Delving intoDeliasHübner (Lepidoptera: Pieridae): fine‐scale biogeography, phylogenetics and systematics of the world's largest butterfly genus

Aim Our objective was to reconstruct a species‐level phylogeny of the genusDelias, to elucidate their finer‐scale biogeography and to test boundaries between closely related taxa. Location Indo‐Australian region, with a focus on Wallacea. Methods Sequence data from 131 taxa, representing all recognized species groups and more than half of the known species ofDelias, were used in the analysis. Phylogenetic analyses based on molecular characters of the mitochondrial gene cytochromecoxidase subunit I (COI) and nuclear geneswinglessand elongation factor 1α (EF‐1α) were carried out using maximum parsimony and Bayesian inference. Biogeographical reconstructions were undertaken using the parsimony‐based method dispersal–vicariance analysis and the dispersal–extinction–cladogenesis model as implemented inraspandLagrange, respectively. Results The phylogenetic hypothesis resolved 14 distinct clades, here designated thenysa,isse,pasithoe,belladonna,ladas,geraldina,aroae,eichhorni,sagessa,aganippe,hyparete,belisama,albertisiandnigrinaspecies groups.Delias blancaFelder andDelias chrysomelaenaSnellen van Vollenhoven were transferred to thepasithoeandissespecies groups, respectively. We demonstrate that the barcode region ofCOIis useful for the delineation of closely related, more recently diverged,Deliasspecies. Species diversification inDelias, for the most part, is shown to pre‐date the Pleistocene, even in montane mainland New Guinea where numerous phenotypically similar sister species co‐occur. Main conclusions SiblingDeliasspecies found in sympatry are largely restricted to those clades confined to mainland New Guinea, where most species occur in high‐elevation habitats. Conversely, clades with large geographical ranges are composed of essentially allopatric taxa. Although an Australian Plate origin is plausible for the genus,Deliasis likely to have colonized islands peripheral to Australia during the early stages of its evolution (i.e. during the Miocene), as evidenced by the presence of older lineages in Wallacea and also in islands of the south‐western Pacific.