DescriptionSexual selection is built on the premise that in most species, females invest significantly more in reproduction and offspring than males. Due to this differential investment, females have evolved mechanisms to correctly assess the quality of their mates before mating. However, in polyandrous species, females can store sperms from different males in their reproductive tract and exert post-mating sexual selection by favoring the sperm of one male over the other, biasing the paternity of their offspring.This process is known as cryptic female choice. While evidence of this cryptic mate choice exists in multiple taxa, the mechanisms underlying this process have remained difficult to unravel. In the vinegar fly Drosophila melanogaster, females can modulate the timing of sperm ejection depending on their social environment, which could be a plausible form of cryptic female choice. The mechanisms behind how females regulate timing of sperm ejection and its functional consequences on paternity remain unclear.To understand how females regulate timing of sperm ejection, we measured the sperm ejection latency of females in different social or pheromonal context. In this study, we show that females eject sperm of their first mate faster when sensing the pheromones of attractive males compared to less attractive males. We identify these particular pheromones as 11-cis vaccenyl acetate or heptanal and their female odorant receptors sensing these pheromones. Using transgenic males expressing fluorescent sperm, we show that twice-mated females can manipulate sperm allocation depending on the quality of the male in their presence after the first mating, affecting the quantity of offspring from the second male. We therefore provide a mechanism for females to exert cryptic female choice, increasing the paternity of more attractive males, thus, giving insight into processes of post-mating sexual selection.
|Event title||European Conference on Behavioural Biology 2022: All of life is social!|
|Degree of Recognition||International|
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