Guild Structure and Niche Differentiation in Echolocating Bats

Abstract

Bats are ecologically more diverse than any other group of mammals. The position of a species within a local ecosystem is best described by its preferred habitat type and foraging mode. Echolocating bats fall into seven guilds, each defined as a group of species that exploits the same class of environmental resources in a similar way. Members of a guild forage under similar ecological conditions and share similar sensory and motor adaptations, so the behavioral patterns of well-studied species have high predictive value for other species of the same guild. Species from different guilds differ in the resources they exploit and how they forage for prey. Species belonging to different guilds usually do not compete for food. Within guilds, niche differentiation results in a partitioning of the available resources. Based on foraging behavior, three main niche spaces can be discriminated. In aerial-hawking and trawling foragers, niche differentiation is dominated by the prey’s position in relation to the background and is reflected mainly in differences in body size, echolocation behavior, and flight morphology. In flutter-detecting foragers, differences in body size and corresponding frequency of the CF-FM signals reflect niche differentiation. In gleaning foragers, niche differentiation is not correlated with clear differences in echolocation behavior but by large differences in body size and by distinct sensory-motor adaptations for specific diets.