Behavioral traits of honeybees (Apis mellifera) influence resistance against infestation of Varroa destructor mite

The parasitic mite Varroa destructor remains the principal threat to honeybees worldwide. Many control measures, including the use of both soft and strong acaricides to eradicate or limit the spread of the parasite, are still very unsuccessful. Although some behavioral traits of honeybees are of great concern, understanding their mode of action is a priority. Therefore, it is necessary to put in place possible measures and outline sustainable approaches against the V. destructor. A total of 50 honeybee colonies were kept in the experimental apiary prior to evaluating their different behavioral outputs. The colony survival rate and infestation rate were determined. The results demonstrated a significant variation between the evaluated traits (hygiene, grooming, postcapping brood period, and Varroa-sensitive hygiene) and shaped it into three main categories based on hygiene and grooming. Hygienic colonies recorded low grooming activity (biting observed after more than 42 seconds) while non-hygienic colonies recorded high grooming activity (biting observed in less than 35 seconds). Colony mortality differed significantly among groups (p < 0.0001). The infestation rate differed significantly among colonies (p < 0.0001). Among the detected diseases, high levels of expression of deformed wing virus, acute bee paralysis virus, and Israeli acute paralysis virus were recorded compared to the prevalence of chronic bee paralysis virus. Though selective breeding of honeybee colonies with V. destructor immune-related traits may be hard to achieve, results have demonstrated that association of multiple traits can yield better outputs. As colonies with some behavioral traits (hygiene and grooming) showed some level of resistance, it is recommended to associate this approach with various soft chemicals and evaluate the efficacy.