Effect of mating frequency and brood cell infestation rate on the reproductive success of the honeybee parasite <i>Varroa jacobsoni</i>

1. The reproductve biology of <i>Varroa jacobsoni</i>, whose females infest honeybee brood, was studied in natural and transparent artificial brood cells. These investigations were made under the headings of maturation behaviour and fertilization, and the influence of infestation rate of brood cells on the number of mated females produced per infesting Varroa. <br> 2. Mating of Varroa daughters, observed in the transparent brood cells with time-lapse video, occurs just after ecdysis and as soon as they arrive on the faecal accumulation prepared by the mother. Such females are remated for as long as no other freshly moulted daughter arrives on the faecal accumulation. <br> 3. The number of spermatozoa stocked in the spermatheca increases with remating, a strong indication for sperm mixing in this species when brood cells contain more than one <i>Varroa</i> foundress. <br> 4. The number of daughters per infesting mother decreases at higher rates of infestation per cell, but the proportion of such daughters with a mate rises sharply due to the higher probability of finding a male within multi-infested cells. The number of mated daughters per mother is maximal in cells with two foundress <i>Varroa</i> females. <br> 5. The frequency distributions of infesting mites in drone cells are aggregated, and approximate to negative binomial distributions. <br> 6. We postulate from the above that the observed non-random infestation by <i>Varroa</i> in drone brood augments the mite's mean reproductive success through the production of a higher number of mated daughters than the corresponding Poisson distributions would.