Elevated recapping behaviour and reduced Varroa destructor reproduction in natural Varroa resistant Apis mellifera honey bees from the UK

Varroa destructor mites remain a major threat to Apis mellifera honey bees, yet many populations across the world have naturally evolved survivorship to infestation. Here, we investigated the roles of recapping and mite reproduction in natural Varroa resistant (NVR) colonies in the UK. Recapping frequency was higher in NVR colonies and targeted mite-infested cells in which the recapped diameters were larger. Mite reproduction was lower in NVR colonies due to increased offspring mortality, although recapping is unlikely the primary mechanism responsible. In an additional small experiment, infested brood removal was immediately present in naive colonies, and recapping increased rapidly following initial mite exposure. Targeted recapping behaviour is a common trait in NVR colonies and may provide a useful indicator for mite resistance. In addition, reduced mite reproduction is a key resistance mechanism in NVR colonies in the UK, as also found in Europe, S. Africa, Brazil and Mexico.