tymbals

Tymbals are specialized sound-producing membranes found in cicadas and some related insects. They are typically paired organs located on the sides of the first abdominal segment. Each tymbal comprises a flexible membrane covered with rib-like ridges. Under neural control, tymbal muscles rapidly buckle the membrane inward and outward. The rapid buckling produces a sequence of audible clicks, and the insect’s body acts as a resonator to amplify and shape these clicks into a loud buzz or trill.

The sound produced by tymbals results from the coordinated action of the membranes and the surrounding body cavities. The waveform, duration, and repetition rate depend on species, temperature, and the activity of the tymbal muscles. This allows individual species to generate distinctive calls that facilitate mate attraction and species recognition.

Ecology and behavior: In males, tymbal-based calls function primarily in courtship and territorial signaling. The calls can vary widely in tone, tempo, and pattern between species, enabling females to identify conspecific males. The production can be energetically costly, and its intensity often increases with temperature, which can raise the rate and frequency of the calls.

Evolution and distribution: Tymbals are a defining feature of cicadas (family Cicadidae) and related cicadomorph insects. The organ has diversified across lineages to produce a variety of mating calls, contributing to the rich acoustic diversity observed in this group.