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dc.contributor.authorMack, Paul Douglas
dc.description.abstractAlthough the phenomenon of sperm competition, the post-mating interaction of ejaculates within multiply mated females, has been studied extensively over the past 30 years, we still have much to learn about the mechanisms underlying sperm competition. Until very recently the majority of research has focused on male aspects of sperm competition. Here we add to the growing body of evidence for a significant female role in the outcome of sperm competition, specifically, and reproductive decisions, in general. First, we show that the ability of male Drosophila melanogaster to incapacitate stored sperm when they mate with previously mated females varies with male genotype and with the time interval since the female last mated. Second, we demonstrate the importance of the age of female D. melanogaster in the outcome of sperm competition. We explicitly tested the effect of age on the proportion of paternity achieved by the last male to mate with the female. However, our result indirectly supports the conclusion that female age may have more significant impacts on the reproductive success of previous (vs. last) males to mate with a female. Third, we test the hypothesis that first (e.g., prior) male paternity, or sperm defense, should be negatively correlated with the degree of relatedness between members of a mated pair in D. melanogaster. We provide the strongest evidence to date for the significance role of genetic relatedness on sperm competitive ability. In addition, taken together, our results from both the sperm incapacitation study and the relatedness study strongly suggest female genotype x male genotype interactions, although they do not explicitly test the hypothesis that such interactions exist. In addition to our investigations of sperm competition, we include a study of the age-specificity of novel mutations on male mating ability and fecundity. In that study, we detail the age-specific effect of cumulative novel mutations acting on both traits. Our result suggests that although age-specificity is present, the affect appears to be transient. Overall, we demonstrate the importance of female age and genotype as well as male genotype, on the outcome of several important reproductive interactions.
dc.subjectintersexual conflict
dc.subjectDrosophila melanogaster
dc.subjectsperm competition
dc.subjectaccessory gland proteins
dc.subjectgenetic relatedness
dc.subjectsperm selection
dc.subjectmale mating ability
dc.subjectmutation accumulation
dc.subjectsenescence. female genotype
dc.subjectsperm offense
dc.subjectsperm defense
dc.titleSperm competition and the role of females in Drosophila melanogaster
dc.description.advisorDaniel Promislow
dc.description.committeeDaniel Promislow
dc.description.committeeWyatt Anderson
dc.description.committeeJohn Avise
dc.description.committeePatty Gowaty
dc.description.committeeKen Ross

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