Andrena (Melandrena) cyanura Cockerell (Hymenoptera: Apoidea, Andrenidae), a valid North American species

Abstract

Andrena (Melandrena) transnigra Viereck, 1904 (Hymenoptera: Apoidea, Andrenidae), a species originally described from Seattle, Washington, is a large, distinctive, and rather common solitary bee that is active in the spring and early summer in western North America. Consideration of morphological variation within females of this species across its range, particularly scopal hair colour, with subsequent genetic analysis led to the discovery of two distinct DNA barcodes attributed to this species; the 6.2% divergence between the sequences was consistent with the distinctive morphology. As a result, A. cyanura Cockerell, 1916 is here removed from synonymy with A. transnigra and resurrected as a valid species. In addition, A. transnigra paysoni Cockerell, 1924 is also removed from synonymy with A. transnigra and is instead treated as a new synonym of A. cyanura. The male of A. cyanura was previously described as A. transnigra by Bouseman and LaBerge (1979), so a diagnosis is provided to distinguish the two species; thus, the male of A. transnigra is treated for the first time. Both sexes of A. cyanura are distinguished from A. transnigra and other similar Melandrena Pérez, 1890. In addition to the morphological and genetic differences between A. transnigra and A. cyanura, each also has a distinctive geography in Canada, albeit overlapping in parts of British Columbia. Andrena transnigra is seemingly restricted to the southern half of British Columbia, whereas A. cyanura is more widespread, ranging from southern British Columbia north to the Yukon and as far east as Saskatchewan. The limited molecular data available for these species from the United States also supports their status as distinct species, although re-examination of specimens in collections will help to clarify their respective distributions in North America.