Juvenile experience and adult female mating preferences in two closely relatedSchizocosaspecies

Abstract

Social experience is well-known to influence female mate preference in vertebrate animals, but such effects have been studied less in invertebrates. Studies have documented flexibility in female mate choice in the wolf spider genus Schizocosa as a result of juvenile female experience with courting adult males. Here we investigate whether juvenile exposure to male courtship influences adult female species-level mate recognition in the wolf spider Schizocosa ocreata (Hentz 1844) and its sympatric sibling species S. rovneri (Uetz & Dondale 1979). Because these species overlap in range, contact between them is probable as interspecies hybrids are occasionally found in nature. Juvenile females were exposed multiple times to conspecific or heterospecific male courtship. Upon maturing, each exposed female was paired with an adult male of the same or different species to which it had been previously exposed, and was observed to determine receptivity and willingness to copulate. Results suggest that juvenile experience plays only a minor role (if any) in development of female mate recognition at the level of species, because the type of juvenile experience (conspecific vs. heterospecific) did not significantly affect mating outcome for either species. However, some context-specific effects of experience were observed, because the amount of juvenile exposure to adult male courtship affected adult receptivity of females in both species in different ways. In S. ocreata, the overall amount of juvenile experience (rather than type) influenced adult female receptivity and aggression toward heterospecific males; females with more exposures were initially more receptive and less aggressive to heterospecifics. In S. rovneri, neither type nor amount of juvenile exposure had significant effects on female receptivity towards conspecific males, although females exposed to heterospecific male courtship as juveniles were initially less receptive towards conspecific males than were unexposed females. While these results confirm earlier findings of behavioral reproductive isolation at the species level, they differ from some other studies, raising intriguing questions about varying degrees of behavioral and genetic isolation in different geographical populations of these two species.