• genetic correlation;
  • genetic integration;
  • heritability;
  • size dimorphism.

Estimates of multivariate selection are becoming increasingly common in the literature. Although it is clearly recognized that genetic information is essential to understanding natural selection, few studies include estimates of genetic parameters. Previous studies of the water strider Aquarius remigis have demonstrated selection on body size and components of body size that may favour the evolution and maintenance of sexual size dimorphism. In this paper we present quantitative genetic estimates of heritabilities and genetic correlations for male and female A. remigis. Overall body size (total length) and the majority of components of body size were significantly heritable for both sexes and the shape of the genetic correlation matrix was similar between the sexes. However, patterns of genetic correlations between the sexes and analysis of genetic integration suggest that some traits may be genetically isolated.