The gall midge asphondylia borrichiae (diptera: Cecidomyiidae) : An indigenous example of host-associated genetic divergence in sympatry

Document Type

Article

Publication Date

10-1-2012

Abstract

Speciation usually is conceptualized as occurring via three biogeographic modes: Allopatry, parapatry, and sympatry. Sympatric speciation has been the most controversial because of the difficulty of developing plausible theoretical models in which the homogenizing effects of gene flow are sufficiently overcome to permit genetic divergence to occur in the absence of geographic barriers restricting gene flow. Recently, a number of hypothetical models for sympatric speciation have been advanced and several candidate study systems have provided evidence of sympatric divergence, although many of the systems so identified involve introduced species, especially in the cases of host-race formation in phytophagous insects, which expand their host range and use a novel host. Although these cases demonstrate the reality of sympatric divergence, they do not address which mode of speciation predominates in indigenous communities. Asphondylia borrichiae Rossi & Strong has been proposed as a potential example of sympatric divergence in a fully indigenous system, based on the results of a host-choice experiment involving three host-plant species. In the current study, we report significant differences in the genetic composition of midge populations collected from each host in situ, supporting the hypothesis of sympatric genetic divergence among the morphologically identical host-associated populations of A. borrichiae and consistent with host fidelity in oviposition choice. © 2012 Entomological Society of America.

Publication Title

Environmental Entomology

Volume

41

Issue

5

First Page

1246

Last Page

1254

Digital Object Identifier (DOI)

10.1603/EN12041

PubMed ID

23068183

ISSN

0046225X

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