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Temperature-Dependent Survival and Activity Level of Four Subterranean Termite Species (Isoptera

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Material Information

Title:
Temperature-Dependent Survival and Activity Level of Four Subterranean Termite Species (Isoptera Rhinotermitidae)
Physical Description:
1 online resource (77 p.)
Language:
english
Creator:
Cao, Runxin
Publisher:
University of Florida
Place of Publication:
Gainesville, Fla.
Publication Date:

Thesis/Dissertation Information

Degree:
Master's ( M.S.)
Degree Grantor:
University of Florida
Degree Disciplines:
Entomology and Nematology
Committee Chair:
Su, Nan-Yao
Committee Members:
Kern, William H, Jr
Moore, Kimberly Anne

Subjects

Subjects / Keywords:
activity -- subterranean -- survivorship -- temperature -- termite
Entomology and Nematology -- Dissertations, Academic -- UF
Genre:
Entomology and Nematology thesis, M.S.
bibliography   ( marcgt )
theses   ( marcgt )
government publication (state, provincial, terriorial, dependent)   ( marcgt )
born-digital   ( sobekcm )
Electronic Thesis or Dissertation

Notes

Abstract:
Temperature is animportant factor that affects the survivorship and activity level ofsubterranean termites. This study is initiated to examine temperaturepreference of Coptotermes formosanus, C. gestroi, Reticulitermesvirginicus and R. flavipes and the effect oftemperature on their survival and activity under the samelaboratory conditions.             Termites’ response to temperaturegradient was studied on an aluminum bridge device with temperaturegradients. The number of termites in each temperature zone wascalculated. The data showed that the distribution pattern of R.flavipes and R. virginicus were more skewed toward thecolder side of the bridge surface, while C. formosanus and C.gestroi were more skewed toward warmer side. Thisresult generally suggests that Reticulitermes spp preferredcolder temperature than Coptotermes spp.             The effect of temperature onsurvival and wood-consumption rate of four species of subterraneantermite was also examined. The experiment was conducted in incubatorsat 10, 15, 20, 25, 30, 35°C under ˜99% relative humidity (RH) inconstant darkness. The results showed that in the intermediatetemperatures of 20 and 25, the survival and wood-consumption rate were not significantlydifferent among four species, while at the extreme temperature of 10, 15, 35°C,both variables were significantly different among species.              Finallythe effect of soil temperature on tunneling speed and food transportationof these four species of subterranean termite was examined at 15, 20, 25, 30and 35°C using two-dimensional arenas. Tunneling speed wascalculated and plotted, and the time when termites reach the food wasrecorded. The number of food particles and the distance of particles beingmoved 6 h after they reached the food were recorded. The resultindicated that tunneling activities of subterranean termite species increasedwith the rise in temperature in certain temperature range, though the tunnelingactivities of some combinations of temperature and species did not showsignificant differences from each other.
General Note:
In the series University of Florida Digital Collections.
General Note:
Includes vita.
Bibliography:
Includes bibliographical references.
Source of Description:
Description based on online resource; title from PDF title page.
Source of Description:
This bibliographic record is available under the Creative Commons CC0 public domain dedication. The University of Florida Libraries, as creator of this bibliographic record, has waived all rights to it worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law.
Statement of Responsibility:
by Runxin Cao.
Thesis:
Thesis (M.S.)--University of Florida, 2013.
Local:
Adviser: Su, Nan-Yao.

Record Information

Source Institution:
UFRGP
Rights Management:
Applicable rights reserved.
Classification:
lcc - LD1780 2013
System ID:
UFE0045963:00001

MISSING IMAGE

Material Information

Title:
Temperature-Dependent Survival and Activity Level of Four Subterranean Termite Species (Isoptera Rhinotermitidae)
Physical Description:
1 online resource (77 p.)
Language:
english
Creator:
Cao, Runxin
Publisher:
University of Florida
Place of Publication:
Gainesville, Fla.
Publication Date:

Thesis/Dissertation Information

Degree:
Master's ( M.S.)
Degree Grantor:
University of Florida
Degree Disciplines:
Entomology and Nematology
Committee Chair:
Su, Nan-Yao
Committee Members:
Kern, William H, Jr
Moore, Kimberly Anne

Subjects

Subjects / Keywords:
activity -- subterranean -- survivorship -- temperature -- termite
Entomology and Nematology -- Dissertations, Academic -- UF
Genre:
Entomology and Nematology thesis, M.S.
bibliography   ( marcgt )
theses   ( marcgt )
government publication (state, provincial, terriorial, dependent)   ( marcgt )
born-digital   ( sobekcm )
Electronic Thesis or Dissertation

Notes

Abstract:
Temperature is animportant factor that affects the survivorship and activity level ofsubterranean termites. This study is initiated to examine temperaturepreference of Coptotermes formosanus, C. gestroi, Reticulitermesvirginicus and R. flavipes and the effect oftemperature on their survival and activity under the samelaboratory conditions.             Termites’ response to temperaturegradient was studied on an aluminum bridge device with temperaturegradients. The number of termites in each temperature zone wascalculated. The data showed that the distribution pattern of R.flavipes and R. virginicus were more skewed toward thecolder side of the bridge surface, while C. formosanus and C.gestroi were more skewed toward warmer side. Thisresult generally suggests that Reticulitermes spp preferredcolder temperature than Coptotermes spp.             The effect of temperature onsurvival and wood-consumption rate of four species of subterraneantermite was also examined. The experiment was conducted in incubatorsat 10, 15, 20, 25, 30, 35°C under ˜99% relative humidity (RH) inconstant darkness. The results showed that in the intermediatetemperatures of 20 and 25, the survival and wood-consumption rate were not significantlydifferent among four species, while at the extreme temperature of 10, 15, 35°C,both variables were significantly different among species.              Finallythe effect of soil temperature on tunneling speed and food transportationof these four species of subterranean termite was examined at 15, 20, 25, 30and 35°C using two-dimensional arenas. Tunneling speed wascalculated and plotted, and the time when termites reach the food wasrecorded. The number of food particles and the distance of particles beingmoved 6 h after they reached the food were recorded. The resultindicated that tunneling activities of subterranean termite species increasedwith the rise in temperature in certain temperature range, though the tunnelingactivities of some combinations of temperature and species did not showsignificant differences from each other.
General Note:
In the series University of Florida Digital Collections.
General Note:
Includes vita.
Bibliography:
Includes bibliographical references.
Source of Description:
Description based on online resource; title from PDF title page.
Source of Description:
This bibliographic record is available under the Creative Commons CC0 public domain dedication. The University of Florida Libraries, as creator of this bibliographic record, has waived all rights to it worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law.
Statement of Responsibility:
by Runxin Cao.
Thesis:
Thesis (M.S.)--University of Florida, 2013.
Local:
Adviser: Su, Nan-Yao.

Record Information

Source Institution:
UFRGP
Rights Management:
Applicable rights reserved.
Classification:
lcc - LD1780 2013
System ID:
UFE0045963:00001


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1 TEMPERATURE DEPENDEN T SURVIVAL AND ACTIVITY LEVEL OF FOUR SUBTERRANEAN TERMITE SPECIES (ISOPTERA: RHINOTERMITIDAE) By RUNXIN CAO A THESIS PRESENTED TO THE GRADUATE SCHOOL OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE UNIVERSITY OF FLORIDA 2013

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2 2013 Runxin Cao

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3 To my parents and fianc for their endless love

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4 ACKNOWLEDGMENTS I w ould like to express all my gratitude to Nan Yao Su for accepting me in his laboratory and guiding me on the scientific road with his patience, encouragement and direction over the last two years. Doing research on termite under his supervision is the most important opportunity for my academic career and changes my whole life. I c ould never imagine what kind of person I would be if I didn t meet him. He was a precious source of inspiration and motivation. It is he who let me know exactly how to become an excellent graduate student and entomologist. I could not have finished my work without advice and guidance from my committee members: Dr. William H Kern Jr. and Dr Kimberly A. Moore All my colleagues and friends in FLREC UF, helped me and encourag ed me during the two years I thank Aaron J. Mullins and Ronald E. Pipin for technical support and Nurmastini S. Bujang for termite identification assistance. I also thank Thomas Chouvenc and Paul M. Bardunias for the discussion on my research and thesis writing. J ohn Zukowski helped me to do termite collection. Garima Kakkar, Ling X in and He Du provided me with lots of academic information. I thank Sarah Kern and Joann e Korvick for help ing me to live a better life in the new environment Last b ut not the least, I am forever grateful to my parents who provided understanding, support and encouragement when times were tough ; as I was so far away from them in the past a few years They always give me courage to realize my dream and pursue the life I want. I also want to express all my gratitude to my fianc Tianqi Li ( He still ow e s me a n official proposal at this moment ) who has been the most supportive, the most patient, the most caring, and the most willing to spend time on my stuff in the past two years.

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5 TABLE OF CONTENTS page ACKNOWLEDGMENTS ................................ ................................ ................................ .. 4 LIST OF TABLES ................................ ................................ ................................ ............ 7 LIST OF FIGURES ................................ ................................ ................................ .......... 8 ABSTRACT ................................ ................................ ................................ ................... 10 CHAPTER 1 GENERAL INTRODUCTION ................................ ................................ .................. 12 Economic I mpact ................................ ................................ ................................ .... 12 Distribution ................................ ................................ ................................ .............. 12 Hypotheses ................................ ................................ ................................ ............. 14 Objectives ................................ ................................ ................................ ............... 14 2 TEMPERATURE PREF ERENCE OF FOUR SUBTERRANEAN TERMITE SPECIES (ISOPTERA: RHINOTERMITIDAE) ................................ ........................ 16 Introduction ................................ ................................ ................................ ............. 16 Materials and Methods ................................ ................................ ............................ 17 Result s and Discussion ................................ ................................ ........................... 19 3 EFFECT OF SOIL TEMPERATURE ON SURVIVAL AND WOOD CONSUMPTION RATE OF FOUR SUBTERRANEAN TERMITE SPECIES (ISOPT ERA: RHINOTERMITIDAE) ................................ ................................ ........ 29 Introduction ................................ ................................ ................................ ............. 29 Materials and Methods ................................ ................................ ............................ 30 Result s and Discussion ................................ ................................ ........................... 31 Termite Survival ................................ ................................ ............................... 31 Wood Consumption Rate ................................ ................................ ................. 36 4 EFFECT OF SOIL TEMPERATURE ON TUNNEL DEVELOPMENT AND FOOD TRANSPORTATION OF FOUR SUBTERRANEAN TERMITE SPCIES (ISOPTERA: RHINOTERMITIDAE) ................................ ................................ ........ 44 Introduction ................................ ................................ ................................ ............. 44 Mate rials and Methods ................................ ................................ ............................ 45 Results and Discussion ................................ ................................ ........................... 48 Time Required to Reach Food ................................ ................................ ......... 48 Tunneling Area Development ................................ ................................ ........... 48 The Number of Moved Food Particles ................................ .............................. 52

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6 The Total Distance of Moved Food Particles ................................ .................... 53 5 SUMMARY AND CONCLUSION ................................ ................................ ............ 62 LIST OF REFERENCES ................................ ................................ ............................... 67 BIOGRAPHICAL SKETCH ................................ ................................ ............................ 77

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7 LIST OF TABLES Table page 2 1 Cold and hot boundaries of live and active termites of four subterranean termite s pecies at 10 min.. ................................ ................................ .................. 25 2 2 Total number of active termites (b) on the bridge and mean t emperature preference value ( m TPV) of four subterranean termite species. ........................ 25 3 1 Survivorships (%) of four subterranean termite species at 28 d.. ....................... 40 3 2 Wood consumption rate (mg worker/g termite/day) of four subterranean termite species after 28 d.. ................................ ................................ ................. 40 4 1 Time required to reach food by four subterranean termite species. .................... 54 4 2 Tunnel area (cm 2 ) of four subterranean termite species at 12 h. ........................ 55 4 3 Tunnel area (cm 2 ) of four subterranean termite species at 48 h. ........................ 55 4 4 Newly developed tunnel area (cm 2 ) by laboratory groups of four subterranean termite species. ................................ ................................ ............ 56 4 5 Number of food particles transported by four subterranean termite species 6 h after they reached food.. ................................ ................................ .................. 57 4 6 Distance of food particles transported by four subterranean termite species 6 h after they reached food (mm).. ................................ ................................ ........ 57 5 1 Economic impact of termite during the last half century ................................ ..... 66

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8 LIST OF FIGURES Figure page 1 1 Northern distribution boundaries of these four subterranean termite species in the US. ................................ ................................ ................................ ............ 15 2 1 An aluminum bridge device modified from Smith and Rust ( 1993 ) formed temperature gradient ................................ ................................ ......................... 25 2 2 Average number of live and active C. gestroi in each temperature zone on the bridge surface. ................................ ................................ .............................. 26 2 3 Average number of live and active C. formosanus in each temperature zone on the bridge surface. ................................ ................................ ......................... 26 2 4 Average number of live and active R.virginicus in each temperature zone on the bridge surface.. ................................ ................................ ............................. 27 2 5 Average number of live and active R. flavipes in each temperature zone on the bridge surface. ................................ ................................ .............................. 27 2 6 Northern distribution boundaries of four subterranean termite species in mean daily minimum ambient temperature map of US (with isothermal lines). .. 28 3 1 Distribution of C.formosanus and C. gestroi on the global scare and the southern distribution boundaries for R. flavipes and R. virginicus in North Ameri ca (modified from Rust and Su 2012). ................................ ....................... 41 3 2 Distribution of C. formosanus and C. gestroi in Florida map (modified from Scheffrahn and Su 2005; Li et al. 2009; Scheffrahn et al. 2013, unpublished data) with January average temperature isothermal lines. ................................ 42 3 3 Ambient temperature, soil temperature and temperature in R. flavipes bucket trap in Secret Woods Park, Plantation, FL (Cao and Su 2013, unpublished data) ................................ ................................ ................................ .................. 42 3 4 Ambient temperature, soil temperature and temperature in R. flavipes bucket trap in Secret Woods Park, Plantation, FL ( Cao and Su 2013, unpublished data). ................................ ................................ ................................ .................. 43 3 5 Ambient temperature, soil temperature and temperature in R. flavipes bucket trap in Secret Woods Park, Plantation, FL (Cao and Su 2013, unpublished data). ................................ ................................ ................................ .................. 43 4 1 Two dimensional arenas set up based on Chouvenc et al. (2011). .................... 58 4 2 Tunnel pattern (with termites) at 48h (sample) (Photo by Runxin Cao) .............. 59

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9 4 3 Tunnel development of C. gestroi within 48 h (cm 2 ). ................................ .......... 60 4 4 Tunnel development of C. formosanus within 48 h (cm 2 ). ................................ .. 60 4 5 Tunnel development of R. virginicus within 48 h (cm 2 ). ................................ ...... 61 4 6 Tunnel development of R. flavipes within 48 h (cm 2 ). ................................ ......... 61

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10 Abstract of Thesis Presented to the Graduate School of the University of Florida in Partial Fulfillment of the Requirements for the Degree of Master of Science TEMPERATURE DEPENDENT SURVIVAL AND ACTIVITY LEVEL OF FOUR SUBTERRANEAN TERMITE SPECIES (ISOPTERA: RHINOTERMITIDAE) By Runxin Cao August 2013 Chair: Nan Yao Su Major: Entomology and Nematology T emperature i s a n important factor that affects the survivorship and activity level of subterranean termite s This study is initiated to examine temperature preference of Coptotermes formosanus C gestroi Reticulitermes virginicus and R flavipes and the effect of temperature on their survival and activity under the same laboratory conditions. T ermites respon se to temperature gradient was studi ed on an aluminum bridge device with temperature gradient s The number of termite s in each temperature z one was calculated The data showed that the distribution pattern of R flavipes and R virginicus were more skewed toward the colder side of the bridge surface while C formosanus and C gestroi were more skewed toward warmer side T his result generally suggest s that Reticulitermes spp preferred cold er temperature than Coptotermes spp. The e ffect of temperature on survival and wood consumption rate of four species of subterranean termite was also examined. The experiment was conducted in (RH) in constant darkness. The result s showed that in the intermediate temperatures of 20 and 25 C the survival and wood consumption rate were not significantly different among four species,

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11 while at the extreme temperature of 10, 15, 35 C, both variables wer e significantly different among species Finally the effect of soil temperature on tunneling speed and food transportation of these four species of subterranean termite was examined at 15, 20, 25, 30 and 35C using two dimensional arenas Tunneling speed was calculated and plotted, and the time required for termites to reach the food was recorded. The number of food par ticles and the distan ce of particles being moved 6 h after they reached the food were recorded T he result indicated that tunneling activities of subterranean termite species increased with the rise in temperature in certain temperature range, though the tunneling activities of some combinations of temperature and species did not show significant difference s from each other.

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12 CHAPTER 1 GENERAL INTRODUCTION Economic I mpact T ermites play an importan t role as decomposers in ecological system due to their ability to digest celluloses (Collins 1981; Genet et al. 2001; Holt and Lepage 2000), but they are considered pest s when they damage structural lumbers or any plant materials used by humans. According to Edwards and Mill (1986) and Rust and Su (2012), 80 termite species were considered serious pests and subterranean termites accounted for 38 species, with the genus Coptotermes containing the largest numb er of species followed by Reticulitermes and Odototermes It was estimated that $32 billion were spent in 2010 worldwide for control and damage repairs of subterranean termit es (Rust and Su 2012). Distribution Each termite species has its own geographic di stribution pattern. Two Coptotermes spp ., Coptotermes formosanus Shiraki and C gestroi Wasmann are economically important species that cause serious structural damage on the global scale. Probably originating from southern China (Kistner 1985), Formosan s ubterranean termite, C. formosanus is primarily found in the subtropical and temperate regions (Su and Tamashiro 1987). It is believed that C. formosanus was introduced to Hawaii before the beginning of 20 th century (Su and Tamashiro 1987; Tamashito et al. 198 7; Yates and Tamashiro 1990). C optotermes formosanus is distributed in many area s of the Unites States, including Alabama (Hu and Oi 2004), Florida (Koehler 1980), Georgia (Borstein 1993; Forschler et al 2000), Hawaii (Tamashito et al. 1987), Louisiana (Spink 1967; Messenger, et al., 2002; Brown, et al., 2007), Mississippi (Jarrat 1999; Jarrat

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13 2000; Sun et al. 2007), North and South Carolina (Beal 1967; Chamber et al. 1988; Horne 1998; Hawthorne et al. 2 000), Tennessee (Su and Tamashiro 1987), Texas (Beal 1967; Gold et al. 1999), and Virginia (Woodson, et al., 2001; Su 2003; Cabrera et al. 2005) (Figure 1 1) Unlike C. formosanus C. gestroi is distributed primari ly in the tropic and subtropic areas (Su 2003). Known as the Asian subterranean termite, C. gestroi is believed to have originate d in the Indo Malayan region (Kirton and Brown 2003) and has been reported in Brazil (Araujo 1958), Caribbean Islands (Scheffrahn et al. 199 9 ), Mauritius, Mex ico, Polynesia, Reunion (Scheffrahn et al. 199 9 ; Su 2003; Jenkins et al. 20 07; Scheffrahn and Su, 2008) Taiwan (Tsai and Chen 2003), and Puerto Rico (Scheffrahn et al. 2003) In the US, it is found in Florida ( Scheffrahn and Su 2005) and Hawaii (Ehrhorn and Kofoid 1934) (Figure 1 2) In Peninsular Malaysia, over 80% of structural infestation is caused by C. gestroi (Kirton and Azmi 2005) The genus Reticulitermes contains 10 species of termite pests (Rust and Su 2012). The eastern subterranean termite, Reticulitermes flavipes (Kollar) is the most common and widely distributed subterranean termite in the United States ( Su and Scheffrahn 1990 ). Contrary to previous assumption s another species of the genus Reticulitermes R virginicus (Banks) also infests a large number of structures (Su and Scheffrahn 1990). Scheffrahn et al. (1988) claimed that in Florida, R. virginicus was found almost as frequently in structures as R. flavipes Both two species are distribute d in many area s of the eastern United State and cause serious da mage to structural lumber in these areas (Su and Scheffrahn 1990). They were both reported in Alabama, Arkansas (Austin et al. 2004c), Florida (Scheffrahn and Su 2005), Georgia, Indiana

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14 ( Wang et al. 2009 ) Kentucky, Louisiana (Messenge r et al. 2002, Austin et al. 2004c), Maryland, Mississippi (Howard et al. 1982; Wang et al. 2003), North and South Carolina, O klahoma (Austin et al. 2004b), Tennessee, Texas (Austin et al. 2004a) and Virginia (Bank and Snyder 1920; Light 1934; Light and Pi ckens 1934; Snyder 1934; Banks 1946; Snyder 1949; Weesner 1965 ; 1970) In addi tion R flavipes i s also found in Colorado Illinoi Iowa, Kansas, Michigan Minnesota, New Mexico, New York, Ohio Oregon etc. ( McKern et al. 2006 ; http://www.termite.com/termites/eastern subterranean termite.html ) (Figure 1 1 ) Hypotheses In addition to the differences in their distributions termite activity change with seasons (Haverty et al. 197 4 ; Su 1991; Evan and Gleeson 2001). Temperature is a general limiting factor for geographic distribution of many organisms, and temperature tolerance and preference, as shown in previous studies (Li et al. 2009; 2013) can be use d to predict termite distribution. Ou r two hypotheses are : 1. Temperature affected geographic distribution of subterranean termite species. 2. Temperature affected seasonal activity of termite s Objectives In order to test the first hypothesis, survival and tem perature preference were measured and the data were used to examine the relationship between temperature and geographic distribution s of these four su bterranean termite species. Three variables were used to me asure the activity of these subte rranean termite species for the second hypothesis including wood consumption rate, tunnel development and food transport ation Three exper iments were conducted to examine the effect of temperature on these five v ariables.

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15 1. To record the temp erature range where liv e and /or active termites were found on a thermal gradient 2. To examine the effect of temperature on termite survival 3. To determine the effect of temperature on wood consumption rate 4. To study the effect o f temperature on tunnel development 5. To examine the effect of temperature on food transportation Objective 1 was cribed in Chapter 2. Objective 2 and 3 cribed in Chapter 3. Objective 4 and 5 Figure 1 1 Northern distribution boundaries of these four subterranean termite species in the US.

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16 CHAPTER 2 TEMPE RATURE PREFERENCE OF FOUR SUBTERRANEAN TERMITE SPECIES (ISOPTERA: RHINOTERMITIDAE) Introduction Kofoid (1934) suggested that temperature is one of the important abiotic factors that determine the establishment of a termite colony. Numerous studies have examined the effect s of temperature on termite activity but most were conducted at different temperatures ( Haverty and Nutting 1976 ; Fei and Henderson 2002; 2004; Nakayama et al. 2004 ; Gautam and Henderson 2011; Wiltz 2012 ) and only a few studies examined termites response to a thermal gradient T hermal gradient s can be generated by using laboratory device to study temperature tolerance and preference of termites Ik ehara (1980) first reported the response of eight termite species in Ryukyu Islands, including C. formosanus and Odototermes formosanus (Shiraki) etc. to thermal gradients Temperature preferences of these termi te species were reported in the study, though the exact definition of temperature preference was not provided. Ik ehara (1980) suggested that cold temperature tolerances of these eight termite species are clo sely related to their distribution on multiple islands with different w inter minimum temperature s The temperature preference of western subterranean termite, Reticulitermes h esperus Banks, on the thermal gradient was reported by Smith and Rust (1993) using a similar experimental device to that of Ik ehara ( 1980 ) When exposed to a temperature gradient of 26 47 C R h esperus preferred temperature range of 29 32 C Smith and Rust (1993) put forward the concept of mean temperature preference value (mTPV) to quantify temperature preference of termite s on the temperature gradient. Cabrera and Rust (1996) demonstrated the behavioral responses to a thermal gradient by western drywood termite, Incisitermes minor (Hagen) using a

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17 device modified from Ikehara (1980) As termite individuals are exposed to the open air during the experiment temperature gradient device used to study drywood termites may not be suitable for subterranean termites, because subterranean termites rely on soil or mud tube s to keep humidity and the unfavorable moisture level in the open air on the device may negatively affect the activity of subterranean termite s Although the environment on the therm al gradient device may be different fro m that in the soil, the st udy of responses to a thermal gradient by four subterranean termite species, C formosanus C gestroi R virginicus and R flavipes could provide important information about their temperature preferences. This study was initiated to examine the ir temperature avoidance and preference s of these four species on a thermal gradient Materials and Methods Termites from three colonies each of C formosanus C gestroi R virginicus and R flavipes were collected from Broward County in Florida with the method of Su and Scheffrahn (1986). C ollected termites were held in 720 ml cans with wood blocks ( Spruce, Picea sp ) ( 2 .0 x 2 .0 x 2.0 cm) and moistened play sand at 28 C before testing. Termites was studi ed by using an alumin um bridge device modified from Ike hara ( 1980 ). The device consist ed of an aluminum strip ( 100 .0 x 5 .0 x 0.5 cm ) with two ends ben t vertical ly down 20 cm ( F ig 2 1) resulting in a surface area of 60 x 5 cm. To obtain a temperature gradient along the length of the bridge, one 20 cm end was soaked in ice water ( 0 C ) while an other end was in b oiling water ( 100 C ) The surface of experiment area was divided into 12 square temperature zone s of 5 x 5 cm A n on contact i nfra r ed (IR) t hermometer

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18 ( Extech Instruments, Massachusetts, USA ) was used to measure t e mperature of each zone for each test. As the temperature of bridge surface was always changing, t e mperature of each zone for each test was measured twice, at the beginning and end of the test, respectively, and the average was used to represent temperature of each zone One hundred and twenty termites ( 1 08 workers undifferentiated larvae of at least the 3rd instar, and 1 2 soldiers for Coptotermes spp. and 1 28 workers and 2 soldier s for Reticulitermes spp .) from a termite colony wer e used as an experimental group A group of termites were released in the middle of bridge surface to observe their movement and distribution. V ideos were taken to record termite movement and distribution for 15 min for each colony with a digital camera (Canon Powershot S45; Canon, Tokyo, Japan) When reviewing the video clips moving termites were considered active individuals and live termites included active individual s and those that were alive but not moving Within extremely cold zones of the temperature gradient active termites were found to be immobilized by the cold temperature The cold and hot boundaries of active termites and liv e termites were recorded at 10 min for each test and 6 tests were conducted for each species ( 2 subsamples x 3 colonies ) Therefore eventually 6 temperature ranges were recorded for each species T emperature ranges of liv e termites might help to explain the geographic distribution of the species, while the t emperature ranges of active termites might indicate that within certain regions, although the termite species is distributed there, activity of termites may be reduced during the cold period of the year. The number of live and active termites within each zone w as counted at 1.5 min interval for 15 min One count was considered as a

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19 pseudo replicate, and the mean of 1 0 pseudo replicates was considered to be a replicate. Means of 6 replicates (2 subsamples x 3 colonies) for each species was plotted against temperature Smith and Rust (1993) first put forward the concept of mean temperature preference value (mTPV) and use this variable to measure the temperature preference of termite. An m TPV was calculated for each test to represent the temperature at wh ich the majority of termites were found i n the temperature gradient m TPV for each test was calculated using the following equation : m TPV= where a is t he average number of active termites of the 10 pseudo replicates in each temperature zone and t is t he average value of two temperature s of each temperature zone measured at the beginning and end of the test b i s t he total number of active termites on the bridge of each test m TPV s (n=6) for each species were analyzed using one way analyses of variance (ANOVA). Significant differences among species were separated by Least Significant Difference (HSD) using statistical software JMP 10 .0 (SAS Institute 1998 ) Results and Discussion The result showed the temperature ranges of live individuals of C. gestroi C. formosanus R virginicus and R flavipes were 9.4 39.0 C 5. 2 38 .7 C 4.1 37 .1 C and 3 .4 34.6 C ,and t he temperature ranges of active individuals of C. gestroi C. formosanus R virginicus and R flavipes were 13.0 38.6 C 9.3 38 1 C 8.2 3 6.7 C and 5.2 34.0 C respectively (Table 2 1) For C gestroi both active and live individuals were found in the highest temperature among the four species, and for R flavipe s both active and live individuals were found in the lowest temperature among the four species

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20 Cold temperature could immobilize termites but did not kill termites in the short period of time of the experiment Extremely high temperature resulted in termite mortality More live and active C. gestroi were found in the warmer temperature zone of >27.2 C on the thermal gradient ( Figure 2 2 ) In the temperature zone of 9.4 10 .5 C all individuals were immobilized resulting in live but not active termite counts As the inactive termites accumulated in this area, it became harder for newly entered individuals to move out. Within the temperature range of 10 .5 13.5 C only half of the termites were able to move and only at a very low speed T he large st number of termites (23 individuals on average ) was recorded in temperature zone of 33.5 38.5 C Th e result concurred with the tropical distribution of C.gestroi According to Scheffrahn and Su (2005) and Li et al. (20 09 ), t he overlapping area of C.gestroi and C. formosanus in Florida lie d between 25.5 and 27 N Alt hough Florida is further north than Taiwan and Hawaii average January temperature s were similar among the area s where these two species co exist ( Henry et al. 1994 ; Li et al. 20 09 ). This may be the evidence that l ow temperature was a limiting factor for the northern geographic boundary of C.gestroi More live and active C. formosanus were distributed in the warmer temperature zone of >27.5C on the thermal gradient (Figure 2 3), with the largest number of C. formosanus found in the t emperature zone of 29.5 3 5. 7 C Within the low temperature range of 4.8 5.0 C termites moved at a very low speed if they moved at all Temperature range of 32 35.5 C was favorable to C.formosanus The result coincided with the subtropical and temperate distribution of C.formosanus I kehara (1980) who reported preferred temperature s of eight termite species indicated that daily minimum

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21 temperature in the nest s of the se species dictate the north ern limit of geographic distribution of these termites in Ryukyu Islands T he distribution of active and live R.virginicus w ere generally skewed towards the cold temperature zone of <25.4 C on the thermal gradient (Figure 2 4 ) Once termites were released in the center of the bridge surface (temperature range of 23.4 27.5 C ) over 50% individuals move d towards the cold side indicating that R.virginicus presented avoidance of the warm temperature. Temperature zone of 4. 1 11 C accounted for the highest proportion of individuals, but about half of them were immobilized due to cold temperature The number of ina ctive individuals remained at lower temperature of <11 C increase d over time as it bec a me crowed and hard for individuals to move out Th e result did not necessarily indicate preference of cold temperature lower than 11 C but R.virginicus did not avoid this cold temperature zone and once they moved in, they were simply immobilized. T ermites entered temperature zone of 3 0 3 7 .1 C usually le ft the area very quickly All of the indi viduals that stayed in area with temperature > 37. 1 C die d eventually. The result suggested that R.virginicus prefer red the cold temperature <25.4 C rather than the warmer temperature >25.4 C and this may be the reason why this species i s widely reported in northern US T he distribution of R. flavipes w ere more skewed towards the cold temperature <25.5 C than R.virginicus on the thermal gradient ( Figure 2 5 ) W hen released on the bridge surface at the beginning of the experiment, most of R. flavipes individuals move d towards the cold side indicating their avoidance of warm temperature T heir movement slowed down as they moved towards lower temperature zone The average number of active termites in temperature zone 2.4 9.5 C was 49 which account ed for 4 5.4 % of

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22 active individuals. This result did not necessarily indicate their preference of cold temper ature lower than 9.5 C but it indicated their lack of avoi dance of cold temperature A s they entered the cold zone, they were slowed and could not leave the zone The proportion of active R. flavipes in warm temperature zone was the lowest among the four subterranean termite species. A ll R. flavipes died where temperature was high er than 34.6 C During t he experiment, as time passed fewer and fewer termite re ach ed the warm side of the bridge because many individuals were trapped in temperature zone <9 C Other random ly mov ing individuals mainly distribute d in medium temperature areas. Th e result demonstrat e d the preference of cold temperature over the warm temperature and suggest ed poor heat tolerance of R. flavipes m TPV s of these four subterranean termite species and total numbers of active termites on the bridge are shown in Table 2 2 The number s of active termites on the bridge exceeded 100 for all species expect R. virginicus for 86 2.10 as the proportion of active to live individuals was low in temperature range of 4.1 11.0 C m TPV s were significantly different among species ( F = 373.49; df= 3, 193; P <0.0001). There was no significant difference between mTPVs of C. gestroi and C. formosanus indicating that temperature preferred by these two species overlapped with each other. R. flavipes and R. virginicus prefer significantly cold er temperature than C formosanus and C. gestroi mTPV of R. flavipes was significantly lower than that of R. virginicus C ompared to R. virginicus individuals of R. flavipes were more active at lower temperature range. m TPV was a index of temperature preference of different termite species, and the result of this study coincide d with the north ern distribution boundaries of the four subterranean

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23 termite species (Figure 1 1, 1 2, 1 3 and 1 4) C. gestroi is the only species among the four that is found in Puerto Rico a typical trophic region although it also has large distribution area overlapped with C formosanus The other three species have never been reported in Puerto Rico probably because the temperature is too high for them to survive. The north ern distribution boundaries of C formosanus and R. virginicus are located between 33 43 N while that of R. flavipes is far north to Canada. North ern distribution boundaries of the four subterranean termite species coincided with the mean daily minimum ambient temperature map of US (with isothermal lines) T h e north ern distribution boundary of C formosanus is located between 7. 2 and 10 C isothermal lines excep t no report of C formosanus was made in Oklahoma and Arizona which may be too dry The cold temperature limitation of active C formosanus in this study was 9.3 C which falls into the temperature range of 7.2 10 C indicating mean minimum temperature might be the limiting factor for activity of C formosanus T h e north ern distribution boundary of R virginicus is generally located between 4.4 and 7.2 C isothermal lines expect that mean minimum temperatures of north Indiana and Pennsylvania are lower than 4.4 C The cold temperature limitation s of live and active R virginicus in this study were 4.1 and 8.2 C respectively, which concurred with the isothermal range. Ohio, Illinoi s and Missouri probably have R virginicus infestation in some areas. R flavipes can tolerant cold temperature s as low as 2.4 C showing the best cold temperature tolerance among the four, and this may explain their largest geographic distribution in US. The reason why they can survive in isothermal range of 0 4.4 C is probably that the lowest temperature in the soil is always higher than ambient temperature (Ikahara 1980; Cao and Su, 2013, unpublished data )

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24 There is only a small area in south Florida infested by C gestroi where the mean minimum ambient temperature is higher than 15.6 C In this study, individuals of C gestroi were active only at temperature higher than 13.0 C Florida is the only known location in continental US where C. formosanus and C. gestroi are sympatric generally because the temperature and subtropical climate overlap here Li et al. (2009) reported that C gestroi distributes from Taichung City to (24 N) southern tip of Taiwan ( 2 2 N ), where the January mean minimum temperature is higher than 12 C (data from The Climate Source, Inc) C formosanus was reported in area with January mean minimum temperature higher than 9 C In summary Reticulitermes spp appeared to prefer cold er temperature than Coptotermes spp R. flavipes had the best cold tolerance among the four subterranean termite species, while C. gestroi was most heat tolerant The results agree d with the north ern limit of their geographic distribution in North America, indicating that cold tolerance may be the main fact or that affected northern distribution boundaries. Temperature gradient experiment was a good method of studying temperature tolerance and preference of termites. T he lowest temperatures for active individuals of these four subterranean termite species rec orded in present study coincide d with the mean minimum temperature s of t heir north ern distribution boundaries, and therefore temperature is believed to be the limiting factor for geographic distribution of these four subterranean termite species.

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25 Table 2 1. Cold and hot boundaries of l ive and active termites of four subterranean termite species at 10 min. Values are presented as means SEs (n=6). ( C ) C gestroi C formosanus R. virginicus R. flavipes Active termites Cold boundary 13.0 0.18 9.3 0.23 8.2 0.21 5.2 0.20 Hot boundary 38.6 0.19 38.1 0.10 36.7 0.06 34.0 0.09 Live termites Cold boundary 9.4 0.07 5.2 0.05 4.1 0.04 3.4 0.08 Hot boundary 39.0 0.21 38.7 0.14 37.1 0.21 34.6 0.13 Table 2 2 Total number of active termites (b) on the bridge and mean t emperature preference value ( m TPV) of four subterranean termite species. Values are presented as means SEs. W ithin a row means of mTPV s with the letter are not statistically different (p <0. 05) (Owo way ANOVA followed by SD tests , n=6). C gestroi C formosanus R. virginicus R. flavipes b 101 1.59 102 1.30 86 2.10 108 1.32 m TPV ( C ) 28.13 0.42a 25.60 0.60 a 21.21 0.64b 15.24 0.96c Figure 2 1 An alumin um bridge device modified from (Ikehara 1980) formed temperature gradient One end of the 60cm bridge contacted ice water and another with boiling water. Termite number and activity was recorded by video camera within 12 temperature zones (5 x 5 cm) on the bridge surface.

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26 Figure 2 2 Average number of live and active C. gestroi in each temperature zone on the bridge surface. Values are presented as means SEs. Figure 2 3 Average number of live and active C. formosanus in each temperature zone on the bridge surface. Values are presented as means SEs. 0 2 4 6 8 10 12 14 16 18 20 22 24 Temperature range ( C ) Number of live termites Number of active termites 0 2 4 6 8 10 12 14 16 18 Temperature range ( C ) Number of live termites Number of active termites

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27 Figure 2 4 Average number of live and active R.virginicus in each temperature zone on the bridge surface. Values are presented as means SEs. Figure 2 5 Average number of live and active R. flavipes in each temperature zone on the bridge surface. Values are presented as means SEs. 0 4 8 12 16 20 24 28 Temperature range ( C ) Number of live termites Number of active termites 0 10 20 30 40 50 Temperature range ( C) Number of live termites Number of active termites

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28 Figure 2 6 North ern distribution boundaries of four subterranean termite species in mean daily minimum ambient temperature map of US (with isothermal lines). Temperature data referred to National Oceanic and Atmosphe ric Administration (NOAA) satellite data base of 1961 1990

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29 CHAPTER 3 EFFECT OF SOI L TEMPERATURE ON SURVIVAL AND WOOD CONSUMPTION RATE OF FOUR SUBTERRANEAN TERMITE SPECIES (ISOPTERA: RHINOTERMITIDAE) Introduction Subterranean termite s forage mainly in soil, and s oil temperature affect s microclimate of subterranean termite nest, which is regulated to maintain a fav o rable environment ( Mackay et al. 1986; Wood 1988). T he minimum temperature in soil is always several degrees higher than minimum air temperature (Ikehara 1980), and texture of soil as well as other substance s affect soil temper ature (Ettershank et al. 1980). Haverty et al. (1974) reported that foraging intensity of Heterotermes aureus (Snyder) increases in the spring and fall but decreased during the winter months in desert grassland Mackay et al. ( 1986 ) reported th at soil te mperature affects arthropod communi ties including a subterranean termite species Gnathamitermes tubiforma ns ( Buckley ) in the northern Chihuahuan desert of New Mexico. The hypothesis of this chapter was that soil temperature affects geographic distribution of C. formosanus C. gestroi R virginicus and R. flavipes as well as their seasonal changes in activity within a certain region Survival and wood consumption have been used to quantify termite activity under both laboratory and field condition s (Haverty and Nutting 197 6 ; Sornnuwat et al. 1995 ) and are known to be affected by a number of factors including ambient temperature ( Nakayama et al. 2004; Fei and Henderson 2002 ; Wiltz 2012), humidity ( Green et al. 2005; Wong and Lee 2010; Gautam and Henderson 201 1 ; Wiltz 2012), the wood species they feed on ( Smythe and Carter 1969; Su and Tamashiro 1986) and soldier proportion (Su and La Fage 1987; Fei and Henderson 2002). Soil temperature

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30 is more lik ely to affect activity of subterranean termite than ambient temperature (Johnson and Whiteford 1975). Alt hough s tudies on these factors have been done they were often conducted independently, making a comparison difficult This study was initiated to examine the effect of soil temperature on survival and wood consumption rate of C. formosanus C. gestroi R. virginicus and R. flavipes under the same laboratory conditions This information may help to explain the effect of soil temperature on termite geographic distribution and their seasonal activit ies Materials and Methods Termites from three colonies each of C. formosanus C. gestroi R. flavipes and R. virginicus were collected from Broward County in Florida, using the method of S u and Scheffrahn (1986). C ollected termites were held in 720 ml plastic cans with s pruce wood ( Picea sp ) and moistened sand at 28 C before testing. Fif ty four exp erimental units ( 18 /colony) w ere prepared for each species. Each unit consist ed of a glass screw top jar (6cm diam. x 5.5 cm high), a spruce wood feeding block (2.0 x 2.0 x 2.0 cm) and 30 ml acetone rinsed play sands moisten ed with 60ml deionized water Each experimental unit of each species at one temperature was considered to be a replicate and nine replicate s were prepared ( 3 subsamples x 3 colonies) for all temperature and species combination Feeding blocks were oven dried at 80 C for 48 h and weighted before testing Mean worker biomass ( wet wt.) for each colony was determined before testing by weighing 10 groups of 10 individuals each. One hundred termites (90 workers and 10 soldiers for Coptotermes spp. and 99 workers and 1 soldier for Reticulitermes spp ) were added to each jar. All units w ere kept in plastic boxe s lined with moistened paper to mainta 99 % RH The experiment w as conducted in incubators at 10, 15, 20, 25, 30 3 5 C in constant darkness for 28 d After

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31 28 d, the numbers of s urviving termites were counted and the feeding blocks were cle aned, oven dried and reweighed to calculate wood consumption rate, mg wood/g worker/day (Su and La Fage 1984a) The percent of survivorship was calculated according to the number of surviving termite s in each experimental unit To adjust deviations from normality arcsine transformation w as applied to the percentage data Surviv orship and wood consumption rate (mg wood/g worker /day) were analyzed using two way analyses of variance (ANOVA) with species and soil temperature as the evaluation factors Significant diffe rences among species and soil temperature s were separated by Significant Difference (HSD) using statistical software JMP 10 .0 (SAS Institute 1998 ) Results and Discussion Termite S urvival Surviv orship (%) of the four subterranean termite species and the results of two way ANOVA are present in Table 3 1. Termite survivorship significantly differ ed among soil temperature s ( F = 86.77 ; df= 5, 193; P <0.0001 ), species ( F = 15.50 ; df= 3, 193; P <0.0001 ) and their interaction ( F = 37.97 ; df= 15, 193; P <0.0001 ). No significant difference was observed among survivorship s of C gestroi at 20, 25, 30 or 35 C indicating that 20 35 C is a favorable temperature range for this tropical species The survivorship of C gestroi drastically decreased at 15 C indicating it was too cold for C gestroi to survive. C gestroi was the only species tested that did not survive at 10 C for 28 d suggesting that C gestroi had the poorest cold tolerance among the four species. The ir preference of warm over cold soil temperature of this species accounts for their geographic distribution in tropical and subtropical areas.

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32 W ithin species t he survivorship s of C formosanus were not significantly different among groups kept at 20, 25 30 and 3 5 C The survivorship of termite kept at 1 0 C was significantly lower than those exposed to 15 C and 2 0 C but n o t significantly different from those of 20, 25 30 and 3 5 C Fei and Herderson (2002) reported that C formosanus had survived significantly bettwe at 30 and 33 C than 20 and 25 C after 12 d, but after 60 d individuals had significantly higher survivorship at 30 C than 20 25 and 3 3 C indicating survivorship s of C formosanus at different temperature were affected by time that termites are maintained at that temperature Nakayama et al. ( 2004 ) reported that there was no significant difference among worker survivorship s for C formosanus at 20, 25 or 30 C with 90% RH indicating that 20 30 C was a favorable soil temperature range for C formosanus which agree s with the result s of the present study. T he survivorship of R. virginicus were not significantly different at 15, 20, 25 and 30 C after 28 d but significan tly lower at 35 C indicating that the high soil temperature of 35 C was unfavorable to this species. The survivorship at 10 C of R. virginicus was significantly lower than those at 15, 2 0 and 25 C but higher than that at 35 C For R. flavipes the survivorships were not significantly different among groups exposed to 15, 20 and 25 C R. flavipes die d off at 3 5 C after 28 d The survivorships at 10 and 30 C were not significantly different from each other The result indicated that within the soil temperature range tested, R. flavipes survived better in cold er soil temperature ( <30 C ) than warm er soil temperature ( >30 C ) Compared to other three species, R. flavipes had the high est survivorship at low soil temperature of 10 and 15 C which may explain its northern distribution in North America. Wiltz (2012) reported that

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33 the maximum survivorships of R. flavipes and C formosanus workers and soldiers occurred at 10 C and 99% RH but workers of both species had the longest survival time until 50% individuals died at 99% RH and 20 and 25 C The survivorships of C formosanus were higher than 70% in the soil temperature range of 10 35 C but C gestroi did not survive at 10 C and the survivorship at 15 C was lower than 50%. This result indicated that C formosanus survived at the widest temperature range, while C gestroi survived within narrowest range When compared the species survivorship at respective temperatures, s urviv orship s were not significantly different among the four species at the same soil temperature at 20 and 25 C At 10 C and 15 C the survivorships of C formosanus R. flavipes and R. virginicus were not significantly different from each other at same soil temperature but those of C gestroi were obviously low indicating that C gestroi ha d the poorest cold tolerance T h e survival of C gestroi was significantly different from those of the other three species at 30 C E xpect for C formosanus and C gestroi the survivorship s of these four subterranean termite species were significantly different from each other a t 35 C when paired comparison s were made T he study concluded that C gestroi presented significantly lower survival than other three species at 10 C while Coptotermes spp presented higher survivorship than Reticulitermes spp. at 35 C C.formosanus is generally found in subtropical and temperate areas on the global scale, whereas C. g estroi is mainly confined in tropical and subtropical range (Figure 2 1 ) Southeast Asia is heavily infested by C. g estroi but has little problem with other three termite species ( Kirton and Brown 2000 ; Trinh et al 2010 ) Puerto Rico ( 1 7 50 18 30 N 6 5 4 0 67 45 W ) is l ocated in the tropics, with mean minimum

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34 temperature of 2 1. 3 C and mean maximum temperature of 3 2 4 C (NOAA data 1961 1990 ) Among the four subterranean termite species, C. g estroi is the only species that survive s in the tropical climate of Puerto Rico Although the result of present study showed that C. formosanus and R. virginicus could survive at temperature s as hig h as 35 C these two species were never recorded in Puerto Rico This may be due to the mean and extreme maximum temperature in the soil that is too high for them to survive or from the effect of other abiotic factors Hawaii ( 18 55 28 27 N 1 54 48 178 22 W ) is another sub tropical area with mean minimum temperature of 18.6 C and mean maximum temperature of 31.5 C (NOAA data 1961 1990 ) The mean minimum and maximum temperature of Hawaii are both slightly lower than those of Puerto Rico C. formosanus and C. g estroi co exist in Hawaii but the two Reticulitermes spp. are not found there The s ou th ern distribution boundary of R. flavipes was reported on Key Largo (25 00 N, 80 30 W) with the extreme lowest temperature of 5 C ( http://www.weatherbase.com/ ). R. flavipes was also found in Grand Bahama Island (26 39 N, 76 39 W) Bahamas ( Scheffrahn et al. 1999 ) The mean minimum temperature and mean maximum temperature recorded at Nassau International Airport were 17.9 C and 31.8 C respectively. However, Reticulitermes spp. were not reported from any other Bah amian island and Turks and Caicos Islands expect R. flavipes that is reported in Abaco (Snyder 1956, Scheffrahn et al. 2006) The south distribution boundary of R. virginicus was reported on Big Pine Key (24 41 N, 81 21 W) which is south to the south distribution boundary of R. flavipes Key Largo coinciding with that R. flavipes preferred colder temperature than R. virginicus. C. g estroi was reported in Cuba, Providenciales and Grand Turk which were all islands in the C aribbean ( Scheffrahn et

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35 al. 2006). However, C. formosanus was not found in Bahamas and Turks and Caicos Islands Lack of report s of an exotic termite species in a certain area does not mean that the climate is un favorable. According to the present study, the temperature condition of Caribbean islands might allow C. formosanus and R. virginicus to survive These four subt erranean termite species are recorded in Florida (24 27 31 00 N 80 02 87 38 W) which is a n overlapping area of temperate and sub tropical climate ( Figure 2 2 ) The north distribution boundary of C. g estroi is about 27 N which corresponds the mean annul minimum temperature of 17.2 C and January average temperature >18 C in Ta iwan (Li et al 2009) The result s of the present study reported that 15 C was the lowest temperature for C. g estroi to survive, which coincided with the minimum temperature of the north boundary of this species in Florida. The mean annul minimum temperature range of the state of Florida is 13.3 2 2.8 C which fall in the survival range of C. formosanus The distribution s of R. flavipes and R. virginicus are statewide except the Key s This study of survivorship s of four termite species concur red with the general notion tha t temperature is one limiting factor for geographic distribution of subterranean termites This notion was widely accepted and supported by previous studies. C formosanus i s mostly found in southern parts of Japan, while R. speratus i s recorded throughout most of the country ( Mori et al. 2002; Yamano 1997 ) This distribution pattern may result from the fact that R. speratus had better cold tolerance than C formosanus ( Nakayama et al. 2004 ) The temperature preferences of eight termite species reported by Ikehara (1980) also coincided with their distribution in Ryukyu Islands

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36 Wood C onsumption Rate Wood consumption rate s (mg worker/g termite/day) of four subterranean termite species and the result of two way ANOVA are shown in Table 3 2 W ood consumption rate s of four subterranean termite species was significantly differed based on soil temperature ( F = 122.30 ; df= 5, 193; P <0.0001), species ( F = 34.58 ; df= 3, 193; P <0.0001) and their interaction ( F = 16.13 ; df= 15, 193; P <0.0001). The wood consumption rate of C gestroi increased as soil temperature rose within temperature range of 15 35 C but mean rate s at 25 and 30 C were not significantly different from each other C gestroi did not survive at 10 C for 28 days, and thus the wood consumption rate could not be computed The highest wood consumption rate occurred at 35 C indi cating that this species had highest feeding activity at 35 C which was an unfavorable temperature for other three subterranean termite species T he result concluded the poor cold tolerance of C gestroi and its preference of warm soil temperature, which explain its tropical distribution. Within species, n o significant differences were observed between the mean wood consumption rate s for C formosanus at 10 and 15 C but both were significantly lower than those of 20, 25, 30 and 35 C There was no significant difference among mean rates of 20, 25, 30 and 35 C Fei and Henderson (2002) reported that the wood consumption rates of C formosanus at 20 and 25 C were not signi ficantly different from those exposed to 30 and 33 C for 12 d, but after 60 d the wood consumption rate at 30 C was significantly higher than those at 20, 25 and 33 C Nakayama et al. (2004) reported that C formosanus had the largest wood consumption rate at 30 C with 90% RH among all the combinations of f ive soil temperatures (20, 25, 30, 35 and 40C) and three RH conditions (50%, 70%, and 90% RH) Gautam and Henderson (2011) reported

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37 that the wood consumption rate of C formosanus at 28 and 35 C was significantly higher than 19 C at high moisture content (125 150%). The result of previous studies together with that of the present study, indicated that the wood consumption rate of C formosanus increased with the rise of soil temperature but only for temperature range of 20 35 C Soil temperature >35 C or <20 C did not increase wood consumption rate of C formosanus For R. virginicus the wood consumption rate at 30 and 35 C was significantly higher than those of other soil temperature indicating that this species has highest feeding activity at 30 35 C No significantly difference was found between the mean wood consumption rate s of 10 and 15 C The mean values at 20 and 25 C were not significantly different from each other. For R. flavipes no significant differen ce was observed among the mean wood consumption rate s at 10, 15, 20 and 25 C which coincided with previous results indicating that R. flavipes had the best cold tolerance among the four subterranean termite species. The soil temperature of 35 C was too high for R flavipes to survive for 28 d and thus the wood consumption rate could not be computed at 35 C The wood consumption rate of this species at 30 C was significantly higher than any other soil temperature indicating that this termite species is most active at 30 C Harahap et al. (2005) reported that cellulose consumption in the bucket monitoring stations were highest during summer time but lowest during winter indicating that the seasonality of termite feeding activity was affected by soil temperature fluctuation Seasonal change in soil temperature s is usual ly smaller than that of ambient temperature s (Ikayara 1980) S ubterranean termites generally forage in the soil, which

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38 is a protection from large fluctuations of ambient temperature. The temperature range in termite bucket traps (Su and Scheffrahn 1986) of C. formosanus was 17 28.4 C (8/31/2012 5/ 2 /2013 Hollywood, FL), while that of R. flavipes was 15 26.5 C ( 9/25/2012 5/2/2013 Secret Wood s Park, Plantation FL ) ( Cao and Su, 2013, unpublished data). Ambient temperature, soil temperature and temperature in the bucket trap of R. flavipes for 8/31/2012 11/4/2012 11/5/2012 1/26/2013 and 1/27/2013 5/3/2013 are s hown in Figure 3 4, 3 5 and 3 6. The fluctuations of trap temperature was smooth er than those of ambient temperature and soil temperature with the low est values higher than those of ambient and soil temperature line and high est values lower than those of ambient and soil temperature line Ambient temperature varied the most over time. During 11/5 /2012 1/30/2013, curves of soil temperature and trap temperature almost overlapped indicating the termite activity decreased and their ability to adjust the temperature in side their colony also d ecreased. According to field observation, the number of termite s in the trap substantially decreases during this period of time and the amount of wood they feed on was also lower than that of summer period indicating the decline of termite activity When temperature rises in the spring, the difference between soil temperature and trap temperature became larger. To sum up, soil temperature was different from ambient temperature, and the activity of subterranean termite s varied in different seasons whi ch coincided with the result of present study Hapukotuwa and Grace (2012) who reported the seasonal activity variation s of C. formosanus and C. gestroi in Hawaii by using the number of active termite trap s as dependent variable also indicate d that the activity of subterranean termites varied in different seasons. Sen Sarma and Mishra ( 1969) reported the seasonal activity variation of Microcerotermes

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39 beesoni Snyder in North India, and Evans and Gleeson (2001 ) that of Coptotermes lacteus (Froggatt) in Australia All the studies supported the notion that temperature affects the seasonality of subterranean termite activity The different activities of sub terranean termite s indicate different damage potential s and economic loss caused by these wood fee ders. The feeding activities of termite generally increased as soil temperature rises within certain temperature range. Too high or too low soil temperature s were not favorable for termites feeding activity. The effect of soil temperature on survival and feeding activity of s ubterranean termite is also influenced by other factors, such as moisture (Collins 1969; Green et al. 2005; Gautam and Henderson 2011). Besides temperature, humidity is another import ant factor that affects survival and feeding activity of subterranean termites. Nakayama et al. (2004) reporte d that the optimum combinations of temperature and humidity for C formosanus and R. speratus were 30 C at 90% RH and 30 C at 70 90% relative humidity respectively. However, when released to unfavorable hot soil temperature, such as 40 C for C formosanus and 35 C for R. speratus lower humidity resulted in longer survival time Gautam and Henderson (2011) reported that the highest wood consumption rate was obtained on the high moisture content (125 150%) at all the three soil temperature treatment of 19, 28 and 35 C Monitoring and baiting system can be improved by understandi ng termite feeding activity affected by various factors. There are many incidents of baiting during the winter that has to be re do ne due to low soil temperature, especially in northern part of the US

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40 ( Su et al 1991 ). The result s of present study provide f urther evidence that cold winte r season may not be ideal for baiting programs that require termites to feed on toxic baits Table 3 1. Survivorships (%) of four subterr anean termite species at 28 d Values are presented as means SEs. W ithin the same column means with the same capital letter are not s ignificant ly different (p <0. 05). Within a row means with the same lower case subscript letter are not s ignificant l y different (p <0. 05) (Two way ANOVA followed by SD tests , n =9). Soil Temperature ( C ) C gestroi C formosanus R. virginicus R. flavipes 10 0 0Ab 75.89 2.88Aa 68.60 3.99Aa 75.30 3.74Aa 15 40.54 6.36Bb 92.11 0.95Ba 91.10 2.90Ba 94.22 0.64BCa 20 90.56 1.43Ca 93.78 1.33Ba 90.40 2.93Ba 94.89 1.75Ba 25 91.22 0.74Ca 87.90 1.67ABa 89.30 1.78Ba 94.56 1.09BCa 30 95.89 0.81Ca 90.10 1.30ABab 80.44 2.03ABb 80.11 5.58ACb 35 92.11 1.40Ca 79.22 5.24ABa 39.40 9.05Cb 0 0Dc Table 3 2 Wood consumption rate (mg worker/g termite/day) of four subterranean termite species after 28 d Values are presented as means SEs. W ithin a column means with the same capital letter are not s ignificant ly different (p <0. 05). Within the same row means with the same lower case subscript letter are not s ignificant ly different (p <0. 05) (Two way ANOVA followed by SD tests ). -: no data. S oil Tempera ture ( C ) C gestroi C formosanus R. virginicus R. flavipes 10 -4.87 1.26Aa 7.11 1.42Aa 6.37 0.93Ba 15 4.98 1.25Ab 9.76 2.51Aab 20.38 2.74ABa 11.11 1.01ABab 20 18.41 1.50Aa 30.61 3.29Ba 25.77 3.00BCa 19.80 1.17ABa 25 34.00 6.47Bab 33.02 1.53Bab 39.02 2.60CEb 24.41 1.92Ba 30 40.28 5.17Ba 40.03 3.30Ba 56.49 1.79Db 40.48 1.82Ca 35 61.64 3.91Cb 36.56 2.19Ba 50.59 4.50DEab -

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41 Figure 3 1 Distribution of C.formosanus and C. g estroi on the global scare and the southern distribution boundaries for R. flavipes and R. virginicus in North America (modified from Rust and Su 2012)

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42 Figure 3 2 Distribution of C. formosanus and C. g estroi in Florida map (modified from Scheffrahn and Su 2005; Li et al. 2009 ; Scheffrahn et al. 2013, unpublished data ) with January average temperature isothermal lines Figure 3 3 Ambient temperature, soil temperature and temperature in R. flavipes bucket trap in Secret Wood s Park, Plantation, FL (Cao and Su 2013, unpublished data) Data were recorded every 12 h.

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43 Figure 3 4 Ambient temperature, soil temperature and temperature in R. flavipes bucket trap in Secret Wood s Park, Plantation, FL (Cao and Su 2013, unpublished data) Data were recorded every 12 h. Figure 3 5 Ambient temperature, soil temperature and temperature in R. flavipes bucket trap in Secret Wood s Park, Plantation, FL (Cao and Su 2013, unpublished data) Data were recorded every 12 h .

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44 CHAPTER 4 EFFECT OF SOIL TEMPERATURE ON TUNNEL DEVELOPMENT AND FOOD TRANSPORTATION OF FOUR SUBTERRANEAN TERMITE SPCIES (ISOPTERA: RHINOTERMITIDAE) Introduction Foragers of subterranean termites search for food through tunnel galleries in the soil or by building mud tubes above ground to maintain moisture level of their bodies and to protect them selves from predators Food searching efficiency of subterranean termites depends on the organization and pattern of their tunnel system ( Traniello and Robson 1995 ). Foraging behavior is affected by several factors, such as t emperature humidity soil texture, preformed tunnels and presence or absence of food ( King and Spink 1969 ; Haverty et aI. 1974 ; Jones and Nutting 1989 ; Reddy and Sammaiah 1991 ; Smith and Rust 1991 ; Jouquet et al. 2002 ; Evans 2003 ; Su and Puche 2003 ; Arab and Costa Leonardo 2005 ; Lee et al. 2008 ; Cornelius and Osbrink 2010 ). Puche and Su (2 001) and Campora and Grace (2001 ) report ed that the formation of tunnel pattern s by R flavipes and C formosanus are not influenced by the presence of food. However, Reinhard et al. (1997) and Hedlumd and Henderson (1999) reported that the pres ence and amount of food affects the development of tunnel system constructed by C formosanus and R. flavipes Soil texture and size of soil particle also affect the tunneling behavior of subterranean termites. Termites excavat e tunnels by picking up soil particles and depositing them elsewhere to develop the new tunnels (B ardunias 2013). Only a few studies examined the effect of soil temperature on tunneling behavior of subterranean termites. Arab and Costa Leonardo ( 2005 ) repor ted that the total tunnel lengths of C. gestroi were signi ficantly impacted by temperature s when the soil moistures were 10 and 15%. No significant difference in tunneling was reported in the

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45 temperature range of 15 25 C when the soil moisture was low, such as 5%, probably because the low moisture became the limiting factor for the tunneling behavior of these two subterranean termite species. No information is available on the effect of soil temperature on foraging speed and food transportation of subterranean termites As foraging and f ood transportation activity related to determine damage potential of subterranean termites, it is necessary to study the factors that may affect the se activities. This study was initiated to examine the effect of so il temperature on tunneli ng and food transportation activity of C. formosanus C. gestroi R. virginicus and R. flavipes under laboratory condition Materials and Methods Termites from three colonies each of C. formosanus C. gestroi R. virginicus and R. flavipes were collected from Broward County in Florida, with the method of S u and Scheffrahn (1986). C ollected termites were held in 720 ml plastic cans with s pruce wood ( Picea sp ) (2.0 x 2.0 cm) and moistened play sand at 28 C before testing. Two dimensional arenas were set up according to Chouvenc et al (2011) Each arena was composed of two sheets of transparent Plexiglas (12 x 12 x 0.2 cm ) with Plexiglas laminates (2 x 0.2 cm in thickness) on the four sides, creating 10 x 10 x 0.2 cm space between two sheets of Plexiglas (Figure 4 1) A 0.8 x 0.8 x 0.2 cm spacer was placed in the center of the arena, holding the two sheets of Plexiglas together by a 3 mm diameter screw. A 0.5 cm diameter hole was drilled n ear one corner of each arena for the introduction of termites. Before assembly, Plexiglas were washed with soap and wiped with 75% ethanol. Colorations Heavyweight Construction Paper s ( 9" x 12" ) were cut into round shap e s (45 mm diam) and then divide d equally into four quarters Four quarter s of paper w ere overlapped and deposited as food source on the

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46 opposite corner of introduction hole. The space was filled with 15 g sterile play sand moistened with 3 ml deionized water, leaving an area of 5 x 2 cm empty near the introduction hole. According to Lee et al. ( 2008 ) subterranean termite tended to follow or merge with the pre formed tunnel at certain angles during their foraging process. O n the corner towards food of the empty area, a leading area of 1cm length by 0.2 cm width was set aside to lead termites to tunnel towards the direction of food. After assembling t he four edges of the arena were sealed using parafilm (Bemis Company, Neenah, WI) to maintain the moisture inside and w ere held together with eight 1 cm binder clips A group of 50 termites (45 workers and 5 soldiers for Coptotermes spp. and 49 workers and 1 soldier for Reticulitermes spp. ) w as released into the arena th r ough the introduction hole, after which the hole was sealed using p arafilm Arenas with termites w ere placed horizontally on the wood frame with a digital camera (Canon Powershot S45; Canon, Tokyo, Japan) positioned above to take digital images The experiment was conducted at 15, 20, 25, 30, 35 C for 48 h. Digital images were taken ev ery hour to record the tunnel development and food particle movement. Each arena prepared for each species at one temperature was considered to be a replicate, and six replicates (2 arenas x 3 colonies) were prepared for each termite speci es for each temperature T ime required for termite s to reach the food of each species and temperature combination was recorded and analyzed using Kruskal Wallis one way test (SAS Institute 1985) with temperature as evaluation factor. S t differences between means ( a= 0.05) The tunnel area was measured on each image using software GIMP, version 2.8 (Free Software Foun dation, Inc., Boston, MA). T unnel areas (cm 2 ) at 12 and 48 h were measured to observe the

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47 tunnel development before and after termites reached food. T unnel areas at 12 and 48 h were analyzed using two way analyses of variance (ANOVA) with species and temperature as evaluation factors Significant differences among species and temperature were separated by using JMP 10 .0 ( SAS Institute 1998 ) Su and Lee (2009) first used exponential function, Y= a*(1 e bt ), to analyze hour ly changes in tunnel areas of subterranean termite. The exponential function fit wel l for tunnel development data of C. formosanus and R. flavipes In our study, this exponential function was used to analyze the newly developed tunnel area ( cm 2 ) f or each temperature and termite species over time using software Origin 8 ( Origin Lab Corporation, MA) where Y is tunnel volume at time t, a wa s maximum volume, and b is relative tunneling speed. Time (hours) required to r each 90% of the maximum volume was calculated as t 90 = ( ln 0.1)/b According to Bardunias (201 3), subterranean termites tend to deposit food particles along their tunnel galleries once they found the food. The number of food particles that were moved by termites and their linear distance from food source can be used as measurement of termite activity. A fter termites reached the construction paper, t he number of food particles at 6 h was counted on each digital image Despite the fact that the numbers of food particles moved by some species at some temperatures were similar the distance that particles were moved from the food source could be different, which implies energy spent on moving the particles to different di stance was differen t. The further the particles were deposit from the food source, the more energy was spent by termites. Therefore the linear distance of food particles from the food source was used to measure the activity of termites. The total linear distance of moved particles

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48 was calculated by summing up all the linear distance (mm) The number and distance of food particles were analyzed using Kruskal Wallis test (SAS Institute 1985) with temperature as evaluation factor and s t differences between means ( a= 0.05) Results and Discussion Time Required to Re ach Food The time required for termites to reach food is shown in Table 4 1 The result of Kruskal Wallis test showed no significantly difference was observed of R. virginicus at different temperature As the temperature increased, the time that termites needed to reach the food decrease d. C. gestroi took the longest time to get the food at 15 C compared to other temperatures, indicating that C. gestroi had the lowest activity at 15 C R. flavipes spen t significantly fewer time getting food at 25 C than at 20 C C. formosanus spent significantly less time getting food at 35 C than at 15 C but no significantly difference was observed among means of other temperatures. Temperature did not have a signific antly impact on the time required to reach food by R. virginicus R. flavipes could not survive at 35 C after 28 d and thus R. flavipes was not observed in the arena experiment at 35 C The Kruskal Wallis test generally reflected the relationship between termite tunneling activity and temperature. Termites spent fewer hours to reach the food at higher temperature, though significant difference did not occur among some means. Tunneling Area Development Tunnel pattern (sample) at 12 h is shown in Figure 4 2 The tunnel area (cm 2 ) by these four subterranean termite species at 12 h significantly differ ed among

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49 temperature ( F = 11.11; df= 4 101; P <0.0001), species ( F = 37.61; df= 3 101; P <0.0001) and temperature by species ( F = 29.25; df= 12 101 ; P <0.0001) (Table 4 1) F or C. formosanus no significant difference wa s observed between the tunnel area at 15, 20, 25 and 30 C while the tunnel area developed at 35 C wa s significantly higher than those of 15, 20 and 30 C T here wa s no significant difference between the tunnel area of R. viginicus at 15, 20 and 25 C and no significant difference was observed between the tunnel area of C. gestroi at 15, 20, 25 and 30 C Tunnel area of R. viginicus at 30 and 35 C was significantly higher than those at 15 and 20 C Tunnel area of C. gestroi at 35 C was significantly higher than those at other temperatures except at 30 C Temperature had no significant impact on the tunnel area of R. flavipes within temperature range of 15 30 C Data of tunneling activity of R. flavipes were not tested as this species could not survive after 28 d at 35 C according to previous results No significant effect of temperature occurred between species at the same t emperature, except at 30 C Tunnel areas developed by C. gestroi and R. viginicus were significantly different from those of C. formosanus and R. flavipes at 30 C The tunnel area (cm 2 ) by these four subte rranean termit e species at 48 h significant differ ed based on temperature ( F = 8.02 ; df= 4 101; P <0.0001), species ( F = 21.21 ; df= 3 101; P <0.0001) and temperature by species ( F = 25 .73 ; df= 12 101; P <0.0001) (Table 4 3 ). C. formosanus tunneled significantly more tunnel area value at 3 5 C than those of all other temperatures Tunnel areas developed by R. virginicus at 25, 30 and 35 C were not significantly different from each other, while their tunnel areas at 30 and 35 C were significantly larger than those of 15 and 20 C No sign ificant difference was indicated among mean tunnel areas of C. gestroi at all temperatures,

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50 indicating that tunneling speed decreased without the decrease of tunnel area after 48h. A t 15, 20, 25 and 35 C tunnel area excavated by these four termite species were not significantly different among the means at same temperature. Tunnel development of four subterranean termite species within 48 h (cm 2 ) i s shown in Figure 4 3 4 4, 4 5 and 4 6 The curves of tunnel area developed by R. flavipes at 15, 20, 25 and 30 C almost overlapped with each other (Figure 4 6) The result, com bined with two way ANOVA at 12 and 48 h suggest that the tunnel development by R. flavipes was temperature independent within the temperature range of 15 30 C For other three species, t he mean area of tunnels increased with the rise in temperature from 15 to 3 5 C al though the mean values of some combination s of temp erature and species presented were not significantly different from each other. The tunneling areas were u ltimately stabilized between 10 2 0 cm 2 The temperature of 35 C greatly increased the t unnel area developed by C. formosanus to nearly 2 0 cm 2 at 48 h, which was significantly higher than those at other temperature For each species, the high r 2 values of 0.9478 0.9993 of all the data set s validated the exponential function in describing the tunnel area developed by these four subterr anean termite species (Table 4 4 ). C. gestroi had the lowest relative tunneling speed of 0.0 7191 h 1 at 20 C while they re ach ed 90% of the maximum volume at 35 C ( Figure 4 3 ). The tunnel area s developed by R. virginicus reach ed 90% equilibrium values before 3 5 h. Individuals of this species presented the largest relative tunneling speed at 25 C but the largest equilibrium tunnel area was 15.6542 cm 2 at 30 C indicating that R. virginicus excavated tunnel s at a faster speed at 25 C but did not develop the largest tunnel area eventually. The equilibrium tunnel areas develop ed by R.

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51 virginicus at 30 and 35 C were larger than th ose of other temperatures, al though previous result s showed that the survivorship of R. viginicus at 35 C was significantly lower than those of other temperatures The tunnel growth curves of R. avipes did not plateau as abruptly as other three species and are partially overlapped, indicating that the tunnel development of R. avipes may be temperature independent The result agreed with two way ANOVA of tunnel areas at 12 and 48 h of this species. The equilibrium tunnel areas developed by C. formosanus at 35 C was larger than that of 30 C but the relative tunneling speed at 30 and 35 C were not very different The equilibrium tunnel areas generally increased with the rise of temperature s but the relative tunneling speed could increase or decrease with rise of temperature This suggests different tunneling strategies by different subterranean termite species (Su and Lee 2009; Hapukotuwa and Grace 2012 ) The number and proportion of primary, seconda ry and tertiary tunnels developed by C. formosanus and R. avipes could be different under the same laboratory condition. Arab and Costa Leonardo ( 2005 ) reported that the lengths of primary and secondary tunnel excavated by C. gestroi at 20 and 25 C were signi ficantly higher than those of 15 C when the soil moi stures were 10 and 15%. However, when the soil moi stures were 15% lengths of primary and secondary tunnel excavated by C. gestroi at 25 C were signi ficantly higher than those at 15 and 20 C The result of the present study indicated that the tunneling activities of C. g estroi C. f ormosanus and R. v irginicus are temperature dependent within the temperature range of 15 35 C indicating that these subterranean termites may have a greater chance to forage at the food source and cause damage at high temperatures than at low temperatures. The

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52 tunneling activities of R. flavipes appear to be temperature dependent within temperature range of 15 3 0 C This may result from the fact that R. flavipes is a species with cold temperature preference and more than 70% individuals of R. flavipes survive in the temperature range of 15 30 C It also may be the result from certain foraging strategy of R. flavipes which is different from that of C. f ormosanus More studies should be done to reveal the reason. The Number of Moved Food Particles T he result of Kruskal Wallis test showed no significant difference in the number of food particles by R. flavipes between different temperatures with range of 15 30 C (Table 4 5) The tunneling activity of R. flavipes was not observed at 35 C as this species could not survive after 28 days at this temperature Temperatures had a significant impact on the number of food particles by C. formosanus R. virginicus a nd C. gestroi T ermites generally show ed greater ability to move food particles as temperature increase d although no significant differences was observed between some mean values I ndividuals of C. formosanus and C. gestroi move d fewe r number s of food particles at 15 C than that at 35 C The numbers of food particles moved by R. virginicus were not significantly different among the groups exposed to 15 25, 30 C while significantly fewe r number of food particles were moved at 35 C than at 20 C indicating 3 5 C might be the un favorable temperature for this species. This conclusion agreed with agreed with previous results that 3 5 C was too hot for R. virginicus though they can survive at this temperature The fact that the C. gestroi move d more particles as temperature increase d up to 35 C and C. gestroi moved the largest number of particles at 30 and 35 C than 15 C suggested that C. gestroi was most active at 35 C which might not be favorable temperature for other three species. However, 15 C was

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53 too cold for food transportation activity of C. gestroi To sum up, temperature affect ed the movement of food particles by subterranean termites, but t he activities of different species were affected by temperature at different levels. The data agreed with the previous results that the two Coptotermes spp. show ed more prefer ence to warm temperature than Reticulitermes spp and latter species had better cold tolerance than the former species. Nonparametric analysis of food transportation data si mply allo cates a sign to each observatio n but d id not take the magnitude of the observation into account and thus could partially reflect the relationship between temperatures and number of food particles. The Total Distance of Moved Food Particles The total distance of food particles that termite moved in 6 h after they reach ed the food i s shown in Table 4 6 The result of Kruskal Wallis test showed no significantly difference in the total distance of moved food particles by R. flavipes among different temperature s with range of 15 30 C Temperatures did impact the total distance of moved food particles by C. formosanus R. virginicus and C. gestroi For C. formosanus and R. flavipes the distance of moved food particle generally increased as temperature increased 15 35 C and 15 30 C though no significantly different was observed between some mean values T he means at 35 C of C. formosanus were significantly higher than that at 15 C The distance of food particles moved by R. virginicus were not significantly different among 15, 20, 25, 30 C but the mean at 35 C was significantly lower indicating 20 30 C might be the favorable temperature range for this species and 35 C was too hot for them to bring food back to their nest T hough it was believed that within temperature range 15 35 C activity of C. gestroi increase d with the rise of temperature the tendency of distance of moved particles were different from that of

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54 number of food particles. T he longest distance for C. gestroi to move food particles was observed at 25 C but the largest n umber of moved particles appeared at 35 C This result suggested that individuals of C. gestroi move d more food particles at 35 C but at a shorter distance, while at 25 C they move d fewer particle s at a greater distance The number and distance of moved food particles both affect ed the food transportation and exploitation efficiency in subterranean termite colony Food deposition and transportation of subterranean termite sp ecies at various temperatures i s not well understood Alt hough feeding behavior is a direct measurement of potential infestation by subterranean termite, to understand how termite transport food back to their nest and what factors influence this process are also important to improve subterranean termite control strategies This study reported the effect of soil temperature on food transportation of subterranean termites for the first time but further study is needed Table 4 1 T ime required to reach food by four subterranean termite species. Values are presented as means SEs. W ithin a row means with the letter are not statistically different (p <0. 05) ( Kruskal Wallis test hoc test ). -: no data. Temperature ( C ) C gestroi C formosanus R. virginicus R. flavipes 15 21.50 1.93a 16.50 2.43a 12.50 2.70a 11.00 1.06ab 20 10.17 1.11ac 10.50 1.38ab 5.50 0.62a 13.83 2.39a 25 5.50 0.85bc 10.67 1.26ab 5.17 0.65a 6.17 0.60b 30 5.83 0.70ab 10.17 4.35ab 5.33 1.17a 9.50 1.78ab 35 3.50 0.22b 4.00 0.45b 5.17 0.70a -

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55 Table 4 2 Tunnel area (cm 2 ) of four sub terr anean termite species at 12 h Values are presented as means SEs. W ithin the same column means with the same capital letter are not statistically different (p <0. 05). Within a row means with the same lower case subscript letter are not statistically different (p <0. 05). (Two way ANOVA followed by SD tests , n=114) Tempera ture ( C ) C gestroi C formosanus R. virginicus R. flavipes 15 5.68 0.70Aa 2.47 0.47Aa 4.81 0.44Aa 5.78 0.32Aa 20 7.24 0.73Aa 5.06 0.71Aa 6.60 0.45Aa 7.11 1.10Aa 25 7.97 0.52Aa 6.45 0.65ABa 8.81 0.39ABa 8.04 0.5Aa 30 10.49 1.58ABab 4.89 0.34Ac 12.96 2.36Ba 7.82 1.37Abc 35 13.45 1.36Ba 10.56 1.3Ba 13.61 0.82Ba -Table 4 3 Tunnel area (cm 2 ) of four sub terr anean termite species at 48 h Values are presented as means SEs. W ithin the same column means with the same capital letter are not statistically different (p <0. 05). Within a row means with the same lower case subscript letter are not statistically different (p <0. 05). (Two way ANOVA followed by SD tests , n=114) Tempera ture ( C ) C gestroi C formosanus R. virginicus R. flavipes 15 8.82 1.36Aa 2.89 0.35Aa 8.13 0.51Aa 8.49 0.67Aa 20 11.44 0.77Aa 6.80 0.68Aa 8.87 0.92ACa 10.14 1.32Aa 25 10.65 0.80Aa 7.82 0.85Aa 9.61 0.49ABa 10.64 0.87Aa 30 13.24 1.33Aab 7.77 0.89Aa 15.70 2.46Bb 11.06 1.84Aab 35 15.11 1.24Aa 16.09 2.21Ba 14.82 0.84BCa -

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56 Table 4 4 Newly developed t unnel area (cm 2 ) by laboratory groups of four subterranean termite species T unnel volume ( Y ) at time t is described by an exponential function, Y= a*(1 e bt ) Time (hours) required to re ach 90% of the maximum volume was calculated as t 90 = ( ln 0.1)/b Species Temperat ure (C) Equilibrium tunnel area (a) (cm 2 ) Relative tunneling speed (b* 10 3 )(h 1 ) r 2 t 90 C. g estro i 15 9.33534 0.03581 78.83 0.9 4 0.9982 29.21 2.45 20 12.33527 0. 05481 71.91 0.9 3 0.9981 32.02 2.48 25 10.96671 0.01924 110.29 0.76 0.9993 20.88 3.03 30 13.20382 0.0496 0 140.65 2.44 0.9945 16.37 0.94 35 14.92892 0.06604 220.92 5.93 0.9860 10.42 0.39 C. f ormo sanus 15 3.02469 0.01156 138.14 2.41 0.9945 16.67 0.96 20 7.02542 0.06895 102.02 3.73 0.9782 22.57 0.62 25 7.81047 0.07102 160.03 7.28 0.9596 14.39 0.32 30 8.12943 0.15162 81.03 4.79 0.9478 28.42 0.48 35 16.94674 0.17001 80.14 2.53 0.9866 28.73 0.91 R. v irgini cus 15 8.77363 0.05984 67.79 1.29 0.9960 33.97 1.78 20 8.94557 0.04232 112.37 2.12 0.9941 20.49 1.09 25 9.58799 0.02025 217.09 2.76 0.9970 10.61 0.83 30 15.6542 0.06428 141.68 2.7 0 0.9935 16.25 0.85 35 14.76951 0.02601 202.04 2.05 0.9982 11.40 1.12 R. f lavip es 15 8.96705 0.05943 84.75 1.84 0.9935 27.17 1.25 20 10.62375 0.03438 89.36 0.98 0.9983 25.77 2.35 25 10.90308 0.10442 109.88 4.13 0.9767 20.96 0.56 30 11.37897 0.06976 97.56 2.16 0.9925 23.60 1.07

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57 Table 4 5 Number of food particles transported by four subterranean termite species 6 h after they reached food. Values are presented as means SEs. W ithin a column means with the same capital letter are not statistically different ( a=0. 05) ( Kruskal Wallis test hoc test ). -: no data. Temperature ( C ) C gestroi C formosanus R. virginicus R. flavipes 15 3.5 0.7a 6. 7 3.7a 10.0 4.8ab 5. 2 1.8a 20 22.3 4.5ab 10.8 1.4ab 47.3 11.4a 6. 2 3.9a 25 63.5 7.2ab 10. 2 2.7ab 4 3.0 15.1ab 11. 7 4.3a 30 68.3 15.5b 19.3 6.1ab 34. 2 6.9ab 16.8 11.8a 35 75. 7 29.1b 38.0 6.3b 8. 7 5.4b -Table 4 6 Distance of food particles transported by four subterranean termite species 6 h after they reached food ( m m) Values are presented as means SEs. W ithin a column means with the same capital letter are not statistically different ( a=0. 05) ( Kruskal Wallis test hoc test ). -: no data. C C. formosanus R. virginicus C. gestroi R. flavipes 15 40 3.0 227.6 a 368.8 165.4 ab 1 60.2 37.2 a 190.2 89.3 a 20 535.1 108.7 ab 1565.2 440.3 ab 1222. 7 501.1 ab 426.5 274.0 a 25 464. 3 130.1 ab 1721. 2 582.4 ab 3939. 5 706.2 b 426.5 150.4 a 30 1128. 5 328.8 ab 1641. 5 350.0 a 2773. 7 877.6 ab 839. 5 490.9a 35 1774. 1 392.1 b 261.2 184. 9 b 2671.4 1156.7 ab -

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58 Figure 4 1 Two dimensional arenas set up based on Chouvenc et al (2011). The arena was filled with moistened sand. A quarter of Coloration Construction paper was deposited as food source on the opposite corner of introduction hole. A 10 cm 2 empty space was set aside under the introduction hole. Termites were released into the arena through the hole, and then the hole was sealed using parafilm (Photo by Runxin Cao)

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59 Figure 4 2 Tunnel pattern (with termites) at 48h (sample) (Photo by Runxin Cao)

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60 Figure 4 3 Tunnel development of C. gestroi within 48 h (cm 2 ). Figure 4 4 Tunnel development of C. formosanus within 48 h (cm 2 ).

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61 Figure 4 5 Tunnel development of R. virginicus within 48 h (cm 2 ). Figure 4 6 Tunnel development of R. flavipes within 48 h (cm 2 ).

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62 CHAPTER 5 SUMMARY AND CONCLUSION Some termi te species are econ omically important insects that can cause serious structural problem and billions of dollars of economic loss on the global scale (Su and Scheffrahn 1990; Su 2003; Rust and Su 2012) According to published data the worldwide control and re pair expenditure on subterranean termite s continues to increas e in the last half century ( Figure 5 1 ) Coptotermes and Reticulitermes are the two gene ra that contain the largest number of serious termite pest species (Rust and Su 2012) C. formosanus was introduced to North America over one century ago and causes more damage than their native counterpart, Reticulitermes spp in l arge areas of southeast states of the United States ( Kistner 1985; Gautam 2011 ) The current control strategies include soil treatment using termiticide, physical barriers, monitoring baiting system and protective method, such as wood treatment. The general objective of monitoring baiting system is to manage termite population by eliminating colonies (Rust and Su 2012) The ac tivity of subterr anean termite is affected by a combination of several abiotic and biotic factors, such as temperature, moisture and food source they feed on ( Smythe and Carter 1969; Su and Tamashiro 1986; Fei and Henderson 2002; Nakayama et al. 2004; Green et al. 2005; Wong and Lee 2010; Gautam and Henderson 2011; Wiltz 2012 ) Geographic distribution and damage potential of termite are affected by multiple factors, including t emperature ( Ikehara 1980; Li et al. 2009; 2013) This study aim ed to reveal t he relationship between temperature on survival and activity of four economically important subterranean termite species, C. formosanus C. gestroi R flavipes and R virginicus under laboratory condition s

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63 In Chapter 2, termites response to temperature gradient on aluminum bridge surface was examined A 60 cm long aluminum bridge with one side contacting ice water and the other side contacting boiling water was set up to generate a temperature gradient. T ermite s were release d at the center of the bridge surface, a nd the movement and distribution of termite s on the bridge surface was recorded by video camera. The result showed the temperature ranges of live individuals of C. gestroi C. formosanus R virginicus and R flavipes were 9.4 39.0 C 5. 2 38 .7 C 4.1 37 .1 C and 3 .4 34.6 C respectively. The temperature ranges of active individuals of C. gestroi C. formosanus R virginicus and R flavipes were 13.0 38.6 C 9.3 38 1 C 8.2 36 7 C and 5.2 34.0 C respectively. T he largest number of C. formosanus was found in temperature range 29.5 35. 7 C while the largest number of C. gestroi were found in the range of 33.6 38.6 C The distributions of C. formosanus and C. gestroi w ere generally skewed towards the warm side (>25.5 C ) instead of cold side (<25.5 C ) of the bridge surface but a few individuals of both species moved into coldest temperature range and became immobilized indicating that they may not avoid cold temperature R flavipes and R virginicus had the largest number of individuals d istributed in temperature range 2.4 9.5 C and 4.1 11 C Both Reticulitermes species were generally found towards the cold side of the bridge (<25.5 C ) indicating their cold temperature preference <25.5 C Very few Reticulitermes moved to temperature zones ( >25.5 C ) and finally the number of individuals in the two hottest temperature zones was low, suggesting hot temperature avoidance by these two species The mTPV of R flavipes was 15.24 0.23 C and that of C. formosanus was 28.11 0.19 C Coptotermes spp had significantly higher mTPV than Reticulitermes spp and this may be the reason why Reticulitermes spp have the

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64 larger distribution area in northeast states in United States probably because they demonstra ted better cold tolerance than Coptotermes spp Surviv or ship and wood consumption rate were used to measure the temperature tolerance and temperature dependent activity level of subterranean termite s The experiment was conducted RH in constant darkness. Survival and wood consumption rate w ere analyzed using two way ANOVA with species and temperature as independent variables. The result showed that in the temperature s of 20 C, the survival and wood consumption rate were not significantly different among four species while at the extreme temperature of 10, 15, 35 C, both variables were significantly different among species R flavipes survive d at 10 C but not at 35 C The activity of C gestroi was high at 35 C but this species was not able to survive at 10 C Th e result agree d with most of the previous studies and may be used to explain the geographic distribution s of these four subterranean termite species and to predict the areas wit h high invasion risks The final experiment examined temperature effects on tu nnel area, tunneling speed, the number of hours required for termites to reach food and the number and distance of moved food particles using two dimensional arena s This experiment aimed to examine the effect of soil temperature on tunneling and food transportation speed of four subt erranean termite species at various temperature s ( 15, 20, 25, 30 and 35C ) T wo dimensional Plexiglas arenas ( 10 X 10cm ) were set up and the tunneling activi ty of termites was recorded for 48 h by digital camera s The result showed that as the temp erature increased, the tunnel development increased and the tunneling speed decreased but no significantly difference was found between some

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65 combination s of temperature and species according to two way ANOVA Time required for termites to reach food decreased as temperature increased Once they reached the food, the tunneling activity substantial ly slowed down. The number and distance of food particles moved by C. formosanus R flavipes and R virginicus increased as temperature rose in the temperature range of 10 3 0 C C. gestroi moved food particles at to the furthest distance at 25 C but the largest number of food particles moved by this species occurred at 35 C Studies of t unneling behavior and food transportation are both important to understand the seasonality of these subterranean termite species. A geographic area with coldest and hottest temperature at which these termites are able to survive may indicate future invasion and potential damage In conclusion the effect of temperature on survivorship and activity level of these subterranean termite species reported by present study generally agree with their geographic distribution in the United States. The cold temperature preference decreased in this order for these four species: R flavipes > R virginicus > C. formosanus > C. gestroi T he warm temperature preference increased in this order: C. gestroi > C. formosanus > R virginicus > R flavipes Information from this study may aid in structure protection and management of subterranean termite

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66 Table 5 1. Economic impact of termite during the last half century $ cost Year Reference Area Remarks 39 million 1959 Ebeling 1959 California 250 million 1963 Su and Scheffrahn 1990 Entire U.S. corrective and preventive work by pr ivate termite control operators costs about $125 million/year 500 million 1968 Ebeling 19 68 169 million 197 6 Willians and Smythe 1978 11SE States in U.S. 471 million 1 976 Su and Scheffrahn 1990 Entire U.S. 579 million 1983 H amer 1985 9 SE States in U.S Drywood termite 18%; Subterranean termite 82% 1.02 billion 1986 Edward and Mill 1986 Entire U.S. 1.5 billion 199 3 Su 199 4 Entire U.S. Subterranean termite 80% 1999 Su et al. 2002 Entire U.S. Subterranean termite 2.2 billion 40 billion 2010 Rust and Su 2012 Global Subterranean termite 80%

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67 LIST OF REFERENCES Arab, A., and A. M. Costa Leonardo. 2005. Effect of biotic and abiotic factors on the tunneling behavior of Coptotermes gestroi and Heterotermes tenuis (Isoptera: Rhinotermitidae). Behav. Processes 70: 32 40. Araujo, R. L. 1958. Contribuio biogeografi a dos trmitas de So Paulo, Brasil (Insecta, Isoptera). Arq. Inst. Biol. 25: 185 217. Austin, J. W. A.L. Szalanski, R. E. Gold, and B. T. Foster. 200 4a Genetic variation and geographical distribution of the subterranean termite genus Reticultermes in Te xas. Southweatern Entomol. 29(1): 1 11 Austin, J. W., A. L. Szalanski, and B. M. Kar d. 2004 b Distribution and genetic variation of Reticulitermes (Isoptera: Rhinotermitidae) in Oklahoma. Fla. Entomol. 87(2) : 152 158. Austin, J. W. A. L. Szalanski, and M. T. Messenger. 2004 c Genetic variation and distribution of the subterranean termite genus Reticulitermes (Isoptera: Rhinotermitidae) in Arkansas and Louisiana. Fla. Entomol. 87(4): 473 480 Bank, F. A., and, T. E. Snyder. 1920. A revision of the Nearct ic termites. Bull. U. S. national Museum. 108: 1 228 Bardunias M. P. 2013. Traffic f low and t actile i nteractions o rganize the l abor of s ubterranean t ermites d uring t unnel e xcavation: an a lternative to s cent m ediated s tigmergy ). Ph. D. Thesis, University of Florida 58. Beal, R. H. 1967. Formo san invader. Pest Control 35(2) : 13 17. Borstein, S. 1993. Our nasty neighbors too close for comfort: a new kind of hard to eradicate termite has shown up in the Atlanta area. The A tlanta Journal a nd Constitution Sec. C: 1. Brown, K. S., B. P. Yokum, C. Riegel, and M. Carroll. 2007 New parish records of Coptotermes formosanus (Isoptera: Rhinotermitidae) in Louisiana. Fla. Entomol. 90(3): 570 572. Cabrera, B. J., and M. K. Rust. 1996 Behavioral responses to light and thermal gradients by the western drywood termite (Isoptera: Kalotermitidae). Environ entomo l 25(2) : 436 445. Cabrera, B. J., N. Y. Su, R. H. Scheffrahn, F. M. Oi and P. G. Koehler. 2005. Formosan Subterranean termite. B ulletin of a series of the Entomological and Nematology Department, University of Florida (ENY 216)

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68 Campora, C. E., and J. K. Grace. 2001. Tunnel orientation and search pattern sequence of the Formosan subterranean termite (Isoptera: Rhinotermitidae). J. Econ. Entomol. 94: 1193 1199. Cham bers, D. M., P. A. Zungoli, and H. S. Hill Jr. 1988. Distribution and habitats of the Formosan subterranean termite (Isoptera: Rhinotermitidae) in South Carolina. J. Econ. Entomol 81:1611 1619. Chouvenc T, P M. Bardunias H F Li, M L Elliott and N Y Su. 2011 Planar arenas for use in laboratory bioassay studies of subterranean termites (Rhinotermitidae). Florida Entomol 94: 817 826. Collins, M. S. 1969. Water rela tions in termites, pp. 433 435. In K. Krishna and, F M. Weesner (eds.), Biology of termites, vol. I. Academic, N Y Collins, N. M. 1981. The role of termites in the decomposition of wood and leaf litter in the Southern Guinea savanna of Nigeria. Oecologia 51(3): 389 399. Cornelius, M. L., and, W. L. A. Osbrink. 2010. Effect of soil type and moisture availability on the foraging behavior of the Formosan subterranean termite (Isoptera: Rhinotermitidae). J. Econ. Entomol. 103: 799 807. Ebeling, W. 1959. Termite control in California residential co nstruction. Amer. Soc. Test. Mat., Spec. Tech. Publ. 282: 92 111 Ebeling, W. 1968. Termites: identification, biology, and control of termites attacking buildings. Univ. Calif., Calif. Agric. Exp. Stn. Ext. Serv. Man. 38: 74 Edwards, R., and A. E. Mill. 1 986 Termites in buildings: t heir biology and control, pp 261. In Termites in Buildings (eds.), Rentokil Ltd, East Grinstead, England. Ehrhorn, E. M., and C. A. Kofoid 1934. The termites of Hawaii, their economic significance and control, and the distribution of termites by commerce. Termites and termite contro l 321 333. Ettershank, G., J. A. Etiershank, and W. G. Whitford 1980. Location of food sources by subterranean termi tes. Environ Entomol 9 (5) : 645 648. Evans, T. A. 2003. The influence of soil heterogeneity on exploratory tunneling by the subterranean termite Coptotermes frenchi (Isoptera: Rhinotermitidae). Bull. Entomol. Res. 93: 413 423. Evans, T. A., and P. V. Gleeson. 2001. Seasonal and daily activity patterns of subterranean, wood eating termite foragers Australian Journal of Zoology 49(3) : 311 321.

PAGE 69

69 Fei, H., and G. Henderson. 2002. Formosan subterranean termite (Isoptera: Rhinotermitidae) wood consumption and worker survival as affected by temperature and soldier proportion. Environ. Entomol. 31: 509 514. Fei, H., and G. Henderson. 2004. Effects of temperature, directional aspects, light conditions and termite species on subterranean termite activity (Isoptera: Rhinotermitidae). Environ. Entomol. 33: 242 246. F orschler, B. T., J. Harron, and T. M. Jenkins. 2000. Case histories involving the Formosan subterranean termite (Isoptera: Rh inotermitidae) in Atlanta, Georgia, USA. Sociobiology 36: 1 11. Gautam B. K. 2011. M. S. thesis. Louisiana State University Gautam, B. K., and G. Henderson. 2011 Wood consumption by Formosan subterranean termites (Isoptera: Rhinotermitidae) as affected by wood moisture content and temperature. Ann. Entomol. Soc. Am 104 (3) : 459 464. Genet, J. A., K. S. Genet, T. M. Burton, P. G. Murphy, and A. E. Lugo. 2001 Response of termite community and wood decomposition rates to habitat fragmentation in a subtropical dry forest. Trap. Ecol. 42(1): 35 49. Gold, R. E, H. N. Howell, and G. J. Glenn. 1999. Formosan subterranean termites. Texas A&M Univ. Agri. Extension Serv. Bulletin L 5233 Green, J. M., M. E. Scharf, and G. W. Bennett 2005. Impacts of soil mo isture level on consumption and movement of three sympatric subterranean termites (Isoptera: Rhinotermitidae) in a laboratory assay. J E con Entomo l. 98 (3) : 933 937. Hamer, J. L. 1985. Southeastern branch insect detection, evaluation and prediction report 1983. Vol 8. Entomol. Soc. Am., College Park, MD. Harahap I. S., E. P. Benson, P. A. Zungoli and H. S. Hill Jr. 2005. Impact of seasonal temperatures and RH on cellulose consumption by Reticulitermes flavipes and Reticulitermes virginicus (Isoptera: Rhinotermitidae). In Proceeding of the fifth internat ional conference on urban pests (eds ), Network, Malaysia. Hapukotuwa, N. K., and Grace, J. K. 201 2 Coptotermes formosanus and Coptotermes gestroi (Blattodea: Rhinotermitidae) exhibit quantitatively different tunneling patterns. Psyche: A J Entomo l. Haverty, M. I. and W. L. Nutting 1974. Natural wood consu m ption rates and survival of a drywood and subterranean termite at constant temperatures. An n. Entomol. Soc. Am. 67: 153 157.

PAGE 70

70 Haverty, M. I., and W. L. Nutting 1976. Environmental factors affecting the geographical distribution of two ecologically equivalent termite species in Arizona. American Midland Naturalist 20 27. Haverty, M. I., J. P. La Fage, and W. L. Nutting. 1974. Seasonal activity and environmental control of foraging of the subterranean termite, Heterotermes aureus (Snyder), in a desert grassland. Life Sciences 15(6) : 1091 1101. Hawthorne, K. T., P. A. Zungoli, and E. P. Benson. 2000. Termites of South Carolina: Entomology Insect Information Series, Cooperative Extension Service Bulletin IIS/HS 27. Henry, J. A., K. M. Portier, and J. Coyne. 1994. The climate and weather of Florida. P ineapple Press, Inc., Sarasota, FL. Hedlund, J. and G. Henderson. 1999. Effect of available food size on search tunnel formation by the Formosan subterranean termite (Isoptera: Rhinotermitidae). J Econ. Entomol. 92: 610 616. Holt, J. A., and, M. Le P age. 2000 Termites and soil properties, pp 389 407 In T, Abe, E. D. Bignell, and, M. Higashi (eds.), Termites: Evolution, Sociality, Symbioses, Ecology. Kluwer Academic Publ, Dordrecht, Netherland. Horne, B. 1998 Termites prevalent in area. Observer time, Fayetteville, NC Howard, R. W., S. C. Jones, J. K. Mauldin, and R. H. Beal. 1982. Abundance, distribution, and colony size estimates for Reticulitermes spp (Isoptera: Rhinotermitidae) in southern Mississippi. Environmental Entomology, 11(6): 1290 1293. Hu, X. P., and F. Oi. 2004. Distribution and establishment of Formosan subterranean termite in Alabama. Sociobiology 44: 35 47. Ikehara. 1980. Termite fauna of Ryukyu islands. Anima. 91: 18 22 (In J apanese) Jarrat, J. H. 1999. Mississippi State Extension Pest Monitor, Feb 1999. Jar rat, J. H. 2000. Mississippi State Extension Pest Monitor, Aug 2000. Jenkins, T. M., S. C. Jones, C. Y. Lee, B. T. Forschler, Z. Chen, G. Lopez Martinez, N. T. Gallagher, G. Brown, M. Neal, B. Thistleton, and S. Kleinschmidt. 2007. Phylogeography illuminates maternal origins of exotic Coptotermes gestroi (Isoptera: Rhinotermitidae). Molecular Phylogenetics and Evolution 42: 612 621. Johnson, K. A., and W. G. Whitford 1975. Foraging ecology and relative importance of subterranean te rmites in Chihuahuan desert ecosystems. Environ Entomol 4 (1) : 66 70.

PAGE 71

71 Jones, S. C., a nd W. L. N utt ing. 1989. Foraging ecology of subterranean termites in the Sonoran desert, pp. 79 106. In Justin O Schmidt ( ed. ) Special biotic relationships in the arid southwest. University of New Mexico Press, Albuquerque. Jouquet, P., M. Lepage, and B. Velde. 2002. Termite soil preferences and particle selections: strategies rel ated to ecological requirements Insectes S ociaux 49: 1 7. K istner D.H. 1985. A new genus and species of termitophilous Aleaocharinae from mainland China associated with Coptotermes formosanus and its zoogeographical significance (Coleoptera: Staphylinidae). Sociobiology 10:93 104 King, E. G., and W. S. Spink. 1969. Foraging galler ies of the Formosan subterranean termite, Coptotermes formosanus, in Louisiana. Ann. Entomol. Soc. Am. 62: 536 542. Kirton, L. G., and M. Azmi. 2005 Patterns in the relative incidence of subterranean termite species infesting buildings in peninsular Malay sia. Sociobiology 46: 1 15. Kirton, L. G ., and V. K. Brown. 2003. The taxonomic status of pest species of Coptotermes in Southeast Asia: Resolving the paradox in the pest status of the termites Coptotermes gestroi C. havilandi, and C. travians (Isoptera: Rhinotermitidae). Sociobiology 42: 43 63. Koehler, P. G. 1980. The Formosan subterranean termite. Florida Coop. Ext. Service, Univ. Florida Inst. Food Agric. Sci. circular ENT 51. Kofoid, C. A. 1934. Termites and t heir c ontrol. U niversity of California Press. Berkeley, CA 795 Lee, S. H., R. L. Yang, and N. Y. Su. 20 08. Tunneling response of termites to a pre formed tunnel. Behavioral processes 79(3) : 192 194. Li, H. F. I. Fujisaki, and N. Y. Su. 2013. Predicting Habitat Suitability of Coptotermes ge stroi (Isoptera: Rhinotermitidae) With Species Distribution Models. J Econ Entomol 106(1) : 311 321. Li, H. F., W. Ye, N. Y. Su, and N. Kanzaki. 2009. Phylogeography of Coptotermes gestroi and Coptotermes formosanus (Isoptera: Rhinotermitidae) in Taiwan. Ann. Entomol. Soc. Am. 102: 684 693. Light, S. F. 1934. The termite fauna of North America with special reference to the United States. In Termite and Termite Control (eds.) C. A. Kofoid, Univ. California Press, Berk eley. 127 135 Light, S. F. and A. L. Pickens. 1934 American subterranean termite, their classification and distribution. In Termite and Termite Control (eds.) C. A. Kofoid, Univ. California Press, Berkeley. 150 156

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72 Mackay, W. P., S. Silva, D. C. Lightfoot M. I. Pagani, and W. G. Whitford 1986. Effect of increased soil moisture and reduced soil temperature on a desert soil arthropod community. American Midland Naturalist 45 56. McKern, J. A., A. L. Szalanski, and J. W. Austin. 2006. First record of Reticu litermes flavipes and Reticulitermes hageni in Oregon (Isoptera: Rhinotermitidae). Fl a. Entomol 89(4) : 541 542. Messenger, M., N Y. Su, and R. H. Scheffrahn. 2002. Current distribution of Formosan subterranean termite and other termite species (Isoptera: Rhinotermitidae) in Louisiana. Fla Entomol. 5: 580 587. Mori, M. T. Yoshimura and Y. Takematsu 2002. Termite inhabitation in the northern Hokkaido Shiroari 127 : 12 19. N akayama, T., T. Yoshimura and Y. Imamura. 2004. The optimum temperature humidity combination for the feeding activities of Japanese subterranean termites. J Wood Sci 50(6) : 530 534. NOAA. http:/ /cdo.ncdc.noaa.gov/cgi bin/climaps/climaps.pl Puche, H., and N. Y. Su 2001 Tunnel formation by Reticulitermes flavipes and Coptotermes formosanus (Isoptera: Rhinotermitidae) in response to woo d in sand. J. Econ. Entomol. 94 : 1398 1404. Reddy, M. V., and C. Sammaiah. 1991. Combined effects of climatic factors on the seasonal termite damage to structural wood in a semi arid urban system. Energy and Buildings 15 16: 947 955. Reinhard, J., H. Hertel, and M. Kaib. 1997. Systematic search for food in the s ubterranean termite Reticulitermes santonensis De Feytaud (Isoptera, Rhinotermitidae). Insectes S ociaux 44: 147 158. Rust, M. K., and N. Y. Su. 20 1 2 Managing Social Insects of Urban Importance. Annu. Rev. Entomol. 2012. 57:355 75. SAS Institute. 1998. s reference manual, 2nd. SAS Institute, Cary, NC. Scheffrahn, R. H., J. A. Chase, J. R. Mangold, and N. Y. Su. 1999 First record of Reticulitermes (Isoptera: Rhinotermitidae) from the West Indies : R. flavipes on Grand Bahama Isl and. Fl a E ntomol 82 (3) : 480 482. Scheffrahn, R.H., J . A. Chase, B Maharajh, and J R. Mangold. 2006. Taxonomy, Biogeography, and Notes on the Termites (Isoptera: Kalotermitidae, Rhinotermitidae, Termitidae) of the Bahamas and Tur ks and Caicos Islands Ann. Entomol. Soc. Amer. 99: 463 486.

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73 Scheffrahn, R. H., S. C. Jones, J. Krecek, J. A. Chase, J. R. Mangold, and Su N. Y. 2003 Taxonomy, distribution, and notes on the termites (Isoptera: Kalotermitidae, Rhinotermitidae, Termitidae) of Puerto Ri co and the US Virgin Islands. Ann. Entomol. Soc. Amer. 96(3) : 181 201. Scheffrahn, R. H., and N. Y. Su. 2005 Distribution of the termite genus Coptotermes (Isoptera: Rhinotermitidae) in Florida. Fla Entomol. 88: 201 203 Scheffrahn, R. H., and N. Y. Su. 2008. Asian subterranean termite, Coptotermes gestroi (=havilandi) (Wasmann) (Insecta: Isoptera: Rhinotermitidae). Florida Coop. Ext. Service, Univ. Florida Inst. Food Agric. Sci. circular EENY 128. Sen Sarma, P. K., and S. C. Mishra 1969. Seasonal varia tions of nest population in Microcerotermes beesoni Snyder. In Proceedings of the National Institute of Sciences of India B, Biological Sciences 35 : 361 367 S cheffrahn, R. H., N. Y. Su, and B. Diehl. 1990. Native, introduced and structure infesting termit es of the Turks and Caicos Islands, B.W.I. (Isoptera: Kalotermitidae, Rhinotermitidae, Termitidae). Fla. Entomol. 73: 622 627. Smith, J. L., and M. K. Rust. 1991. Factors affecting the tunneling behavior of the western subterranean termite, Reticulitermes hesperus Banks, USDA Forest Service. Gen. Tech. Rep. 1: 28 33. Smith, J. L., and Rust, M. K. 199 3 Temperature preferences of the western subterranean termite, Reticulitermes hesperus Banks. Jour nal of arid environments 28(4) : 313 323. Smythe, R. V, and F., Carter. 1969. Feeding responses to sound wood by the eastern subterranean termite, Reticulitermes flavipes Ann. Entomol. Soc. Am. 62: 335 337 Snyder, T. E. 1934. American subterranean termites other than those of the pacific Coast. In Termite and T ermite Control (eds.) C. A. Kofoid, Univ. California Press, Berkeley. 187 195 Snyder, T. E. 1949. Catalog of the termites (Isoptera) of the world. Smithsonian Misc, Collections vol. 112. S ornnuwat Y C Vongkaluang T Yoshimura K Tsunoda and M Takahashi 1995. Wood c onsumption and s urvival of the s ubterranean t ermite, Coptotermes gestroi Wasmann using the Japanese Standardized Testing Method and the Modified Wood Block Test in Bottle." Wood research: bulletin of the Wood Research Institute Kyoto University 82 : 8 13. Spink, W. T. 1967. The Formosan subterranean termite in Louisiana. Louisiana State Univ. Circ. 89: 12

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74 Su, N. Y. 1991. Evaluation of bait toxicants for suppression of subterranean te rmite populations. Sociobiology 19(21) : 21 1 2 13 Su N. Y. 1994. Field evaluation of a hexaflumuron bait for population suppression of subterranean termites (Isoptera: Rhinotermitidae). J. Econ. Entomol. 87(2) : 389 397. Su, N. Y. 2003. Overview of the global distribution and control of the Formosan subterranean termite. Sociobiology 41: 7 16 Su, N. Y. 2003. Baits as a tool for population control of the Formosan subterranean termite. Sociobiology 41: 177 192. Su, N. Y., P. M. Ban and R. H. Schelfrahn. 1991. Population suppression of field colonies o f the Formosan subterranean termite (Isoptera: Rhinotermitidae) by dihaloalkyl arylsulfone (A 9248) baits. J. Econ. Entomol. 84: 1525 1531. Su, N. Y. and J. P. La Fage. 1984 a Comparison of laboratory method for estimating wood consumption rate by Coptotermes formosanus Shiraki (Is optera: Rhinotermitidae). Ann. Entomol. Soc. Am. 77: 125 129. Su, N. Y., and J. P. La Fage. 1987 Effects of soldier proportion on the wood consumption rate of the Formosan subterranean termite (Isoptera: Rhinotermitidae). Sociobiology 13: 145 151. Su, N. Y., and Lee, S. H. 2009. Tunnel volume regulation and group size of subterranean termites (Isoptera: Rhinotermitidae). Ann. Entomol. Soc. Am. 102(6) : 1158 1164. Su, N. Y P. M. Ban, and R. H Scheffrahn. 2002. Control of subterranean termite populations at San Cristbal and El Morro, San Juan National Historic Site. Journal of Cultural Heritage 3( 3) : 217 225. Su, N. Y., and H. Puche. 2003. Tunneling activity of subterranean termites (Isoptera: Rhinotermitidae) in sand with moisture gradients. J. Econ. Entomol. 96: 88 93. Su, N. Y., and R. H. Scheffrahn. 1986. A method to access, trap, and monitor field populations of the Formosan subterranea n termite (Isoptera: Rhinotermitidae) in the urban environment. Sociobiology 12: 299 304. Su, N. Y., and R. H. Scheffrahn. 1990. Economically important termites in the United States and their control. Sociobiology 17: 77 94 Su, N. Y., and M. Tamashiro. 19 86. Wood consumption rate and survival of the Formosan subterranean termite (Isoptera: Rhinotermiti dae) when fed one of six woods commercially used in Hawaii. Proc. Hawaii Entomol. Soc. 26: 109 113. Su, N. Y., and M. Tamashiro. 1987. An overview of the Formosan subterranean termite (Isoptera: Rhinotermitidae) in the world, pp 3 15. In M. Tamashiro and, N. Y. Su

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75 (eds.), Biology and control of the Formosan subterranean termite. College of Trop. Agric. Human Res., Univ. of Hawaii, Honolu lu, Hawaii. Sun, J Z., M. E. Lockwood, J. L. Etheridge, J. Carroll, C. Z. Hollomon C. E. H. Coker, and P. R. Knight. 2007. Distribution of Formosan subterranean termite (Isoptera: Rhinotermiti dae) in Mississippi. J. Econ Entomol 100(4): 1400 1408. Tamas hiro, M., J. R. Yates, and R. H. Ebesu. 1987 The Formosan subterranean termite in Hawaii: Problems and control. pp 15 22. In M. Tamashiro and, N. Y. Su (eds.), Biology and control of the Formosan subterranean termite. College of Trop. Agr. Human Resouces. Univ. of Hawaii, Honolulu, HI. Traniello, J.F.A. and, S. Robson, 1995. Trail and territorial phero mones in the social insects. In Chemical Ecology of Insects W.J. Bell and R. Carde (e ds. ), Chapman and Hall publishers, Oxford. pp. 241 285. Trinh V. H., T. H. Tran, T H. Nguyen, 201 0 Diversity of termite species in Vietnam, Proc. 7th Pacific Rim Termite Research Gr oup Conference, Singapore, Science and Technics Publishing House. Tsai C C and C S. Chen 2003. First Record of Coptotermes gestroi (Isoptera : Rhinotermitidae) from Taiwan. Formosan Entomol. 23: 157 161 Wang, C., J. E. Powell, and R. H. Scheffrahn. 2003 Abundance and distribution of subterranean termites in southern Mississippi forests (Isoptera: Rhinot ermitidae). Sociobiology, 42(2) : 533 542 Wang, C., X. Zhou, S. Li M. Schwinghammer, M. E. Scharf G. Buczkowski, and G. W. Bennett, 2009. Survey and Identification of Termites (Isoptera: Rhinotermitidae) in Indiana. Ann. Entomol. Soc. Am 102 (6) : 1029 1036. Weesner, F. M. 1965. Termites of the United States. The National Pest Control As sociation. Elizabeth, N J Weesner, F. M. 1970. Termites of the Nearctic Region. In Biology of Termites, Vol. 1 (eds.) F. M. Weesner and, K. Krishna. Academic Press, New York and London. 477 525 Wiltz, B. A. 2 012. Effect of Temperature and Humidity on Survival of Coptotermes formosanus and Reticulitermes flavipes (Isoptera: Rhinotermitidae). Sociobiology 59(2): 381 394. Wong, N., and C. Y. Lee 2010. Influence of d ifferent s ubstrate m oistures on w ood and m ovement p atterns of Microcerotermes crassus and Coptotermes gestroi (Blattodea: Termitidae, Rhinotermitidae). J. Econ. Entomol. 103(2):437 442. Wood, T. G. 1988. Termites and the soil environment. Biol Fertil Soils. 6:228 236

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76 W oodson, W. D., B. A. Wiltz, and A. R. Lax. 2001 Current distribution of the Formosan subterranean termite (Isoptera: Rhinotermitidae) in the United States. Sociobiology 37(3B): 661 671. Yamano K 1997 Practical knowl edge for biology of termites Shiroari 107:12 21 (in Japanese). Yates, J. R, and M. Tamashiro 1990 The Formosan subterranean termite in Hawaii. Research extension series 117 of College of tropical agriculture and human resources, University of Hawaii

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77 BIOGRAPHICAL SKETCH Runxin Cao was born in Jinan, Chin a in 1989. Alt hough she grew up in downtown area of the capital city, she was fascinated with plants and small animals during her childhood. There were always many ornamental flowers raised by her parents, and she reared silkworms as pets when she was in p rimary school. During her middle school period, chemistry and biology were her favorite subjects. In 2007, Runxin entered the undergraduate program in Plant Protection at the South China Agricultural University in Guangzhou, China. There she met Dr. Zaifu Xu, who led her into the world of entomology. Dr. Zaifu Xu was her instructor in her general entomology course and then became her research mentor. Runxin worked in Dr. Zai Agri. Key Lab. of Entomology as a research assistant for two a nd half year She studied the biological characteristics on cotton mealybug, Phenacoccus solenopsis Tinsley, parasitoid wasp, Aenasius bambawalei Hayat and ornamental butterfly, Delias pasithoe porsenna and published two scientific papers. Runxin got her bachelor s degree from South China Agricultural University i n June, 2011 and was accepted at the Fort Lauderdale Research and Education Center, University of Florida, as a master s student and research assistant in August. During the two years at U F, she studied ecology and behavior of subterranean termite. Dr. Nan Yao Su was her advisor. She graduated with her Master of Science degree from the Univers ity of Florida in Aug ust 20 13