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Counter‐perfume : using pheromones to prevent female remating
Strong selection to secure paternity in polyandrous species leads to the evolution of numerous chemicals in the male’s seminal content. These include antiaphrodisiac pheromones, which are transmitted from the male to the female during mating to render her unattractive to subsequent males. An increasing number of species have been shown to use these chemicals. Herein, I examine the taxonomic distribution of species using antiaphrodisiac pheromones, the selection pressures driving their evolution in both males and females, and the ecological interactions in which these pheromones are involved. The literature review shows a highly skewed distribution of antiaphrodisiac use; all species currently known to use them are insects with the exception of the garter snakes Thamnophis sirtalis parietalis and T. radix. Nonetheless, many taxa have not yet been tested for the presence of antiaphrodisiacs, in groups both closely and distantly related to species known to express them. Within the Insecta, there have been multiple cases of convergent evolution of antiaphrodisiac pheromones using different chemical compounds and methods of transmission. Antiaphrodisiacs usually benefit males, but their effect on females is variable as they can either prevent them from mating multiple times or help them reduce male harassment when they are unreceptive. Some indirect costs of antiaphrodisiacs also impact both males and females, but more research is needed to determine how general this pattern is. Additional research is also important to understand how antiaphrodisiacs interact with the reproductive biology and sexual communication in different species.Ecology, Evolution and Behavio
Impact of the mate-finding Allee effect on the competitiveness of diploid versus haplodiploid parasitoids: a theoretical approach
International audienceInsect parasitoids can either be diploid, and require mating prior to ovipositing, or haplodiploid, in which case females can produce male offspring through parthenogenesis. In small or low-density populations, parasitoid females might face a mate-finding Allee effect, that is they might not be able to find a male to mate with. Incidences of low-densities populations may be frequent in parasitoid due to the host-parasitoid interaction, which can lead to cycling dynamics, or because of their use in biological control where they might be introduced in small numbers. The ability of virgin haplodiploid females to produce offspring might favor them when confronted with mate-finding difficulties. Using modeling tool to simulate a host-parasitoid dynamics, we investigated whether haplodiploidy confers a competitive advantage over diploidy in parasitoid populations undergoing mate-finding Allee effect. Our results suggest that the Allee effect impacts parasitoid dynamics by inducing competitive exclusion between diploid and haplodiploid parasitoids. Haplodiploidy is favored when mate-finding difficulties are strong