Data from: Postmating isolation and genetically variable host use in ecologically divergent host forms of Neochlamisus bebbianae leaf beetles

Ecological speciation studies have more thoroughly addressed premating
than postmating reproductive isolation. This study examines multiple
postmating barriers between host forms of Neochlamisus bebbianae leaf
beetles that specialize on Acer versus Salix trees. We demonstrate cryptic
isolation and reduced hybrid fitness via controlled matings of these host
forms. These findings reveal host-associated postmating isolation,
although a non-ecological, ‘intrinsic’ basis for these patterns cannot be
ruled out. Host preference and performance results among cross types
further suggest sex-linked maternal effects on these traits, while family
effects indicate their genetic basis and associated variation. Genes of
major effect appear to influence these traits. Together with previous
findings of premating isolation and adaptive differentiation in sympatry,
our results meet many assumptions of ‘speciation with gene flow’ models.
Here, such gene flow is likely asymmetric, with consequences for the
dynamics of future ecological divergence and potential ecological
speciation of these host forms.