INFERTILITY OF VARROA-JACOBSONI FEMALES AFTER INVASION INTO APIS-MELLIFERA WORKER BROOD AS A TOLERANCE FACTOR AGAINST VARROATOSIS

The fertility of Varroa jacobsoni females was studied in worker brood invaded by a single mite. Africanized and European colonies of Apis me llifera were used as sources to sample capped brood cells in a tropica l area of Brazil and, in addition, Carnolian colonies were sampled in Germany. In the Africanized bees over 40% of the female mites in worke r brood were infertile, whereas in European bees only 10-20% infertile Varroa females were found. These differences do not depend on broodne st or ambient temperatures. If a female mite was fertile, then the fec undity, measured as the mean number of eggs produced, was the same, ir respective of the host honey bee race. The low Varroa fertility in wor ker brood of the Africanized bees resembles the situation known from t he original host species, Apis cerana. Since host-dependent infertilit y evidently has a strong influence on the population dynamics of this parasite, it should be properly considered in future selection and bre eding efforts in order to produce European bee strains tolerant agains t varroatosis.