The genetic variance–covariance matrix (G-matrix) summarizes the genetic architecture of multiple traits. It has a central role in the understanding of phenotypic divergence and the quantification of the evolutionary potential of populations. Laboratory experiments have shown that G-matrices can vary rapidly under divergent selective pressures. However, because of the demanding nature of G-matrix estimation and comparison in wild populations, the extent of its spatial variability remains largely unknown. In this study, we investigate spatial variation in G-matrices for morphological and life-history traits using long-term data sets from one continental and three island populations of blue tit (Cyanistes caeruleus) that have experienced contrasting population history and selective environment. We found no evidence for differences in G-matrices among populations. Interestingly, the phenotypic variance–covariance matrices (P) were divergent across populations, suggesting that using P as a substitute for G may be inadequate. These analyses also provide the first evidence in wild populations for additive genetic variation in the incubation period (that is, the period between last egg laid and hatching) in all four populations. Altogether, our results suggest that G-matrices may be stable across populations inhabiting contrasted environments, therefore challenging the results of previous simulation studies and laboratory experiments.

Data MorphologyThis file corresponds to the morphological data. All the variables required to perform the morphological animal models are contained in this table.Data.Morphology.csvData.LHTThis file corresponds to the life-history trait data. All the variables required to perform the life-history animal models are contained in this table.Pedigree MorphologyThis table contains the pedigree for the individuals used in the morphological animal models.Pedigree.Morphology.csvPedigree LHTThis table contains the pedigree for the individuals used in the life history animal models.Pedigree.LHT.csv