Ultrasonic hearing in moths

Abstract

Many moths possess ultrasound-sensitive ears, directly resulted from bat predation. Moth ears display an abundant diversity due to their body location, accessory structures, and number of auditory sensory cells. Anatomically, the moth ears are the simplest hearing organs in insects and most are tympanal organ with a tympanum. Eared moths have an optimal frequency range between 20 kHz and 50 kHz, which coincides with the peak frequency used by most insectivorous bats. The primary function of the moth ear is to detect and avoid the hunting of bats. Eared moths show a series of defensive behaviors, when they are exposed to the cries emitted by insectivorous bats. The presence of these tympanal organs also set the stage for the later evolution of ultrasonic courtship signals in the eared moth families. Over the years, entomologists worldwide have performed large numbers of studies on hearing of moths and their interactions with bats. This paper presents an overview of moth hearing, focusing on morphology, neurophysiology, and behavioral ecology.