Female mating decisions are often environmentally dependent plastics. With a spider giving a wedding gift Pisaura Mirabilisthe optimal number of mats, i.e., the number that maximizes fitness, depends on prey availability and is regulated by hunger dependent acceptability. We determined the optimal number of female marts and upper-level numbers (high and low prey availability, respectively), and tested the hypothesis that women who get the optimal number will achieve the same reproduction as successful regardless of the optimal number. In laboratory experiments, women were provided with flies of 0, 1, 2, or 3 houses per day as supplementary feeding, and men were presented daily carrying four gifts until spawning. Fertility, egg latency, successful egg hatching, and number of live spider-lyings were independent of supplementary feeding levels. For women, mating and aggression towards men (gift stealing and sexual cannibalism) is an alternative method to compensate for low foraging success. 2-3 was confirmed as the minimum number of mats. The optimal number of mats varied between 12 and 22-24 depending on the female aggression level. The plasticity of women’s behavior allows fitness to be isolated from dependence on environmental prey availability through hunger-dependent acceptability.
Søren Toft, Maria J Albo, Hungry-dependent female acceptability leads to variable optimum polyandry with equal fitness in spiders giving marriage gifts, Evolution, 2025;, QPAF087, QPAF087. https://doi.org/10.1093/evolut/qpaf087
