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 Manduca pellenia to vocalizations in Sphecodina abbottii. 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?
Explanation
Context: Veronica L. Bura, Akito Y. Kawahara, and Jayne E. Yack studied sound production in silk moth and hawk moth caterpillars during harmless simulated attacks. About a third of tested species produced sounds, ranging from clicks in Manduca pellenia to vocalizations in Sphecodina abbottii. The researchers claim these sounds are directed primarily at predators rather than at other caterpillars of the same species. The question asks what finding would most directly support that claim.
Answer: A) 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.
Why? Sounds that occur only during attacks and cease immediately after are clearly a direct predator-response mechanism. Communication with same-species members would occur at other times too. The attack-exclusive pattern directly supports the predator-directed claim.
Traps:
- B) "in most cases, the sound a caterpillar produced during simulated attacks was different from other species' sounds" → about species-specific sound variation, not about predator vs. same-species targeting
- C) "caterpillar chirps were emitted in a frequency detectable by birds that preyed on them" → shows birds can hear them but doesn't show birds actually stop attacks
- D) "each caterpillar species tended to produce one sound during simulated attacks" → about consistency of each species' sound, not about its function