Behavioural defenses of the honey bee ecotype from Sjenica - Pester against Varroa destructor

Abstract

Two behaviours of honey bees, hygienic and grooming, are mechanisms of defense against brood diseases and parasitic mites, including Varroa destructor. Apis mellifera colonies remove the worker brood infested with Varroa destructor mites from the nest (hygienic behaviour), and groom the mites off other adult bees (grooming behaviour). In this study hygienic and grooming behaviours of Syenichko-Peshterski honey bee ecotype were analysed in 440 honey bee colonies from 11 localities in the region of Syenichko-Peshterski plateau, Podpeshterje, Golija Mt. and Rogozna Mt. At each locality 40 honey bee colonies were investigated: 10 potent colonies with one-year old queen, 10 potent colonies with two-year old queen, 10 medium potent and 10 weak honey bee colonies. Hygienic behaviour was expressed in a range from 95.12% to 99.50% in potent honey bee colonies with one-year old and two-year old queens. Statistically highly significant (p<0.01) differences were registered among the analysed honey bee colonies at the investigated region, in favour of the potent honey bee colonies, compared to the medium potent and weak colonies. Also, statistically highly significant (p<0.01) differences were recorded between potent colonies with one-year old queens and colonies with two-year old queens, in favour of the colonies with one-year old queens. In general, investigated colonies belong to a category of the so called "hygienic colonies", as the efficiency of elimination of damaged pupae amounted to 91.50%. Grooming behaviour of Syenichko-Peshterski honey bee ecotype potentially exists, but its significance cannot be discussed as, on the whole, investigated colonies showed potential of 34,04%. Our results point to an indisputable relationship between analysed behaviours and the strength of honey bee colonies: hygienic behaviour is more expressed in potent colonies (from 95.12% to 99.50%) regardless of queen age; grooming behaviour was expressed only in potent honey bee colonies with one-year old queen at all 11 localities, where the number of damaged mites ranged from 36,05% to 39,61%. The damaged mites were separated into six categories. The most frequent category of damage was damaged legs (53.38% in potent colonies with one-year old queens and 52.02% in potent colonies with two-year old queens). The potent honey bee colonies from the investigated region, especially with one-year old queen, could be used for highly selectioned breeds improving and queens rearing.