Out of south america: Phylogeny of non-biting midges in the genus labrundinia suggests multiple dispersal events to central and north america

Abstract

Non-biting midges of the genus Labrundinia (Chironomidae: Tanypodinae) are minute dipterans with immature stages living in a variety of unpolluted water bodies, from small streams and ponds to lakes and bays. Extensively recorded in ecological studies, the genus comprises 39 species, all except one described from areas outside the Palearctic region. Internal structure among Labrundinia species was postulated by S. S. Roback, who recognized four species groups based on morphological characters of immature stages. We examined phylogenetic relationships among known Labrundinia species using partial DNA sequences of the nuclear protein-coding gene CAD and morphological characters. Both analyses with Bayesian inference and parsimony methods recovered the monophyly of Labrundinia, strongly supported by five morphological synapomorphies. Internal relationships within the genus partly supported Roback's species groups with the addition of later described species. Biogeographical inferences were obtained by applying Bayesian binary MCMC (BBM) analysis and favoured a scenario where Labrundinia had its initial diversification in the Neotropical region and that current presence in the Nearctic region and southern South America is due to subsequent dispersal.