Until a recent rediscovery, the Oobius depressus wasp hadn't been seen by scientists for 101 years. Photo by Serguei Triapitsyn/UC-Riverside
RIVERSIDE, Calif., June 20 (UPI) -- The last time scientists identified the wasp species Oobius depressus, World War I was just getting underway. Researchers in California and Michigan recently confirmed the rediscovery of the elusive species, having gone missing for more than a century.
The discovery is significant, as the black-bodied wasp is a natural enemy of a wood-boring beetle that infests and kills black locust trees, whose wood is greatly valued for its strength, durability and resistance to rot.
The last specimens were found in 1914 in Morristown, Ill., but they weren't well-preserved and are missing their heads and antennae, making it difficult for scientists to match new specimens.
However, researchers knew from descriptions of the wasp that the species targets locust borers. Toby R. Petrice, an entolomogist with the USDA Forest Service Northern Research Station in Lansing, Mich., decided to try to locate the wasp by placing a trap under the bark of several black locust trees, where locust borers lay their eggs. Female O. depressus look for locust borer eggs to parasitize under the bark of black locust trees.
Petrice's traps caught lots of beetles and other insects, including one female wasp that matched the scientific descriptions of O. depressus, as well as the headless specimens collected 101 years ago.
The specimen was sent to a team of scientists at the University of California, Riverside, led by Serguei V. Triapitsyn, director of the university's Entomology Research Museum, where its identity was confirmed.
Petrice, Triapitsyn and their colleagues recounted the once-missing wasp's rediscovery in the journal The Great Lakes Entomologist.