Scientists Discover Unique New Parasitic Wasp Species in Texas

Chrysonotomyia susbelli
Another new wasp species, Chrysonotomyia susbelli, was discovered by Rice researchers. Credit: Rice University

The wasp’s color is “almost identical” to the official colors of the residential college.

A new wasp species, Chrysonotomyia susbelli, has been discovered in Houston, Texas, becoming the 18th species identified by Rice University’s Scott Egan and his research team since 2014. This marks the fourth wasp species found on the university campus in the past seven years, shedding light on the hidden world of parasitoid wasps and the complex ecosystems that flourish in our immediate surroundings.

The Chrysonotomyia susbelli is a parasitoid wasp, about 1 millimeter long, that emerges from galls, or tumorlike growths created by the gall wasp Neuroterus bussae found on southern live oak leaves. The galls serve as microhabitats within which larvae feed, develop and pupate. The research team’s study was published in the journal ZooKeys.

Significance of the New Species

“Chrysonotomyia susbelli represents the sixth species of its genus described from North America and the first globally known to parasitize cynipid gall wasps,” said Egan, an associate professor of ecology and evolutionary biology.

The wasp was discovered and named by Brendan O’Loughlin, a Rice senior and the study’s first author. “The wasp’s goldenrod color is almost identical to the official colors of Wiess College, my residential college,” O’Loughlin said.

Chrysonotomyia susbelli Side
The Chrysonotomyia susbelli is a parasitoid wasp, about 1 millimeter long. Credit: Rice University

To confirm the uniqueness of the species, the research team conducted a genetic analysis and a detailed study of the wasp’s physical features under a microscope. Its investigation also included a review of the historical literature to ensure that the species had not been previously described.

This research was complemented by DNA barcode data and observations of the wasp’s natural history, including host associations and a unique leaf-scanning behavior exhibited by female wasps. The researchers also modified the identification key of New World members, groups of species found exclusively in the Americas, to incorporate this new species.

Importance of Local Biodiversity

Egan emphasized the importance of studying local biodiversity. “You don’t have to travel to a distant rainforest to find new and beautiful things — you just have to step outside and look,” he said.

The discovery hints at a previously unexplored ecological niche involving Chrysonotomyia parasitoids, cynipid gall wasps, and oaks, suggesting that there may be many more undiscovered species within this system.

“Generations of Chrysonotomyia susbelli have likely lived unnoticed on the oaks of Rice University since its founding,” Egan said.

Reference: “Description of a new species of Chrysonotomyia Ashmead from Houston, Texas, USA (Hymenoptera, Chalcidoidea, Eulophidae)” by Brendan O’Loughlin, Pedro F. P. Brandão-Dias, Michael W. Gates and Scott P. Egan, 18 September 2024, ZooKeys.
DOI: 10.3897/zookeys.1212.127537

Co-authors of the study include Pedro FP Brandão-Dias, Ph.D. graduate of ecology and evolutionary biology at Rice and current postdoctoral scholar at the University of Washington, and Michael Gates, parasitoid wasp specialist of the U.S. Department of Agriculture’s Systematic Entomology Laboratory at the Smithsonian National Museum of Natural History.