Data from: Insect mating signal and mate preference phenotypes covary among host plant genotypes

Sexual selection acting on small initial differences in mating signals and
mate preferences can enhance signal-preference co-divergence and
reproductive isolation during speciation. However, the origin of initial
differences in sexual traits remains unclear. We asked whether biotic
environments, a source of variation in sexual traits, may provide a
general solution to this problem. Specifically, we asked whether genetic
variation in biotic environments provided by host plants can result in
signal-preference phenotypic covariance in a host-specific, plant-feeding
insect. We used a member of the Enchenopa binotata species complex of
treehoppers (Hemiptera: Membracidae) to assess patterns of variation in
male mating signals and female mate preferences induced by genetic
variation in host plants. We employed a novel implementation of a
quantitative genetics method, rearing field-collected treehoppers on a
sample of naturally-occurring replicated host plant clone lines. We found
remarkably high signal-preference covariance among host plant genotypes.
Thus, genetic variation in biotic environments influences the sexual
phenotypes of organisms living on those environment in a way that promotes
assortative mating among environments. This consequence arises from
conditions likely to be common in nature (phenotypic plasticity and
variation in biotic environments). It therefore offers a general answer to
how divergent sexual selection may begin.