Predator presence decreases food consumption in juvenile Xenopus laevis

Abstract

Abstract: Predators impact prey in direct (lethal) and indirect (non-lethal) manners. Predator-avoidance models capitalize on the non-lethal effects of predators to study how predator-induced fear impacts prey behavior and physiology. Here, we aimed to develop a predator avoidance model to determine how predators alter feeding and anxiety-like behavior in the African clawed frog (Xenopus laevis). We determined (1) the repeatability of frog behavior over time, (2) the effect of a stimulus (nothing, a size-matched or a large conspecific [potential predator]) on frog behavior, and (3) the effect of a stimulus on frog behavior in the presence of food. Twelve juvenile experimental frogs were exposed to all three stimulus conditions over 1 week. We predicted that (1) frog baseline behavior would be repeatable, and that (2) the presence of the large frog, but not size-matched frog, would increase fear and anxiety-like behaviors (hiding and inactivity) and would decrease food consumption and the number of air gulps. In the presence of both food and stimulus, experimental frogs ate significantly less when exposed to a large (potential predator) vs. a size-matched and no frog and took more time to first contact the food. Time spent inactive and number of air gulps did not differ across conditions. Few frogs hid during the behavioral trials. Time spent exploring and inactive and tank locations were repeatable over time. Overall, our paradigm is a viable model for studying the effects of predators on prey behavior, especially as it relates to feeding. Significance statement: Predators can induce fear and anxiety in prey and can alter prey behavior. We sought to develop a predator-avoidance model to study prey anxiety and feeding behavior in African clawed frogs. We determined (1) the repeatability of baseline behavior over time, (2) the effect of a stimulus (no, a size-matched, or a large [predatory] frog) on frog behavior, and (3) the effect of a stimulus on behavior in the presence of food. The presence of a potential predator alone did not significantly alter prey behavior. With predator + food, experimental frogs took longer to contact food, ate less, and spent less time feeding. Most activity and location behaviors were repeatable over time. This paradigm is a viable model for studying the effects of predators on prey feeding behavior.