Molecular Ecology (2011) 20, 2676-2692

A.T. Groot, A. Classen, O. Inglis, C.A. Blanco, J. López Jr., A. Téran Vargas, C. Schal, D.G. Heckel and G. Schöfl (2011)
Genetic differentiation across North America in the generalist moth Heliothis virescens and the specialist H. subflexa
Molecular Ecology 20 (13), 2676-2692
Abstract: The two moth species Heliothis virescens (Hv) and H. subflexa (Hs) are closely related, but have vastly different feeding habits. Hv is a generalist and an important pest in many crops in the USA, while Hs is a specialist feeding only on plants in the genus Physalis. In this study, we conducted a comparative population genetic analysis to assess whether and how generalist and specialist life styles are reflected in differences in population structures. In Hv 98% of the total variation occurred within populations. The overall differentiation (FST) between regions was 0.006 and even lower between years (0.0039) and hosts (0.0028). Analyses of population structure suggest that all individuals form one genetically homogeneous population, except for at most 12 individuals (6%) that diverged from this cluster. Population homogeneity likely results from the high mobility of Hv and its generalist feeding behaviour. Hs exhibited substantially more population structure. Even though 96% of the total variation was attributable to within-population variability, FST-values between Hs populations were 10 times higher than between Hv populations. Hs populations showed significant isolation by distance. Analyses of Hs population structure suggest at least two subpopulations and thus some degree of metapopulation structure. We speculate that the patchy distribution of Physalis- the exclusive food source of Hs - contributes to differences in population structure between these closely related species. The finding that the specialist shows more population differentiation than the generalist corroborates the notion that host specialization is not an evolutionary dead end but a dynamic trait.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): Astrid T. Groot, Carlos A. Blanco, Coby Schal, David G. Heckel

Research topic(s) for pests/diseases/weeds:
molecular biology - genes
general biology - morphology - evolution

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Heliothis virescens
	Aspila subflexa	Physalis (crop)