Nomenclatural changes and new geographic distribution records for New World species of Dacnusini (Hymenoptera Braconidae)

Authors: Kula, Robert

Submitted to: Proceedings of the Entomological Society of Washington
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/23/2025
Publication Date: 7/16/2025
Citation: Kula, R.R. 2025. Nomenclatural changes and new geographic distribution records for New World species of Dacnusini (Hymenoptera Braconidae). Proceedings of the Entomological Society of Washington. 127(1):30-38. https://doi.org/10.4289/0013-8797.127.1.30.
DOI: https://doi.org/10.4289/0013-8797.127.1.30

Interpretive Summary: Parasitic wasps attack agricultural pests that cause billions of dollars of damage to crops annually. The wasps treated in this paper belong to a group with species that attack rice leaf miner, wheat stem maggot, and carrot rust fly. Collectively, these wasps help control pest plant-mining flies in rice, wheat, carrot, celery, parsley, and parsnips. This paper updates the classification of these wasps via name changes for three species, including a new synonymy that places the name of one species under the name of another species. Two species previously known only from Asia and Europe are reported from North America for the first time, and one species previously known only from the U.S. is reported from Europe for the first time. New geographic distribution records in the U.S., Canada, and Mexico are also reported for six species. This paper will be useful to personnel in insect pest management and regulation, as well as scientists conducting research on these wasps, to help reduce the impact of plant-mining flies on the crops mentioned above.

Technical Abstract: Nomenclatural changes are provided for species of Dacnusini that occur in the New World. Chorebus aquaticus Muesebeck is a new synonym of Chorebus astigmus (Ashmead), with the former the junior synonym. The status of specimens in the type series for Rhizarcha astigma Ashmead (treated herein as C. astigmus) is clarified. Coelinius meromyzae Forbes revised combination and Dacnusa alaskensis (Ashmead) revised combination are returned from Coelinidea Viereck and Chorebus Haliday, respectively. Two species, Chorebus posticus (Haliday) and Synelix semirugosa (Haliday), are reported from the Nearctic Region for the first time—the former from the U.S. (Kansas, New Mexico, North Carolina), and the latter from Canada (Manitoba, Northwest Territories, Quebec, Yukon) and the U.S. (Alaska, Michigan). Chorebus posticus is also reported within the Palearctic Region from Denmark for the first time. Chorebus astigmus is reported from the Palearctic Region for the first time (Czech Republic, England, Germany); it is also reported within the Nearctic Region from Mexico and Utah for the first time. The new distribution records for those three species represent their first documentation as having a Holarctic distribution. These new distribution records, taken together with other documented occurrences of dacnusine species in both the Nearctic and Palearctic regions associated with Holarctic hosts and host plants, suggest that Holarctic species of Dacnusini are likely more common than perceived historically. Additional new country, state, and provincial distribution records are reported for Chorebus crassitelus (Provancher) (Manitoba, North Carolina), Chorebus harringtoni (Ashmead) (Canada), Coelinius hopkinsii Ashmead (Missouri), and Chorebus laeviceps (Cresson) (Kansas, Ohio).