Worthless and nutritive nuptial 1 gifts: mating duration, sperm stored and potential female decisions in spiders

ALBO, M. J.; PERETTI, A. V.

PLOS ONE

PUBLIC LIBRARY SCIENCE

Lugar: San Francisco; Año: 2015 p. 1 - 15

1932-6203

In nuptial gift-giving species females sometimes select their potential mates based on the presence and size of the gift. But in some species, such as the Neotropical polyandrous spider Paratrechalea ornata male gifts vary in quality, from nutritive to worthless, and this male strategy can be in conflict with female nutritional benefits. In this species, males without gifts experience a reduction in mating success and duration, while males that offer worthless or genuine nutritive gifts mate with similar frequencies and durations. The duration of copulation is apparently controlled by the female. Thus, there is scope for females to favour males offering gifts and further if these are nutritious, via post-copulatory processes. We first tested the hypothesis that females differentially store sperm from males that offer the highest nutritional benefits by experimentally presenting females with males that offer either nutritive or worthless gifts (uninterrupted matings). Since, males offering gifts have longer matings than males offering no gifts, we carried out another set of experiments to examine whether females can select sperm based only on gift presence. This time we interrupted matings after the first pedipalp insertion, thus matching number of insertions and mating duration for males that: offered and did not offer gift. We investigated in all groups how sperm storage is related to mating duration. Our results showed that the amount of sperm stored is positive related with mating duration in all groups, except in matings with worthless gifts. Gift presence itself did not affect the sperm stored by females, as we found similar number of sperm in the interrupted matings with and without gifts. Females mating with males offering either nutritive or worthless gifts store similar number of sperm. We discuss alternative hypothesis on whether females discriminate or not the sperm from males offering nutritive and worthless gifts.