Phylogeny, classification and evolution of the Cynipoidea

Abstract

I review cynipoid phylogeny and evolution and present an improved higher classification of the superfamily, including the proposal of some nomenclatural changes at the family and genus level. There is convincing morphological evidence for cynipoid monophyly. Relationships with other apocritan wasps are unclear although some characters suggest that diapriids may form their sister group. Cladistic analysis based on adult morphology indicates that cynipoids fall into five monophyletic lineages arranged in a Hennigian comb or ladder: (Austrocynipidae (Ibaliidae (Liopteridae (Figitidaesensu lato, Cynipidae)))). The three first families comprise the macrocynipoids, the two latter the microcynipoids. Relationships among macrocynipoids have been analysed down to the genus or species level and considerable attention has been paid to their historical biogeography. In the microcynipoids, comprising the bulk of cynipoid diversity, phylogenetic research has focused on the gall wasps (Cynipidae). Higher‐level relationships are well studied and this allows reconstruction of the early evolution of the gall wasp‐host plant association and the origin of the inquilines. The Figitidae are by far the least known cynipoid family and their classification is chaotic; here, I present a first attempt at a cladistic analysis of their higher‐level relationships. Biogeographic and fossil evidence, as well as a morphological clock estimate, suggest that the cynipoid crown‐group initially diverged in the Jurassic but the earliest cynipoid fossils are from the mid Cretaceous. Existing cynipoid fossils are here tentatively placed in a phylogenetic context but explicit cladistic analysis is likely to shed more light on their exact relationships. Current phylogenetic estimates suggest that cynipoids went through three successive phases in their early evolution, each leaving a set of surviving lineages: first in the community of wood‐boring insects, then in the gall community, and finally in the aphid community. The parasitic cynipoids have apparently shifted only four times between hosts in different insect orders, demonstrating extreme conservatism in host association as might be expected of koinobiont endoparasites.