Agapostemon fasciatus Crawford (Hymenoptera, Halictidae), a valid North American bee species ranging into southern Canada

Abstract

Sweat bees of the genus Agapostemon Guérin-Méneville, 1844 (Hymenoptera: Halictidae) are common and widespread in the Americas. Despite distinct morphological characters that were recognised in earlier taxonomic treatments, Agapostemon fasciatus Crawford, 1901 has been considered a variety of A. melliventris Cresson, 1874 since the 1930s and later placed into synonymy under A. melliventris in the early 1970s. A more detailed study of morphology (including examination of type materials), distribution and genetic data (i.e. DNA barcodes) of these two taxa suggests they are not conspecific. As such, A. fasciatus is resurrected as a valid North American bee species. Agapostemon fasciatus ranges further north in North America than A. mellivenrtis, reaching the southern Prairies Ecozone of Canada (Alberta, Saskatchewan), while most records of A. melliventris are from the south-western United States and northern Mexico. More accurate distributions for both species can be modelled as specimens in collections are identified using the diagnostic features provided. However, additional work is required on the A. melliventris species complex in the southern United States as genetic data suggest that multiple taxa could be present.