Changes in a population of Apis mellifera L. selected for hygienic behaviour and its relation to brood disease tolerance

Honeybee colonies were evaluated for hygienic behaviour using a pin-killed brood assay. Presence and absence of visual symptoms of brood diseases were recorded. Colonies that removed more than 80% of dead brood after 24 hours were selected for queen and drone production and new colonies were evaluat ed for hygienic behaviour. This procedure was repeated pearly from 1992 thr ough 1997. The degree of total hygienic behaviour (brood removed) and parti al hygienic behaviour (brood uncapped but not totally removed) were determi ned. Colonies were classified as hygienic and non-hygienic and these data w ere related to the incidence of brood diseases. Total hygienic behaviour in creased in the population after four years of selection on queens without m ating control from 66.25% in 1992 to 84.56% in 1997. Hygienic colonies had a lower frequency of brood diseases when compared to non-hygienic colonies. It is suggested that this trait can be used as a selection criterion in qu een breeders' apiaries.