Date of this Version
Scarpulla EJ. 2022. Lasioglossum (Dialictus) semicaeruleum (Cockerell, 1895) (Hymenoptera: Halictidae) in Maryland: A disjunct population in eastern North America? Insecta Mundi 0958: 1–7.
Since 2004, three specimens of Lasioglossum (Dialictus) semicaeruleum (Cockerell, 1895) (Hymenoptera: Halictidae) have been collected in Maryland. Other than three specimens from Wisconsin, there are no additional records of this western United States species known east of the Mississippi River. I document the three Maryland records and offer possible scenarios of how the specimens could have arrived in Maryland.
Lasioglossum (Dialictus) semicaeruleum (Cockerell, 1895) (Hymenoptera: Halictidae) is an abundant western North American species that ranges from the Canadian Prairie Provinces (Alberta, Manitoba, and Saskatchewan) through the United States west of the Mississippi River (Arizona, California, Colorado, Iowa, Kansas, Minnesota, Montana, Nebraska, Nevada, New Mexico, North Dakota, Oklahoma, South Dakota, Texas, Utah, and Wyoming) and into northern Mexico (Chihuahua, Coahuila, Durango, Nuevo León, and Sonora) (Gibbs 2010; Ascher and Pickering 2022; GBIF 2022; Fig. 1). Gibbs (2010) noted two enigmatic Maryland specimens: USGS_DRO029678, Bowie, Prince George’s County, and USGS_DRO141684, Wittman, Talbot County (Fig. 2–3) and cautioned that these might be mislabeled. In 2015, a bee survey of the Paul S. Sarbanes Ecosystem Restoration Project at Poplar Island (hereafter Poplar Island), Chesapeake Bay, Talbot County, yielded a third Maryland specimen: USGS_DRO556278 (Fig.2).