Varroa destructor infestation impact on Apis mellifera carnica capped worker brood production, bee population and honey storage in a Mediterranean climate

This study investigated the impact of Varroa destructor infestation on the amount of capped worker brood, the adult bee population and honey production of authenticated Apis mellifera carnica colonies kept in a Mediterranean climate. For this purpose, colonies were set-up and either maintained mite-free or artificially mite-infested and allowed to develop an infestation. Periodical evaluations of those colonies unravelled the pattern of the previously mentioned variables across the season, and allowed for comparative numerical analyses. Progressive reductions on the amount of capped worker brood, bee population and honey storage in mite-infested colonies only became increasingly evident during spring and summer, apparently associated with impressive mite population increases. By the end of the experiment, mite-infested colonies showed a unitary average reduction of 45% in the amount of capped honey they stored, meaning an average annual loss of $\approx$ 24 kg of honey per colony. However, the amount of capped honey stored per bee and day was found to be independent from colony V. destructor status, indicating a lack of direct effect of mite infestation on honey hoarding behaviour