Influence of Habitat Use on Prey Capture Behavior and Kinematics in the Pyrenean Brook Newt (Calotriton asper)

Caves are extreme environments that impose stringent selective pressures on organisms. Consequently, many cave dwellers show extreme adaptations such as the loss of eyes, depigmentation, and a low resting metabolic rate. Yet, how the initial stages of adaptation to these extreme environments take place remains poorly understood. Calotriton asper is a species of salamander that is ideal to understand the initial stages of adaptation to underground environments. This species presents two genetically distinct morphotypes that live either in surface streams or in cave streams, yet without showing obvious morphological differences. Here, we test for differences in the capacity to locate prey and differences in feeding kinematics between cave-dwelling and surface-dwelling populations under different light conditions. To do so, we quantified prey location ability using a Y-maze and filmed animals capturing prey using high-speed video cameras, both in light and in full darkness. Our results show that animals change capture style and exploration behavior in function of light conditions suggesting an intrinsic plasticity in the species allowing it to feed in both environments. However, the kinematics of capture suggest population-specific behaviors allowing cave-dwellers to be more efficient in capturing prey under total darkness.