Hidden diversity in European bees: Andrena amieti sp. n., a new Alpine bee species related to Andrena bicolor (Fabricius, 1775) (Hymenoptera, Apoidea, Andrenidae)

We revise the Alpine bee taxa related toAndrenabicolor(Fabricius, 1775), includingA.montanaWarncke, 1973 andA.allosaWarncke, 1975, the status of which has remained contentious. Phylogenetic analyses of one mitochondrial gene and one nuclear gene, as well as morphological examination reveal the presence of four Alpine species in this complex, one of which is new to science,A.amietisp. n.This new species is widely distributed in the Alps from southern France throughout Switzerland, northern Italy and southern Germany to Austria; a single record is known from the Apennines. The type locality is located within the Unesco World Heritage site “Swiss Alps Jungfrau-Aletsch”. Two widely divergent mitochondrial lineages are found in sympatry inA.amietisp. n.; the status of these lineages, which together form a paraphyletic unit from whichA.allosaarose, is briefly discussed. We show thatA.allosa,A.amietisp. n.andA.montanaare polylectic but that each species exhibits a distinct spectrum of pollen hosts: the univoltineA.allosashows affinities for pollen of the early-blooming Alpine plant genusCrocus.A.amietisp. n.is bivoltine and, as inA.bicolor, the summer generation exhibits a distinct preference for Campanulaceae, while the spring generation is widely polylectic.A.montanahas a single generation in the summer and forages on a diversity of flowers such as Campanulaceae, Cistaceae and Caryophyllaceae. An identification key is presented for central European members of the subgenus Euandrena Hedicke, 1932. Lastly, the new Alpine species appears to represent the tip of the iceberg of substantial cryptic diversity in southern European Andrena (Euandrena):A.croaticaFriese, 1887 is resurrected from synonymy withA.bicolorand treated as a valid species (stat. rev.),A.pileataWarncke, 1875, described as a subspecies ofA.allosa, is elevated to species rank (stat. n.), and three additional unclear taxa are briefly described.