Female responses to isolated signals from multimodal male courtship displays in the wolf spider genus Schizocosa (Araneae: Lycosidae).

Male wolf spiders within the genus Schizocosa display considerable variation in foreleg ornamentation as well as in courtship communication. Multiple modes of male signalling have evolved in a number of species. Divergence in courtship signals among species within this genus may be directly associated with variation in the sensory sensitivities of conspecific females. We isolated the visual and vibratory courtship cues of four species of Schizocosa and recorded conspecific female receptivity to each isolated cue. We also examined female receptivity to complete multimodal courtship signals. We found that the sensory sensitivities of conspecific females were associated with the predominant modes of male courtship communication. Species in which females use mostly stridulatory cues in assessing conspecific males tended to have stridulation-based male courtship displays (S. duplex and S. uetzi) while the opposite was true for species in which females used more visual cues in male assessment (S. stridulans and S. crassipes). This study suggests coevolution between male signal design and female sensory design. We discuss possible scenarios that could be driving this coevolution, including hypotheses of sensory bias and environmental constraints. Copyright 1999 The Association for the Study of Animal Behaviour.