There are many species of parasitic wasps, many of which we've posted. But even parasites can become the victim of parasites, in this case a plant that feeds on wasps that feed on plants. The oak leaf gall wasp invades oak trees and induces them to develop galls, or abnormal growths, that the wasps use to draw nutrition from and lay their eggs in. A research team led by Scott Egan of Rice University noticed a vine among collected galls that seem to have attached suction cups to the galls.
So, Dr. Egan went back to the Florida sand live oak forest where his collaborator, Glen Hood, first found the gall. Dr. Egan walked through the trees and kept his eyes open. Soon, he realized that in one patch, the oaks and their galls were threaded with a plant called the parasitic love vine. There the researchers found numerous instances of the vine entering the galls.
The connection did not seem harmless. When the researchers dissected 51 love-vine-infested galls from one wasp species, they found that 45 percent contained a mummified adult wasp, compared with only 2 percent of uninfested galls.
That suggests that the love vine interferes with the wasp’s nutrition such that it develops fully but is not able to leave. And the host tissue within dissected galls was twisted toward the vine's entry points, hinting that it was co-opting the gall's nutrients.