Localization Error and Search Costs during Mate Choice in Túngara Frogs,Physalaemus pustulosus

Search costs can have profound influences on female choice, causing females to become less choosy or sample less of the diversity of available mates. Predator foraging strategies, however, determine exactly how search time affects predator encounter rates. Ambush predators are more likely to be encountered by females traveling longer distances to evaluate males, but evaluation time is unlikely to influence encounter‐rate with this type of predator. Actively searching predators, however, may be more likely to be encountered by females employing longer travel times and evaluation times. In this study, we examine the effects of perceived search costs on both temporal and spatial aspects of the search behavior of female túngara frogs, Physalaemus pustulosus. Females were collected from natural choruses and presented with conspecific calls at a distance of 50, 115, or 180 cm from their release point. Assays were conducted in either darkness or simulated full moon light levels. Longer starting distances caused longer choice latencies, but choice latency was considerably lowered under higher light conditions. Females spent considerably less time moving under higher light conditions; however, light levels did not affect path length. Females were more likely to leave the release point with more accurate orientation to the sound source under higher light conditions. We demonstrate that females can respond to perceived search costs by altering spatial and temporal aspects of female search behavior. The overall emphasis of females on reducing time spent moving and increasing movement speed indicates that predation by actively searching predators represents a stronger cost to females than ambush predators.