Search mechanism of a stream grazer in patchy environments: the role of food abundance.

摘要: The search behavior of the grazing stream insect Baetis tricaudatus (Ephemeroptera: Baetidae) was examined in field and laboratory experiments. Regardless food abundance experimental habitats, nymphs spent significantly more time patches than predicted if they had moved randomly with respect to patches. A significant reduction movement rate within relative between largely accounted for these results. pattern highly systematic agreement predictions optimal foraging theory since uniformly distributed Between-patch movements were affected by most recently grazed patch. Search intensity after departure from a patch positively related while inversely level. These effects produced between-patch patterns that suboptimal habitats because resulted revisitation previously depleted However, differences natural spatial occurrence types suggest may be adaptive habitats.