A preliminary study of the sounds produced by artiid moths

Within Ontario, there are 60 described species of Arctiidae (Tiger Moths) of which 22 were captured and tested for sound production. Sound in the form of rapidly repeated, high frequency pulses generated by the buckling action of the tymbal organ of the moth's thorax was produced by 15 species under tactile stimulation. Stridulations could be further produced in seven of these 15 species by exposing them to bursts of ultrasonic sound resembling bat echolocatory/hunting cries.The structure of the sound emitted by the moths can be related to the form of their tymbals. The sound produced by those tymbals typically possessing a row of ridges or "microtymbals" is in the form of pulse-trains whereas the non-striated tymbals of Callarctia spp. produce single pulses as the entire tymbal is collapsed and recovered. The measurements of a variety of acoustic parameters of the sounds are given, all of which exhibit a high degree of variability. There are no differences in the sounds emitted by male or female Cycnia tenera Hübner except in pulse repetition rates where males deliver a slightly higher number of pulses per second.The reponse of C. tenera, which will produce sounds when exposed to artificial bat cries, is tested against stimuli of varying frequency and intensity. Cycnia tenera appears to exhibit an avoidance reaction to the sounds of conspecifics while in free flight.