PLATT, J.P.*; TURINGAN, R.G.: Kinematic and behavioral consequences of diet-induced phenotypic plasticity in the feeding morphology of sheepshead, Archosargus probatocephalus

Studies of phenotypic plasticity in fishes commonly focus on the correlation between diet and morphology of the feeding apparatus, but few studies have directly measured the performance consequences of diet-induced morphological changes. We conducted a novel study, designed to elucidate the effects of diet-induced changes in feeding apparatus morphology on behavioral and kinematic performance during prey capture in Archosargus probatocephalus. We tested the following hypotheses: (1) the kinematics of prey capture and prey-handling efficiency vary among fish reared in different diets and (2) the kinematics of prey capture and prey-handling efficiency vary between soft and hard prey types. We compared prey-handling efficiency and the kinematics of prey capture in A. probatocephalus reared on (1) hard prey, (2) soft prey, and (3) mixed prey. Using high-speed video, the kinematics of prey-capture behavior in post-training fish, fed both natural and novel prey, were compared. Our results revealed that (1) on average, the kinematics of prey capture did not differ among fish reared on different diets, (2) the velocity of mouth opening and closing was slightly faster for fish feeding on soft prey, regardless of rearing diet, and (3) prey-handling efficiency varied between soft and hard prey, independent of rearing diet. It appears that the kinematics of prey capture in A. probatocephalus are stereotyped and were not influenced by training or diet-induced morphological changes, at least during the time-scale of the current experiment. Phenotypic plasticity in this case seems to be limited to morphological changes and has little effect on the systems controlling feeding apparatus movements.