Katydids and Bats
Crickets are not the only animals that inadvertently signal to another species. A close cousin of the field cricket, the greener, longer-legged katydid, faces a similar challenge. Instead of attracting the female he bargained for when he launched into full voice, a male katydid may find himself becoming a meal for a bat. A repetitive staccato trill made up of many frequencies proves easy to locate, no matter what species produces it. This is, of course, the purpose of the male katydid’s trill. But in bat-infested Panama, katydids change their tune. They sing a higher-pitched song, with a narrower frequency range, much harder to locate. They also sing a lot less. In an experimental situation, loud, enthusiastic katydids caged with hungry bats survived less than a minute. Shyer, quieter males lasted more than half an hour before becoming bat bait.
But if males must remain quiet to survive, how can they attract Ms. Right? A quiet, infrequent trill can bring a female into the vicinity, perhaps to the same plant. The quieter males then complete their attractive act with a silent dance so enthusiastic they shake the leaf they’re standing on. Females detect the dance through the plant, locating the source of both the beautiful voice and the swiveling hips.