Meeting Abstract
Mantises (Mantodea) are a group of 2600+ ecologically diverse species that all use raptorial forelegs for prey capture and processing. The mantis foreleg is comprised of the coxa, trochanter/femur, and tibia. During a feeding strike, extension of the coxa and trochanter/femur places the femoral and tibial spines in place for prey capture, which occurs when the tibia is flexed, trapping the prey in the spines. Variation in lengths of each segment may affect the mechanical advantage of the foreleg and influence feeding performance. While research on terrestrial, vertebrate locomotion has shown that variation in limb proportions have adaptively evolved across environments, much less is known about adaptive diversification of invertebrate feeding appendages. Furthermore, as feeding performance is influenced by the sensory system, few studies have examined the coevolution of sensory-motor structures. Using 97 species of mantises I examined foreleg diversification with a combination of methods, including ternary plots for morphospace visualization, phylogenetically informed allomteric relationships, and comparison of evolutionary rates of diversification. Furthermore, using head width as a proxy for depth perception, I examined the correlated evolution of foreleg diversity with depth perception. The results show that among the three segments of the foreleg, the tibia is the smallest, most diverse, and has the highest rate of evolution after body size corrections. Furthermore, while all foreleg segments were related to head width, head width explained the most variation in tibial length. The results suggest a potential adaptive functional role of the length of tibia related to the velocity or force produced in this second class mechanical lever. Furthermore, results from this study support distinct ecomorphs of mantises, as several independent evolutions to grass mimicry evolve similar morphologies.
