Baryscapus rugglesi (Rohwer, 1919) (Hymenoptera: Eulophidae) discovered in western North America: Redescription, notes on biology, and implications as a parasitoid of its host, Agrilus cuprescens (Menetries, 1832) (Coleoptera: Buprestidae)

Eulophid larvae discovered in galleries of Agrilus cuprescens (Menetries, 1832) within canes of Rubus sp. (Rosaceae) in the Pacific Northwest, U.S.A. region between 2018 and 2021 were identified as Baryscapus rugglesi (Rohwer, 1919) (subfamily Tetrastichinae). This species had previously only been found in eastern North America. Identification was based on numerous specimens reared from larvae collected from eight disparate locations in western Oregon and Washington State, U.S.A., in 2019 and 2021, and examination against its type series from 1919 in Minnesota, U.S.A. and specimens from 1938 in New York, U.S.A (Mundinger 1941). Both sexes of B. rugglesi are herein redescribed and illustrated. Additionally, DNA sequences from specimens collected in 2019 were direct sequence matches with original specimens collected in 2018. The ubiquitous occurrence of B. rugglesi suggests it is likely a predominant parasitoid of A. cuprescens in the region. Baryscapus rugglesi is a gregarious larval parasitoid of several native Agrilus spp. in North America, so it is presumably native to the Nearctic region and has adapted as an alternative parasitoid of A. cuprescens, a Eurasian-native pest introduced into North America. However, COI sequences of B. rugglesi were similar to those of an unidentified eulophid from Europe in the Barcode of Life Database (almost 96% identity), possibly indicating a Holarctic distribution. Observed wasp biology, behavior, and perspectives on the potential role of B. rugglesi as a natural enemy within integrated pest management programs for A. cuprescens control are discussed.