Oviposition behavior partitions aquatic landscapes along predation and nutrient gradients

Abstract

That individuals attempt to minimize the ratio of mortality risk/growth rate (μ/<it>g</it>) when foraging within individual habitat patches is well established. Do species partition among spatially discrete communities embedded in complex landscapes in a similar manner? We investigated how 3 ovipositing species (2 <it>Hyla</it> treefrogs and a hydrophilid beetle, <it>Tropisternus lateralis</it>) responded to simultaneous gradients of nutrients and predation risk. Species partitioned our experimental metacommunity primarily by reducing oviposition with fish. <it>Tropisternus</it> positively responded to increased nutrients, but the effect decreased with increasing risk, as predicted by μ/<it>g</it> theory. Use of fish habitats by <it>Tropisternus</it> was unrelated to breeding intensity. In contrast, <it>Hyla</it> showed no nutrient response but oviposited with fish only on nights with high breeding activity. Behavioral responses to the spatial distribution of resources and risk among discrete patches generated substantial variation in habitat-specific colonization rates, which has been identified as a primary mechanism generating both community and metacommunity structure.