Seminal influences: The role of nuptial gifts in sequential episodes of sexual selection.
Abstract: 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 se... read morexual 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.
Thesis (Ph.D.)--Tufts University, 2012.
Submitted to the Dept. of Biology.
Advisor: Sara Lewis.
Committee: Philip Starks, Frances Chew, Mitch McVey, Colin Orians, and Erik Dopman.
Keywords: Biology, Evolution & development, and Animal behavior.read less