Optimal foraging theory

Traits that allow individuals to forage more efficiently can be expected to be naturally selected. The hypothesis that natural mechanisms should drive foraging organisms to maximize their energy intake gave rise to what became known as optimal foraging theory. The idea can be traced to studies undertaken by MacArthur and Pianka [219] and Emlen [109] in 1966.

Optimal foraging theory predicts that foragers will behave to maximize the net caloric gain per unit time of foraging. It assumes differentiated functional classes of predators (grazers, parasites, etc.) and provides insight into correlations between physiological features and predation skills (e.g., digestion and ingestion rates). It also highlights the importance of handling time (e.g., for killing and eating prey) [156, 190, 191, 192, 218, 267].

A large body of theoretical work [162, 171] grew in an attempt to deal with the multitude of determinant factors and in order to identify the relevant parameters involved in the predicted optimization [328]. An important example is the marginal value theorem [75, 76], which states that for the forager to maximize the net energy gain per unit time while foraging in a (more or less uniformly) patchy environment, the forager must leave a given patch when the expected net gain from staying in the patch drops to the expected net gain from traveling to (and starting to search in) the next patch.