APICULTURE AND SOCIAL INSECTS Winter Losses of Honeybee Colonies (Hymenoptera: Apidae): The Role of Infestations With Aethina tumida (Coleoptera: Nitidulidae) and Varroa destructor (Parasitiformes: Varroidae)

Multiple infections of managed honeybee, Apis mellifera, colonies are inevitable due to the ubiquitous ectoparasitic mite Varroa destructor and might be an underlying cause of winter losses. Here we investigated the role of adult small hive beetles, Aethina tumida, alone and in combination with V. destructor for winter losses and for infections with the microsporidian endoparasite Nosema ceranae. We found no signiÞcant inßuence of A. tumida and V. destructor alone or in combination on the numbers ofN. ceranae spores. Likewise,A. tumida alone had no signiÞcant effects on winter losses, which is most likely due to the observed high winter mortality of the adult beetles. Therefore, ourdata suggest thatA. tumida is unlikely tocontribute to lossesofoverwinteringhoneybee colonies. However, high losses occurred in all groups highly infested with V. destructor, supporting the central role of the mite for colony losses.