| Wolf spiders (Lycosidae) use multi-modal communication to mediate social interactions in many contexts. This research investigated the use of chemical, visual and vibratory signals in Schizocosa ocreata (Hentz), their role in mate recognition, and potential consequences of signal interception by unintended receivers.; Female chemical signals elicit male courtship behavior and have been assumed species-specific, but some species differences are subtle enough that males court heterospecifics or their silk. I tested male discrimination of female chemical signals using behavioral assays. Discrimination varied significantly by phylogenetic distance, with greatest response on conspecific silk and that of a sibling species, S. rovneri. In reciprocal tests, focal males of both these species did not discriminate between conspecific or heterospecific female silk, suggesting that female chemical signals are conserved within closely-related wolf spider species. Courtship and exploratory responses of male S. ocreata were greater on silk of adult, unmated females than sub-adult or mated females. Male responses also varied with female age post-maturity, with greatest response to silk of females past the first week of adulthood. In addition to species identity and sex, female silk cues may also provide information about female age and reproductive status to male receivers.; Courtship signaling by male S. ocreata occurs in multiple modalities (visual and vibratory) concurrently and includes active leg-waving behaviors and secondary sexual traits. Schizocosa ocreata co-occurs with a high density of conspecifics and potential predators that might intercept courtship signals, including other wolf spiders, jumping spiders (Salticidae), and toads (Bufonidae). Therefore, conspicuous multi-modal courtship signals favored by sexual selection to enhance detection by intended (female) receivers may also be intercepted by unintended receivers, including predators and competitors. I tested the potential for exploitation of male S. ocreata courtship signals by conspecific male competitors and these three representative predators, using video/audio playback. Visual signaling of S. ocreata did not result in social facilitation of courtship by conspecific competitors. However, variation in expression of male secondary sexual characteristics and the presence of multi-modal courtship resulted in differential detection by predators. These results suggest a potential for trade-offs between natural and sexual selection in evolution of multi-modal communication. |
