An investigation of the efficacy of hygienic behavior of various honey bee (Apis mellifera) races toward Varroa destructor (Acari: Varroidae) mite infestation

Hygienic behavior in honey bees reflects the social immunity against parasites and diseases and is considered one of the main factors of genetic resistance of the bee breeding program. Hygienic behavior refers to the uncapping and removal of diseased and dead larvae and pupae from sealed brood cells by the worker bees. Here, the hygienic behavior of Apis mellifera races was investigated in response to pin-killed assay and artificial Varroa mite-infested brood cells. Moreover, the reproduction behavior of Varroa mites was determined in various sizes of honey bee race comb cells. The results revealed that the percentage of uncapping and removal of dead broods were significantly higher in the Italian as compared to the Carniolan bee colonies (p < 0.05). Similarly, a significant difference was present in response to artificially infested brood cells with Varroa mites in Italian and Carniolan colonies over the day of inspection (p < 0.05). Overall, the width of cells of the two types of combs was significantly different. The smaller width of cells size combs reduces the Varroa mite reproduction behavior compared to larger cell size combs. More infestation of Varroa mite occurred in drone brood cells as compared to worker brood cells in both old and new comb types. This study contributed to understand the hygienic behavior of A. mellifera races in preparation for selecting and developing hygienic lines of bees given the important contribution of hygienic behavior to honey bee health.