Heritability of the Varroa-specific hygienic behaviour in honey bees (Hymenoptera: Apidae)

The hygienic behaviour of the honey bees is considered to be a potential characteristic associated with resistance to Varroa destructor n.sp. In this study the heritability of the hygienic behaviour of L. bees was estimated on the basis of the mother-daughter regression. Data were measurements of the bees' hygienic behaviour towards V. destrutor-infested cells and towards pin-killed sealed brood. The heritability for the hygienic behaviour towards V. destructor-infested brood cells was h(2) = 0.18 (+/- 0.27) and h(2) = 0.36 (+/- 0.30) for the hygienic behaviour towards dead brood cells. The repeatability was likewise higher for the pin-killed brood assay (W=0.46) compared with the assay using living mites-infested Ibrood cells (W = 0.24). The genetic correlation between the behavioural responses to either the mite infested or pin-killed brood cells was calculated to be r(g)=0.61 (+/- 0.51) and the phenotypic correlation to be r(p)=0.11 (p=0.28, n=100). Since hygienic colonies demonstrate resistance to brood diseases such as American foulbrood and chalk-brood, it may be worthwhile to intensify the expression of the hygienic behaviour through selective breeding and thus strengthen these potential characteristics associated with resistance to V. destructor in honey bee stock.