Investigating Patterns of Variation in Reproductive Dispersal and Wolbachia Infection in Malagasy Ants (Hymenoptera: Formicidae) by Fiona J. Tsoi A Thesis presented to The University of Guelph In partial fulfilment of requirements for the degree of Master of Science in Integrative Biology Guelph, Ontario, Canada © Fiona J. Tsoi, September, 2013 ABSTRACT INVESTIGATING PATTERNS OF VARIATION IN REPRODUCTIVE DISPERSAL AND WOLBACHIA INFECTION IN MALAGASY ANTS (HYMENOPTERA: FORMICIDAE) Fiona J. Tsoi Advisor: University of Guelph, 2013 Professor M. A. Smith I examined patterns of variation in queen dispersal state and Wolbachia infection in Malagasy ants. My first study compared intraspecific genetic divergence between reproductive dispersal states. Using calculations of isolation by distance (IBD), all species with ergatoid (wingless) queens exhibited IBD as a result of short distance dispersal. The majority of species possessing alate (winged) queens also exhibited IBD despite their ability to travel farther distances. Alate body size was hypothesized to influence IBD, but this was not supported and requires further investigation. My second study investigated the prevalence of Wolbachia, a genus of endosymbiotic bacteria, in ants. Overall, 61.67% of species were infected and no correlation was observed between infection and ant queen dispersal state. Furthermore, DNA extracted from somatic tissue did not underestimate Wolbachia detection as was previously thought. Dispersal and Wolbachia infection influence reproductive outcomes in ants and are important factors for future investigations of genetic diversity. Acknowledgements Firstly, I would like to thank my advisor Dr. Alex Smith for his patience, guidance and encouragement throughout this entire process. Thank you for opening the world of ants and Wolbachia to me. I truly appreciate the last minute meetings, rapid feedback and for always providing a different perspective to my ideas. I would also like to thank my committee members Dr. Teresa Crease and Dr. Brian Fisher for their support and expert advice. Dr. Crease, thank you for your insightful ideas and for your valuable administrative advice for completing graduate school. Brian, thank you for sharing your knowledge and passion for ants with me. As well, I would like to thank Brian and other members of the California Academy of Sciences for hosting me during my visit and for allowing me to access their extensive Madagascar ant collection. I would like to thank the Biodiversity Institute of Ontario (BIO) for their assistance with retrieving archived DNA extracts, hitpicking and sequencing. Additionally, I would like to thank the Genomics Facility for their assistance with sequencing and for their patience and efficiency with high volume submissions. A special thanks to all past and present members of the Adamowicz, Crease, Hajibabaei, Smith and Gregory labs for their advice and reassurance that everything out of the ordinary was really quite ordinary in graduate school. I appreciate the breaks and distractions from hectic life in the lab and the office. Most importantly to my family, thank you so much for your unwavering emotional support and patience throughout this time. To Bradley, thank you for your continuous optimism and encouragement. I am extremely grateful for your support. Field work in this project was supported by a National Geographic grant (no. 8429-08) and a National Science Foundation grant (no. DEB-0072713, DEB-0344731 to BLF and DEB- 0842395 to BLF and MAS). Research was supported by the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery and Research Tools and Instruments Grants and a Leaders Opportunity Fund (LOR) from the Canada Foundation for Innovation (CFI) to MAS. iii Table of Contents Abstract .......................................................................................................................................... ii Acknowledgements ...................................................................................................................... iii List of Tables ................................................................................................................................ vi List of Figures .............................................................................................................................. vii Chapter 1: Introduction ............................................................................................................... 1 Overview of Ants ................................................................................................................................. 1 Overview of Madagascar ..................................................................................................................... 2 The Role of DNA Barcoding ............................................................................................................... 2 Genetic Variation and Dispersal .......................................................................................................... 3 Wolbachia and Ants ............................................................................................................................. 4 Chapter 2: Patterns of Intraspecific Variation as Influenced by Dispersal in Malagasy Ants ......................................................................................................................................................... 6 Abstract ................................................................................................................................................... 6 Introduction ............................................................................................................................................ 7 Female Reproductive Dispersal and Nest Establishment ..................................................................... 8 Characterizing Ant Reproduction: From Morphology to Markers ..................................................... 10 Objective of Study .............................................................................................................................. 13 Methods ................................................................................................................................................. 14 Taxon Sampling ................................................................................................................................. 14 Molecular Analyses ............................................................................................................................ 15 Isolation-By-Distance......................................................................................................................... 16 Alate Body Measurements ................................................................................................................. 18 Results .................................................................................................................................................... 18 Among-Genera Comparisons of IBD ................................................................................................. 18 Species-Specific Comparisons of IBD ............................................................................................... 19 Alate Body Size Measurements ......................................................................................................... 22 Discussion .............................................................................................................................................. 22 Ergatoid vs. Alate Comparisons ......................................................................................................... 23 Unusual Relationships of Geographic vs. Genetic Distance .............................................................. 23 Environmental Factors Affecting Variation ....................................................................................... 25 The Effects of Body Size on Dispersal .............................................................................................. 25 Conclusions ........................................................................................................................................... 26 Chapter 3: A Survey of Wolbachia Infection in Malagasy Ants ............................................. 58 Abstract ................................................................................................................................................. 58 Introduction .......................................................................................................................................... 59 What are Wolbachia? ......................................................................................................................... 59 Methods of Transmission ................................................................................................................... 59 Endosymbiotic Relationships: Parasitism and Mutualism ................................................................. 61 The Effects of Wolbachia Infection on Host Evolution ..................................................................... 62 Detecting Wolbachia .......................................................................................................................... 63 Prevalence in Ants .............................................................................................................................