Taxonomy, phylogeny and evolution of the bumblebee bot flies (Oestridae: Hypodermatinae: Portschinskia)

Abstract

The first phylogenetic study of Portschinskia is presented based on 42 adult morphological characters scored for all 11 species, including four new species Portschinskia burmensis sp. nov., Portschinskia sichuanensis sp. nov., Portschinskia xizangensis sp. nov. and Portschinskia yunnanensis sp. nov.Portschinskia luliangensis is established as a junior synonym of Portschinskia magnifica. Monophyly of Portschinskia is strongly supported by nine non-homoplasious synapomorphies. All cladograms resolve P. yunnanensis as a basal taxon and a well-resolved Portschinskia gigas clade {P. gigas + ((Portschinskia bombiformis + (P. burmensis + (P. magnifica + P. xizangensis))) + (Portschinskia himalayana + (Portschinskia przewalskyi + P. sichuanensis)))}. The only topological difference is Portschinskia loewii and Portschinskia neugebaueri either being sister taxa or branching off successively at the base of the P. gigas clade. Three colour-pattern types are recognized, with the yellow-tailed pattern optimized as the ancestral state. Our data show that the modal colour pattern of Portschinskia species is the same as in bumblebees, and a regional correlation in species diversity and colour patterns can be detected between sympatric Portschinskia and Bombus species. As a result, we suggest that colour patterns of Portschinskia can be explained as Batesian mimicry tracking locally dominant bumblebees.