Using Insect Sounds to Estimate and Monitor Their Populations

Accurate estimates of population size are needed to understand the population dynamics of any species. They are also needed to determine when to implement a specific control tactic, and to measure whether that control tactic has been effective. This paper discusses the use of acoustic signals produced by insects and the feasibility of using these signals to census populations. Insect sounds are either incidental (produced as a by-product of some activity) or non-incidental (produced to cause a response in some other animal). Incidental sounds differ from non-incidental sounds with respect to several features that are important to using sound to census populations. These features include species specificity, frequency content, ease of localization, distance traveled, and the duration and timing of sound production. Studies of crickets show that information about which individuals in a population are producing sound, when the individuals produce sound (seasonally and daily), and the probability that individuals produce sound during census periods must be known to accurately estimate the size of a population.