Meeting Abstract
Sexual dimorphism often results in different relationships between morphology and performance for males and females. Increased loads associated with reproductive investment often hinder female locomotor behavior. However, sexual selection could help compensate for increased loads and reduced escape performance by increasing the length and mechanical advantage of limbs. We tested this hypothesis in Cave (aka Camel) Crickets (Ceuthophilus spp.) and predicted that cave cricket females would have longer legs than males for a given body size in order to allow for increased load during reproductive cycles without decreased escape performance. We simulated predator attacks and measured average jump distance in 120 individuals. As predicted, females were heavier for a given total length when compared to males and juveniles (ANCOVA; p=0.0339) and have longer legs for a given total length than males and juveniles (ANCOVA; P=0.0048). Females, males, and juveniles all jumped similar distances for their leg length (ANCOVA; p=0.7877). Our results suggest that sexual selection on jump performance in cave crickets has increased female leg length to compensate for reproductive load. This provides support for the differential equilibrium hypothesis which posits that sexually dimorphic life history strategies are caused by unique environmental pressures in male and female Orthoptera. Since female orthopterans are often larger than males, leg length may be under selection in other species with similar morphological constraints on morphology and escape performance.
