Practice question

In the classic optimal diet model, rejection of a lower-ranked prey type depends on how quickly the predator expects to encounter the more profitable prey type. Search time for prey 1 is therefore decisive. If prey 1 is encountered frequently, rejecting prey 2 costs little time and preserves a high long-term intake rate. If prey 1 becomes rare and its expected search time increases, accepting prey 2 can raise average energy gain despite its lower E/h ranking. A notable prediction is that the abundance of prey 2 does not directly control the decision after prey 2 has already been encountered; diet breadth changes primarily with encounter rate of the superior item. Predator size and temperature may influence handling or metabolism, but they are not the specified threshold variable in the basic model. Formally, prey 2 is included when its profitability exceeds the expected average return from continuing to search for prey 1. This links a post-encounter choice to the opportunity cost imposed by future search.