They are some 2 mm long and are common in freshwater ponds and lakes across Europe, preferring stagnant to moderately moving water.

[2] The male of this species produces its underwater courtship song by stridulating a ridge on its penis across corrugations on its abdomen.

[4] Almost all volume is lost when sound moves from water to air, but even so remains audible to humans walking along the pond shore.

[3] Despite knowing the mechanism of its sound production, researchers are still mystified by the volume produced and feel that once the process is understood, it could open up a useful avenue in ultrasonics.

[5] Not many insects are known to generate sound with reproductive organs, but there is another, the pyralid moth, Syntonarcha iriastis, which emits ultrasonic squeaks.