Meeting Abstract
Predators constantly make decisions about whether to pursue or evade prey, especially when their prey has the capacity to injure them. The nudibranch mollusc, Berghia stephanieae provides a special opportunity to study the neuroethology of predator pursuit and avoidance. Like many nudibranchs, it is a specialist predator, feeding exclusively on the sea anemone, Exaiptasia pallida. However, unlike other nudibranchs, it and its prey can be reared in the lab in large numbers facilitating experimentation on behavioral choice. When feeding, Berghia is repeatedly stung by the Exaiptasia’s nematocysts and must decide whether to approach and feed or turn and evade. We characterized the feeding behavior and the probabilities of response to contact with the Exaiptasia in starved and sated animals to elucidate the neural mechanisms underlying the approach-avoidance decision making in this animal. The Exaiptasia can sting Berghia with its tentacles or with its acontia, structures with a higher concentration of nematocysts that are extruded as a threat response. The hunger state of the Berghia modulated their decision-making; hungry animals endured more stinging than sated animals. In response to contact with Exaiptasia tentacles, starved Berghia had a significantly higher probability of engaging with their prey than sated individuals, furthermore after contacting the Exaiptasia acontia, starved Berghia also had a significantly lower probability of an evasion response than sated animals. Moreover, starved animals spent a smaller proportion of time exploring the arena and more time feeding than sated animals. Thus, the choice of whether to pursue or evade is modulated by the animal’s internal state; it seems that they make riskier choices when hungry. Future work will examine potential neural mechanisms for this cost benefit decision making.
