ARS | Publication request: Winter losses of honeybee colonies (Apis mellifera): The role of infestations with Aethina tumida and Varroa destructor

Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 29, 2009
Publication Date: September 29, 2009
Citation: Schafer, M.O., Ritter, W., Pettis, J.S., Neumann, P. 2009. Winter losses of honeybee colonies (Apis mellifera): The role of infestations with Aethina tumida and Varroa destructor. Journal of Economic Entomology. 103:10-16.

Interpretive Summary: Honey bee colonies are attacked by a host of pest and diseases. These pest and diseases can become more problematic in the winter as the colony struggles to survive. Here we investigated the role of adult small hive beetles alone and in combination with the parasitic mite Varroa for winter losses and as stress factors that might increase infections of the gut parasite Nosema. We found no significant influence of small hive beetles on Nosema infections and winter loss, which is most likely due to the observed high winter mortality of the adult beetles in our study. Likewise, infestations with the Varroa mite or small hive beetles had no significant effects on the amount of Nosema in adult bees. However, high losses occurred in all groups highly infested with Varroa mites, supporting the central role of the mite for colony losses. Our data suggest that the small hive beetle alone is unlikely to contribute to losses of overwintering honeybee colonies. This information will be used by beekeepers to better manage their colonies for winter survival.

Technical Abstract: Multiple infections and infestations of honeybee colonies with pathogens and parasites are inevitable due to the ubiquitous ectoparasitic mite Varroa destructor and might be one of the mechanisms underlying 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 infections with the microsporidian endoparasite Nosema ceranae. We found no significant influence of A. tumida on winter losses or N. ceranae infections, which is most likely due to the observed high winter mortality of the adult beetles. Likewise, infestations with V. destructor and/or A. tumida had no significant effects on the numbers of N. ceranae spores. However, high losses occurred in all groups highly infested with V. destructor, supporting the central role of this mite in colony losses. Our data suggest that A. tumida alone is unlikely to contribute to losses of overwintering honeybee colonies.