Interaction Between Echolocating Bats and Their Prey

Abstract

This paper describes the complex acoustic relationship between predator and prey. Many species of insect are known to have functional ears that are sensitive to ultrasound. High frequency signals provoke these insects to react in some way. This is generally accepted to be a defensive mechanism against insectivorous bats using ultrasonic location. Other insects can emit "clicks" in response to bat echolocation calls, which may "jam" bat sonar. Considering the orders of species exhibiting this defensive strategy, it is likely that 50% of European moth species have the capability to evade predation by bats. Insects are a known valuable source of nutrition for bats. This implies that bats have developed methods of overcoming the defence mechanisms of their prey. The structure of bat echolocation calls reflects their temporal and spatial resolution needs when foraging and navigating in their preferred environments. This is coupled with the physical constraints of bat biology, notably wing-related. Within the structure of bat echolocation calls, the call frequency, intensity, duration and pulse repetition frequency may affect the defensive reactions of insects. The acoustic capabilities of some families of insects are reviewed and their influence on bat echolocation calls is discussed.