Open AccessStructure of a mosaic hybrid zone between the field crickets Gryllus firmus and G. pennsylvanicus
Author(s) -
Larson Erica L.,
Guilherme Becker C.,
Bondra Eliana R.,
Harrison Richard G.
Publication year - 2013
Publication title -
ecology and evolution
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.17
H-Index - 63
ISSN - 2045-7758
DOI - 10.1002/ece3.514
Subject(s) - introgression , hybrid zone , biology , ecology , habitat , hybrid , gene flow , genetic variation , gene , botany , biochemistry
Hybrid zones provide insight into the nature of species boundaries and the evolution of barriers to gene exchange. Characterizing multiple regions within hybrid zones is essential for understanding both their history and current dynamics. Here, we describe a previously uncharacterized region of a well‐studied hybrid zone between two species of field crickets, Gryllus pennsylvanicus and G. firmus . We use a combination of mitochondrial DNA sequencing, morphological data, and modeling of environmental variables to identify the ecological factors structuring the hybrid zone and define patterns of hybridization and introgression. We find an association between species distribution and natural habitat; Gryllus pennsylvanicus occupies natural habitat along forest edges and natural clearings, whereas G. firmus occupies more disturbed areas in agricultural and suburban environments. Hybridization and introgression occur across patch boundaries; there is evidence of substantial admixture both in morphological characters and mt DNA , over a broad geographic area. Nonetheless, the distribution of morphological types is bimodal. Given that F 1 hybrids are viable and fertile in the lab, this suggests that strong pre‐zygotic barriers are operating in this portion of the hybrid zone.