Seminal influences: The role of nuptial gifts in sequential episodes of sexual selection

Sexual selection drives the evolution of diverse traits that can prove advantageous in reproduction. Because females often mate with multiple males, traditional premating processes such as female choice and male-male competition have counterparts both during and after mating in the form of cryptic female choice and sperm competition. Therefore, it is critical to expand our view of sexual selection. The goal of this research was to investigate how nuptial gifts in the form of spermatophores operate in sequential episodes of sexual selection in several species of beetle. Examining how nuptial gifts affect male and female fitness components can provide insight into male trait evolution, patterns of female choice and potential sexual conflict.;The impact of receiving relatively different quantities of genital nuptial gifts on female fitness parameters across many arthropod taxa was examined using a meta-analysis. In response to greater amounts of nuptial gifts, females demonstrate enhanced fecundity but reduced longevity. In two studies, spermatophore size in Photinus fireflies is manipulated to evaluate the effect of variation in nuptial gift size on female fitness parameters and male reproductive success. One of these studies documents a significant effect on female post-mating lifespan of receiving a single large spermatophore relative to a single small spermatophore, but no significant effect on female reproductive output. In the other study, firefly males with larger spermatophores experienced dual benefits in terms of both higher mate acceptance and increased paternity share. Additionally, rigourous phylogenetic methods are utilized to demonstrate a link between female flight and male spermatophore production in worldwide firefly species, with loss of female flight leading to a loss of male spermatophore production. An evaluation of the use of close chemical contact cues, cuticular hydrocarbons, to mediate communication in diurnal and nocturnal fireflies was done with gas chromatography. This analysis revealed undetectable levels of these cues in nocturnal species. Finally, proteomics and mass spectrometry were used to identify the seminal fluid proteome of male spermatophores in Tribolium castanuem. The results of these studies contribute a number of novel and broadly applicable insights into the nature and evolution of nuptial gifts in animal species.