Glen R. Hood

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Oneof the fundamentalquestions inevolutionaryecology seeks tounderstandhownew biodiversity is created and structured into communities. The apple maggot, Rhagoletis pomonella (Walsh) (Diptera: Tephritidae), a model for rapid ecological speciation via host plant shifting for phytophagous insects, and its parasitoid community can offer insight into answering(More)
Ecological speciation occurs when reproductive isolation evolves as a consequence of divergent natural selection among environments. A direct prediction of this process is that ecologically divergent pairs of populations will exhibit greater reproductive isolation than ecologically similar pairs of populations. By comparing allopatric populations of the(More)
Studies of related populations varying in their degrees of reproductive isolation can provide insights into speciation. Here, the transition from partially isolated host races to more fully separated sibling species is investigated by comparing patterns of genetic differentiation between recently evolved (∼150 generations) apple and ancestral(More)
Theory predicts that speciation-with-gene-flow is more likely when the consequences of selection for population divergence transitions from mainly direct effects of selection acting on individual genes to a collective property of all selected genes in the genome. Thus, understanding the direct impacts of ecologically based selection, as well as the indirect(More)
Host-specific phytophagous insects that are short lived and reliant on ephemeral plant tissues provide an excellent system in which to investigate the consequences of disruption in the timing of resource availability on consumer populations and their subsequent interactions with higher tropic levels. The specialist herbivore, Belonocnema treatae(More)
Ecological speciation with gene flow may be an important mode of diversification for phytophagous insects. The recent shift of Rhagoletis pomonella from its native host downy hawthorn (Crataegus mollis) to introduced apple (Malus domestica) in the northeastern United States is a classic example of sympatric host race formation. Here, we test whether R.(More)
A powerful approach to address the general factors contributing to ecological speciation is to compare distantly related taxa that inhabit the same selective environments. In this design, similarities among taxa can elucidate general mechanisms of the process whereas differences may uncover specific factors important to the process for individual taxa.(More)
The apple maggot ßy, Rhagoletis pomonella Walsh (Diptera: Tephritidae), is a major pest of commercially growndomesticated apple (MalusdomesticaBorkhausen) inNorthAmerica.The shift of the ßy from its native host hawthorn (Crataegus mollis) to apple in the eastern United States is often cited as an example of incipient sympatric speciation in action. However,(More)
Ecological speciation occurs when inherent reproductive barriers to gene flow evolve between populations as a result of divergent natural selection. Frequency dependent effects associated with intraspecific resource competition are thought to be one important source of divergent selection facilitating ecological speciation. Interspecific competition may(More)
Successive generations of multivoltine species experience selection specific to the spatiotemporal environments encountered that may lead to adaptive divergence in reproductive traits among generations. To compare reproductive effort within and between generations, appropriate volumetric models, selected on the basis of the analysis of egg shape, are(More)