Harvest rates and patch-use strategy of Egyptian fruit bats in artificial food patches

Abstract

The amount of food left by a forager after feeding in a depletable patch of known volume, the giving-up density (GUD), estimates the quitting harvest rate. I constructed a feeder for measuring GUD in Egyptian fruit bats (Rousettus aegyptiacus). The feeder contained liquid food mixed with pieces of hose that interfered with the drinking behavior of the bats and forced them to work progressively harder to obtain more food as the depth of the liquid in the feeder decreased. Harvest rates in bats using these feeders declined with time. When presented with feeders containing different initial food densities, the bats equalized GUD and consumed proportionately more food from rich patches than from poor ones. Thus, the bats recognized patches of different quality and foraged following a fixed quitting harvest rate patch-use strategy. © 2006 American Society of Mammalogists.