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

Abstract

We revise the Alpine bee taxa related to Andrena bicolor (Fabricius, 1775), including A. montana Warncke, 1973 and A. allosa Warncke, 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. amieti sp. 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 in A. amieti sp. n.; the status of these lineages, which together form a paraphyletic unit from which A. allosa arose, is briefly discussed. We show that A. allosa, A. amieti sp. n. and A. montana are polylectic but that each species exhibits a distinct spectrum of pollen hosts: the univoltine A. allosa shows affinities for pollen of the early-blooming Alpine plant genus Crocus. A. amieti sp. n. is bivoltine and, as in A. bicolor, the summer generation exhibits a distinct preference for Campanulaceae, while the spring generation is widely polylectic. A. montana has 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. croatica Friese, 1887 is resurrected from synonymy with A. bicolor and treated as a valid species (stat. rev.), A. pileata Warncke, 1875, described as a subspecies of A. allosa, is elevated to species rank (stat. n.), and three additional unclear taxa are briefly described.