Defensive Behaviors of the Central Highland Honeybees, Apis mellifera bandasii against Varroa destructor in Ethiopia

Abstract

The parasitic mite V. destructor has caused long-lasting losses to the survival of European honeybee colonies. In contrast, African honeybees are likely capable of surviving the effects of this parasitic mite with varying defense mechanisms. This study provides insights into two defense behavioral traits, including hygienic and grooming behaviors of local honeybee, Apis mellifera bandasii colonies against V. destructor mite in Ethiopia. Hygienic behavior (HB) was evaluated using the standard pin-killed brood method by calculating the dead brood removal rates (%) at 24 and 48 hrs. While grooming behavior (GB) was assessed by measuring the number of daily fallen mites and the percentage of damaged mites. The results of hygienic behavior showed greater brood removal rates of 83.1±14.3% and 97.6±3.4% at 24 hrs and 48 hrs, respectively. There were strong negative correlations between the HB and Varroa infestation rates, indicating that HB has the potential to reduce the mite population in colonies. Grooming behavior also showed higher mean daily fallen mites per colony (16.3±10.2), of which about 80% of the total fallen mites (n=488) were damaged. Ten body damage categories were identified, with most damages inflicted on mites’ legs, dorsal shield, and gnathosoma because of the GB. Our study suggests that combined hygienic and grooming behaviors could be used as effective defenses against V. destructor infestations in A. m. bandasii colonies. Therefore, future selective breeding programs should integrate these specific host defenses in order to produce sustainable colonies resistant to this parasitic mite.