Hearing above the din of a katydid’s cocktail party.

As darkness descends upon the tropical rainforests of Malaysia, male chirping katydids of the Mecopoda complex are just getting warmed up for their usual nightly concerts to woo the females. These nocturnal suitors are favoured for chirping in synchrony as a chorus; however, singing in time with one another is no easy task as they have to co-ordinate in the presence of the noisy serenades from a very closely related katydid species. This is particularly difficult, as Manfred Hartbauer from Karl-Franzens University, Austria, explains: ‘This species uses almost the same frequency spectrum [2–80 kHz] in their acoustic signal [as the chirping katydid species], but produces this signal in an ongoing train of syllables, so it’s a trill, and we wondered how the chirping species could establish chorus synchrony in the presence of such a noisy masker.’ Hartbauer decided to find out with the help of PhD student Marian Siegert and colleague Heiner Römer (p. 4656).