Behaviour 2019
Hunger causes riskier decision-making in a specialist predator of dangerous prey
Kate Otter, Saida Gamidova, Shane Ziemba, Joseph Bima Jenie, Paul S. Katz. University of Massachusetts Amherst, Amherst, Massachusetts, United States

When hunting and feeding, animals make cost-benefit decisions about where, when, and how to find food while avoiding predation. In this study we focused on the specialist nudibranch predator Berghia stephanieae, which eats a single species of sea anemone, Exaiptasia pallida. Sea anemones also predate upon foraging nudibranchs. This provides a unique opportunity to study how hunger influences the approach-avoidance decision-making of a specialist predator of dangerous prey. We characterized the feeding behavior and the probabilities of response to contact with the Exaiptasia in starved and sated animals to understand approach-avoidance decision making using machine-learning based software (DeepLabCut). We found that food-depriving Berghia decreases the probability that it exhibits an avoidance response after contact with its prey.  Testing a cohort of animals over a period of food-deprivation, showed  that the behavioral differences shifted gradually, rather than abruptly. Thus, the choice of whether to pursue or evade is incrementally modulated by the animal’s internal state; they make riskier choices when hungry.