Unraveling female mate choice in Schizocosa mccooki: The interplay of male mass and vibratory courtship

Abstract

Sexual selection is an important evolutionary force and despite extensive research, understanding mate choice on naturally occurring trait variation remains an intriguing area of study. The correlation between mass, a trait associated with courter viability and common target for mate choice, and signals is particularly noteworthy. This study focuses on Schizocosa mccooki, the largest member of a wolf spider genus renowned for its diverse complex male courtship. Our objective was to understand the relationship of male mass and other courtship signals on female choice within this species. We conducted lab experiments involving random pairings of field caught males and females, recording vibratory courtship and its outcomes. Our findings revealed that S. mccooki courtship consisted of vibratory signals with two major components, thumps and raps. Male mass, overall courtship vigor, and thump duration were found to predict mating success. Interestingly, we found no correlation between temporal traits and mass suggesting independent information and an absence of trade-offs between mass, courtship vigor, and signal component rates/durations. Instead, we found that heavier males tend to produce thumps with lower frequencies. The finding that male mass predicts mating success contrasts with patterns observed in other species in this well-studied genus. By uncovering the mate choice patterns of S. mccooki, this study underscores the importance of comparative studies to understand the ways in which sexual selection drives diversification, even among closely related taxa.