TEMPERATURE-DEPENDENT 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 1 © 2013 Runxin Cao 2 To my parents and fiancé, for their endless love 3 ACKNOWLEDGMENTS I would 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 could 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 encouraged 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. John Zukowski helped me to do termite collection. Garima Kakkar, Ling Xin and He Du provided me with lots of academic information. I thank Sarah Kern and Joanne Korvick for helping me to live a better life in the new environment. Last but 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 fiancé, Tianqi Li (He still owes me an 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. 4 TABLE OF CONTENTS page ACKNOWLEDGMENTS .................................................................................................. 4 LIST OF TABLES ............................................................................................................ 7 LIST OF FIGURES .......................................................................................................... 8 ABSTRACT ................................................................................................................... 10 CHAPTER 1 GENERAL INTRODUCTION .................................................................................. 12 Economic Impact .................................................................................................... 12 Distribution .............................................................................................................. 12 Hypotheses ............................................................................................................. 14 Objectives ............................................................................................................... 14 2 TEMPERATURE PREFERENCE OF FOUR SUBTERRANEAN TERMITE SPECIES (ISOPTERA: RHINOTERMITIDAE) ........................................................ 16 Introduction ............................................................................................................. 16 Materials and Methods............................................................................................ 17 Results and Discussion........................................................................................... 19 3 EFFECT OF SOIL TEMPERATURE ON SURVIVAL AND WOOD- CONSUMPTION RATE OF FOUR SUBTERRANEAN TERMITE SPECIES (ISOPTERA: RHINOTERMITIDAE) ........................................................................ 29 Introduction ............................................................................................................. 29 Materials and Methods............................................................................................ 30 Results 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 Materials and Methods............................................................................................ 45 Results and Discussion........................................................................................... 48 Time Required to Reach Food ......................................................................... 48 Tunneling Area Development ........................................................................... 48 The Number of Moved Food Particles .............................................................. 52 5 The Total Distance of Moved Food Particles .................................................... 53 5 SUMMARY AND CONCLUSION ............................................................................ 62 LIST OF REFERENCES ............................................................................................... 67 BIOGRAPHICAL SKETCH ............................................................................................ 77 6 LIST OF TABLES Table page 2-1 Cold and hot boundaries of live and active termites of four subterranean termite species at 10 min.. .................................................................................. 25 2-2 Total number of active termites (b) on the bridge and mean temperature preference value (mTPV) 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 (cm2) of four subterranean termite species at 12 h. ........................ 55 4-3 Tunnel area (cm2) of four subterranean termite species at 48 h. ........................ 55 4-4 Newly-developed tunnel area (cm2) 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 7 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 America (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). .................................................................................................................