New species of cockroach-killing wasps discovered in 25-million-year-old amber

This ensign wasp was trapped in amber 25 million years ago.

George Poinar Jr./Oregon State University

If you hate cockroaches, then you might find some satisfaction in a fascinating piece of ancient insect history that recently came to light. 

Oregon State University entomologist George Poinar Jr. discovered four new species of ensign wasps in 25-million-year-old amber found in the Dominican Republic and Mexico. These cockroach-killing wasps are still around today, and the amber finds offer an intriguing glimpse into their past.

Poinar is the author of a study on the amber-encased wasps published in the paleobiology journal Historical Biology this month.

This is one of four new species of ensign wasp found trapped in 25-million-year-old amber.

George Poinar Jr./Oregon State University

Ensign wasps let their young handle the cockroach-killing duties. Female wasps lay eggs in or on a cockroach egg case. 

“When the wasp egg hatches, the larva eats the cockroach egg where it was laid,” said Oregon State University. The larva uses the egg case as a shelter as it grows toward adulthood.

“Our study shows these wasps were around some 20 or 30 million years ago, with probably the same behavioral patterns regarding cockroaches,” said Poinar in an OSU statement Friday.

The wasps fit right in with some of Poinar’s other amber discoveries, which include a fascinating flea, a microinvertebrate “mold pig” and an alien-looking “E.T.” insect.     

Poinar didn’t find any cockroaches in the fossilized tree resin along with the wasp remains, but he did spot some flying termites, which may have been sharing space with cockroaches. 

And if you see an ensign wasp today, it’s a friend, not a foe. They don’t sting, but they do wreak havoc on cockroaches. 

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