Phylogenetic patterns of geographical and ecological diversification in the subgenus Drosophila

PLoS One. 2012;7(11):e49552. doi: 10.1371/journal.pone.0049552. Epub 2012 Nov 12.

Abstract

Colonisation of new geographic regions and/or of new ecological resources can result in rapid species diversification into the new ecological niches available. Members of the subgenus Drosophila are distributed across the globe and show a large diversity of ecological niches. Furthermore, taxonomic classification of Drosophila includes the rank radiation, which refers to closely related species groups. Nevertheless, it has never been tested if these taxonomic radiations correspond to evolutionary radiations. Here we present a study of the patterns of diversification of Drosophila to test for increased diversification rates in relation to the geographic and ecological diversification processes. For this, we have estimated and dated a phylogeny of 218 species belonging to the major species groups of the subgenus. The obtained phylogenies are largely consistent with previous studies and indicate that the major groups appeared during the Oligocene/Miocene transition or early Miocene, characterized by a trend of climate warming with brief periods of glaciation. Ancestral reconstruction of geographic ranges and ecological resource use suggest at least two dispersals to the Neotropics from the ancestral Asiatic tropical disribution, and several transitions to specialized ecological resource use (mycophagous and cactophilic). Colonisation of new geographic regions and/or of new ecological resources can result in rapid species diversification into the new ecological niches available. However, diversification analyses show no significant support for adaptive radiations as a result of geographic dispersal or ecological resource shift. Also, cactophily has not resulted in an increase in the diversification rate of the repleta and related groups. It is thus concluded that the taxonomic radiations do not correspond to adaptive radiations.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animal Migration
  • Animals
  • Bayes Theorem
  • Biodiversity*
  • Calibration
  • Drosophila / classification*
  • Geography*
  • Likelihood Functions
  • Models, Biological
  • Phylogeny*
  • Species Specificity

Grant support

This work was funded by the Fundação para a Ciência e Tecnologia (FCT) through research projects PTDC/BIA-BDE/66765/2006 and PTDC/BIA-BEC/099933/2008, funded by Programa Operacional para a Ciência e Inovação (POCI-2010), co-funded by Fundo Europeu para o Desenvolvimento Regional (FEDER) and Programa Operacional para a Promoção da competividade (COMPETE). Ramiro Morales-Hojas is supported by a Ciência 2007 contract. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.