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Behaviour and ecology of mating in the jumping spider Servaea incana (Araneae: Salticidae)
thesisposted on 2022-03-28, 12:11 authored by Vivian Méndez Álvarez
Female sexual receptivity has been studied in great detail in insects, but very little is known about female sexual receptivity in spiders. I studied female sexual receptivity and associated life history traits in Servaea incana (Salticidae), a common jumping spider of temperate Australia. S. incana inhabit the trunks of eucalypt trees, where they build retreats and nests under loose pieces of bark. The display repertoire of S. incana is typical of salticids, although relatively simple compared to the displays of some of Servaea’s closest relatives. Context-dependent courtship versatility was evident in S. incana although not as pronounced as in many other jumping spiders. Adult males cohabit with subadult females at retreats, copulating shortly after females mature. Cohabiting pairs tended to assort by size and this may reflect size-dependent outcome of contests between males for access to larger females. In a population where virgin females were most abundant at the beginning of the mating season, males of S. incana were found to mature earlier than females (protandry). I report for the first time in a jumping spider the number of copulations a female had over her entire life, and the occurrence and latency of sexual inhibition in this species. Mating status was found to have a potent effect on receptivity. Virgin females were highly receptive, but after only a single mating became aggressive towards males. Context was also important; virgin females in the open encountered more males before mating than was the case if they were in a retreat. However, after an initial mating, females in the open required a fewer number of exposures to males prior to remating, compared to females in retreats. Mating-induced sexual inhibition of females appears to have consequences for life history; protandry and cohabitation likely increases a male's access to receptive virgin females. The findings of empirical studies of S. incana are placed in the broader literature through a detailed review of mating patterns of female spiders in an ecological context, and likely mechanisms underpinning mating-induced sexual inhibition. Although little explicit research exists on receptivity and the mechanism that induces sexual inhibition in spiders, a range of studies was found that included species that, like S. incana, tend to copulate only once in their life (e.g., many Lycosidae) and species that mate readily even after many copulations (e.g., many Nephiliidae). Variation is also very common within species as in S. incana, with some females mating only once and others mating repeatedly. Here we present the first study on mating-induced sexual inhibition during the entire life of a female spider. We used the observations on female remating to understand better the phenology, natural history and mating decisions of males and females in a population.