Variance decomposition: observed contributions of the variances and covariances in M, N and P in explaining the variance in the number of offspring sired by males (T).

The decomposition is based on the approach proposed by Webster, PruettJones [15]. Var(x) represents the variance component of the factor x (i.e. M, N or P), and cov(x, y) represents the covariance components between the factors x and y (e.g. covariance between M and P–cov(M, P)). D represents the variance in the error term ε. HomL–Homogeneous Large; HomS–Homogeneous Small; HetL–Heterogeneous Large, HetS–Heterogeneous Small, Het–Heterogeneous. The Female Experiment–varying female body size; The Male Experiment–varying male body size and The Female-Male Experiment–varying both female and male body size.