levels and fewer eggs to be retained in the oviducts. . Final Test of Hybridization with 4 Species of Pictonemobius The final study of Pictonemobius hybridization involved crossing each of the four species of Pictonemobius in all 16 possible combinations, and replicating the experiment four times. Before this test was initiated, improvements were made in the selection of test females and in the evaluation of mating sequences. Methods for Improvement of Mating Tests To assure the greatest possible success when crossing the four species of Pictonem.obius with one another, some

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97 proof of each female's willingness to mate was needed. The effect of age upon a female's willingness to mate was determined by exposing eight virgin laboratory-reared Pictonemobius of each of three species--528 531-D, and 531-B--to a mature male of their song type for one hour each day. During that time if a mating sequence had proceeded to the stage where the male had produced a spermatophore, the male was removed from the jar and the test scored + for that day. The results of these tests are in Table 11. Three individuals tested on or before their fourth day exhibited no mating behavior. Mating first occurred on the fifth day in two out of four females tested. Mating had occurred by the ninth day in six out of seven females tested. Positive responses were still being recorded on day 43 and later (Table 11) For each of the four song types only virgin females more than seven days old were set aside for further screening prior to testing. One or two conspecific males were placed in each of several rearing jars containing these age-selected virgin females. When a mating sequence had progressed to where a male with a spermatophore was courting the female, the male was removed from the jar and either used again to determine the readiness of another female or as a test male in the final cross breeding experiment. The female, now considered to be ready to mate, was left alone until the morning of the following day at which time a test male of

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98 2S-TS

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99 one of the four song types was placed with her for a 4-hour period of observation. This was done for each possible combination of the four different song types (16 crosses) and was replicated four times. The individuals used in this test were from the following localities: (528) 5 mi east and .5 mi. north of Bronson, Levy Co : (531-D and 531-B) 3/4 mi. west of Archer, Alachua Co.: (525) .3 mi. east of Clay Co. line on SR.16 and vicinity of Starke Country Club. The events of Pictonemobius mating (Mays 1971) leading to the production of a spermatophore by the male and its passage to the female were divided into 6 classes to illustrate the degree to which test pairs completed a mating sequence. The test jars were maintained in the laboratory for three months following to determine which crosses resulted in the production of progeny. ~ Results of Crosses ; In the 16 control pairings the mating sequence proceeded normally, although one of these failed to produce progeny. In the remaining 48 heterospecif ic crosses (Fig. 34) 26 produced calling song; 12 courtship song; 10 the first spermatophoreless mounting; 9 a spermatophore and an attempt at mounting; 4 a spermatophore transfer and its retention by the female for more than 5 minutes; and 1 hybrid progeny with a pulse rate (50.3 n=8) intermediate between the parental types 531-D (47.2 n=9) and 525

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100 I FfFNII Resulting progeny intermediate pulse rate (50.3,n=8) -1-tUtm! between 531-D (47.2,n=9) and 525 (59.9,n=8). blank = no male calling song = calling song 1 = courtship song i § = above plus spermatophorless mounting I I t = above plus spermatophore produced f t f I = above plus mounting and spermatophore insertion f I C I I = mounted and feeding on tibial spur, spermatophore remains on female minimum 5 minutes. progeny present in jars during following three months. Fig. 34. Mating behavior and progeny production in crosses of Pictonemobius 528, 531-D, 531-B, and 525.

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101 :(59.9 n=8) All other reported interspecific crosses between crickets have resulted in intermediate songs (Alexander 1968). •

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LITERATURE CITED Alexander, R. D. 1960. Sound communication in Orthoptera and Cicadidae in W. E. Lanyon and W. N. Tavolga. Animal sounds and communication. Washington A.I.B.S. 38-92. Alexander, R. D. 1962. The role of behavioral study in cricket classification. Syst. Zool. 11: 53-72. Alexander, R. D. 1967. Acoustical communication in arthropods. Annu. Rev. Entomol 12: 495-526. Alexander, R. D. 1968. Arthropods. Pages 167-216 in Sebeok, T. A. ed. Animal communication. Indiana Univ. Press, Bloomington. Alexander, R. D., and E. S. Thomas. 1959. Systematic and behavioral studies on the crickets of the Nemobius fasciatus group (Orthoptera: Gryllidae: Nemobiinae) Ann. Entomol. Soc Amer 52: 591-605. Busnel, R. G. (ed.) 1963. Acoustic behavior of animals, Elsevier, New York. 933 p. Fulton, B. B. 1933. Inheritance of song in hybrids of two subspecies of Nemobius fasciatus (Orthoptera) Ann. Entomol. Soc. Amer. 26: 368-76. Hill, K. G., J. J. Loftus-Hills, and D. F. Gartside. 1972. Premating isolation between the Australian field crickets Teleogryllus commodus and T. oceanicus {Orthoptera: Gryllidae) Aust. J. Zool. 20: 153-63. Laessle, A. M. 1942. The plant communities of the Welaka area. Univ. Fla. Biological Science Series 4(1) 143 p. Loher, W. and K. Edson. 1973. The effect of mating on egg production and release in the cricket Teleogryllus commodus Entomol. Exp. and Appl 16: 403-90. Marler, P. 1962. Species specificity in animal communication signals. Amer. Zool. 2(4): 538. 102

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103 Mays, D. L. 1971. Mating behavior of Nemobiine crickets — Hygronemobius Nemobius and Pteronemobius (Orthoptera: Gryllidae) Fla. Ent. 54(2): 113-26. Scudder, S. H. 1877. The Florida Orthoptera collected by J. H. Comstock. Proc. Bost. Soc. Nat. Hist. 19: 80-94. Ulagaraj S. M. 1974. Mole crickets: Ecology, behavior, and acoustical communication (Orthoptera: Gryllotalpidae: Scapteriscus ) Ph.D. Dissertation. Univ. Fla. 71 p. Walker, T. J. 1957. Specificity in the response of female :_1.. crickets (Orthoptera: Gryllidae, Oecanthinae) to calling songs of the males. Ann. Entomol. Soc. Amer. 50: 626-36. Walker, T. J. 1962. Factors responsible for intraspecif ic variation in the calling songs of crickets. Evolution :.:^: 16: 407-428. ... ':-.;

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APPENDIX A The Use of Stridulatory File Characteristics in Identification of Pictonemobius The stridulatory files of more than 150 Pictonemobius from 7 sites of sympatry were measured, and the number of teeth counted (Table 1, Appendix). Tape recorded specimens were used whenever possible. In general, 528 and 531-D had the longest files. For all of the Pictonemobius examined, the longer files tended to have more teeth. The use of stridulatory file characteristics can som.etimes be of assistance in identification of Pictonemobius. 104

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105 Q) •H U Q) u 3 O m iw O 01 Q) iH •H 4-f >i M O -P (C rH •H M -M tn J3

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106 + 1 + 1 + 1 +1 +1 +1 + 1 + 1 + 1 +1 +1 +i + 1 + 1 + 1 0)

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4^^ 107 A

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: APPENDIX B • A Key to the Adults of Pictonemobius The following key should provide the user with a greater than 90% chance of identifying a pinned specimen of the genus Pictonemobius to species, providing locality and habitat information are available and color pattern (especially of females) is not altered by poor preservation techniques. The distribution maps (Figs. 3, 4, 5, & 6) will aid in the use of this key. Specimens from west of Lafayette and Dixie counties in the panhandle region of Florida are difficult to classify in terms of color pattern and song (Table 1, 525) This area is ecologically different from the rest of Florida where Pictonemobius occurs. Such a region could contain a fifth Pictonemobius or may represent a zone of introgression where two or more of the species defined for peninsular Florida are united. The status of these populations can only be ascertained by further studies. 108

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109 A Key to Adults of Pictonemobius la. Male tegmina with distinct yellow or cream-colored border; female tegmina with light-colored dorso-lateral stripe and dorsal field usually speckled or flecked; occurring in mesic to xeric habitats over most of Florida. ............. 2 r';--2a. Fem.ale tegmina dark ground color; entire lateral :.-' '-. stripe bright* at least 1/4 as wide as tegmina, ; :." -.. epiproct white (living specimens); males, pron6tum ;lighter than wings, often purplish; metathoracic r. femora uniform buff to orange brown, lighter than 1 • pronotum, striping or marking absent or nearly 5 r absent* [*Collier County tegmina (female) lighter, i? ^ • stripe less distinct; metathoracic femora more strongly spotted and striped] . Pictonemobius 531-B 2b. Female tegmina color tan to black with white and :::--: : brown spots; lateral stripe diminishing in color and : .. width distally less than 1/4 as wide as tegmina, "^' ^' ;-epiproct not white; m,ale pronotum usually darker r. than wings, metathoracic femora bicolored, striped and dark spotted on white to nearly dark brown 'r-\ ground color 3 3a. Female tegmina usually brovzn with a central dark spot proximally and faint light specks overall, lateral stripe indistinct beyond humeral angle; female abdomen concolorous with

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110 tegmina, no distinct lateral striping; general •_ body color of both sexes brown, lacking conr-. — ^ ^ trasting patterning or speckling Pict onemobius 531-D -.7 -.ab. Female tegmina usually charcoal, with numerous : light brown to v/hite speckled areas; lateral .• .. stripe extending beyond humeral angle; female = abdomen with dorsal black central stripe darker ._. than tegmina, 1/3 width of abdomen bordered by white speckled to brown dorso-lateral areas; general body color of both sexes black with .white speckling overall. . Pictonemobius 528 lb. Male tegmina without distinct border; female tegmina without dorso-lateral stripe and with dorsal field usually uniform dense flat chocolate brown or black; occurring in pine flatwoods in northeast Florida, and from flatwoods and river bottom land to the pine forests in the northwest and the panhandle of Florida.* [*northwest and panhandle Florida individuals are lighter in overall coloration, resembling 531-D].

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Biographical Sketch David Lee Mays was born 22 May 1941 in Santa Monica, California. His interests in insects began when he was 10 years of age. With generous parental encouragement he developed a collection of more than 15,000 insect specimens by the time he entered University High School in West Los Angeles. He attended Santa Monica City College in early 1960 and transferred to Oregon State University later that fall to enter the School of Forestry. Upon learning of 'the staff and facilities of the Department of Entomology at Corvallis he instead entered the School of Science and received the degree of Bachelor of Science in entomology in 1964, and the degree of Master of Science in entomology with a minor in genetics in 1966. From that time to present date he has worked toward the Doctor of Philosophy degree in the Department of Entomology and Nematology at the University of Florida. Ill

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I certify that I have read this study and that in my opinion it conforms to acceptable standards of scholarly presentation and is fully adequate, in scope and quality, as a dissertation for the degree of Doctor of Philosophy. Thomas J. Walker, Chairman Professor ofyEntomology and Hematology I certify that I have read this study and that in my opinion it conforms to acceptable standards of scholarly presentation and is fully adequate, in scope and quality, as a dissertation for the degree of Doctor of Philosophy. ^^^r/^$0^ Milton D. Huettel Assistant Professor of Entomology and Hematology I certify that I have read this study and that in my opinion it conforms to acceptable standards of scholarly presentation and is fully adequate, in scope and quality, as a dissertation for the degree of Doctor of Philosophy. U. Ixfrt^.A^^hj/""^ F. C. Johnson Professor of Zoology I certify that I have read this study and that in my opinion it conforms to acceptable standards of scholarly presentation and is fully adequate, in scope and quality, as a dissertation for the degree of Doctor of Philosophy. yy /jimesL. Natron / Professor of Ento/nology and Nematology

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I certify that I have read this study and that in my opinion it conforms to acceptable standards of scholarly presentation and is fully adequate, in scope and quality, as a dissertation for the degree of Doctor of Philosophy. ^'A\-'\C(?r^/^S. H. Kerr Professor of Entomology and Nematology This dissertation was submitted to the Graduate Faculty of The College of Agriculture and to the Graduate Council, and was accepted as partial fulfillment of the requirements for the degree of Doctor of Philosophy. June 1975 Dean, Graduate School

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UNIVERSITY OF FLORIDA 3 1262 08553 0383