The genetic variance but not the genetic covariance of life-history traits changes towards the north in a time-constrained insect

Seasonal time constraints are usually stronger at higher than lower latitudes and can exert strong selection on life history traits and the correlations among these traits. To predict the response of life history traits to environmental change along a latitudinal gradient, information must be obtained about genetic variance in traits and also genetic correlation between traits, i.e., the genetic variance-covariance matrix, G. Here, we estimated G for key life history traits in an obligate univoltine damselfly that faces seasonal time constraints. We exposed populations to simulated native temperatures and photoperiods and common garden environmental conditions in a laboratory setup. Despite differences in genetic variance in these traits between populations (lower variance at northern latitudes), there was no evidence for latitude-specific covariance of the life history traits. At simulated native conditions, all populations showed strong genetic and phenotypic correlations between trai...