RETICULITERMES FEEDING PREFERENCE AND EXPERIMENTAL DESIGN by GRETCHEN DENISE PERKINS (Under the Direction of Brian T. Forschler) ABSTRACT Subterranean termites are a prevalent urban pest that cost billions of dollars in damage, control, and repair costs in the United States annually. In order to understand how to better control these pests, accurately measuring their food preference is critical. We examined three bioassay designs (multiple-choice, paired choice, and no choice) with four species of wood (Sequoia sempervirens, Pinus sp., Liriodendron tulipifera, and Quercus sp.) using three sympatric Reticulitermes species, R. flavipes, R. malletei, and R. virginicus. Results indicated that no choice and four choice bioassay designs should be used simultaneously to accurately establish a preference hierarchy. The amount of wood in a trial affects the wood consumption rate: 12 blocks of wood inspires more feeding than 3 blocks. INDEX WORDS: Reticulitermes flavipes, Reticulitermes malletei, Reticulitermes virginicus, subterranean termite, wood preference, bioassay design RETICULITERMES FEEDING PREFERENCE AND EXPERIMENTAL DESIGN by GRETCHEN DENISE PERKINS B.S., Old Dominion University, 2010 A Thesis Submitted to the Graduate Faculty of The University of Georgia in Partial Fulfillment of the Requirements for the Degree MASTER OF SCIENCE ATHENS, GEORGIA 2012 © 2012 Gretchen Denise Perkins All Rights Reserved RETICULITERMES FEEDING PREFERENCE AND EXPERIMENTAL DESIGN by GRETCHEN DENISE PERKINS Major Professor: Brian T. Forschler Committee: Dan L. Horton Daniel R. Suiter Electronic Version Approved: Maureen Grasso Dean of the Graduate School The University of Georgia August 2012 DEDICATION This is dedicated to my awesome parents for their unwavering support and solid belief that I can accomplish anything. And to Gerald, Gabrielle, and Gunther, who should always remember they can achieve anything with hard work, a little stubbornness, and a good attitude. Sorry I didn’t visit more. iv ACKNOWLEDGEMENTS I would like to thank my major professor, Dr. Brian T. Forschler, for providing me with the opportunity to pursue this degree and helping to instill invaluable professional skills in me. I am also grateful to Dr. Dan Suiter for his careful revision of my thesis and Dr. Dan Horton, who provided me with fresh perspectives, no matter the topic, and encouraged me to look at the big picture. Your guidance has been invaluable. I will never be able to thank everyone I have met on this journey enough. Ashley, we started this process together and we are, at long last, graduating together. You have been my sounding board, travel buddy, and constant companion. We have been to Hawaii, New Orleans, Asheville, Savannah, Little Rock, and Atlanta together. I will always be ready to take a weekend trip with you and wish you the best of luck on your travels—I hope you stop back by Athens every once in a while. Sonja, I am forever grateful to your wisdom and advice and introducing me to the world of graduate school. The knowledge I got from you, I could never have found anywhere else. Thanks for the many lunches! Su Yee, thank you for all the encouragement and the support that you provided the past two years. You have an endless supply of enthusiasm and kindness that is infectious—you will make a fantastic advisor one day. Jacob, you are always good for a laugh and some sound advice. Continue making those memories. Scott, I couldn’t have gotten through the last few months without you. You listen to my whining without complaint, accept my messy apartment without judgment, and give the best hugs. You have helped me with statistics, learning to relax, and have even done my dishes! I couldn’t have dreamed of finding a better partner. v To all my friends back home, thank you for the phone calls, cards, and late night conversations. Christine—thank you for the many visits and encouragement! You always understood what was going on and put everything into perspective. Chrissy—you have been my best friend since forever and I cherish every conversation and wish we weren’t quite so far apart. Thank you for being there through it all. Sarah—thank you for always brightening my day with a random text. You never fail to make me laugh. And finally, and most importantly, the biggest of thank you to my family: To my grandma, who always allowed me to invade her house for a weekend when I wanted to get away from Athens. Many thanks to my parents who supported me throughout this process, both financially and emotionally. They never complained when I continually changed my mind about what I want to do with my life. Daddy, thank you for always providing me with a way to come home and for teaching me to question everything. Momma, thanks for providing me a shoulder to cry on, the best advice, and always answering your phone. vi TABLE OF CONTENTS Page ACKNOWLEDGEMENTS .................................................................................................v LIST OF TABLES ............................................................................................................. ix LIST OF FIGURES .............................................................................................................x CHAPTER 1 INTRODUCTION AND REVIEW OF RELEVANT LITERATURE ON TERMITE WOOD PREFERENCE ...................................................................1 Introduction ..................................................................................................1 Biology .........................................................................................................2 Wood Preference Bioassays.........................................................................5 Resource Partitioning...................................................................................9 References..................................................................................................12 2 WOOD PREFERENCE OF THREE RETICULITERMES SPECIES IN NO- CHOICE, FOUR-CHOICE, AND PAIRED CHOICE BIOASSAY DESIGNS.........................................................................................................17 Abstract ......................................................................................................18 Introduction ................................................................................................18 Materials and Methods ...............................................................................22 Results........................................................................................................26 Discussion..................................................................................................29 Conclusion..................................................................................................32 vii References...................................................................................................35 3 CONCLUSION ................................................................................................48 16 viii LIST OF TABLES Page Table 2.1. Mean wood consumption rate (mg of wood consumed/g of termite/day) of each wood type tested in three bioassay designs by species. .................................... 43 Table 2.2. Mean mass loss (mg) of each wood type tested in three bioassay designs by species. ...................................................................................................................... 46 Table 2.3. Wood preference rankings (from most to least preferred) by mass lost and wood consumption rates in no choice and four choice bioassay designs for R. flavipes, R. malletei, and R. virginicus...................................................................... 47 ix LIST OF FIGURES Page Figure 2.1. Illustration of four-choice bioassay design arenas. Left: top view. Right: side view & paired and no choice design illustration. ...................................................... 42 Figure 2.2. Mean wood consumption rates (mg of wood consumed/g of termite/day) for three species (R. flavipes, R. malletei, and R. virginicus) separated by test type and wood type. ................................................................................................................. 44 Figure 2.3. Combined mean wood consumption rates (mg of wood consumed/g of termite/day) in each test for R. flavipes (RF), R. malletei (RM), and R. virginicus (RV). ......................................................................................................................... 45 x CHAPTER 1 INTRODUCTION AND REVIEW OF RELEVANT LITERATURE ON TERMITE WOOD PREFERENCE Introduction Termites, members of the order Isoptera, are xylophagous insects that have earned the reputation of being voracious pests (Snyder 1954). Forty-five species of termites are found in the United States, 30 of which are known to consume wooden structures or live plants (Su and Scheffrahn 1990). The family Rhinotermitidae contains five described species in the Southeastern United States (Snyder 1954, Weesner 1969, Su and Scheffrahn 1990, Austin et al. 2007, Lim and Forschler 2012) including Reticulitermes flavipes, considered to be the most economically important termites in the United States (Snyder 1954). Up to $11 billion dollars in damage per year to structures in the United States is attributed to termites (Su 2002, Green et al. 2011). Termites are also considered ecologically important yet little is known about how these sympatric species partition food resources in order to share the same niche (Houseman et