Engel, Gonzalez & Gustafson & Engel, 2019

Gonzalez, Victor H., Gustafson, Grey T. & Engel, Michael S., 2019, Morphological phylogeny of Megachilini and the evolution of leaf-cutter behavior in bees (Hymenoptera: Megachilidae), Journal of Melittology 2019 (85), pp. 1-123 : 6

Diversity of Megachilidae

Megachilidae are the third largest bee family containing more than 4100 species worldwide ( Michener, 2007; Ascher & Pickering, 2018). Megachilids utilize a high diversity of nesting materials and substrates. For example, they use mud, petals, leaves (intact pieces or macerated to a pulp), resins, gravel, and plant trichomes to build their brood cells in the soil, attached to twigs, under surfaces of rocks, or inside pre-existing cavities including man-made constructions (e.g., Rozen et al., 2010; Gonzalez & Griswold, 2013). The most recent higher-level classificatory proposal for the family (Gonzalez et al., 2012) recognizes four subfamilies and nine tribes, three of which are extinct ( Ctenoplectrellini , Glyptapini , and Protolithurgini ). Morphological (Gonzalez et al., 2012) and molecular data ( Litman et al., 2011) support the monophyly of these tribes, except that of Osmiini , which has long been suspected to be paraphyletic (e.g., Engel , 2001; Michener, 2007; Praz et al., 2008). In these morphological and molecular analyses, either Megachilini or Megachilini + Dioxyini renders Osmiini paraphyletic. The phylogenetic relationships of Dioxyini are also still not clear. This small monophyletic group of cleptoparasitic bees (~36 spp.) appeared as sister of Aspidosmia Brauns ( Aspidosmiini ) in the molecular analysis, but in the morphological analysis it was the sister group of Megachilini .