It had long been known that the aptly named frog-eating bat eavesdrops on frog calls to find its prey. On a hunch that midges might be doing the same thing, McKeever broadcast prerecorded frog calls in the field. “He collected bucketloads of the midges,” Borkent told me. By playing recorded frog calls over a trap—a fan blowing into a net—many specimens could be collected in a single evening. On one of their first forays, McKeever and a colleague caught 566 midges in 30 minutes. Suddenly, biologists had a tool—a cassette tape recorder—to collect and document a group of flies that for a century
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