No preference for novel mating partners in the polyandrous nuptial-feeding spider Pisaura mirabilis (Araneae: Pisauridae)

Polyandrous females may gain genetic benefits for their offspring through postmating sexual selection. To facilitate postcopulatory choice for males of superior genetic quality females are expected to bias precopulatory mate choice towards novel males (i.e. genetically novel sources). Preference for novel partners is also expected to maximize male lifetime reproductive success by allowing males to increase the number of mates. We investigated male and female preference for novel or former mating partners in the spider Pisaura mirabilis by offering females novel males (polyandry) or the same male (monogamy). Precopulatory (mate acceptance) and prefertilization (latency to copulation, mating interruption and copulation duration) behaviours were compared between the two treatments. Males provide females with a nuptial prey gift during courtship. Because of the direct benefit associated with nuptial feeding, females should accept males indiscriminately and exert preference only at the prefertilization level. We found that monogamous females remated more readily than polyandrous females, suggesting less resistance to remating with the same male than with novel mates. No differences in female prefertilization responses were found. Lack of preference for novel mates may suggest that direct selection exerted by the nuptial gift rather than indirect selection for genetic benefits is a more likely driver of female remating propensity. Females were nevertheless resistant to remating, suggesting a trade-off between direct benefits and costs of remating. We found no effect of mate novelty on male mating behaviour, indicating either lack of discriminatory ability or that risk of sperm competition creates paternity benefits from remating with the same female. (C) 2010 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.