title: Evidence for ecological speciation via a host shift in the holly leaf miner,Phytomyza glabricola(Diptera: Agromyzidae).
abstract: Evolutionary radiations have been well documented in plants and insects, and natural selection may often underly these radiations. If radiations are adaptive, the diversity of species could be due to ecological speciation in these lineages. Agromyzid flies exhibit patterns of repeated host-associated radiations. We investigated whether host-associated population divergence and evidence of divergent selection exist in the leaf minerPhytomyza glabricolaon its sympatric host plants, the holly species,Ilex coriaceaandI. glabra. Using AFLPs and nuclear sequence data, we found substantial genetic divergence between host-associated populations of these flies throughout their geographic range. Genome scans using the AFLP data identified 13 loci under divergent selection, consistent with processes of ecological speciation. EF-1αdata suggest thatI. glabrais the original host ofP. glabricolaand thatI. coriaceais the novel host, but the AFLP data are ambiguous with regard to directionality of the host shift.
authors: BEES Program University of Maryland 4112 Plant Science Building College Park Maryland 20742.
authors: Julie B
authors: JB
authors: Hébert
authors: Systematic Entomology Laboratory USDA-ARS 10300 Baltimore Av. Beltsville Maryland 20705.
authors: Sonja J
authors: SJ
authors: Scheffer
authors: Department of Entomology University of Maryland 4112 Plant Science Building College Park Maryland 20742.
authors: David J
authors: DJ
authors: Hawthorne
keywords: Amplified fragment length polymorphism; Ilex; host forms; host races; sympatric speciation