Which finding, if true, would most directly support Bura and colleagu…

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Veronica L. Bura, Akito Y. Kawahara, and Jayne E. Yack investigated the evolution and function of sound production in silk moth and hawk moth caterpillars. They found that during harmless simulated attacks on isolated caterpillars, 33% of the tested species produced sound, which ranged from clicks in Actias luna to whistles in Phyllosphingia dissimilis. Although some insects use sound to communicate with members of the same species, the researchers claim that the caterpillar sounds recorded in their study are directed primarily at predators.

Which finding, if true, would most directly support Bura and colleagues' claim?

In most cases, the sound that a caterpillar species produced during simulated attacks was not produced by other caterpillar species during simulated attacks.

Caterpillar clicks were emitted in a frequency detectable by birds that prey on caterpillars, but caterpillar whistles were not.

Each caterpillar species tended to produce one sound during simulated attacks, although individuals occasionally made a variety of other sounds during simulated attacks as well.

None of the species that emitted sounds did so before the simulated attacks, and nearly all stopped emitting sounds within ten seconds after the attacks.