Inter-host transfer and survival of Varroa jacobsoni under simulated and natural winter conditions

Abstract

SUMMARYVarroa jacobsoni transferred between living bees and from dead and dying bees on to living bees under both natural and laboratory-simulated winter cluster temperatures. In trials involving 261 bees and 161 mites, 26% of the mites moved from one live host to another within 7 days. When an infested bee was dead or dying, up to 75% of the mites would transfer to a live bee within 24 h. When their host died, mites would remain on the dead bee, provided an alternative bee was not available, for an average of 48 ± 26.5 h before dismounting. During this time they continued to feed and exhibited behaviour which would enhance their chances of transfer to a new host. These results question previous suggestions that V. jacobsoni seldom moves between hosts during overwintering and that the majority of them would inevitably die with their host. This has important consequences for models of varroa population dynamics and implications for the transmission of pathogens between bees by the mites.