Systematics, biogeography and diversification of the Indo-Australian genus Delias Hübner (Lepidoptera: Pieridae): phylogenetic evidence supports an 'out-of-Australia' origin

Abstract Two alternative hypotheses for the origin of butterflies in the Australian Region, that elements dispersed relatively recently from the Oriental Region into Australia (northern dispersal hypothesis) or descended from ancient stocks in Gondwana (southern vicariance hypothesis), were tested using methods of cladistic vicariance biogeography for the Delias group, a diverse and widespread clade in the Indo‐Australian Region. A phylogenetic hypothesis of the twenty‐four species‐groups recognized currently in Delias and its sister genus Leuciacria is inferred from molecular characters generated from the nuclear gene elongation factor‐1 alpha (EF‐1α) and the mitochondrial genes cytochrome oxidase subunits I and II (COI/COII) and NADH dehydrogenase 5 (ND5). Phylogenetic analyses based on maximum parsimony, maximum likelihood and Bayesian inference of the combined dataset (3888 bp, 1014 parsimony informative characters) confirmed the monophyly of Delias and recovered eight major lineages within the genus, informally designated the singhapura, belladonna, hyparete, chrysomelaena, eichhorni, cuningputi, belisama and nigrina clades. Species‐group relationships within these clades are, in general, concordant with current systematic arrangements based on morphology. The major discrepancies concern the placement of the aganippe, belisama and chrysomelaena groups, as well as several species‐groups endemic to mainland New Guinea. Two species (D. harpalyce (Donovan), D. messalina Arora) of uncertain group status are currently misplaced based on strong evidence of paraphyly, and are accordingly transferred to the nigrina and kummeri groups, respectively. Based on this phylogeny, a revised systematic classification is presented at the species‐group level. An historical biogeographical analysis of the Delias group revealed that the most parsimonious reconstruction is an origin in the Australian Region, with at least seven dispersal events across Wallacea to the Oriental Region. The eight major clades of Delias appear to have diverged rapidly following complete separation of the Australian plate from Gondwana and its collision with the Asian plate in the late Oligocene. Further diversification and dispersal of Delias in the Miocene–Pliocene are associated with major geological and climatic changes that occurred in Australia–New Guinea during the late Tertiary. The ‘out‐of‐Australia’ hypothesis for the Delias group supports an origin of the Aporiina in southern Gondwana (southern vicariance hypothesis), which proposes that the ancestor of Delias + Leuciacria differentiated vicariantly on the Australian plate.     

Phylogeny,diversification patterns and historical biogeography of euglossine orchid bees (Hymenoptera: Apidae)

The orchid bees constitute a clade of prominent insect pollinators distributed throughout the Neotropical region. Males of all species collect fragrances from natural sources, including flowers, decaying vegetation and fungi, and store them in specialized leg pockets to later expose during courtship display. In addition, orchid bees provide pollination services to a diverse array of Neotropical angiosperms when foraging for food and nesting materials. However, despite their ecological importance, little is known about the evolutionary history of orchid bees. Here, we present a comprehensive molecular phylogenetic analysis based on ～4.0 kb of DNA from four loci [cytochrome oxidase (CO1), elongation factor 1‐α (EF1‐α), arginine kinase (ArgK) and RNA polymerase II (Pol‐II)] across the entire tribe Euglossini, including all five genera, eight subgenera and 126 of the approximately 200 known species. We investigated lineage diversification using fossil‐calibrated molecular clocks and the evolution of morphological traits using disparity‐through‐time plots. In addition, we inferred past biogeographical events by implementing model‐based likelihood methods. Our dataset supports a new view on generic relationships and indicates that the cleptoparasitic genus Exaerete is sister to the remaining orchid bee genera. Our divergence time estimates indicate that extant orchid bee lineages shared a most recent common ancestor at 27–42 Mya. In addition, our analysis of morphology shows that tongue length and body size experienced rapid disparity bursts that coincide with the origin of diverse genera (Euglossa and Eufriesea). Finally, our analysis of historical biogeography indicates that early diversification episodes shared a history on both sides of Mesoamerica, where orchid bees dispersed across the Caribbean, and through a Panamanian connection, thus reinforcing the hypothesis that recent geological events (e.g. the formation of the isthmus of Panama) contributed to the diversification of the rich Neotropical biota. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 100 , 552–572.