Evolution of the hymenopteran megaradiation

Abstract

a b s t r a c tThe Hymenoptera -ants, bees and wasps -represent one of the most successful but least understood insect radiations. We present the first comprehensive molecular study spanning the entire order Hymenoptera. It is based on approximately 7 kb of DNA sequence from 4 gene regions (18S, 28S, COI and EF-1a) for 116 species representing all superfamilies and 23 outgroup taxa from eight orders of Holometabola. Results are drawn from both parsimony and statistical (Bayesian and likelihood) analyses, and from both by-eye and secondary-structure alignments. Our analyses provide the first firm molecular evidence for monophyly of the Vespina (Orussoidea + Apocrita). Within Vespina, our results indicate a sister-group relationship between Ichneumonoidea and Proctotrupomorpha, while the stinging wasps (Aculeata) are monophyletic and nested inside Evaniomorpha. In Proctotrupomorpha, our results provide evidence for a novel core clade of proctotrupoids, and support for the recently proposed Diaprioidea. An unexpected result is the support for monophyly of a clade of wood-boring sawflies (Xiphydrioidea + Siricoidea). As in previous molecular studies, Orussidae remain difficult to place and are either sister group to a monophyletic Apocrita, or the sister group of Stephanidae within Apocrita. Both results support a single origin of parasitism, but the latter would propose a controversial reversal in the evolution of the wasp-waist. Generally our results support earlier hypotheses, primarily based on morphology, for a basal grade of phytophagous families giving rise to a single clade of parasitic Hymenoptera, the Vespina, from which predatory, pollen-feeding, gall-forming and eusocial forms evolved.

The first mitochondrial genome for the wasp superfamily Platygastroidea: the egg parasitoidTrissolcus basalis

“…As expected, a monophyletic Aculeata is recovered, as is a monophyletic Apoidea. Evania + Aculeata form a clade, consistent with the resolution of the Aculeata inside the Evaniomorpha in more taxon-rich analyses Heraty et al 2011;Sharkey et al 2011). However, support for a range of relationships within the Aculeata is low, with posterior probabilities below 0.95.…”

“…The Proctotrupomorpha have been consistently recovered as a monophyletic group in molecular phylogenetic studies (Dowton and Austin 2001;Heraty et al 2011). Shared gene rearrangements are considered reliable indicators of shared ancestry (Boore et al 1995), and have been used to infer phylogeny in the Hymenoptera (Dowton 1999), although examples of homoplastic gene rearrangements have been reported (Flook et al 1995;Dowton and Austin 1999).…”

“…Although much progress has been made to investigate the phylogeny of the Hymenoptera (Dowton and Austin 1994;Ronquist et al 1999;Dowton and Austin 2001;Heraty et al 2011;Sharkey et al 2011), there are also many relationships remaining unresolved. For example, the monophyly of the Proctotrupomorpha (sensu Rasnitsyn 1988) is well supported by recent studies, but the relationships among the proctotrupomorph families are still controversial (Dowton and Austin 2001;Rasnitsyn and Zhang 2010;Heraty et al 2011). Several analyses have demonstrated that the whole mt genome is a useful tool to resolve hymenopteran evolutionary relationships (Castro and Dowton 2007;Cameron et al 2008;Dowton et al 2009a;Wei et al 2010a).…”

Independent origins of parasitism in Animalia

“…Parasitism is clearly linked to spectacular speciation in groups like Hymenoptera and Platyhelminthes [3,34].…”

Function of the Dufour’s gland in solitary and social Hymenoptera

“…The evolution of the parasitic life history has been considered to be an important factor that led to the massive divergence and adaptive radiation of the Hymenoptera (Heraty et al 2011). Unfortunately, the function of the Dufour's gland remains poorly explored in parasitic Hymenoptera that are basal to the more advanced groups of aculeates.…”