Heritabilities for several colony traits in the honeybee (Apis mellifera carnica)

Abstract

Colony traits in honeybees result from the sum of the queen contribution and of an average contribution of the workers. To estimate separately the heritability of queen and worker effects, observed covariances of related colonies are expressed as functions of theoretical causal components of phenotypic variance. Covariances were estimated by REML (Restricted Maximum Likelihood) and weighted parent-offspring covariance analysis. Causal components are estimated by weighted least squares analysis of this system of equations. The data (n = 5 581) come from an Apis mellifera carnica population in northern and mid-Germany. Honey and wax production have medium h2 values for worker (0.26/0.39) and queen effects (0.15/0.45). The corresponding values for aggressiveness, calmness during examination and spring development were higher. Strongly negative genetic correlations were found between worker and queen effects with respect to all colony traits. This negative genetic relationship impedes selection response, since it reduces the phenotypic variance within population, and therefore tends to stabilize it at a particular value.