University of Kentucky UKnowledge Theses and Dissertations--Entomology Entomology 2015 A Comprehensive Understanding of Corpse Management in Termites Qian Sun University of Kentucky, [email protected] Right click to open a feedback form in a new tab to let us know how this document benefits ou.y Recommended Citation Sun, Qian, "A Comprehensive Understanding of Corpse Management in Termites" (2015). Theses and Dissertations--Entomology. 23. https://uknowledge.uky.edu/entomology_etds/23 This Doctoral Dissertation is brought to you for free and open access by the Entomology at UKnowledge. It has been accepted for inclusion in Theses and Dissertations--Entomology by an authorized administrator of UKnowledge. For more information, please contact [email protected]. STUDENT AGREEMENT: I represent that my thesis or dissertation and abstract are my original work. Proper attribution has been given to all outside sources. I understand that I am solely responsible for obtaining any needed copyright permissions. I have obtained needed written permission statement(s) from the owner(s) of each third-party copyrighted matter to be included in my work, allowing electronic distribution (if such use is not permitted by the fair use doctrine) which will be submitted to UKnowledge as Additional File. I hereby grant to The University of Kentucky and its agents the irrevocable, non-exclusive, and royalty-free license to archive and make accessible my work in whole or in part in all forms of media, now or hereafter known. I agree that the document mentioned above may be made available immediately for worldwide access unless an embargo applies. I retain all other ownership rights to the copyright of my work. I also retain the right to use in future works (such as articles or books) all or part of my work. I understand that I am free to register the copyright to my work. REVIEW, APPROVAL AND ACCEPTANCE The document mentioned above has been reviewed and accepted by the student’s advisor, on behalf of the advisory committee, and by the Director of Graduate Studies (DGS), on behalf of the program; we verify that this is the final, approved version of the student’s thesis including all changes required by the advisory committee. The undersigned agree to abide by the statements above. Qian Sun, Student Dr. Xuguo Zhou, Major Professor Dr. Charles W. Fox, Director of Graduate Studies A COMPREHENSIVE UNDERSTANDING OF CORPSE MANAGEMENT IN TERMITES ___________________________________ DISSERTATION ___________________________________ A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the College of Agriculture, Food and Environment at the University of Kentucky By Qian Sun Lexington, Kentucky Director: Dr. Xuguo Zhou, Associate Professor of Entomology Lexington, Kentucky Copyright © Qian Sun 2015 ABSTRACT OF DISSERTATION A COMPREHENSIVE UNDERSTANDING OF CORPSE MANAGEMENT IN TERMITES Undertaking behavior is the disposal of dead individuals in social colonies to prevent potential pathogenic attack. This behavioral trait has convergently evolved in social insects (primarily termites, ants, and honeybee), and is considered an essential adaptation to social living. In honey bee and ants, workers recognize dead colony members through the postmortem change of chemical profile, and corpses are usually removed out of nest. However, in termites, little is known about the behavioral pattern, chemical cue or molecular basis. In the eastern subterranean termite, Reticulitermes flavipes, this study investigated undertaking behavior toward corpses of different origins and postmortem times. Corpses of a competitive species, R. virginicus, were buried onsite by R. flavipes workers with a large group of soldiers guarding the burial site; while dead conspecifics of R. flavipes were retrieved and cannibalized. In addition, postmortem time played an important role in corpse management. Early death cue, a blend of 3-octanone and 3-octanol, emitted from workers to attract colony members to consume their bodies; the two volatiles rapidly decreased while the corpse decomposed, and burial behavior was alternatively employed at a late postmortem stage. Gene expression profiles of R. flavipes workers were established during cannibalism of freshly dead nestmates, burial of decayed nestmates, and burial of dead competitors. The results showed that gene expression signatures were associated with the behavioral responses, and burial behavior involved more differentially expressed genes in metabolic pathways, indicating a higher energetic output in burial than cannibalism. Our findings suggest that undertaking responses in R. flavipes are associated with the type of risk posed by the dead: cannibalism allows nutrient recycling in the colony, but burial would be warranted toward increased risks of pathogen infection or territorial intrusion. The use of early death cues that promotes cannibalism is adaptive to subterranean termites that feed on nutritionally poor diet. This study advances our understanding of social behavior in insects, and provides fundamental knowledge that may lead to new pest control approaches against R. flavipes. KEY WORDS: eusociality, Reticulitermes flavipes, undertaking behavior, cannibalism, chemical communication, sociogenomics Qian Sun _ Student’s Signature 10 December, 2015 _ Date A COMPREHENSIVE UNDERSTANDING OF CORPSE MANAGEMENT IN TERMITES By Qian Sun Dr. Xuguo Zhou _ Director of Dissertation Dr. Kenneth F. Haynes _ Co-Director of Dissertation Dr. Charles W. Fox _ Director of Graduate Studies 10 December, 2015 _ Date Acknowledgments My deepest gratitude goes to my advisor, Dr. Xuguo Zhou. It was Dr. Zhou’s passion that first ignited my enthusiasm for studying social animals, a field I would like to dedicate my career to. It is difficult to imagine a more supportive advisor than him, who has always allowed me to pursue my research interests and guided me to be a better scientist. Any accomplishments I have had and may have in future should be credited to him. Dr. Zhou took great care to assemble a team of motivated, hardworking and caring students and postdocs, which has made the lab a friendly and fun environment to do science. I own special thanks to my co-advisor, Dr. Kenneth Haynes, who has provided tremendous guidance in every single step throughout my research. He has introduced me to the field of chemical ecology, and greatly inspired me to study insect behavior as well as present and publish my findings. I’ve learned how to appreciate the nature of science through his humble attitude, which would be a lifelong influence on me. I would also like to thank the other members of my committee, Drs. Michael Sharkey, Christopher Schardl and Ruriko Yoshida, as well as my outside examiner, Dr. Nicholas McLetchie, for their advices and patience that improved the dissertation. I would like to acknowledge my lab members. Li Tian, who has been along the journey of graduate study with me, has made my work all the better through countless discussions, help with experiments, and assistance with insect collections for almost five years. Moreover, I appreciate Drs. Xiangrui Li, Zhen Li, Huipeng Pan and Hu Li, and iii Dongyan Song, Tian Yu, Linghua Xu, Jeffery Noland and Jordan Hampton for their help with techniques or sharing theirs thoughts on my research. I am grateful for the supports, advices and help from the Department of Entomology, and specific thanks go to Drs. John Obrycki, Charles Fox, Ricardo Bessin, Daniel Potter and Janet Lensing. I also want to thank the graduate students in the department, who have created a vigorous, warm and friendly atmosphere for me during my life and work as an international student. I acknowledge the recognitions by and the financial supports from the Graduate School, Kentucky NSF-EPSCoR Research Scholars Program, the Kentucky Science and Engineering Foundation, the Entomological Society of American, and the International Union for the Study of Social Insects. Science is a community enterprise, and I appreciate lots of help outside of University of Kentucky. I want to thank Drs. Susan Jones (the Ohio State University) and Brian Forschler (University of Georgia) for teaching me termite biology and providing termite colonies for my study. Also appreciated are insightful comments on my work from Drs. Colin Brent (USDA), Amy Toth (Iowa State University), and Cassandra Extavour (Harvard University). I reserve my final expressions of gratitude for my family. Without the love, supports and understandings from my mother (Chaoying Liu), father (Zhaofeng Sun), brother (Yi Sun), and very importantly, my husband (Xinguo Wang), I could not have the perseverance to pursuit and finish my doctorate in science. iv Table of Contents Acknowledgments.............................................................................................................. iii List of Tables ................................................................................................................... viii List of Figures .................................................................................................................... ix Chapter 1. Literature review: corpse management in social insects ................................... 1 Abstract ........................................................................................................................... 1 Introduction ....................................................................................................................