Data from: Axes of multivariate sexual signal divergence among incipient species: concordance with selection, genetic variation, and phenotypic plasticity

Sexual signaling traits are often observed to diverge rapidly among
populations, thereby playing a potentially key early role in the evolution
of reproductive isolation. While often assumed to reflect divergent sexual
selection among populations, patterns of sexual trait diversification
might sometimes be biased along axes of standing additive genetic
variation and covariation among trait components. Additionally, theory
predicts that environmentally-induced phenotypic variation might
facilitate rapid trait evolution, suggesting that patterns of divergence
between populations should mirror phenotypic plasticity within
populations. Here we evaluate the concordance between observed axes of
multivariate sexual trait divergence and predicted divergence based on (1)
interpopulation variation in sexual selection, (2) additive genetic
variances, and (3) temperature-related phenotypic plasticity in male
courtship song among geographically isolated populations of the Hawaiian
swordtail cricket, Laupala cerasina, which exhibit sexual isolation due
sexual signaling traits. The major axis of multivariate divergence, dmax,
accounted for 76% of variation among population male song trait means, and
was moderately correlated with interpopulation differences in directional
sexual selection based on female preferences. However, the majority of
additive genetic variance was largely oriented away from the direction of
divergence, suggesting that standing genetic variation may not play a
dominant role in the patterning of signal divergence. In contrast, the
axis of phenotypic plasticity strongly mirrored patterns of
interpopulation phenotypic divergence, which is consistent with a role for
temperature-related plasticity in facilitating instead of inhibiting male
song evolution and sexual isolation in these incipient species. We propose
potential mechanisms by which sexual selection might interact with
phenotypic plasticity to facilitate the rapid acoustic diversification
observed in this species and clade.