Communication between potential mates is of vital importance to the fitness of many taxa, allowing individuals to find one another, as well convey and receive information important in assessing a suitable mate. Signals involved in sexual communication can be transmitted through visual, vibrational and chemical modalities, with chemical communication being the oldest and most widespread. The ability to detect visual and vibrational cues often occurs across a range of inputs, while chemical communication has the potential for much higher specificity, as only those receivers possessing chemosensory cells attuned to the compounds used will be able to detect their presence.
The detection and integration of multimodal signals into a behavioral response has been extensively studied in the Schizocosa ocreata (Hentz 1844) wolf spider (Lycosidae) model system. In this ground dwelling species, males respond to substrates containing female chemical signals with visual and vibratory courtship displays. While this response has been well characterized, the chemical identity of these signaling compounds is currently unknown, and pheromone identity has been understudied across spiders as a whole. The behavioral response of male S. ocreata to conspecific chemical signals has primarily been studied in the context of substrate bound female cues, though past studies have suggested that chemicals produced by conspecific male competitors may inhibit male courtship behavior, and have even suggested a role for olfaction.
We further examined the role olfaction plays in male detection and location of females, and while we found no evidence that males are utilizing olfaction to find mates, we did observe behavioral changes to conspecifics of both sexes, and a reduction of activity in the presence of volatile cues from a predator. At levels of competitor cues that males are expected to encounter in nature, we found no evidence that male-male inhibition occurs in this species.
In examining male response to substrate bound cues, we found that males are able to discern female trails, and will preferentially follow them, although they are not able to determine the direction the trail was laid. We also utilized a custom built silk collection device to obtain sufficient quantities of clean silk for extraction and preliminary chemical analysis. Following solvent extraction of cues from the silk, we were able to reestablish searching behavior in response to the extract from female silk, but it did not elicit courtship display, suggesting a multicomponent chemical signal involved in sexual signaling in this species.