HERITABILITY OF GROOMING BEHAVIOUR IN GREY HONEY BEES (Apis mellifera carnica)

Grooming behaviour is considered an important defensive mechanism of honey bees against Varroa mites. The aim of this study was to reveal whether grooming behaviour is a useful criterion in breeding of Varroa-tolerant bees. To obtain a reliable evaluation the environmental influences were excluded. The degree of grooming potential was estimated by the percentage of damaged mites in the total number of fallen mites. The heritability of grooming behavior throughout the three consecutive generations of queens was assessed by mother-daughter regression method. Among unselected queens, expressed grooming behaviour was recorded only in colonies with F1 queens (36.27%), but not in colonies with P queens and F2 queens (33.69%, 31.66%, respectively). Significant differences in grooming behaviour were found between colonies of P and F1 queens (p<0.001), and between colonies of P and F2 queens (p<0.05). However, all of the three generations of selected queens showed expressed grooming behaviour (37.99%, 39.42% and 38.58% in Ps, F1s and F2s, respectively) without significant (p>0.05) difference among them. Nevertheless, the relatively low heritability of grooming behaviour in the three generations of queens examined (h2yx=0.49±0.02; h2zx=0.18±0.01; h2zy=0.16±0.01) indicate that breeding colonies for grooming behaviour only cannot be advised to beekeepers whose aim is to breed bees highly tolerant to Varroa mites.