Adaptive complexity of interactions between feeding and escape in crayfish.

If crayfish (Procambarus clarkii) are presented with food or threat stimuli, or both, their feeding behavior and escape from threat by tail flips show flexible patterns of interaction. If they are engaged in eating large, relatively immovable pieces of food, escape is inhibited, whereas if small pieces of food are being eaten, the probability of escape is enhanced. If escape occurs during a feeding bout, large pieces of food are usually released, but small ones are not. These observations suggest that the neural circuitry responsible for coordination of behavior in invertebrates may not be as simple as usually assumed.