Learning how to eavesdrop in multiple modalities: a test of associative learning using unimodal and multimodal playback

Abstract

Across animal taxa, individuals eavesdrop upon courting conspecific males, often in an attempt to steal mating opportunities. While multimodal signals can increase the likelihood that choosers respond to courters, such multimodal signals might also attract the unwanted attention of conspecific eavesdroppers. Previous studies of the brush-legged wolf spider, Schizocosa ocreata, demonstrate that field-experienced males court in response to visual displays of conspecific male courtship more than do laboratory-raised males. Furthermore, other studies demonstrate that males can learn to associate visual signals with the presence of a nearby female. Male S. ocreata, however, use a combination of vibratory and visual signals in their multimodal courtship display. Whether such associative learning varies based on which signal modality is experienced or whether multimodal signals result in enhanced learning remains unknown. Consequently, we examined eavesdropping on courtship behaviours of S. ocreata, with added emphasis on learning to respond to unimodal versus multimodal playback. We used vibratory and video playback techniques to test whether associative learning results in varied courtship levels when males associate unimodal or multimodal courtship signals with the presence of a nearby female. Results show that male S. ocreata associated courtship playback with the presence of a nearby female (i.e. courted at higher levels), regardless of whether courtship playback was unimodal or multimodal, demonstrating that male S. ocreata are capable of learning in multiple modalities. Multimodal playback, however, did not appear to enhance males’ ability to associate conspecific courtship signals with female cues. Courtship behaviours were greater in response to vibratory playback, though, suggesting that male S. ocreata weight modalities differently than females do. We further discuss the implications of this result regarding the communication network of S. ocreata.