Evidence for short-range sonic communication in lymantriine moths

[Display omitted] ▶ Sexual communication in lymantriid moths was known to be mediated by sex pheromones. ▶ We show that male moths at close range are attracted by sound from conspecific females. ▶ Females produce species- and sex-specific wing beat and associated click sounds. ▶ The males’ tympanate ears are tuned to frequency components of wing fanning females. ▶ Sound reception appears to have evolved not only to evade bats, but also to find mates. Sexual communication of nun moth, Lymantria monacha (L.), pink gypsy moth, Lymantria mathura Moore, and fumida tussock moth, Lymantria fumida Butler (all Lepidoptera: Noctuidae: Lymantriinae), is known to be mediated by pheromones. We now show that males are attracted by the sounds of conspecific females over short distances and that wing fanning male and female L. monacha, L. mathura and L. fumida produce species- and sex-specific wing beat and associated click sounds that could contribute to reproductive isolation. Evidence for short-range communication in these lymantriines includes (i) scanning electron micrographs revealing metathoracic tympanate ears, (ii) laser interferometry showing particular sensitivity of tympana tuned to frequency components of sound signals from conspecifics, and (iii) phonotaxis of male L. monacha and L. fumida to speakers playing back sound signals from conspecific females. We conclude that tympanate ears of these moths have evolved in response not only to bat predation, but also for short-range mate finding and possibly recognition.