Near-far search: An evolutionarily stable foraging strategy

This study addresses the momentary rules of nectar foraging behavior on carpet-type, small inflorescences. It has been suggested that patchiness in the distribution of nectar can give an advantage to “near-far” type of foraging strategies; that is, to foragers which search “near” (in the neighborhood of the last visited flower) as long as the nectar yield is high enough and go “far” otherwise. To explore the evolutionary stability of near-far search, various foraging strategies were compared, according to two, slightly different optimality criteria: the number of flowers emptied during a fixed length bout and the number of flowers visited until total extraction of the entire inflorescence. With long bouts (in the case of a single forager) or a substantial probability of revisits to the same inflorescence (in the case of multiple foragers), a near-far foraging strategy is an ESS. Furthermore, prior patchiness in the nectar distribution is not a necessary condition for the evolutionary stability of near-far search. It turns out that during near-far foraging some patchiness is created by the foraging process itself, which the near-far forager can exploit later on.