Selection response in genetic (co)variances
In testing whether the selection response was associated with (i) a
reduction in genetic variance in Z11-16:OAc (a change in the diagonal
elements of the G matrix) and (ii) re-orientation of genetic covariances
among pheromone components (changes in the off-diagonal elements of the
G matrix), we found no evidence for decreasing genetic variance in
Z11-16:OAc (Fig 4A) or in the other components (Fig S1). In contrast to
genetic variances, we did find variation in the genetic covariance
structure across generations. First, the posterior mode of the pairwise
genetic correlations differed between the starting and selected
generations. Although the change in the covariance between Z11-16:OAc
and the two aldehydes was limited (Fig 4B,C), genetic covariance between
Z11-16:OAc and Z11-16:OH switched direction (from negative to positive)
and became more pronounced, especially in the low line (Fig 4D).