Syracuse University SURFACE Dissertations - ALL SURFACE May 2016 IDENTIFYING THE INFLUENCE OF SELECTIVE EPISODES AND MECHANISMS ON REPRODUCTIVE SUCCESS IN TRIBOLIUM CASTANEUM AND DROSOPHILA MELANOGASTER Elizabeth Metta Droge-Young Syracuse University Follow this and additional works at: https://surface.syr.edu/etd Part of the Life Sciences Commons Recommended Citation Droge-Young, Elizabeth Metta, "IDENTIFYING THE INFLUENCE OF SELECTIVE EPISODES AND MECHANISMS ON REPRODUCTIVE SUCCESS IN TRIBOLIUM CASTANEUM AND DROSOPHILA MELANOGASTER" (2016). Dissertations - ALL. 427. https://surface.syr.edu/etd/427 This Dissertation is brought to you for free and open access by the SURFACE at SURFACE. It has been accepted for inclusion in Dissertations - ALL by an authorized administrator of SURFACE. For more information, please contact [email protected]. Abstract: Parsing out what makes some individuals more reproductively successful than others is a key pursuit in evolutionary biology. While reproductive success can ultimately be defined as the number of offspring produced over an individual’s lifetime, there are many selective episodes that shape this outcome. Because the majority of animals have multiple mates, achieving matings is but one influence on reproductive success. After copulation occurs, sperm from multiple males compete within the female reproductive tract to fertilize eggs, while females morphologically or behaviorally bias fertilization to preferred males, further shaping reproductive success. Additionally, the act of mating itself may influence parental lifespan or rate of offspring production. Here, I investigate the influence of multiple selective episodes on different aspects of reproductive success in two insects: the fruit fly, Drosophila melanogaster and the red flour beetle, Tribolium castaneum. Established genomes in both systems enabled the generation of transgenic, fluorescently labeled lines: green fluorescent protein (GFP) driven by a ubiquitin promoter in D. melanogaster to look at paternity in eggs, and GFP or red fluorescent protein (RFP) tagged protamines to identify different male’s sperm by head color in T. castaneum. I investigated relationships between different episodes of reproductive success in D. melanogaster and found positive correlations between sperm competitive success and offspring viability; offspring viability itself was influenced by a male × female interaction on hatching success. In T. castaneum, I explored potential drivers of their extremely promiscuous mating system and how that system influences mechanisms of postcopulatory reproductive success. I found that repeated receipt of a complete ejaculate directly benefits female reproductive success, but comes at a longevity cost to males. This direct benefit of remating to females may explain why I found that the proportion of different male’s sperm in the main chamber of the female reproductive tract, and not the specialized sperm storage organ as in D. melanogaster and many other arthropods, determine the proportion of offspring sired by each male. The great differences in postcopulatory mechanics between D. melanogaster, found previously, and T. castaneum, found here, illustrate the importance of mating system in shaping aspects of reproductive success. IDENTIFYING THE INFLUENCE OF SELECTIVE EPISODES AND MECHANISMS ON REPRODUCTIVE SUCCESS IN TRIBOLIUM CASTANEUM AND DROSOPHILA MELANOGASTER by Elizabeth M. Droge-Young B.S. Biology, Colorado State University 2005 DISSERTATION Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Biology Syracuse University May 2016 Copyright Elizabeth M. Droge-Young All rights reserved Table of Contents Chapter 1: Covariance among premating, postcopulatory and viability fitness components in Drosophila melanogaster and their influence on paternity measurement ........................................................................................................................................ 1 Introduction ...................................................................................................................................................... 3 Materials and Methods .................................................................................................................................. 5 Results .............................................................................................................................................................. 13 Discussion ....................................................................................................................................................... 17 Acknowledgements ..................................................................................................................................... 20 References ...................................................................................................................................................... 21 Supplemental materials ............................................................................................................................. 32 Chapter 2: Extreme ecology and mating system: discriminating among direct benefits models in red flour beetles ............................................................................................................. 43 Introduction ................................................................................................................................................... 45 Materials and Methods ............................................................................................................................... 48 Results .............................................................................................................................................................. 56 Discussion ....................................................................................................................................................... 60 Acjnowledgments ......................................................................................................................................... 68 References ...................................................................................................................................................... 69 Chapter 3. Resolving mechanisms of competitive fertilization success in the red flour beetle ...................................................................................................................................................... 87 v Introduction ................................................................................................................................................... 89 Materials and Methods ............................................................................................................................... 92 Results ............................................................................................................................................................ 103 Discussion ..................................................................................................................................................... 106 Acknowledgments ...................................................................................................................................... 113 References .................................................................................................................................................... 114 vi List of Illustrative Materials Chapter 1 Table 1.1 Mean and standard deviation of study variables .............................................. 26 Table 1.2 ANOVA analyzing female fecundity and hatching success ............................ 28 Table 1.3 Minimal general linear models of episodic variables’ influence on focal male fitness ........................................................................................................................................................ 29 Figure S1.1 Significant interactions in minimal linear models ........................................ 32 Table S1.1 Minimal general linear models of variables on number of offspring sired by the focal male as well as offspring development time .......................................................... 34 Table S1.2 Minimal general linear models of effect of sexually and viability selected variables on focal male fitness, including cases of 100% paternity ................................ 38 Chapter 2 Figure 2.1 Influence of experimental male treatment and environment on female life history traits ............................................................................................................................................ 81 Figure 2.2 Influence of female exposure level, experimental male treatment and environment on male longevity ...................................................................................................... 82 Table 2.1 Predicted treatment effects on offspring production ...................................... 83 Table 2.2 ANOVAs identifying contributions of environment and male on variance in three female life history traits ......................................................................................................... 85 Table 2.3 ANOVAs identifying contributions of environment, male treatment and female exposure on variance in male longevity ...................................................................... 86 vii Chapter 3 Table 3.1 Minimally significant