Submitted to: Proceedings of the Entomological Society of Washington
Publication Type: Peer reviewed journal
Publication Acceptance Date: 11/8/2010
Publication Date: 12/27/2010
Citation: Lewis, T.M., Horton, D.R. 2010. Orius diespeter Herring in North America: Color Variation and Updated Distribution (Hemiptera: Heteroptera: Anthocoridae). Proceedings of the Entomological Society of Washington. 112(4):541-554. Interpretive Summary: The minute pirate bugs (Orius) are important predators of insect pests on crops, but identification of species within certain species complexes can be difficult. Scientists with USDA-ARS, Yakima Agricultural Research Laboratory, Wapato, WA examined specimens of two widely distributed species to re-examine diagnostics currently used to identify them. Specimens of Orius diespeter were found to exhibit enough variation in traits that available keys may often fail to separate this species from a second species, Orius tristicolor. New diagnostics were developed, and were then used to correct identifications in the literature and to update geographic ranges of both species. These results clarify our understanding of the pirate bug complexes in North America, information that is necessary to make completely effective use of these predators as agents of biological control of insect pests such as psyllids.
Technical Abstract: Orius diespeter Herring was described in 1966 from two specimens collected in western British Columbia, Canada. The original description relied mainly on color of the hemelytra to distinguish this species from a second species common in western North America, Orius tristicolor (White). Orius diespeter is shown here to have variation in color; hemelytra coloration ranges from entirely dark, to dark with contrasting white on the apical half of the corium. Specimens of O. diespeter with white markings are easily confused with O. tristicolor. Orius diespeter is separated from O. tristicolor by having shorter dorsal setae, a shorter copulatory tube, and a shorter flagellum on the paramere. The distribution of O. diespeter in North America is updated to include most of the northern states of the United States, as well as western and southeastern provinces and territories of Canada. Early 1900’s records for O. tristicolor in eastern North America may actually refer to O. diespeter, and we suggest that those records merit reexamination.