Ensign wasps discovered preserved in amber in Central America indicate the presence of cockroaches, their natural prey, 25 million years ago.
A study at Oregon State University in the United States identified four ancient species of parasitic ensign wasps preserved in amber 25 million years ago.
Currently, there are about 400 species of wasps distributed among 20 genera and they can be found all over the planet, except for the polar regions.
They belong to the order Hymenoptera and the family Evaniidae, and have earned the nickname of ensign wasps because their abdomen resembles an ensign, a flag flying on a ship.
These insects typically measure 5 to 7 millimeters in length and do not bite or sting – they are lethal only to some insects, such as cockroaches.
“The wasps sometimes are called the harbingers of cockroaches – if you see ensign wasps you know there are at least a few cockroaches around,” said George Poinar Jr., a researcher at Oregon State University.
“Our study shows these wasps were around some 20 or 30 million years ago, with probably the same behavioral patterns regarding cockroaches.”
Poinar Jr. was the main author of the study where he described the four new extinct species, three of which were found in the Dominican Republic (Evaniella setifera, Evaniella dominicana, and Semaeomyia hispaniola) and one in Mexico (Hyptia mexicana).
All lived during the tertiary period, between 65 and 2.6 million years ago.
The fame of “cockroach killers” is due to the fact that female wasps lay their eggs on the eggs of these insects, which become food for wasp larvae after they hatch.
No cockroaches were observed in the ambers, but in one of the Dominican pieces, three flying termites were next to one of the wasps.
The termites were probably sharing a nest with the cockroaches and this attracted the wasp.