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The Killer Wasp That Saws Its Way Out of Its Victims

A six-legged terror the size of a sesame seed.

<em>Dendrocerus scutellaris</em> hails from Costa Rica.
Dendrocerus scutellaris hails from Costa Rica. Courtesy Carolyn Trietsch

Wasps can be difficult creatures to appreciate. They’re aggressive, they sting, and, if they really don’t like you, they’ll do it more than once. A newly identified species of wasp, named Dendrocerus scutellaris, unsurprisingly has few redeeming features—and plenty to make you wince.

This tiny insect is from Costa Rica. It measures just a few millimeters in length and has spiny ridges along its back. Its life is brutish and short: It is laid and hatches inside another living creature, perhaps an aphid. After feasting on the host, it uses the spines on its back like a saw to cut its way out, enabling an Alien-style break-out before it flies off into the sunset. In time, it meets another wasp, mates, lays eggs, and the cycle begins all over again.

That, at least, is what researchers have gleaned from 30-year-old samples of the parasitoid. This new species has never been observed in the wild, and so scientists are limited to using specimens collected in 1985 and loaned out to the Frost Museum at Penn State by London’s Natural History Museum.

But D. scutellaris may be less appalling than it seems, the researchers said in a statement. “While their lives may sound gruesome, parasitoid wasps are harmless to humans and can even be helpful,” researchers said, in a statement. “Depending on the host they parasitize, parasitoids can benefit agriculture by controlling pest insects like aphids that damage crops.” Precisely what that host is remains to be seen—though aphids and the like had better keep an eye out for this tiny killer.