title: Comparative phylogeography across two trophic levels: the oak gall wasp Andricus kollari and its chalcid parasitoid Megastigmus stigmatizans.
abstract: Insect parasitoids are important components of many terrestrial ecosystems. However, relatively little is known about the mechanisms responsible for structuring their populations. Here we investigate the ability of Megastigmus stigmatizans, an oak gall wasp parasitoid, to track its host Andricus kollari over two different timescales, and examine its current population structure across a divide in host population structure. The divide represents a transition in gall wasp host-plant species and offers the opportunity to examine whether the split, which divides gall wasp populations, manifests itself in the next trophic level. Analysis of mitochondrial haplotype data for parasitoid and host reveals: (i) A similar phylogeographic population structure for both, with Iberian populations more derived with respect to more eastern populations. (ii) It is likely that the host colonized the Iberian refuge earlier than the parasitoid, probably by at least one glacial cycle. (iii) Recent range expansion of central European host populations northwards has resulted in pursuit by parasitoids from the same geographic origin. (iv) In addition, Iberian parasitoid populations have crossed a major divide in host population structure to invade northern Europe. Such human-facilitated escape from natural refugial distributions may have important implications for the composition and structure of northern European gall wasp communities.
authors.affiliation: Institute of Evolutionary Biology, The University of Edinburgh, The Ashworth Laboratories, The King's Buildings, West Mains Road, Edinburgh EH9 3JT, UK. a.hayward@ed.ac.uk
authors.forename: Alexander
authors.initials: A
authors.lastname: Hayward
authors.forename: Graham N
authors.initials: GN
authors.lastname: Stone
mesh_terms: D000818:Animals; D045303:Cytochromes b / Q000235:genetics; D004272:DNA, Mitochondrial; D003576:Electron Transport Complex IV / Q000235:genetics; D005060:Europe; D005828:Genetics, Population; D006239:Haplotypes / Q000235:genetics; D006927:Hymenoptera / Q000235:genetics* / Q000469:parasitology* / Q000502:physiology; D010802:Phylogeny; D014863:Wasps / Q000235:genetics / Q000469:parasitology / Q000502:physiology
chemical_list: D004272:DNA, Mitochondrial; D045303:Cytochromes b; D003576:Electron Transport Complex IV