Journal of Hymenoptera Research
For the first time ever, scientists have discovered two different species of parasitic wasps in the United States that had been previously found only in Europe. How they got here is a question they have yet to answer, however.
The parasitic wasps were discovered on both the East and West Coast by a research team including faculty at Binghamton University, State University of New York. Oak gall wasps create benign tumor-like plant growths known as “galls” where they lay their eggs. These tiny parasitic wasps use those galls to lay their own eggs which then go on to devour the entire oak gall wasp inside, according to a press release. Researchers at the University of Iowa also identified a similar wasp from collections they made in the state of New York.
“Finding this putative European species on the two coasts of North America inspired our group to confirm this parasitic species’ identity and whether it was, in fact, an introduced parasite from Europe,” said Kirsten Prior, associate professor at Binghamton University.
Where did they come from and how did they get here?
So, how did these European parasitic wasps end up in the United States? According to the scientists’ report published in the Journal of Hymenoptera Research, they could have been brought here during an increase in oak tree planting that occurred during the 17th century, or they could have hitchhiked on a plane, according to Prior, because adult parasitic wasps can live for 27 days.
The East Coast wasps found to have from Portugal, Iran, and Italy, while those found on the West Coast are related to species in Spain, Hungary, and Iran, according to the report. Whether they pose a hazard to native North American species of wasps is another question that needs to be answered.
“We did find that they can parasitize multiple oak gall wasp species and that they can spread, given that we know that the population in the west likely spread across regions and host species from a localized small introduction,” Prior said. “They could be affecting populations of native oak gall wasp species or other native parasites of oak gall wasps.”
Thankfully, these new species of wasps being in North America pose no threat to humans. However, the fact that there are now more wasps in North America is not something most people, outside of scientists who studies such things, ever want to hear.