Front Cover
 Table of Contents
 Female reproductive patterns
 Male reproductive patterns
 Cyclic type and ecological or behavioral...
 Abdominal fat bodies
 Seasonal insect abundance
 Differential seasonal representation...
 Seasonal color changes
 Literature cited
 Back Cover

Group Title: Bulletin of the Florida State Museum
Title: Reproductive patterns in sympatric Philippine skinks (Sauria Scincidae)
Full Citation
Permanent Link: http://ufdc.ufl.edu/UF00095818/00001
 Material Information
Title: Reproductive patterns in sympatric Philippine skinks (Sauria Scincidae)
Series Title: Bulletin - Florida State Museum ; volume 34, number 5
Physical Description: p. 201-247 : ill. ; 23 cm.
Language: English
Creator: Auffenberg, Walter
Auffenberg, Troy
Publisher: University of Florida
Place of Publication: Gainesville, Fla.
Publication Date: 1989
Copyright Date: 1989
Subject: Skinks -- Philippines   ( lcsh )
Genre: bibliography   ( marcgt )
government publication (state, provincial, terriorial, dependent)   ( marcgt )
non-fiction   ( marcgt )
Spatial Coverage: Philippines
Bibliography: Includes bibliographical references (p. 246-247).
General Note: Cover title.
General Note: Abstract in English and Spanish.
Statement of Responsibility: Walter Auffenbert, Troy Auffenberg.
 Record Information
Bibliographic ID: UF00095818
Volume ID: VID00001
Source Institution: University of Florida
Holding Location: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: oclc - 20375831

Table of Contents
    Front Cover
        Page 199
        Page 200
        Page 201
        Page 202
    Table of Contents
        Page 203
        Page 204
        Page 205
        Page 206
        Page 207
        Page 208
        Page 209
    Female reproductive patterns
        Page 210
        Page 211
        Page 212
        Page 213
        Page 214
    Male reproductive patterns
        Page 215
        Page 216
        Page 217
        Page 218
        Page 219
    Cyclic type and ecological or behavioral factors
        Page 220
        Page 221
        Page 222
        Page 223
        Page 224
    Abdominal fat bodies
        Page 225
        Page 226
        Page 227
        Page 228
    Seasonal insect abundance
        Page 229
        Page 230
        Page 231
    Differential seasonal representation of sexes
        Page 232
        Page 233
        Page 234
    Seasonal color changes
        Page 235
        Page 236
        Page 237
        Page 238
        Page 239
        Page 240
        Page 241
        Page 242
        Page 243
        Page 244
        Page 245
    Literature cited
        Page 246
        Page 247
        Page 248
    Back Cover
        Page 249
Full Text

BiU ,iL Tlll

of the
Biological Sciences
Volume 34 1989 Number 5


Walter Auffenberg
Troy Auffenberg



SCIENCES, are published at irregular intervals. Volumes contain about 300 pages and are not
necessarily completed in any one calendar year.


RHODA J. BRYANT, Managing Editor

Communications concerning purchase or exchange of the publications and all manuscripts should
be addressed to: Managing Editor, Bulletin; Florida State Museum; University of Florida;
Gainesville FL 32611; U.S.A.

This public document was promulgated at an annual cost of $2714.00 or $2.714
per copy. It makes available to libraries, scholars, and all interested persons
the results of researches in the natural sciences, emphasizing the circum-
Caribbean region.

ISSN: 0071-6154


Publication date: 7/6/89

Price 34(5): $2.80


Walter Auffenberg and Troy Auffenberg*


The reproductive biology of 11 species of geographically sympatric scincid lizards was
studied in southern Luzon, Philippines. These are Mabuya multicarinata, Mabuya multifasciata,
Lipinia pulchella, Lamprolepis smaragdina, Sphenomorphus jagori, Dasia grisia, Otosaurus
cumingii, Emoia atrocostata, Brachymeles samarensis, Brachymeles boulengeri, and Tropidophorus
grayi. Collectively they represent a broad range of local microhabitats, life styles (arboreal to
fossorial), and sizes (among the smaller skink species of the world to some of the largest).
Analyses were based on a total of 3252 adult individuals collected in more or less equal samples
monthly over an entire year. Testis size, follicular development, oviductal eggs, body fat, skin
color, and activity patterns were all investigated in the context of season, climate, sex, and size.
The results suggest that there is great diversity in reproductive strategies represented by
the 11 species studied. This diversity in reproductive mode and timing is much greater than
expected on the basis of published summaries, statements of general principal, or theoretical
models of tropical lizard biocoenoses. It is clear that we are still far from understanding those
factors that dictate clutch size and timing of cycles in tropical lizards. Cues triggering seasonal
reproductive phases must either be numerous or reacted to in totally different ways by sympatric
species. Many more data are needed on other tropical lizard communities before we can begin to
unravel the complexity of the signals to which these lizards are responding and the physiological
responses elicited by those cues. We found almost every conceivable type of annual reproductive
strategy represented. Some species are egg-layers and others live bearers; some breed
continuously throughout the year, whereas others are periodic. Those that are periodic have
either one or two reproductive peaks, and these may fall at entirely different times of the year,
despite their geographic and broad ecological sympatry. Even within specific microhabitats,
patterns are remarkably variable among the resident species. There is no evidence for a single
tropical forest reproductive pattern. There is, however, a tendency for reproduction to be
collectively highest during and immediately after both the first (June-July) and second
(September through December) monsoons. In general, reproduction is collectively lowest during
the dry months preceding each of the monsoon periods.
There is no significant correlation between number of eggs (young)/clutch and habitat,
female size, or reproductive mode. There are, however, two basic strategies represented in
regard to number of eggs (young)/clutch. In one group, species lay consistently small clutches; in

Walter Auffenberg is Curator of Herpetology, Florida Museum of Natural History, University of Florida, Gainesville FL
32611; his son Troy is a graduate student in the Department of Microbiology, University of Kentucky, Lexington KY 40536.

AUFFENBERG, W., and T. AUFFENBERG. 1989. Reproductive Patterns in Sympatric
Philippine Skinks (Sauria: Scincidae). Bull. Florida State Mus., Biol. Sci. 34(5):201-200.


the other group, species lay significantly larger clutches. All oviparous species belong to the last
group; viviparous species occur in both groups.
Several of the scincids studied show significant seasonal change in coloration of both males
and females. These can be correlated with the reproductive period and are believed important in
this context. The frequency of these color changes in members of the family Scincidae is
somewhat surprising in view of the fact that these lizards are generally considered more scent-
than sight-oriented. This may be a phenomenon of tropical Asian skink communities, where
sympatric species are more numerous than in temperate forests, where most previous studies of
skinks have occurred.


Se estudi6 la biologia reproductive de once species simpitricas geogrAficamente de
lagartijas scincidas en el sur de Luz6n, Filipinas. Las species son Mabuya multicarinata, Mabuya
multifasciata, Lipinia pulchella, Lamprolepis smaragdina, Sphenomorphus jagori, Dasia grisia,
Otosaurus cumingii, Emoia atrocostata, Brachymeles samarensis, Brachymeles boulengeri, y
Tropidophorus grayi. En conjunto estas species representan una amplia variaci6n de
microhabitats locales, hibitos (arboricolas a fosoriales), y tamafos (el grupo incluye desde
algunas de las species de scincidos mis pequefias del mundo hasta algunas de las mas grandes).
El andlisis se bas6 en un total de 3252 individuos adults colectados en muestras mis o menos
iguales cada mes a lo largo de un afio. Se registraron el tamafio de los testiculos, desarrollo
folicular, huevos en el oviducto, grasa corporal, color de la piel y patrons de actividad, en el
context de 6poca del afio, clima, sexo, y tamafio.
Los resultados sugieren que hay una gran diversidad entire las estrategias reproductivas
representadas por las once species estudiadas. Esta diversidad en patrons y ciclos
reproductivos es much mayor que la esperada sobre la base de reports publicados, principios
generals, o models te6ricos de biocenosis de lagartijas tropicales. Es evidence que adn estamos
lejos de comprender los factors que controlan el tamafio de nidada y los ciclos en lagartijas
tropicales. Las sefiales ambientales que desencadenan las fases estacionales reproductivas deben
ser numerosas, o tal vez las species simpatricas reaccionan de maneras totalmente diferentes a
sefiales similares. Se necesita adn much mas informaci6n sobre otras comunidades de lagartijas
tropicales para empezar a aclarar la complejidad de los factors a los que estos reptiles
responded y las respuestas fisiol6gicas causadas por estas sefiales. Encontramos casi todos los
tipos concebibles de estrategias anuales reproductivas. Algunas species ponen huevos y otras
son viviparas; algunas se reproducen continuamente a lo largo del ailo, mientras otras lo hacen
peri6dicamente. Estas dltimas muestran uno o dos picos reproductivos, que pueden ocurrir en
moments totalmente diferentes en el afio, a pesar de su amplia simpatria ecol6gica y geografica.
Adn dentro de microhabitats especificos, los patrons varian notablemente entire las species
residents. No hay evidencia de que exista un solo patr6n reproductive para el bosque tropical.
Sin embargo, hay una tendencia hacia una mayor incidencia reproductive colectiva durante e
inmediatamente despu6s del primer (Junio-Julio) y segundo (Septiembre a Diciembre)
monzones. En general, el punto mAs bajo de reproducci6n colectiva ocurre durante los meses
secos que preceden a cada period de monz6n.
No hay una correlaci6n significativa entire el nimero de huevos (crias)/nidada y habitat,
tamafo de la hembra, o tipo de reproducci6n. Sin embargo, hay dos estrategias bAsicas en
relaci6n con el n6mero de huevos (crias)/nidada. En un grupo, las species ponen nidadas
pequefias uniformemente; las species en el otro grupo ponen nidadas significativamente
mayores. Todas las species oviparas pertenecen al segundo grupo; las viviparas ocurren en
ambos grupos.
Varios de los scincidos estudiados muestran un cambio significativo en la coloraci6n tanto
de machos como de hembras. Estos cambios pueden estar correlacionados con el period
reproductive y se cree que son importantes en ese context. La frecuencia de estos cambios de
color en miembros de la familiar Scincidae es relativamente sorprendente en vista del hecho de


que se consider que estas lagartijas se orientan por el olfato, mis que por la vista. Este puede
ser un fen6meno particular de las comunidades de scincidos de Asia tropical, donde las species
simpAtricas son mis numerosas que en bosques templados, donde se han realizado la mayoria de
los studios sobre scincidos.


Introduction........................................ ...................................................... ... ......................... ...... 203
Acknowledgements......................................... 208
Methods..................................................... 208
R esults.............. .................................... .......... ................................................. 209
Female Reproductive Patterns............................................. 209
Male Reproductive Patterns. ..................... 215
Cyclic Type and Ecological or Behavioral Factors........................... ... .......... 220
Abdominal Fat Bodies.................................... ............. ........ .... 225
Seasonal Insect Abundance.................................................. ............. 229
Differential Seasonal Representation of Sexes................................. ..... .............. 232
Seasonal Color Changes........ .................. ........................................ ........ ........................... 235
Conclusions .............................................. .... 242
Literature Cited .......................... ..................................... ........ 246


The present publication is the second part of a study of tropical forest
scincids of Luzon Island, Philippines. The first (Auffenberg and Auffenberg
1988) dealt with feeding biology of sympatric species, whereas this one stresses
their reproductive strategies. In the current study, we examined aspects of the
reproductive biology of 11 geographically sympatric species in southern Luzon,
in which the major goal was to obtain empirical quantitative data on their
annual reproductive cycles. The most important question in this study was, "In
what ways do these skinks vary in responses to annually changing
environmental factors, even though these may be slight in this tropical area?".
Most studies published on scincid reproduction are of single species; only a few
compare sympatric forms, and none has explored broader patterns in areas
where they dominate the local lizard fauna. With the exception of those by
Alcala (1966), no studies have been published on Philippine scincid
reproductive biology.
Most of our knowledge of the reproductive patterns of lizards is based on
studies of temperate iguanids and lacertids. Much less is known of these
patterns in tropical lizards, and especially scincids. On the other hand, the


annual reproductive activity of temperate scincids is understood in at least
broad outline. All the temperate scincid species studied so far have restricted
breeding seasons, though of varying length (Kehl 1944; Mount 1963; Guillette
1983). The testes of males have been shown to fluctuate cyclicly in size and in
spermatogenic activity. Similarly, ovarian development is rhythmic, and all the
females generally oviposit during the same several months.
Few investigations have been conducted on the annual breeding activity of
tropical skinks (India, Mabuya macularis, McCann 1840; Africa, M. spilogaster,
M. occidentalis, and M. variegata. Huey and Pianka 1977. M. buettneri, M.
maculilabris, and Panapsis nimbaensis, Barbault 1974a, b; Mabuya striata and
M. quinquetaeniata, Simbotwe 1980; Australia, Wilhoft and Reitter 1965;
Philippines, Emoia atrocostata, Alcala and Brown 1967, the same species, plus
Lamprolepis smaragdina and Mabuya multifasciata, Alcala 1966; South Pacific,
Emoia wemeri and E. cyanura. Baker 1947; Surinam, M. mabouya, Hoogmood,
1973; and Brazil, Mabuya heathi, Vitt and Blackburn 1983). Of these studies,
the only ones that compare geographically sympatric species are those by Huey
and Pianka, Baker, Wilhoft and Reiter, Alcala, and Barbault. Most tropical
scincids studied live in savanna or thorn brush habitats. Only the studies of
Baker (1947), Alcala (1966), Inger and Greenberg (1966), and Barbault (1974a,
b) include tropical forest-dwelling species.
Fitch (1982) concluded that tropical reptiles possess a much wider variety
of reproductive strategies than would be found in temperate species. Vitt
(1986) reported nearly every known lizard reproductive strategy among
sympatric lizards in a tropical semi-arid environment in Brazil. Barbault
(1974a,b, 1983) believed there are two major reproductive patterns among
tropical lizards. Those living in seasonal tropical environments tend to
produce one, or at most only a few clutches during a limited part of the year,
and their reproductive effort is proportional to average snout vent length of the
females--a pattern typical of temperate lizards. The second tropical pattern he
recognized was said to occur only in seasonal environments. Here females
tend to produce many small clutches throughout the year, and the number of
eggs per clutch is not correlated with female snout vent length. Contrary to
Barbault's findings (based mainly on African lizards), our results show that
there is no single reproductive pattern among scincids living in wet tropical
evergreen forests, but a number of patterns. This is in agreement with the
conclusions of Fitch (1982) and Vitt (1986).
The present publication also addresses questions relating to the kind and
degrees of seasonal changes in coloration of adult scincid males and females in
a tropical forest setting. Normally scincids are believed to be largely scent-
oriented, and coloration as either an intra- or interspecific discriminatory
factor is not as generally associated with species in this family as with those of
agamids and iguanids. Both seasonally and sexually correlated color patterns
have been well demonstrated in many species of the last two families, as well as


the teiids and the lacertids. In general, they have received little attention from
ethologists and reproductive physiologists in the case of scincids. This is the
first time that seasonal color changes have been studied in a community of
tropical skinks.
To place the results in a proper comparison context, the general
characteristics of the species with which we worked that are believed to have
bearing on their reproductive strategies are summarized below. Unless
otherwise stated, the latest review of the taxonomy and distribution of the
skinks examined occurs in Brown and Alcala (1980).

Emoia atrocostata Lesson.-- A moderate-size species of the genus, with
no Luzon congenerics. Caramoan females are larger than males (P = 0.05, X
SVL females 88.2 2.1 mm, X Wt. 12.6 1.lg, N = 119; males 84.2 + 3.3
mm, X Wt 10.9g, N = 60). Mean hatchling size is 35 mm (N = 6). Though
widespread in the Philippines, E. atrocostata has a completely coastal
distribution and is found on rocky beaches, fish pond dikes, and rocky outcrops
in mangrove swamps.

Dasia grisia (Gray).-- A large member of the genus, with only one species
on Luzon. In Caramoan the sexes are not significantly different in either
length or weight (adult X SVL 105.0 1.5 mm, X Wt 24.3 4.1 g, N = 23).
No hatchlings were found. It is widespread in the Philippines and has
previously been reported from Luzon, though considered uncommon. Brown
and Alcala (1980) reported finding individuals on rotting tree stumps and
under loose bark in forests from 100 to 200 m. Our specimens were collected
from widely scattered localities in the study area from sea level to 250 m, but
always in relatively disturbed forest.

Lamprolepis smaragdina philippinica (Mertens).-- This is a relatively large
species of the genus, with no congenerics on Luzon. In the Caramoan area the
sexes are not significantly different in either length or weight (adult X SVL
92.0 + 1.8 mm, X Wt. 18.6 + 0.6 g, N = 151). The species is widespread in the
Philippines and has previously been reported from Luzon. Brown and Alcala
(1980) stated that it is almost completely arboreal, being found in gardens,
coconut and abaca plantations, and dipterocarp and mangrove forests. Near
Caramoan we found it in all generally open situations, particularly in secondary
growth and coconut plantations, from sea level to 350 m (higher elsewhere,
Brown and Alcala 1980). It is one of the most common of Caramoan lizards.

Lipinia pulchella pulchella Gray.-- This is a species of intermediate size
within the genus. Though one other species is said to occur on Luzon, we
found only this one at the study area. Here the sexes were not significantly
different in either length or weight (adult X SVL 38.1 + 0.8 mm, X Wt 0.6 g, N



= 106). Mean neonate SVL is 21.1 mm (N = 6). It has been reported from
most northern Philippine islands south to Leyte, including the Caramoan area.
We found it common on exposed tree trunks and large boulders--particularly
in primary forest. Brown and Alcala (1980) found it from 300 to 1000 m; we
extend this to sea level in the Caramoan area.

Mabuya multifasciata multifasciata (Kuhl).-- This is a large species of the
genus, with two congenerics on Luzon. There is no significant sexual
difference in either length or weight. However, in the Caramoan area this
species is somewhat smaller than reported elsewhere in the Philippine Islands
(adult X SVL in study area 90.5 2.0 mm, X Wt 22.6 2.2 g, N = 135). The
species is widespread over much of Southeast Asia and has previously been
reported from Luzon. Wherever it occurs, it is usually very common, being
found on the ground in open sunny places, especially field and forest borders,
and in secondary forests, and abaca and coconut plantations. It hides in heaps
of vegetation and under logs, but also in tree holes close to the ground and
under loose bark. It has been reported from sea level to 1200 m.

Mabuya multicarinata borealis Brown and Alcala.-- This is a medium-
sized species of the genus, with no significant sexual differences in either length
or weight in the Caramoan area (adult X SVL 71.0 2.5 mm, X Wt 11.5 0.8
g, N=160). Mean neonate SVL locally is 28.5 mm (N = 8). It is widely
distributed in the central and northern parts of the archipelago from sea level
to 1200 m. At Caramoan it is common in primary forest, but only in sunlit
openings and along trails, occasionally in secondary forest. In both habitats it
is found under leaves, rocks, rotting logs, or climbing about on stumps, tree
trunks close to the ground, or on large boulders. There are two congenerics on
Luzon, but only one other species locally.

Brachymeles samarensis Brown.-- A small species of the genus, with
adults in the Caramoan area having a mean SVL of 60.7 2.3 mm, and a
mean Wt of 1.9 0.6 g, N= 43. Neonates have a mean SVL of 28.0 mm (N =
3). Locally this species is found from sea level to 100 m, under leaves,
vegetation mats on logs and rocks, and in rotten logs in both primary and
secondary forests. It has been previously reported from southeastern Luzon.
Two other species are reported from the same island, but only one other in the
study area.

Brachymeles boulengeri boulengeri Taylor.-- A moderately large species of
the genus, with adult females significantly longer than males (P = < 0.05,
female X SVL 86.3 3.0 mm, X Wt 13.9 0.8 g, N = 97; male X SVL 77.0
3.0 mm, X Wt 11.0 1.0 g, N = 90). Locally it is usually found under rotting
logs, piles of vegetation (particularly leaves and humus) in open situations


(pastures, overgrown fields, secondary forests, and plantations of abaca and
coconut). Brown and Alcala (1980) reported it from 300 to 800 m, but we
found it to nearly sea level (18 m). Two conspecifics occur on Luzon, but only
one other locally.

Sphenomorphus jagori jagori (Peters).-- A large member of the genus,
with a significant difference (P = < 0.05) in length of adult males and females;
overall X SVL 76.0 6.1 mm, N = 162; adult females X SVL 75.0 5.1 mm,
X Wt 13.9 0.9 g, N = 41; males X SVL 81.1 4.1 mm, X Wt 15.8 + 0.8 g, N
= 121). Mean hatchling SVL = 29.4 mm (N = 5). It is widely distributed in
the archipelago and has previously been reported from Luzon. Locally it is
found in areas of primary forest with a rocky substrate; rarely in secondary
growth. It may be found under leaves or logs, but also clambers actively over
boulders. Brown and Alcala (1980) reported it as occurring from sea level to
1000 m.

Tropidophorms grayi Guenther.-- A relatively large member of the genus.
Local males and females are not significantly different (P = < 0.05) in either
SVL or Wt; adult X SVL 94.1 8.1 mm, X Wt 18.9 4.8 g, N = 121.
Neonates have a X SVL of 28.3 mm (N = 5). It is widely distributed in the
Philippines and has previously been reported from Luzon. Locally it is found
mainly in holes in banks and under boulders along small streams ( from where
we "fished" them with baited hooks). Taylor (1922) and Brown and Alcala
(1980) reported finding them under logs and rocks, where we also took them,
though less frequently. In the Caramoan area, they occur from 80 to 350 m.
No congeners are found on Luzon.

Otosaurus cumingii Gray.-- This is the largest species of skink in the
Philippine Islands. There is no significant difference (P = < 0.05) in length or
weight of males and females from the Caramoan study area, in spite of the fact
that the mean SVL for females (121.1 15.9 mm) is greater than that for
males (113.9 8.9 mm). Average Wt of adults is 41.1 g (N = 63). Two
hatchlings had SVL's of 34.1 and 31.0 mm. Widely distributed in the
Philippines, this species has previously been reported from Luzon. Locally it is
found on rocks at the base of large boulders and cliffs, sometimes along steep
banks of larger streams. Altitudinally it occurs from near sea level to 100 m
locally, but probably extends higher into the hills in appropriate habitats. No
other species of the genus is known from Luzon.
A discussion of the relevance of mean body size distributions in this skink
community is discussed in Auffenberg and Auffenberg (1988).



Thanks are extended to the Philippine government for allowing this study to be conducted
and to the citizens of the Caramoan Municipality for their cooperation during its tenure. Steve
Alba, Forest Development Office, Naga District, obtained much of the data on densities and
activity patterns of skinks. Sam Telford, Florida Museum of Natural History read an early draft
and corrected many of our errors, for which we are very thankful. Finally, it is impossible to
express our gratitude to Elinor and Garth Auffenberg. Without their massive assistance
throughout all phases of the study in the field, the analyses and ideas expressed in the following
pages would have been completely impossible. We extend to them both our deep appreciation
for the countless hours they spent in behalf of the project.


Of the 11 skink species studied, 9 are the better represented: Emoia atrocostata,
Lamprolepis smaragdina, Brachymeles boulengeri, Mabuya multifasciata, M. multicarinata,
Sphenomorphus jagori, Lipinia pulchella, Otosaurus cumingii, and Tropidophorus grayi. For these
species, 30 large individuals were collected each month for a period of one year (July 1982-August
1983) close to the field camp at, the village of Terogo, Caramoan Peninsula, Camarines Sur,
southern Luzon, Philippines (123 51' E, 13 55' N). Fewer individuals were obtained of Dasia
grisia and Brachymeles samarensis. Collection of most individuals was by hand or sling shot,
though T. grayi and 0. cumingii were often caught by "angling" for them with a baited hook
lowered into their burrows.
The study area (ca 15 km) is largely covered with limestone karst mountains, with
elevations ranging from sea level to 350 m. Most of the area is clothed with mixed dipterocarp
evergreen forest (Whitmore 1975), though secondary forest is extensive, particularly near sea
level. Agricultural lands include abaca and coconut plantations, as well as terraced rice lands.
Mangrove forest, nipa palm swamp, rocky beaches, and headlands occur along the coast. The
climatic year can be divided into four seasons. Though rain fall is relatively high all year (Fig. 1),
some seasons have less than others, and this forms the basis for the four annual climatic phases
recognized here: January through May has the least rainfall (= dry period I in the following
pages); during June and July the southwest monsoon sweeps over the area (= monsoon I);
August is an intermonsoon "dry" period (dry period II); September through December is the
time of highest rainfall and most severe storms (monsoon II). Total annual rainfall is 2858 mm.
Other details regarding the local vegetation, topography and climate are available in Auffenberg
(1988) and Auffenberg and Auffenberg (1988).
Individuals utilized in the study were collected on a monthly basis. These were
immediately killed by injecting a very small amount of alcohol into the brain. The specimens
were then measured (hereafter snout-vent length = SVL, total length = TL) to the closest mm
and weighed to the closest 0.1 g (= Wt hereafter). They were then preserved by fixing in 10%
formalin. Several days after preservation the following data were recorded: gonadal state (testes
diameter and weight); presence, number, diameter, state (yolked or not) of ovarian eggs; number,
diameter, state (shelled or not) and weight of oviductal eggs (SVL of embryos if ovoviviparous),
and any evidence of recent release of oviductal eggs were recorded; body fat was weighed to the
closest 0.1 g, and, finally, certain colors and patterns of possible significance in indicating
breeding readiness as well as sex and collection data were also recorded.
All similar data for each species per month were combined to obtain means and standard
errors/deviations. One-way ANOVAs were performed to determine significant changes
throughout the year (Sokal and Rohlf, 1981).
The total numbers of individuals of each species examined for reproductive state are: E.
atrocostata 318, L. smaragdina 358, B. samarensis 43, B. boulengeri 350, M. multifasciata 378, M.



o0 3 30
, 031

S/A 20
M 30 \ ca
1 10/ 0 c
E 1

29- 0
Figure 1. Annual temperature and precipitation cycles, Terogo, Caramoan, Luzon.

multicarinata 353, D. grisia 61, S. jagori 363, 0. cumingii 305, T. grayi 368, and L. pulchella 355.
Selected individuals were used for other analyses and these totals are indicated in the appropriate
Seasonal diurnal insect abundance was established by placing, once each week for the
entire year, four 10 X 15 cm sheets of a good quality flypaper at each of several stations near the
base camp. These were left for an entire day and collected in the late afternoon. The trapped
insects were then categorized by family and individuals in each category counted. Locations of
the seven stations overlapped part of the transect used for studying lizard densities and activity
patterns. All the microhabitats represented along the transect were included in the seven stations
used to determine insect abundance and density.
Throughout the text, figures, and tables standard symbols are used for the mean (X),
sample size (N), standard error of the mean (SE), standard deviation (SD), correlation
coefficient (R"), and Spearman rank correlation coefficient (R ). If not defined, standard
deviation is meant.


Female Reproductive Patterns

Female skink reproductive patterns in the Caramoan area are
presented below. Figure 2 shows the percent of the monthly total of females of
each species that possessed eggs/embryos in the oviducts.
Mabuya multifasciata.-- We measured 81 females (SVL 45.5-117.0 mm)
and examined their ovaries and oviducts. The smallest lizard with yolking
ovarian follicles was 72.7 mm SVL and the smallest with oviductal eggs was
101.0 mm; thus sexually mature females are > 72 mm. Follicles begin to
accumulate yolk at a diameter of about 3.0 mm (as determined by macroscopic
observation) and reach at least 7.0 mm before they are ovulated. The largest
ovarian follicle was 10.3 mm and the smallest oviductal egg was 7.0 mm. The

L. p.

l I- -

B. b.

. T.g.


S E. a.





M. f.

M. c.

S. j.

O. c.

D. g.


Figure 2. Seasonal variation (in %) of females taken each month with embryos/eggs in the oviducts. Abbreviations and numbers examined
(N) are: B. b., Brachymeles boulengeri (N=52); D. g., Dasia grisia (N=13); E. a., Emoia atrocostata (N=52); L. p., Lipinia pulchella (N=57);
L. s., Lamprolepis smaragdina (N=62); M. f., Mabuya multifasciata (N=81); M. c., Mabuya multicarinata (N=76); O. c., Otosauria cumingii
(N= 28); S. j., Sphenomorphusjagori (N= 76); T. g., Tropidophorus grayi (N = 73).


species is a live-bearer, producing from 1 to 8 young at a time (X = 4.2, SD
1.3), mode 4. (Alcala 1966 reported a range of 2-7 on Negros Island,
Females contain vitellogenic ovarian follicles all months except March,
May, July, September, and October. Oviductal eggs/embryos were found
during most months except November and December. These data suggest that
mature females may have several broods each year. The number of mature
females containing embryos per month comprised from 0 to 54.5 percent of the
total monthly samples; highest values (50.0-54.4) occur during dry season I
(March to May), and the lowest values during monsoon II (September through
December). Whereas some young are produced throughout most of the year,
the annual reproductive pattern is strongly modal (Fig. 2) in the sense that
there is a clearly defined annual reproductive peak, followed by a resting
phase. We found neonates only from early April through May, though some
may be found later in the year.

Mabuya multicarinata.-- We measured 76 females (SVL 41.8-80.5 mm)
and examined their ovaries and oviducts. The smallest lizard with oviductal
eggs was 56.0 mm SVL, and the smallest with vitellogenic ovarian follicles was
53.9 mm. Sexually mature individuals are estimated > 56 mm. The species is
oviparous, with the number of eggs per clutch varying from 1 to 3 (X = 2.0, SD
0.3), mode 2. It is likely that mature females lay several clutches annually.
Vitellogenesis begins when follicles are about 3.0 mm. Vitellogenic ovarian
follicles occur in all months except November through January. They are
ovulated at a diameter of 9 to 10 mm; one was found loose in the coelom that
measured 9.5 X 5.3 mm. Oviductal eggs (shelled or not) are found every
month except November and December. The smallest oviductal eggs are 10 X
6 mm, and the shell is formed at a size of about 11 X 8 mm, or when the egg
weighs about 0.7 g. They are laid when their length is 12.8 to 14.1 mm.
The percent of gravid females in the monthly samples varied from 0 to
36.3. The annual pattern (Fig. 2) is bimodal. A weak, flat pulse occurs during
dry period I (February through May), but a stronger pulse occurs at the end of
monsoon I (July) and through the following dry period II (August). No eggs
are laid in November and December, or during the heaviest rains of monsoon
Newly hatched young are found in September and October, and May and
June--the former during the early rains of monsoon II and the latter during dry
period I. Thus one batch of young is born during a rainy period and the other
during a dry one.

Sphenomorphus jagori.-- We measured 76 females (SVL 40.6-88.9 mm)
and examined their ovaries and oviducts. The smallest lizard containing
oviductal eggs was 70.2 mm SVL and the smallest having yolking ovarian


follicles was 71.8 mm SVL. We have therefore used the SVL of > 70.2 mm as
the approximate size of sexual maturity. Ovarian follicles begin to accumulate
yolk at about 2.5 mm diameter and reach a diameter of at least 9 mm before
being ovulated. The largest ovarian follicle measured 9.0 mm and the smallest
oviductal egg 12.8 mm. Eggs are laid when about 18 X 8.6 mm and have a wet
mass of 11.5 g. The new batch of ovarian follicles grow to about 8 to 9 mm
before the oviductal eggs are laid, suggesting that this species has multiple
annual clutches. Each clutch contains 1 to 4 eggs (X = 1.9 0.3), mode 2.
The annual reproductive pattern is similar to that of Mabuya
multicarinata in being mainly bimodal, although the peaks are more clearly
defined (Fig. 2). The annual resting periods are January through February,
and May through July. Except for October, gravid females are common
throughout the year. March and April represent a second, less important peak
period of gravid females before the resting phase during dry period I and
monsoon I. Gravid females represent from 0 to 40 percent of the total monthly
samples during the year (Fig. 2). Unlike the local Mabuya species, S. jagori
produces no abdominal fat bodies.
Hatchlings were collected from the middle of October to January, and
from the middle of May to near the end of June. Thus the early clutches
produce young during a dry season and the late clutches during a wet season.

Lipinia pulchella.-- We measured 57 females (SVL 21.3-43.2 mm) and
examined their ovaries and oviducts. The smallest lizard with oviductal eggs
was 35.2 mm SVL, and the smallest with yolking follicles was the same length.
Sexually mature individuals are estimated to be > 35 mm SVL.
The species is oviparous, with from 1 to 2 eggs per clutch (X = 1.8 0.4),
mode 2. Yolking follicles (> 2 mm diameter) are found every month. They
are ovulated at a diameter of about 7.5 mm. The smallest oviductal eggs are
7.2 mm. Oviductal eggs occur all months except April, June, and July. The
size of shelled oviductal eggs varies from 8.5 mm to 10.5 mm, with a mean wet
mass of 0.04. Laid eggs are about 10.5 mm long, with an overall range within a
single clutch of about 1 mm.
Gravid females constitute from 0 to 72.7 percent of the monthly mature
females collected (Fig. 2). The greatest number of gravid females occurs in
August and September (after monsoon I). A second, lower peak occurs in the
early part of dry period I (February, March). There is no fat accumulation in
the abdominal cavity at any time of the year. In the Caramoan area neonates
are seen from October through May.

Brachymeles boulengeri and B. samarensis.-- Based on an examination of
52 female B. boulengeri and 21 female B. samarensis, we conclude that these
species have nearly identical reproductive patterns (Fig. 2), and only the
former will be described in detail. Both produce living young, in B. boulengeri


from 1 to 5 (X = 3.1 0.9), mode 4, and in B. samarensis from 1 to 2. In B.
boulengeri yolking follicles are recorded for all months except May and June
and are ovulated at a diameter of about 8.5 mm. Embryos have absorbed
almost all their yolk when SVL is about 34 mm and therefore assumed to be
Percent of gravid females per month varied from 0 to 88.2 of the total
monthly female sample individuals collected (Fig. 2). The pattern is distinctly
bimodal, with the most important peak for gravid females occurring from
February through June (entire dry period I). The second peak occurs during
monsoon II. Thus young are produced during one dry and one wet period per
There is no fat accumulation in the abdominal cavity of either species
during any time of the year. Neonates are seen in all months except July
through September.

Tropidophorus grayi.-- We measured 73 females and examined their
ovaries and oviducts. The smallest lizard with oviductal eggs was 85.0 mm, and
the smallest with yolking ovarian follicles was 85.2 mm SVL. Sexually mature
individuals are estimated > 85 mm SVL. The species bears living young,
having from 1 to 8 (X = 3.8 1.1), mode 4. Vitellogenic ovarian follicles
occur during all months except September through November and are ovulated
at a diameter of about 11 mm. Embryos, believed to be near-term, have
absorbed most of their yolk when they attain an SVL of about 31 mm.
From 0 to 85.7 percent of the monthly total female sample are gravid
each month (Fig. 2). The annual female reproductive pattern is essentially
unimodal, with the high peak in May and June (end dry period I and beginning
of monsoon I, Fig. 2). A much lower pulse occurs in dry period I. The non-
reproductive period is long, about one half year, from August through January
. In this species young are produced chiefly during the dry periods, probably
because it lives along small mountain streams that become torrents during the
wet periods. Neonates are seen from March through June. Abdominal fat is
not accumulated at any time.

Otosaurus cumingii.-- We measured 28 mature females (SVL 91.1-142.0
mm) and examined their ovaries and oviducts. The species is oviparous, laying
from 2 to 3 eggs per clutch (X = 2.1 + 0.3), mode 2. SVL at sexual maturity is
> 110 mm. Yolking follicles are about 3.0 mm in diameter and occur January
through May, and in October. Ovarian follicles are 11 to 14 mm when
ovulated. The largest is 14.1 mm and the smallest oviductal egg 11.9 mm.
Oviductal eggs are completely shelled at about 21 mm diameter. Eggs are laid
when longer than 29.5 mm.
The percent of gravid females per month varies from 0 to 41.7 (Fig. 2).
The annual female reproductive pattern appears to be weakly bimodal. Most



females are gravid during dry period I (February and particularly March). A
second, low peak of gravidity occurs during October (early monsoon II).
There is a long resting period for almost all females from April (June ?)
through September and a short one during November and December. Thus,
most production of young occurs during the cool, dry season. Neonates are
seen during April and May. There are no abdominal fat bodies.

Dasia grisia.-- Only 13 females were available for measurement and
examinations of ovaries and oviducts. The species is an egg layer, with clutch
size varying from 2 to 5 (X = 3.3 1.5, mode 3).
Relatively few gravid females (8) were found, almost all in February
through April (Fig. 2). Although many more data are needed for confirmation,
we believe that breeding in this species is seasonal, probably with a short
reproductive peak during the cool, dry period. There is apparently a very long
resting phase of at least 8 months for most females. The species clearly needs
additional study.
Young of the year were seen only in May. Fat accumulation is not well
documented, but seems erratic, occurring throughout the year except during
April and May, when it is depleted to a certain extent. This suggests that the
fat cycle may be related to the reproductive cycle (see below), but this requires
additional study.

Emoia atrocostata.-- We measured 52 mature females and examined their
ovaries and oviducts. The reproductive cycle of this species in the Philippines
has been studied by Alcala (1966) on Negros Island, and the Caramoan pattern
is very similar.
The species is oviparous, with clutches varying from 1 to 3 at Caramoan
(X = 2.0 + 0.4), mode 2. The smallest female with vitellogenic ovarian
follicles is 71.3 mm SVL, suggesting that females are sexually mature at SVL >
71 mm. Gravid females are found in almost every month of the year (Fig. 2),
with the percent gravid of the total varying from 0 in December and February
to 50.0 in November. The annual cycle is possibly weakly modal; the highest
peak occurs in November. It is clearly an almost continuous breeder in the
Caramoan area.
Yolking follicles are found every month except November. They are
ovulated at about 10.2 mm diameter. The smallest shelled eggs in the oviduct
are 13 mm and have a mass of 0.8 g. Neonates are seen from April through
November, or two thirds of the year.
Most abdominal fat is accumulated after the low-peaked spring breeding
season, with the highest values in May and June (Table 2). The least fat occurs
in December, following the peak reproductive period in November. Thus,
abdominal fat is lowest following one peak and highest just below another.


Lamprolepis smaragdina.-- The reproductive cycle of this species also was
studied by Alcala (1966) on Negros Island. Its cycle in Caramoan is similar.
We measured 52 mature females and examined their ovaries and oviducts
during the present study. The smallest lizard with yolking follicles was 83.0
mm, and the smallest with oviductal eggs was 82.5 mm SVL. One to two eggs
are laid in a single clutch (X = 1.9 + 0.3), mode 2. Yolking follicles were
found every month and are ovulated at a diameter of about 12.7 mm (N = 2 ).
Oviductal eggs are completely shelled at a length of about 16.2 mm and are
laid when about 22.7 X 10.5 mm.
Gravid females are found every month of the year, representing from 2.2
to 77.8 percent of the total monthly female samples (Fig. 2). The annual
pattern represents a case of relatively high, sustained monthly production, with
a low, broad reproductive peak lasting from January to July Abdominal fat
bodies are present, with accumulation highest during the peak reproductive
period and lowest during the lowest reproductive period (Table 2).
During this study, neonates were seen in September and October, but
most occurred over a longer time period on the basis of oviductal data. Alcala
(1966) reported young in every month.

Male Reproductive Cycles

Generalities.-- In males of the species studied the right testis is almost
always located anterior to the left (in Mabuya multicarinata the testis of both
sides may be in the same position, or the left may be slightly anterior). In
almost all species, the right testis has a greater diameter than the left, though
this is not true in all Mabuya multifasciata examined. Species mean testis size
is not significantly correlated with species mean SVL (R2 = 0.14). Though
Otosaurus cumingii is the largest of all the local skink species, its mean testis
diameter is the second smallest--only the diminutive Lipinia pulchella has
smaller ones. To a certain extent, testis shape varies seasonally in all species
except Lipinia pulchella. In most they are distinctly ovoid, but more spherical
in Sphenomorphus jagori and often decidedly spindle-shaped in both Dasia
grisia and 0. cumingii. The testes in Lipinia pulchella are a deep black color.
Melanin-covered testes have been reported in other reptiles. Those of the
remaining species are white to yellow, sometimes tan in Dasia grisia.
Examination of sectioned testes shows that those that are white in color are
usually inactive, and those yellow, orange, or tan are involved in
spermatogenesis, when they also become turgid with a greater volume. Figures
3 and 4 show the close approximation of testis size and mature and/or
maturing sperm (stages II, III, and/or IV) in M. multifasciata and S. jagori.
Similar data are available for the other species studied, and the relationship





Figure 3. Above, mean monthly percent of sectioned testes of Mabuya multifasciata with
mature/maturing sperm (stages II-IV, dotted line), compared with testes diameter histogramm).
Below, solid line, diagrammatic, see Figure 6.


Figure 4. Above, mean monthly percent of sectioned testes of Sphenomorphus jagori with
mature/maturing sperm (stages II-IV, dotted line), compared with testes diameter histogramm).
Below, solid lines, diagrammatic, see Figure 6.



__ _


has been repeatedly demonstrated in other reptiles (Fitch 1970). We thus feel
justified in using testis diameter as an indication of sperm production, and in
assuming that these diameters are indicative of the annual breeding cycles of
male skinks in the Caramoan area.

Seasonal Cycles.-- In most temperate lizards, seasonal testicular growth
exhibits relatively short-lived, spring-peaked patterns (e. g. Sceloporus
fonnosus, Guillette and Sullivan 1985; see Fitch 1970 for review). In the
tropics, reproductive patterns are much more varied, and many variations of
continuous and discontinuous reproductive activity occur (Fitch 1982). Study
of the seasonal variation in testis diameter in Caramoan skinks shows that
interspecific patterns are highly variable, even within a small area of tropical
Table 1 provides data on seasonal changes in testes diameter for those
Caramoan species for which sufficient material is available for analyses.
Figures 5 and 6 illustrate seasonal changes for each species. From these data
we conclude that none of the reproductive cycles of any Caramoan skink
species are as sharply pulsed as those of most temperate male lizards that have
been studied. Rather, the pulses representing periods of maximum testicular
activity are less clearly defined, and often occur at different times of the year in
different local species.
Males of some Caramoan species exhibit significant variability in testes
size throughout the year, whereas others show less seasonal size variation. The
former is represented by Mabuya multicarinata, Lipinia pulchella, Lamprolepis
smaragdina, Tropidophorus grayi, and Otosaurus cumingii. Coefficients of
variation (CV = SD/X, facilitating comparisons of variability about different-
sized means) in this group range from 13.8 (0. cumingii) to 22.9 (T. grayi).
Those species with the least seasonal variation in testis size are Mabuya
multifasciata, Brachymeles boulengeri, and Sphenomorphus jagori (CV ranges
from 5.7 in B. boulengeri to 9.3 in M. multifasciata). Lipinia pulchella is
intermediate (CV = 11.8). The degree of annual variation in testis size is a
continuum, with no clear separation into groups.
We do not mean to imply that males exhibiting less seasonal variability
are equally sexually active during all months of the year. That this is not the
case is clearly shown in Figure 5, in which plots of mean monthly deviation on
mean annual testis size demonstrate a weak seasonal pattern of mean testis
size in even those species showing least annual size variation. The figure shows
even more clearly the great differences in annual testicular cycles among
Caramoan skink species. In the case of B. boulengeri, sperm maturation takes
place in most males during January, though at least some testes are still active
until June. In July, a majority of individuals experience testicular collapse.
Recrudescence occurs quickly during January. Thus only one period of
spermatogenesis, almost five months, is suggested for this species. The pattern

Table 1. Seasonal variation in testis diameter (X/mo, in mm) in Caramoan skinks. SE = standard error.

CV Jan. Feb. Mar. Apr. May Jun. Jul. Aug. Sep. Oct. Nov Dec.

Mfs 9.3 4.2 4.0 4.7 3.4 4.2 4.6 4.9 4.8 4.5 4.6 4.0 4.4
(SE) 0.2 0.1 0.5 0.1 0.2 0.1 0.1 0.1 0.2 0.2 0.2 0.2
Mme 15.4 4.0 3.8 4.7 4.4 4.6 4.4 4.4 4.5 3.5 2.7 3.2 3.3
(SE) 0.2 0.1 0.2 0.1 0.1 0.1 0.2 0.3 0.5 0.2 0.1 1.1
Ea 7.1 4.6 4.3 4.2 4.4 4.0 3.7 3.7 4.4 4.4 4.4 4.1 4.4
(SE) 0.2 0.2 0.1 0.1 0.1 0.1 0.1 0.2 0.1 0.3 0.3 0.3
Lp 13.3 1.5 1.3 1.3 1.0 1.3 1.7 1.3 1.5 1.7 1.7 1.5 1.8
(SE) 0.1 0.1 0.1 0.1 0.5 0.1 0.1 0.1 0.1 0.1 0.1 0.1
Bb 5.7 3.9 3.6 3.7 3.7 3.6 3.5 3.2 3.2 3.2 3.3 3.4 3.3
(SE) 0.2 0.2 0.1 0.1 0.1 0.2 0.2 0.2 0.1 0.1 0.1 0.2
Ls 15.1 3.0 3.2 3.2 4.5 2.8 2.8 3.5 4.0 3.3 3.5 2.6 3.0
(SE) 0.1 0.1 0.1 0.6 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1
Tg 22.9 3.5 4.1 3.8 3.0 2.1 2.3 2.8 3.7 3.8 3.9 4.1 4.6
(SE) 0.3 0.1 0.2 0.1 0.1 0.1 0.3 0.3 0.2 0.3 0.1 0.2
Oc 13.8 2.7 3.3 3.0 2.7 3.0 3.1 3.1 2.2 2.4 3.5 3.8 2.8
(SE) 0.2 0.1 0.2 0.4 0.2 0.2 0.1 0.2 0.3 0.2 0.1 0.2
Sj 8.9 4.3 3.8 4.6 4.9 4.2 4.2 4.7 5.1 4.6 5.0 4.5 4.2
(SE) 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.3 0.2 0.2 0.1 0.1


B. b.

S. j.

M. f.

L. p.

O. c.

M. c.

L. s.

T. g.


Figure 5. Deviation in mean monthly testes diameter (in mm) from mean annual diameter (in
mm) in male Caramoan skinks, arranged in increasing levels of seasonal variation.


for Sphenomorphus jagori is clearly quite different, for there appear to be two
major periods of quiescence and two of spermatogenic activity. Mature sperm
are apparently available throughout much of the year, though the major
periods are the end of dry period I and early monsoon II. Testicular
quiescence occurs during the early part of dry season I and monsoon I. The
pattern in Emoia atrocostata is similar, as is that of Mabuya multifasciata.
Lipinia pulchella apparently produces sperm for most of the second half of the
year, with testicular quiescence occurring from February through May. In
Otosaunms cumingii the major quiescence and activity periods are more sharply
pulsed and both occur late in the year. Some males probably produce sperm in
February as well. Mabuya multicarinata has a much longer, but more distinct,
sperm maturation cycle, with the long active phase occurring from March
through August, followed by four months of rest. The pattern in this species is
most like that known to occur in most temperate species (see Fitch 1970). The
maturation cycle of Lamprolepis smaragdina is sharply pulsed in what appears
to be two decreasingly active periods, starting in April and separated by two
resting phases. Tropidophonms grayi possesses a testicular maturation pattern
similar to that of M. multicarinata in having both long and distinct active and
resting periods, though each is during opposite times of the year, as those of M.
Figure 6 summarizes and diagrams the main features of these
spermatogenic patterns in Caramoan skinks for comparison with the local
rainfall pattern. The variety in sperm maturation cycles is evident, as well as
the fact that peak and lowest phases occur under all possible weather
conditions. However, whereas peak activity periods are scattered through most
of the year, only in December are the spermatogenic activity peaks of any two
local species coincident. No peaks occur in May-June (late dry I period and
early monsoon I period), or September-October (early monsoon II). All other
months have one peak each. Thus, spermatogenesis among the resident
species is rather remarkably spread evenly through most of the year. We
conclude that each species is responding to different environmental cues, or
responding differently to some of the same cues. There is no single, or even
dominant pattern of sperm maturation for the skink species in this tropical
evergreen forest.

Cycle Type and Ecological or Behavioral Factors

Annual reproductive patterns in tropical lizards are categorized as either
continuous or exclusively periodic. Continuous breeders may be
intraspecifically asynchronous as an seasonal sustained reproductive species
pattern, or continuous breeding may exhibit some form of seasonal pulsation in


B. b.

E. a. .

S. j.


1 DRY 2
L. p.


Figure 6. Diagrammatic representation of those periods of the year (black) when male testes size
is distinctly enlarged (i.e. spermatogenesis proceeding). Abbreviations as in Figure 2. The two
major periods of rainfall are shown as crosshatching.
major periods of rainfall are shown as crosshatching.


the reproductive pattern. Periodic breeders have periods of reproductive
activity interspersed with reproductive resting periods. Peak production of
young in this case is often related to precipitation patterns (Fitch 1982). In the
Caramoan area the reproductive year is further divisible into first and second
wet seasons (monsoons I and II). All permutations of these factors are
represented in the Caramoan skink biocoenosis.
Of the skinks in the Caramoan area, 64 percent produce young
"continuously" through the year (eight months or more). These include L.
smaragdina, L. pulchella, M. multifasciata, and E. atrocostata (Fig. 2). Of
these, only L. smaragdina is known to produce eggs/embryos every month. E.
atrocostata, both species of Brachymeles and M. multifasciata may do so. S.
jagori, 0. cumingii, T. grayi,, and D. grisia are discontinuous "periodic"
Of the presumed "continuous" breeders, two species are semi-arboreal,
two are terrestrial, and two are semifossorial. Each species represents a
different microhabitat, though most live in rather open situations. With the
exception of L. smaragdina, the annual patterns of all of them are distinctly
modal, in spite of nearly continuous reproduction. E. atrocostata, L. pulchella,
B. boulengeri, and M. multicarinata are all weakly bimodal. Typically in these
species a high percentage of the females are gravid during many months of the
year. Three species are viviparous. Viviparity also occurs in the discontinuous
breeding T. grayi. The peak reproductive period for E. atrocostata is January
through March; for M. multicarinata it is March through June; for L.
smaragdina it is May through July, and for L. pulchella it is August and
September. Thus the peak reproductive period of each species in the
"continuous" breeder category falls at a different time of year. All but L.
pulchella accumulate fat seasonally, though there is no consistent pattern in the
season of fat accumulation in respect to the reproductive peaks.
Figure 7 diagrams the second major reproductive pattern in female
Caramoan skinks. When the peak period for percent of gravid females is
considered for each species we see that none falls during January to February
(early dry period I), October, or December (both monsoon II). Most species
have the highest proportion of gravid females in March (late dry period I). By
the time the eggs are laid and then hatched, the young would be active during
the early part of monsoon I (when food resources are high, see below). Two of
the three species with peak periods of gravidity in May (T. grayi and M.
multifasciata) are viviparous, so that the young would be born during the same
early part of monsoon I. The remaining species (E. atrocostata) lives in the
equitable marine littoral, and the May peak is barely discernible from several
others during the year. Several species (both Brachymeles species, S. jagori, L.
pulchella, and M. multicarinata) have one peak falling during a dry period and
the second during a wet period. Reproductive quiescent periods for females


B. b.

E. a.

S. j.

M. f.

L. p.


M. c.

L. s.

T. g.

D. g.

Figure 7. Generalized diagram of proportion of gravid females per month in major Caramoan
species studied. The two major rainfall periods are shown as crosshatching.

I # r ,

1 DRY 2

r r d .

I r , I
I d / I /


1 DY


are most common in November and December (late monsoon II) when rainfall
is particularly heavy. No species is completely inactive in March.
The above descriptions of breeding cycles for these skinks demonstrates
that almost every conceivable annual pattern occurs among them. Some are
egg-layers and others live-bearers; some breed continuously throughout the
year, others are periodic. Those that are periodic have either one or two
reproductive peaks, and these may fall at entirely different times of the year,
despite their geographic and often ecological sympatry. Patterns even vary
among the resident species of the same microhabitats. We conclude that these
species must depend on either different cues for their reproductive cycling or
use the same cues (such as the first or second rainy season) in different ways to
initiate or stop breeding activity. Mendez de la Cruz et al. (1988) have
suggested that a multiplicity of cues probably determine the reproductive cycles
of not only different species of Neotropical iguanids, but of the different sexes
as well. We find no evidence for "tropical forest" or "tropical woodland"
reproductive patterns among the skinks we studied (savannas do not occur
naturally in the Philippine Islands). However, there is a tendency for
maximum reproduction to occur during and immediately after the first
monsoon, as well as after the second monsoon, regardless of type of annual
reproductive cycle. Even among some of the continuous breeders, there is an
increase in percent of gravid females during these seasons. Reproduction
often reaches annual lows during the dry months preceding the first monsoon
and particularly during the wettest parts of the second monsoon.

Fecundity.-- About half of the local skink species have small clutches of 1
to 3 (means range from 1.8 to 2.1), usually 2 eggs. Within these species, clutch
size is consistent (standard deviations range from 0.1 to 0.4) and all are
oviparous. None of these species has been proven to have multiple annual egg
clutches/litters, though this is highly likely. The species comprising the small
clutch group are 0. cumingii, M. multicarinata,E. atrocostata, L. pulchella, and
L. smaragdina.
The remaining five species (1) have more eggs per clutch (ranges in mean
clutch size vary from 2.1 to 4.0), and (2) exhibit less consistency in clutch
number (1-8; standard deviations range from 1.3 to 1.9). Of this group, two
species are oviparous (S. jagori and D. grisia). The remaining three species are
all viviparous (T. grayi, M. multifasciata, and B. boulengeri). The live-bearing
species occur in a variety of habitats semiaquaticc, T. grayi; fossorial, B.
boulengeri; and terrestrial, M. multifasciata). None is arboreal.
There is no significant correlation between number of eggs/clutch and
microhabitat. Those species with the largest clutches live in a variety of
microhabitats semiaquaticc T. grayi, terrestrial M. multifasciata, and arboreal
D. grisia). Regression of number of eggs (or young)/ clutch against mean SVL
of females shows a poor correlation (R = 0.13). Vitt and Cooper (1986) also


found no significant correlation between female SVL and clutch size in a
species of skink, though Guillette (1983) did for the viviparous Eumeces copei.
The common association between clutch size and SVL found in lizards
(iguanids, lacertids, agamids) may be less frequent in scincids than generally
In summary, we find no significant pattern between number of eggs
(young)/clutch and habitat, female size, or reproductive mode. There are,
however, apparently two strategies in number of young(eggs)/clutch in which
one group of species lays consistently small clutches and the other group lays
larger clutches. Except that all local viviparous species belong to the last group
(through there are some egg-layers in it as well), no general principals) can
be deduced from the distribution.

Abdominal Fat Bodies

Female Abdominal Fat Cycle.-- The annual cycle in fat bodies of female
Caramoan skinks exhibits considerable interspecific variability (Table 2).
Some of this variation can be explained; some cannot.
Of the 11 species studied, 6 (55%) possess no appreciable amount of
abdominal fat at any time of the year. These are S. jagori, 0. cumingii, L.
pulchella, B. boulengeri, B. samarensis, and T. grayi. These include taxa found
in semiaquatic, terrestrial forest, terrestrial arboreal, and fossorial
microhabitats. Comparison of these microhabitats with insect seasonal
abundances in each (see below) suggests that these habitats do not have high
food resources throughout the year. In fact, some of these microhabitats (such
as forest trees and rocky forest substrates) have rather low food resources
compared to other microhabitats in the immediate area in which other species
of skinks live. Additionally, the list includes species representing a wide range
of annual reproductive patterns (see below), so that the lack of abdominal fat
cannot be related to a specific breeding pattern.
The remaining species produce a seasonally variable amount of
abdominal fat. In M. multifasciata the most abdominal fat is usually present
from about August through January. Though females are gravid throughout
most of the year, the peak reproductive period is from about March through
May. Thus, abdominal fat depletion more or less coincides with the period of
vitellogenesis. M. multicarinata has approximately the same fat accumulation
and depletion pattern, followed by a period of high proportion of gravid
females. Abdominal fat accumulation may be an important factor in the
reproductive cycle of this species as well. The relationship of fat loss and
reproductive cycle is not as clear in E. atrocostata and L. smaragdina, for they

Table 2. Seasonal variation in abdominal fat (in g) of Caramoan skink species by sex. Species missing do not produce any abdominal
fat. t= trace only.

Species a

Sex Jan. Feb. Mar. Apr. May Jun. Jul. Aug. Sep. Oct. Nov. Dec.

E. arrocostata F 0 2 0.1 0.2 t t t 0 0.4 0.2 0.5 0.3 0.3
M 0.4 t 0.1 0 t t 0 0.4 t 0.5 0.3 0.6
M. mnlticarinata F 0.5 0.5 0.4 0.1 t t .3 t 0.5 0.2 1.2 0.7
M 0.2 0.3 0.1 0.1 t 0 0 0.2 0.6 0.3 0.9 0.4
M. multifasciata F 0.7 0.5 0.8 0.3 0.2 t t 0.8 0 1.0 0.9 0.7
M 0.1 0.3 0.3 0. t 0 .2 0.6 0.6 0.5 0.6 0.5
L. smaragdina F 0.2 0.3 0.2 t 0.1 t 0 0.2 0.1 0.3 0.3 0.3
M 0.4 0.2 0.1 0.1 0.5 0.2 0.3 0.2 0.4 1.0 0.4 0.8
D. grisia F 1.5 0.5 t 0.2 0.4 0.9 2.5 1.0 0.3 0.9 2.5 1.6
M 0.9 0.1 t 0.2 0.3 0.1 t 0.9 t 0.5 1.6 1.6

a Only those species with abdominal fat bodies.


both tend to produce eggs over much of the year, and fat is mainly
accumulated during the second monsoon (September through December).
Thus, while the abdominal fat accumulation and degradation cycle of
some local skink species can be correlated with vitellogenesis, others produce
no major abdominal fat bodies at all, yet are obviously able to produce clutches
or young without it. In some other lizards Hahn and Tinkle (1965) have shown
that as long as the female has an adequate diet, abdominal fat bodies are not
needed for vitellogenesis. Some of those Caramoan skink species that do
accumulate abdominal fat bodies tend to produce the greatest quantity of fat
during the second monsoon (October through December, see Table 2), and
utilize it at about the time when vitellogenesis takes place. However, the best
correlation for all species seems to be with annual fluctuation in insect
abundance (see Fig. 8). The accumulation cycle of abdominal fat always begins
during monsoon I (a period of high insect abundance). The rate is increased
over the ensuing months, and the process is generally completed by the
beginning of the heaviest rains (November and December) of monsoon II
(when insect food resources become low). Fat reserves are then steadily
depleted through dry season I, reaching their lowest levels during the end of
that season and the beginning of monsoon I. Thus, the fat accumulated during
monsoon I and the period following it (about four months) is used during the
remaining seven to eight months. Some may be used for reproductive
activities, but its increased rate of use is also correlated with generally low food
resources at the same time.

Male Abdominal Fat Cycle.-- The species that lack abdominal fat in
females also lack it in males. Of those species in which the males do contain
abdominal fat, it is also seasonally variable, as in conspecific females.
In general, the seasonal pattern of males is similar to that of females, i.e.
the fat is accumulated from monsoon I through monsoon II. In L. smaragdina
males the season of high fat resource is longer than in either sex of any other
species studied; it begins in September, with the peak occurring in October.
This is also the only local species in which the males contain a significantly
greater mass of abdominal fat than females (t = 24.3, df = 20, P < 0.001). In
the remaining species females have higher amounts of mean monthly fat, but
the differences in means are not statistically significant in any sex-related
The variation of abdominal fat weight in males and females in the
monthly samples of each species shows significant values that can be related to
seasonal food supply. Coefficients of variation (CV) for abdominal fat weight
were calculated for the male and female data for each species for each month.
Such coefficients negate the size differences among the species and allow direct
comparison of the percentage values. There is no significant difference
between the annual mean CV values of the males and females of M.


multicarinata and E. atrocostata, whereas the males of M. multifasciata and L.
smaragdina have a significantly lower variation in abdominal fat weight
throughout the year than females of the same species. The reasons for this are
not clear.
The seasonal pattern in abdominal fat weight indicates that the greatest
variation occurs during the end of dry season I and the very earliest part of
monsoon I. This has been shown above to be the period when abdominal fat
reserves are usually the lowest of the entire year in all species that have such
reserves. The fact that variation is greatest during this period may be due to
reproductive dynamics. On the other hand, in all species studied, the time of
year when fat reserves show the least variation in both males and females of all
species is during the heavy rains of monsoon II and the beginning of the period
immediately following dry season I. This is the time when food resources
begin to drop significantly after a period of previous high food levels. The fact
that all individuals of both sexes in all species with abdominal fat accumulate it
in more equal amounts at the same time suggests that fat deposition during
monsoon I is an important strategy for all these species. This similar seasonal
pattern occurs in spite of the fact that among these species fat accumulation
and utilization cannot be directly related to the reproductive pattern in the
same way (see below and Fig. 8).
Most authorities believe abdominal fat is critical for vitellogenesis.
This view is based mainly on the work of Hahn and Tinkle (1965), who
demonstrated that abdominal fat body lipid is mobilized for vitellogenesis in
Uta stansburiana (Iguanidae), though it is not essential. Some Philippine
scincid species are here shown to lack abdominal fat at any time of the year.
One then wonders about the source of lipids for vitellogenesis in these species.
For these Philippine skinks it seems likely that this lipid is derived from some
other as yet unidentified fat storage area(s)--perhaps the tail, in which fat is
known to vary seasonally in several lizard families, including Scincidae or the
body wall, as has been demonstrated in an American skink species (Vitt and
Cooper 1985). These data suggest that the dependence of vitellogenesis on
abdominal fat bodies as demonstrated for many temperate Iguanidae,
Lacertidae, and Agamidae is less clear for other lizard families, such as
Scincidae (this study, Vitt and Cooper 1985) and Varanidae (Auffenberg 1988).
That stored lipids are required for vitellogenesis seems definite. The question
raised here is whether the abdominal fat bodies of at least tropical scincids are
the source of these lipids. Our results suggest that they are probably not--at
least not in all Luzon species. Vitt and Cooper (1985) provide a clue to a
potentially important source of lipid for vitellogenesis in their study of lipid
cycling in the skink Eumeces laticeps. They show that fat in the tail alone
comprises nearly one half of the standing lipids in individuals of this scincid
species. It seems that the matter of lipid sources for vitellogenesis in tropical


lizards requires additional study before we can generalize about lizard
reproduction and lipid cycling.

Seasonal Insect Abundance

Diurnal insect abundance varies seasonally (Fig. 8). In general, diurnal
insects are least common from November through April, and much more
common from May through July (with a dip in June). This pattern agrees
fairly well with the rainfall pattern of the same area. Other studies of seasonal
abundance in tropical forests demonstrate similar high peaks during early parts
of the rainy season (Robinson and Robinson 1970, Fogden 1972, Janzen 1973,
Smythe 1974). In the Caramoan area, both the driest and wettest parts of the
year have the least insects. The greatest number is found in May, just before
monsoon I. From dry season II (August) through monsoon II insects become
steadily less common. There is no correlation between insect abundance and
seasonal temperature (Fig. 8).
Eight different microhabitats were regularly sampled for the seasonal
abundance of diurnal insects (total insects trapped 4212, Table 3). These
microhabitats are the trunks of trees in the forest and the more dispersed ones
in the open, an overgrown field seasonally used for crops, a rocky exposure in
the same field, the edge of the field adjacent to the forest, leaf litter in the
primary forest, a rocky substrate in the same forest, and a series of rock
crevices on the surface of the same forest.
Of these microhabitats insects were most abundant at the ecotone of field
and forest--the major habitat of M. multifasciata. Insects were also common in
the overgrown field and rock outcrops in them (also microhabitats of the same
species), though less common there (perhaps because of seasonal disturbance
related to agriculture) and in the forest leaf litter. The latter is the major
microhabitat (with the forest-field ecotone) of M. multicarinata. Isolated trees
in open situations have few insects when compared to the above microhabitats,
but are the major microhabitats of L. smaragdina. Forest trees also have fewer
insects than terrestrial habitats, but more than those trees inhabited by L.
smaragdina. These forest trees are inhabited by two species of semi-arboreal
skinks--D. grisia and L. pulchella. The rocky forest substrate is the primary
microhabitat of S. jagori and contains relatively few insects. Those skinks living
in microhabitats with lower insect abundance tend to feed on a greater
proportion of small fruits (see Auffenberg and Auffenberg 1988 for details).
On the basis of seasonal differences in insect abundance in different
microhabitats, the only microhabitat without seasonal insect shortages is field
edge--the major habitat of M. multifasciata. The microhabitat of M.
multicarinata (mainly leaf litter in shaded forest) also has abundant insect food

0 20

'- uO


Figure 8. Insect abundance compared with annual rainfall pattern and fat abundance curves for each species.


Table 3. Seasonal insect abundance in local skink microhabitats.

Field Forest

Open Edge Rocks Trees Crevices Rocks Litter Trees

Jan. 12.3 20.9 24.1 4.8 10.2 7.3 13.1 7.3
Feb. 8.9 22.1 12.6 5.3 9.6 8.2 25.1 8.2
Mar. 8.3 15.7 31.4 7.4 5.0 4.1 24.0 4.1
Apr. 13.6 48.3 4.0 1.7 5.1 9.1 9.1 9.1
May 31.6 32.1 5.8 2.7 2.3 5.1 15.3 5.1
Jun. 16.6 28.9 12.4 6.5 4.5 6.3 18.5 6.3
Jul. 14.0 14.2 19.7 6.2 3.0 13.8 15.3 13.8
Aug. 16.1 23.4 12.4 6.5 4.5 10.1 16.9 10.1
Sep. 26.8 21.3 12.4 6.5 4.5 6.3 16.0 6.2
Oct. 18.3 21.8 13.4 9.5 5.6 5.6 20.2 5.6
Nov. 19.0 18.0 30.8 3.7 6.0 6.1 10.3 6.1

Means 17.7 24.7 15.3 5.4 6.0 8.9 16.9 8.9
SD 7.6 7.3 9.7 3.3 2.8 2.7 5.1 4.9


throughout most of the year. The same is true of the microhabitats of the
semiarboreal L. pulchella and D. grisia. While insect food is generally low
throughout the year for L. smaragdina, the most stressful time seems to be
during dry season I.
We conclude that, in general, while some microhabitats support more
insect prey than others, the lowest insect abundance in most of them occurs
during dry season I, and it is probably this time of the year that is most
important from the standpoint of food availability. Comparison of Table 3 and
Figure 14 shows that there is no strong correlation between the time when
young are injected into the microhabitat and seasonal variation in insect
abundance; except that neonates of none of the scincid species but L. pulchella
hatch during periods of lowest local insect abundances.

Differential Seasonal Representation of Sexes

Among skinks, adult females are often disproportionately represented in
collections made at different seasons of the year, due largely to factors
associated with reproduction (egg brooding, differences in feeding habits, etc.).
Males may be poorly represented in some species because they may be
spending much time "guarding" females during the reproductive period (Vitt
and Cooper 1985). Some Caramoan skinks show very significant shifts in
number of females during some months, and these can be shown to be related
to reproduction.
Figure 9 demonstrates that female T. grayi are more common than males
for most months. The high proportion of females in June and July is actually
due to the fact that fewer males were taken, rather than more females. The
two months of fewest females (February and September) are associated with
breeding periods ( Fig. 7).
Mabuya multifasciata is represented by fewer females than males during
much of the year (Fig. 9). Two periods of high male representation are noted--
one in April (following the March breeding peak), and the other in October,
when (on the basis of color changes) another breeding season is believed to
occur. The few females in November-December is clearly caused by an
unexplained increase in males, rather than a decrease in females.
Brachymeles boulengeri is represented by more or less the same number
of females throughout the year (Fig. 9). However, March is apparently a peak
month of activity for females, and this is correlated with the high proportion of
gravid females during the same time. This high female representation in
March is probably associated with courtship activity. The large number of
females in June is, however, not correlated with any increase in number of

S. ij. D. g.

L. T. g.

80< c. Ls.

U- U-
z I-
w z

100 100

0 0

Figure 9. Percent females of each species collected each month. Species abbreviations as in Figure 2.


gravid females. The lowest monthly representation of females (September) is
associated with that time of year when no females are gravid.
Otosaurus cumingii females are particularly common from December to
January and during April (Fig. 9). The lowest numbers occur in February.
This is the month of the greatest number of gravid females. Thus it is possible
that Otosaurus broods its eggs. The highest number of females per month
(April) is associated with the second, lower breeding peak. The increase in
female number in December and January is probably related to an increase in
female activity prior to the February breeding peak. The low number of
females during February also is partly due to not only a reduction in females
caught, but an increase in males during the same period. The latter may be
related to territorial or courtship behaviors.
Sphenomorphus jagori (Fig. 9) is peculiar in that there are relatively few
females active during the entire year. The monthly number of females
approaches one half of the total monthly specimens only during September.
The lowest number of females is found during the time of highest proportion
of gravid individuals (January-February). This is followed by a significant
increase in number of females per month, and this may be associated with
increased feeding of the females. The month with the highest number of
females per year (September) also follows a breeding period (July), suggesting
post-laying increase in female activity. These data sets suggest the possibility
of egg brooding in this species as well.
Mabuya multicarinata (Fig. 9) exhibits a female monthly frequency
pattern similar to that of Otosaurus cumingii and S. jagori, i.e., the period of
fewest females is the period of most gravid females (February). This is
followed by a period of increased female activity. The low number of females
in June is unexplained, and there is no significant change in number of females
per month during the secondary breeding peak of July and August.
Lipinia pulchella (Fig. 9) has a similar pattern, i.e. the periods of highest
gravid females are periods of lowest number of active females (March and
August). There is a significant increase in females after both inactive periods--
particularly during April.
Lamprolepis smaragdina (Fig. 9) males and females are more or less
equally represented during most months. However, after both the major
breeding peak in April and the lesser breeding peak in July, the following two
months have a significant decrease in female activity.
Emoia atrocostata (Fig. 9) exhibits remarkable changes in monthly
proportion of females in view of the nearly uniformly sustained breeding
throughout the year. The fewest females are recorded in January and
November. Most gravid females occur in February, after which the number
decreases in March. The long, low breeding pulse from July through
September is similarly associated with a high representation of females


To summarize these data, there seem to be two major patterns regarding
the relationship of major breeding and activity peaks in females. In one,
female activity seems to decrease following the seasonal breeding peak(s).
Among Caramoan skinks this is illustrated by Lamprolepis smaragdina and
Brachymeles boulengeri. Both live in totally different microhabitats, the former
being arboreal and the latter fossorial. The remaining skinks illustrate the
second pattern, in which female activity increases after the major breeding
peak(s). The numbers of females available per month for most of these
species show that the fewest females are found during the peak breeding
period, suggesting that females are particularly inactive at this time. This may
be related to brooding of parturient females. No data are available on
brooding in any Philippine skink species. Emoia atrocostata is slightly set apart
because the breeding seems to occur at the same time that females are
becoming more active. In this case, the part of the year in which females are
least active would have preceded the peak breeding period. M. multifasciata is
similar to E. atrocostata, but the pattern is more or less intermediate.

Seasonal Color Changes

Changes in lizard body color, particularly males, is known to be associated
with the breeding season. Hadley and Goldman (1969) and Bagnara and
Hadley (1973) have shown that in at least some iguanids, male breeding colors
are under hormonal control and directly associated with testosterone levels in
mature males during certain times of the year. However, seasonal color
changes in those skinks previously studied suggest they occur only in males and
that they serve in agonistic encounters during the breeding season. We were
thus surprised to find that in our study area seasonal color changes also occur
in females, and one wonders how this might be correlated with those changes
in the males and how they might be important in intra- and intersexual
behavioral contexts. To determine the level of correspondence between such
color changes and season and reproductive condition, we noted the coloration
of all mature specimens dissected during the study with the hope that such
color changes might be found useful in further defining breeding readiness by
individuals of different species at different times of the year.
Our studies show that not all Caramoan skink species exhibit seasonal
color changes. But of those that do, similar changes can be demonstrated in
both males and females in almost all the local species, though the seasonal
colors of the males are always more intense. There are no color changes in
mature individuals of either sex of either Brachymeles or T. grayi. Dasia grisia
may not have seasonal color changes, but our sample is too small to be certain.
Excluding Dasia, these three species are all semi- or nearly completely


fossorial--Brachymeles lives in mesic situations and Tropidophorus in nearly
hydric ones. Thus seasonal color changes are completely absent in those local
skinks that spend most of their time under the surface and evidently court and
breed there as well. All the other species show some form of seasonal color
change which can be related to breeding periodicity.
Only in Lipinia pulchella does this seasonal color change occur in only
one of the sexes (males). Color changes occur in both sexes in all other local
skink species. At least some mature Lipiniapulchella males have a large bright
yellow to orange blotch on the chin and throat. The same color is occasionally
seen around the cloaca and the inferior surface of the hindlimbs. These males
are evidently in breeding condition, and the color appears in some individuals
in all months of the year, except April and May, when the same areas are
white. The chins of immature females and juveniles are always white. These
months correspond with periods of increased testicular size (Fig. 6), and with
increased percentages of gravid females in the local population (Fig. 7). These
data suggest that mature males are ready to breed during all months except
April and May. The highest percentage of males with this color occur in
March and September (Fig. 10). The yellow chin in male Lipinia pulchella
suggests very strongly that combat occurs at this time and that courtship is also
Both mature male and female Lamprolepis smaragdina often have a deep
yellow cloacal area. Only the males have a yellow glandular heel patch during
the breeding season (also noted by Alcala 1966). At least some individuals of
both sexes have yellow cloacal areas every month of the year, though the
percentage varies seasonally (Fig. 10). The monthly proportion of males and
females having this color is concordant, though males consistently have more
individuals per month with this color than females. The lowest percentage of
both sexes with yellow cloacal color occurs from just before to just after
monsoon I (May through August) and in December (monsoon II). The
highest proportions of colored males occur in the early part of dry period I
(January through April) and in the early part of monsoon II (September
through November). However, the proportion of L. smaragdina males "ready"
to breed is higher during all months of the year than in any other local species.
Testicular size is greatest during April and August.
The seasonal curve for yellow-colored females is more distinctly pulsed
than that for males, with the highest peaks in March and October. The highest
peak for colored females does not correspond with the peak for monthly
proportion of gravid females (May and July). The July peak for gravid females
corresponds with a sharp rise in colored males as well as females. However,
the Caramoan data presently available suggest that the period of courtship
during dry season I is much longer than that during monsoon I, and that while
both males and females may have been ready to breed during monsoon II, they
did not do so (see Fig. 2). Dissections reveal that yellow cloacal color occurs in







o 100







Figure 10. Above, percent of males (M) and females (F) of Lamprolepis smaragdina in which the
cloaca is yellow. Below, the same for Lipiniapulchella males with yellow or orange on the chin.


females with both yolking ovarian and developing oviductal eggs. Immatures
of both sexes lack the yellow cloacal color.
Some mature male and female 0. cumingii have gray chins. The belly is
additionally washed with yellow in those individuals with the darkest chins.
Immatures of both sexes have white chins. Gray-chinned individuals are found
during every month of the year, varying from 50 to 100 percent in the total
monthly male sample, and 62.5 to 100 percent in the monthly female samples.
This is the only local skink species in which females sometimes possess more
intense color than males during the breeding season. The curves of monthly
proportion of individuals with dark chins are highly coincident in both sexes
(Fig. 11), with the highest proportions for both sexes from December through
March and the lowest in April and May. The curves for both sexes fit those
curves for both testis size (Fig. 6) and proportion of gravid females per month
(Fig. 7), though the highest peaks in the two latter curves are reversed.
Some mature E. atrocostata are also seasonally colored. In this species
the chin of both males and females is medium gray and the belly often yellow
to peach. Immature individuals of both sexes have a white chin and belly. The
proportion of colored to non-colored mature individuals per month is shown in
Figure 11; both male and female curves are concordant. In both, the variation
is from 0 to 100 percent of the total monthly sample. Males are more
commonly colored than females and have the highest number of colored
individuals from December through March and July through September. This
curve is almost opposite that for testis size in males of the same species for the
months of July through September, but coincides with the high February peak
(Fig. 6). The curve for the proportion of gravid females per month (Fig. 7)
illustrates that the fewest colored females occur during the peak period of
gravidity (November) and the highest number of colored females at the lowest
point of the annual gravidity cycle (February).
Immature S. jagori of both sexes have a white belly. In some mature
individuals it becomes bright yellow, and this varies seasonally and coincidently
in both sexes (Fig. 12). Monthly variation in colored individuals of both sexes
is from 0 to 100 percent, with colored males only slightly more common than
colored females, and then only for some months. No colored individuals of
either sex are found from April through May. This corresponds with one
period of testicular degradation (May through June). The reduction in number
of colored males in November also corresponds with a second decrease in
testicular size during the same month. The highest proportions of gravid
females (Fig. 7) occur during March and April, just after the January-February
high proportion of colored females, and the two curves are coincident during
the respective peaks in August-September. The increasing proportion of
gravid females during December is correlated with an increase in number of
colored females at the same time.


I 100 ---
cc: \./ ', ./

S\ I

\ / /
60 \ \

2 \
\ I f

0 .. ---

Figure 11. Above, percent males (M) and females (F) of Otosaurus cumingii in which the chin is
gray. Below, the same for males and females of Emoia atrocostata with gray chin and yellow to
peach belly.



o 100



Figure 12. Above, percent males (M) and females (F) of Sphenomorphusjagori with yellow belly.
Below, the same for males and females of Mabuya multicarinata with brassy green or blue belly.


Immature males and females of M. multicarinata have white bellies.
Some mature males and females have a distinct metallic brassy tint on their
bellies that can be either greenish or bluish. The seasonal proportion of
colored males and females are coincidental (Fig. 12), with generally more
females having this color during most months than males. The color is present
in 46 to 75 percent of all males during most months, except January when the
proportion sharply falls to 0. Females have a similar seasonal pattern, with the
proportion of colored individuals ranging from 50 to 100 percent, except for
January, when it drops to 12 percent. Though the proportion of colored males
remains generally high throughout the year, peak values occur during April and
October. There is no correspondence with the curve for testis size (Fig. 6),
except for the rapid rise in both curves during the early part of the year. The
remaining parts of each curve are, in general, opposite. Breeding colors are
usually associated with plasma testosterone, but the latter is not directly
associated with testes size. Therefore, testicular mass is not a valid
measurement of testosterone level in the individual. Apparently the operant
system in breeding color development of M. multicarinata is different from that
in the other Caramoan skinks studied. However, the female seasonal color
curve does correspond with monthly percent gravid females, though the peaks
do not coincide.
Mabuya multifasciata is known to be quite variable in regard to color over
its extensive geographic range. Some individuals have a red to yellow stripe,
running for varying distances down the sides of the neck and body behind the
axilla. Mertens (1927) was the first to point out that both sexes have such
stripes. Auffenberg (1980) showed that the intensity of these colors was
related to the timing of the breeding season. No immature individuals of
either sex have the stripes, though some mature individuals do so seasonally.
In the Caramoan area the stripes are absent during June, July, and August.
The monthly pattern in proportion of individuals having such stripes is rather
concordant in both sexes (Fig. 13), though more males have the stripes than
females. Our dissections show that in females the yellow stripe may be found
in individuals with either yolking follicles late in their development or with
oviductal eggs early in their development. Females with well-developed
embryos usually have only faint stripes, while those with large yolking follicles
usually have brilliant red stripes. The highest peak of the male color curve
matches the period of increased testicular size in March (Fig. 6), and the
second somewhat lower peak coincides with the broad-pulsed period of
testicular size increase during monsoon II. The curve for proportion of
colored females shows two monthly peaks in place of the single early peak of
the males. These two peaks are nearly completely coincident with the two
peaks during the same time for percent of gravid females (Fig. 7). However,
while the color of both males and females suggests they were in a state of
reproductive readiness during monsoon II, very few females became gravid.



80 -

z 60 /' l /
S !// \\ N. .

40 \ /


0 --'- . -. -. 1 -- _- .-- -
Figure 13. Percent males (solid line) and females (dashed lines) of Mabuya multifasciata with
anterolateral yellow to red stripes.


Table 4 is a composite of all data available relating to reproduction in
those skinks studied for which adequate information is available. What is
immediately obvious is that though all these species were sympatric, there is
great diversity of reproductive patterns represented in the species studied.
This suggests that the local environment is not the only determining factor of
lizard life history patterns, in spite of the fact that other workers (Tinkle et al.
1970; Barbault 1974a, b) have repeatedly suggested that it is. Vitt (1986) drew
this same conclusion for lizards of Brazilian forests. Furthermore, he
demonstrated that the reproductive patterns of the Brazilian forest lizards are
more similar to those of species within the same family than to species in other
families. In the current study we show that within even one family (Scincidae),
reproductive patterns show considerable pattern diversity, in spite of the fact
that all live in the same tropical forest area in the Philippine Islands.
All the factors shown in Table 4 for each species are seasonally variable,
but undoubtedly linked to one another physiologically. Of these factors, the
seasonal injection of young into the local ecosystem is ultimately the most


important; and all other reproductive events are coupled to this in a necessarily
sequential array.
Taken as a whole, the Caramoan skink biocoenosis introduces young into
the system every month of the year, in both dry and wet periods. However,
when the species are individually examined, only Lamprolepis smaragdina does
so the entire year (11 % of total species in area). Of the remaining species,
four (50%; Emoia atrocostata, Lipinia pulchella, Brachymeles boulengeri, and
B. samarensis.) are long-pulsed breeding types (i.e., produce young over a
period of 6 months or more, see Table 4). None are found in the same habitat,
and none share even their microhabitat with any other skink species (see
Auffenberg and Auffenberg 1988 for details). In the last three listed species,
the annual non-productive phase is during monsoon I and the short dry period
between it and the beginning of monsoon II. Emoia atrocostata has its rest
period from the end of monsoon II through the early dry period (la), i.e. the
coolest time of the year.
Collectively the short-pulsed species (55%) also produce young during
almost every month of the year, but each species in one or two major bursts
(Table 4). The only "cool-wet" producer in this category is Sphenomorphus
jagori, most young appearing from October through January (heaviest rainfall
period of monsoon II). It probably also injects neonates into the system during
monsoon I, but none were noted (Table 4). In the same dense forest habitat
(but slightly different microhabitat, see Auffenberg and Auffenberg 1988),
Mabuya multicarinata produces young during two short-pulsed periods, one
near the beginning of monsoon I and the second at the beginning of monsoon
II. Mabuya multifasciata injects its young into the system over a single long
pulse of four months, spanning both the driest time of the year (April-May)
and the entire first monsoon (June-July).
Tropidophomrs grayi has a similar strategy, but with a cycle beginning and
ending one month earlier. This pattern evidently avoids injecting the young
into the system when torrents are produced in the mountain streams along
which the species occurs.
Otosaumrs cumingii has one of the most restricted reproductive periods of
all. Neonates are found in the Caramoan area only in April and May; gravid
females mainly during a a short time in February and March (with another
very low peak in October). Thus this species is mainly an early dry season I
breeder, with most of the young emerging before the rain and the concomittant
increase in insect biomass associated with monsoon I.
The most significant conclusion regarding our study of reproduction in
sympatric Philippine skinks is that we are still far from understanding the
factors that dictate relative clutch mass, individual egg size, total clutch number
and timing of cycles in tropical scincids. However, our study does suggest a
much greater diversity within a single tropical lizard biocoenosis than expected
on the basis of published summaries, statements of general principalss, or

Table 4. Composite of the seasonal representation for those reproductive factors studied in the Caramoan skink biocoenosis.a

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec


Cool Warm Early Late Condition

Mfs I ----------##### ------ ############ Sperm
##### ##### Courtship
I ---------- ###############--------- I Gravid

Mmc ############################## Sperm
~- ---------------- ------------ ---------- --- Courtship
-------- #####------- ---##########--- -I Gravid Z
I-LOW-1 Fat

Sj I########## I##################### Sperm
###########---- ######################------------##### Courtship
########## ######### ########### Gravid
(No Abdominal Fat) Fat

Lp I------ ##### ##### ######### ##### Sperm
################ --############################# Courtship
---- -----#####- I I----##########-- ----- ------- Gravid
(No Abdominal Fat) Fat

Table 4 Continued.

Bb #######################----- Sperm
(No Breeding Color) Courtship
----------------- -#####---------# # ###------ ------------------------ Gravid
(No Abdominal Fat) Fat

Tg ####------------------ ########### Sperm
(No Breeding Color) Courtship
########### ###########----I I -----I Gravid
(No Abdominal Fat) Fat

Oc ---##### --- I------------------ ##### Sperm
############### ######################################### Courtship
--------##### ---------- I Gravid
(No Abdominal Fat) Fat

Ea #####---##### ########## ##### Sperm
################# ######################------------##### Courtship
##### -------- ---------- -------##### Gravid

Ls #####---- I I -----#####-------- Sperm
----##################- ------ ------ ################# Courtship
---#####--- ###### ------- -Gravid
I-LOW- Fat

a Dashed months represent periods during which reproductive activity was noted; #'s are the periods) of most intense activity.






theoretical models. Clearly more data are needed on reproductive output and
annual patterns within sympatric tropical species where those climatic
constraints known to be of great importance in temperate scincid breeding
patterns are reduced or even lacking.


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