Detection of wolf spider courtship signals against complex chromatic backgrounds by intended and unintended receivers

This is a study using video digitization and playback of courting male Schizocosa ocreata wolf spiders to examine responses of intended receivers and eavesdroppers. We combined altered male morphology (color / pattern) with aspects of environmental backgrounds (chromatic / spatial information) to test how visual signals affect detection and discrimination by: a) intended receivers (female S. ocreata); b) social eavesdroppers (male S. ocreata); and c) interceptive eavesdroppers (predators). We tested predictions of several current hypotheses: 1) The structure and color of visual signals will affect detection by receivers (both intended and unintended conspecifics and predators) against a complex visual background; and 2) visual systems of vertebrate and invertebrate receivers will respond to different aspects of signal structure. Analyses of chromatic and luminance intensity contrast values for spiders and backgrounds suggest that for both intended female receivers and eavesdroppers, intensity and chromatic contrast influence detection and mate recognition in complex and subtle ways. Results support the hypothesis that receivers with different visual sensory capacities vary in response to color and contrast of courting male spiders against complex backgrounds.