Phylogeny and systematics of the bee genus Osmia (Hymenoptera: Megachilidae) with emphasis on North American Melanosmia: subgenera, synonymies, and nesting biology revisited

The predominantly Holarctic bee genus Osmia Panzer is species-rich and behaviourally diverse. A robust phylogeny of this genus is important for understanding the evolution of the immense variety of morphological and behavioural traits exhibited by this group. We infer a phylogeny of Osmia using DNA sequence data obtained from three nuclear genes (elongation factor 1-α, LW-rhodopsin and CAD) and the mitochondrial gene COI. Our taxon sampling places special attention on North American members of the subgenus Melanosmia Schmiedeknecht; we discuss the novel placement of a number of species traditionally assigned to O. (Melanosmia) and examine the relative support for alternative classifications of this species-rich subgenus. We use this new phylogeny to guide a reassessment of morphological and behavioural characters within Osmia. Our results provide support for the recognition of Osmia (Hapsidosmia), subgen.n., a monotypic subgenus containing Osmia iridis Cockerell & Titus. We synonymi...