A gray moth with orange highlights called Bertholdia trigona “goes berserk,” making lots of noise above the range of human hearing when a hunting bat approaches, says William Conner of Wake Forest University in Winston-Salem, N.C. Bats rely on their natural sonar to locate flying moths in the dark, but in a lab setup, the bats rarely managed to nab a loud moth.

When researchers disabled the moth’s noisemaking organs, though, bats caught the moths in midair with ease, Conner reported at the annual meeting of the Society for Integrative and Comparative Biology.

Conner says the work is “the first example of any prey item that jams biological sonar.” Conference attendee David Yager of the University of Maryland in College Park says Conner’s experimental paradigm is “very strong, and I do think he has documented jamming by a species of moth.”

Insect-hunting bats and their moth prey have become a classic in the study of evolutionary arms races, Conner says. “This is warfare … The first counter-adaptation is that the insects developed ears.”
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Jamming isn’t the only possible explanation for moth noises, he said. An explosive clicking sound coming back out of the night might startle a bat just a split-second long enough for the moth to get away.