Selective Responsiveness to Long-Range Acoustic Signals in Insects and Anurans

Abstract

SYNOPSIS. Insects and anurans show various patterns of selective responsiveness to playbacks of natural and synthetic sounds. Preferences and tuning of the auditory system most often match one or more strongly emphasized frequency components in long-range, mate-attracting signals typical of conspecific individuals, but exceptions, in which frequencies lower or higher than the mean are preferred, occur in some species. In some insects the most preferred frequencies may correspond to regions that maximize localizability of signals rather than regions of maximum sensitivity. Patterns of preference for fine-temporal properties are typically stabilizing within a population; females prefer values near the mean and few males produce calls with values that deviate sufficiently to make them less attractive than calls with average values. Preferences for gross temporal properties {e.g., the rate and duration of signaling) are usually highly directional, with much higher than mean values preferred. In anurans, call rate is a better predictor of male mating success than dominant frequency. Nevertheless, a variety of factors, especially close-range assessments that are common in insects, may modify or negate the advantages of producing long-range signals of high relative attractiveness. The evolutionary consequences of selective responsiveness in anurans and insects are discussed