FORAGING TIME OPTIMIZATION AND INTERACTIONS IN FOOD WEBS

The consequences of foraging time optimization by 1 sp. in a food web on interactions in the food web are investigated using several simple mathematical models. The situation modeled is one in which a forager must expose itself to a greater risk of predation while foraging, and it adjusts foraging time adaptively to maximize fitness. In this system the forager''s behavior results in a number of indirect effects between species: it causes interactions between the forager''s predator and the forager''s food; it causes predator self-limitation; and it may cause interactions between different food species. Some simple models are used to show that these trophically mediated indirect effects theoretically can be comparable to or larger in magnitude than the direct interactions between adjacent trophic levels. The possibility of such indirect effects has important implications for theoretical and empirical studies of food webs.