The Response to Sound in Certain Lepidoptera

Abstract

The work of Eggers (1925, 1926, and 1928), of von Kennel and Eggers (1933), and of Schaller and Timm (1950) leaves little doubt that many nocturnal Lepidoptera are sensitive to airborne vibrations of high or of ultrasonic frequency, and that the reactions are mediated by the tympanic organs. The responses reported by these authors were often complex and unpredictable, as though dependent upon conditions not easily recognized or controlled. Some specimens showed prompt excitatory reactions such as running or taking flight at the onset of the experimental sound, while others gave inhibitory responses such as the interruption or cessation of movement, sometimes with complete tonic immobility (“Totstellung”). During flight, the moths often reacted with sudden swerving or diving movements. Eggers (1926) suggested that the excitatory responses might be characteristic of brightly colored or striking marked species, while the inhibitory reactions might be more typical of procryptically colored forms. Schaller and Timm were unable to detect species differences of this kind, and attributed the variations in behavior entirely to changes in the physiological condition (“Zustand”) of their experimental insects.