One of the most remarkable examples of Batesian mimicry occurs in the genus Temnostoma Le Peletier & Audinet-Serville, 1828 (Diptera: Syrphidae). Adults of this genus have an overall resemblance to hymenopterans combined with behavioural mimicry (they move the fore legs in front of the head mimicking hymenopteran antennae). While some species of Temnostoma are considered highly accurate mimics of social wasps, other species have a darker colour pattern and are rather relatively poor yellowjacket mimics. Both colour phenotypes are widespread through the Holarctic. Here, we infer for the first time the evolutionary history of the genus with special focus on the evolution of mimicry and biogeography. With material covering 75 % of known species of Temnostoma and both colour phenotypes from each biogeographical region, we inferred a molecular phylogeny based on six molecular markers (mitochondrial protein-coding COI gene, nuclear 28 s rRNA gene, and four nuclear protein-coding genes: AATS, CK1, TULP, and RBP-15). Using Bayesian inference, we obtained a highly resolved phylogenetic tree supporting the monophyly of the genus Temnostoma as a sister group of genus Takaomyia Hervé-Bazin, 1914. Within Temnostoma, Te. daochus and Te. barberi (two Nearctic species with strikingly different mimicry patterns) were found to be closely related to each other and together form a lineage sister to the rest of the genus. Our results suggest that the behavioural mimicry of wasp antennae is a plesiomorphic state inherited from a common ancestor that includes the genera Temnostoma and Takaomyia. Within Temnostoma, the dark colour pattern (poor yellowjacket mimicry) appears to be an ancestral state and highly accurate social wasp mimicry has appeared two times independently within the genus. In some species inhabiting northern parts of the Holarctic, secondary darkening and consequent degradation of the yellowjacket mimicry appeared. This indicates high evolutionary plasticity and ongoing selection pressure on morphological characters related to mimicry in hover flies.

Canadian National Collection of Insects Arachnids and Nematodes Agriculture and Agri Food Canada K W Neatby Building 960 Carling Avenue Ottawa ON K1A 0C6 Canada

Department of Zoology Faculty of Science Charles University Viničná 7 128 43 Praha 2 Czech Republic

Institute of Entomology Biology Centre of the Czech Academy of Sciences Branišovská 31 370 05 České Budějovice Czech Republic

Institute of Entomology Biology Centre of the Czech Academy of Sciences Branišovská 31 370 05 České Budějovice Czech Republic; Department of Biology Faculty of Science Jan Evangelista Purkyně University Pasteurova 3632 15 400 96 Ústí nad Labem Czech Republic

Museum Koenig Bonn Leibniz Institute for the Analysis of Biodiversity Change Adenauerallee 127 D 53113 Bonn Germany

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