Temporal rhythms in the signals of insects

The signals generated by acoustic insects exhibit temporal patterns on several time scales. Annual or seasonal rhythms provide information about temporal changes in insect population size. Knowledge of such changes might be useful in ecological monitoring programs. Circadian or daily rhythms commonly seen in insect signaling are generated by endogenous ‘‘clocks’’ that are reset by environmental cues. Understanding these daily patterns is also important for monitoring insect populations. Within insect populations, the signals of neighbors sometimes show temporal patterns of synchrony or alternation with timing on the order of seconds. The phase relationships among individuals are maintained by acoustic resetting, whereby an individual’s temporal rhythm will change depending on the phase that neighboring signals are received. On still smaller time scales, temporal patterns of insect songs are diverse and generally differ among species. These small-scale patterns are often essential components of mating signals and are used in mate recognition and mate choice.