Developing EPIC markers for chalcidoid Hymenoptera from EST and genomic data

Abstract

Increasing numbers of phylogeographic studies make comparative inferences about the histories of co-distributed species. Although the aims of such studies are best achieved by jointly analysing sequences from multiple loci in a model-based framework, such data currently exist for few nonmodel systems. We used existing genomic data and expressed sequence tags (ESTs) for Hymenoptera and other insects to design intron-crossing primers for 40 loci, mainly ribosomal proteins, for chalcidoid parasitoids. Amplification success was scored on a range of taxa associated with two natural communities; oak galls and figs. Taxa were chosen at increasing distance from Nasonia, which was used for primer design, (i) within Pteromalids, (ii) within Chalcidoidea (Eupelmidae, Eulophidae, Eurytomidae, Ormyridae, Torymidae) and (iii) for a selection of distantly related gall and fig wasps (Cynipidae, Agaonidae). To assess the utility of these loci for phylogeographic and population genetic studies, we compared genetic diversity between Western Palaearctic refugia for two species. Our results show that it is feasible to design a large number of exon-primed-intron-crossing (EPIC) loci that may be informative about phylogeographic history within species but amplify across a large taxonomic range.