Practice question

A lower-ranked prey should not be accepted merely because it is abundant. In the classic optimal diet model, acceptance depends on whether its energy per handling time exceeds the average return expected from rejecting it and searching for more profitable prey. If prey 1 remains sufficiently available, consuming prey 2 would occupy handling time that could be spent obtaining a better item, so prey 2 is rejected. The density of prey 2 itself has little effect on this encounter decision because the choice is made after prey 2 has already been found. However, the statement is conditional: if preferred prey become scarce enough, the optimal diet broadens and the less profitable prey can be included. This interpretation follows ecological definitions based on effects on fitness, energy flow, behavior, and population performance. It also shows why superficially similar alternatives can represent different mechanisms once the direction of benefit, harm, or resource transfer is considered.