Sister-Species Diverge in Modality-Specific Courtship Signal Form and Function

Understanding the relative importance of different sources of selection (e.g. the environment, social/sexual selection) on the divergence or convergence of reproductive communication can shed light on the origin, maintenance, or even disappearance of species boundaries. Using a multi-step approach, we tested the hypothesis that two presumed sister-species of wolf spider with overlapping ranges and microhabitat use, yet differing degrees of sexual dimorphism, have diverged in their reliance on modality-specific courtship signaling. We predicted that male Schizocosa crassipalpata (no ornamentation) rely predominantly on diet-dependent vibratory signaling for mating success. In contrast, we predicted that male S. bilineata (black foreleg brushes) rely on diet-dependent visual signaling. We first tested and corroborated the sister-species relationship between S. crassipalpata and S. bilineata using phylogenomic scale data. Next, we tested for species-specific, diet-dependent vibratory and v...