Silk Investment in Gifts By Males of the Nuptial Feeding Spider Pisaura Mirabilis (Araneae: Pisauridae).
In: Behaviour, Vol. 133, No. 9: pp. 697-716
Adult males of the hunting spider Pisaura mirabilis wrap up prey with silk and pass these nuptial gifts to females prior to copulation. The females digest the nuptial gifts, including the silk, during mating. Laboratory experiments were carried out to determine the amount of silk males of P. mirabilis invest in nuptial gifts, and its possible role in sexual reproduction. The amount of silk was always small, indicating that the silk of the nuptial gift has little nutritional value for females. Males that had more time to wrap up the prey produced a larger amount of silk. Starved males required more time than satiated males to produce a given amount of silk. A larger male body size had a positive effect on the amount of silk. In general, the size of the prey used for nuptial gifts had no influence on the amount of silk. However, due to handling problem, smaller males produced no silk for very large flies. Females took more time to digest a nuptial gift with a larger amount of silk than a nuptial gift with a smaller amount of silk. A possible interpretation of the adaptive significance of wrapping is that males use silk to prolong the copulation time during mating.