Ontogenesis of the mite Varroa jacobsoni Oud. in worker brood of the honeybee Apis mellifera L. under natural conditions

A study was carried out during May 1993, in southern England, on eight chemically untreated Apis mellifera L. colonics heavily infested with Varroa jacobsoni (15–40% of worker sealed brood). The position and time of capping of 3.228 worker sealed brood were recorded. At two hour intervals, starting from when each cell was capped, groups of worker cells were uncapped and their contents recorded. It was found that each V. jacobsoni female could deposit five or sometimes six larvae in a worker cell, of which four (1 male and 3 females) may reach maturity before the bee emerged from its cell. However, mortality of the offspring resulted in only 1.45 female offspring reaching maturity, for each normally reproducing mother mite, before the bee emerged. The mean development time of the first three female offspring was 134 hours (±=3 h.n=3), shorter than that of the male (154 hours). The first larva was deposited approximately 60 hours after the cell was capped, and developed into a male. Subsequent larvae were deposited at intervals varying from 26–32 hours, and all developed into females.