for National Geographic News
In a nighttime chorus of insects, the easiest way to identify individual katydid and cricket species is by listening to their songs, according to one of the world's leading authorities on the jumping insects.
"Without sound, we'd be in a pickle," said Thomas Walker, an entomologist at the University of Florida in Gainesville.
Relying on morphologybody shape, structure, and colorto identify some katydids and crickets is next to impossible, he says.
"With DNA and so forth, we can. But for some species there's no way to identify them on the pin," he said, referring to insects held on display boards with special pins.
Crickets and katydids are closely related insects that all have big hind legs for jumping, long antennae, ears on their front legs, and wings that fold like a fan.
Trained scientists can tell the difference between the two types of insects, because crickets have three segmented feet while katydids have four.
But even for experts, just looking at the creatures doesn't easily reveal when two distinct species are side by side.
For example, the sand field cricket (Gryllus firmus) and the southeastern field cricket (Gryllus rubens) look nearly identical and inhabit the same geographical areas.
To tell them apart, Walker relies on his ears.
"A three-year-old can tell the difference," Walker said.
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