【英语时差8,16】巨大的声响

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Ya?l: On today's Moment of Science: The praying mantis¹, an auditory Cyclops.

D: Sounds like a B-Movie from the 1950's!

Y: To small insects, praying mantids probably do seem like something out of a monster      movie. Mantids are some of the most impressive insect predators², regularly snaring³      other insects or even the occasional lizard⁴, snake or frog.

     But despite their hunting skills, mantids are ill-equipped to avoid predation      themselves. Camouflage⁵ keeps some well hidden from visual hunters such as birds,      but matching the color of your background won't hide you from nocturnal predators,      like bats. Many bats locate their prey⁶ in total darkness by echolocation---producing      ultra-high pitched calls and listening to the reflections, or echoes off objects in their      environment.

D: I thought this show was about the praying mantis?

Y: Right. Praying mantids were long thought to be deaf, but neuroscientists at Cornell      and the University of Maryland discovered a single teardrop-shaped ear along the      middle of praying mantis' thorax. Praying mantids don't produce sounds, and don't      use sound to locate their prey, so why would they need to hear?

D: Bats?

Y: Bats. The researchers tested whether the mantids' unique ear could hear the      ultrasonic⁷ cries of bats, which are too high pitched for human ears to detect. When      the scientists played recordings⁸ of bat echolocation calls to free-flying mantids, the      mantids abruptly⁹ stalled in the air and erratically¹⁰ spiraled downward, dropping out of      the sky. The evasive maneuvers¹¹ enable a normally slow-flying mantids to escape bat      attacks in nearly eighty-percent of trials. When scientists deafened¹² the mantids, they      only escaped bat attacks thirty-four percent of the time. So ultrasonic hearing gives      mantids a huge advantage.

D: And the one-eared mantis lives to hunt another day!  

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