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Ecological adaptation and reproductive isolation in sympatry: genetic and phenotypic evidence for native host races of R hagoletis pomonella
Author(s) -
Powell Thomas H. Q.,
Forbes Andrew A.,
Hood Glen R.,
Feder Jeffrey L.
Publication year - 2014
Publication title -
molecular ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.619
H-Index - 225
eISSN - 1365-294X
pISSN - 0962-1083
DOI - 10.1111/mec.12635
Subject(s) - biology , reproductive isolation , sympatric speciation , ecological speciation , gene flow , sympatry , host (biology) , ecology , population , rhagoletis , botany , tephritidae , genetic variation , gene , genetics , demography , sociology , pest analysis
Ecological speciation with gene flow may be an important mode of diversification for phytophagous insects. The recent shift of R hagoletis pomonella from its native host downy hawthorn ( C rataegus mollis ) to introduced apple ( M alus domestica ) in the northeastern U nited S tates is a classic example of sympatric host race formation. Here, we test whether R . pomonella has similarly formed host races on four native C rataegus species in the southern United States: western mayhaw ( C. opaca ), blueberry hawthorn ( C . brachyacantha ), southern red hawthorn ( C. mollis var. texana ) and green hawthorn ( C. viridis ). These four southern hosts differ from each other in their fruiting phenology and in the volatile compounds emitted from the surface of their fruits. These two traits form the basis of ecological reproductive isolation between downy hawthorn and apple flies in the north. We report evidence from microsatellite population surveys and eclosion studies supporting the existence of genetically differentiated and partially reproductively isolated host races of southern hawthorn flies. The results provide an example of host shifting and ecological divergence involving native plants and imply that speciation with gene flow may be commonly initiated in R hagoletis when ecological opportunity presents itself.