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Abstract

Abstract. Leafcutter and mason bees of the genus Megachile are common members of the North American bee fauna and many Megachile species are important pollinators of summer flowering crops and native plant species. Despite this, no comprehensive account of species in Canada and Alaska has been published. Our objective is to provide an up-to-date revision of the genus Megachile of this region, including an interactive key to the species, and summaries of biogeographic distribution and life history. Additionally, divergence in a 658 bp segment of the mitochondrial COI gene (the "DNA barcode" region) was used to clarify the taxonomic status of several Megachile species in North America. Based on morphological differences and over 6% sequence divergence in COI, M.

A new species of <i>Megachile</i> (<i>Litomegachile</i>) from Cuba, the Antilles (Hymenoptera: Megachilidae)

“…In that study, M. onobrychidis Cockerell, traditionally considered a subspecies of M. brevis, differed from the latter species by 5.47% COI (cytochrome c oxidase, subunit 1) sequence divergence, and was most similar to M. pseudobrevis Mitchell (which was also considered a subspecies of M. brevis) (Sheffield et al, 2011). The geographic distribution of these two species is allopatric; M. onobrychidis is primarily a western species, occurring into southern British Columbia (Sheffield et al, 2011) and apparently as far south as western Mexico (Bzdyk, 2012), while M. pseudobrevis occurs in the southeastern United States, including Florida (Mitchell, 1935;Bzdyk, 2012). Bzdyk (2012) recognized ten species in her recent revision of Litomegachile, including a new species, M. pankus Bzdyk, known only from the female, and only from Mexico.…”

“…Litomegachile was revised by Mitchell (1935) who recognized five species, three of which (i.e., M. brevis Say, M. mendica Cresson, M. texana Cresson) were treated as polytypic species. Michener (2007) included seven species, while Sheffield et al (2011) and Bzdyk (2012) raised several of the previously known forms to species level, the former study integrating mitochondrial DNA sequences with morphological data. In that study, M. onobrychidis Cockerell, traditionally considered a subspecies of M. brevis, differed from the latter species by 5.47% COI (cytochrome c oxidase, subunit 1) sequence divergence, and was most similar to M. pseudobrevis Mitchell (which was also considered a subspecies of M. brevis) (Sheffield et al, 2011).…”

“…Michener (2007) included seven species, while Sheffield et al (2011) and Bzdyk (2012) raised several of the previously known forms to species level, the former study integrating mitochondrial DNA sequences with morphological data. In that study, M. onobrychidis Cockerell, traditionally considered a subspecies of M. brevis, differed from the latter species by 5.47% COI (cytochrome c oxidase, subunit 1) sequence divergence, and was most similar to M. pseudobrevis Mitchell (which was also considered a subspecies of M. brevis) (Sheffield et al, 2011). The geographic distribution of these two species is allopatric; M. onobrychidis is primarily a western species, occurring into southern British Columbia (Sheffield et al, 2011) and apparently as far south as western Mexico (Bzdyk, 2012), while M. pseudobrevis occurs in the southeastern United States, including Florida (Mitchell, 1935;Bzdyk, 2012).…”

“…Currently, 57 extant subgenera are recognized globally Michener, 2007), most requiring revision (Gonzalez & Griswold, 2007); 31 subgenera are found in the Western Hemisphere (Raw, 2006), though Durante & Abrahamovich (2006) recognized Chaetochile Mitchell as a distinct monotypic subgenus separate from Dasymegachile Mitchell. In North America, 13 subgenera are indigenous, but species belonging to three additional subgenera have been introduced (Cane, 2003;Michener, 2007;Sheffield et al, 2010Sheffield et al, , 2011, these also occurring in Cuba (Genaro, 2008).…”

Subgeneric classification and biology of the leafcutter and dauber bees (genus Megachile Latreille) of the western Palearctic (Hymenoptera, Apoidea, Megachilidae)

“…However, if a couplet of the key asks whether a cutting edge is visible or invisible in front view, such recessed cutting edges are considered invisible. Michener (2007) considered new world taxa such as Megachile (Megachile) montivaga Cresson, 1878 (see Sheffield et al 2011: Fig. 26a), or the subgenus Chrysosarus Mitchell, 1943 to lack cutting edges; here species with similar mandibular structure are considered to have cutting edges, although strongly recessed and invisible in front view.…”