INVASION OF VARROA-JACOBSONI INTO HONEY-BEE BROOD CELLS - A MATTER OFCHANCE OR CHOICE

Invasion of Varroa jacobsoni into honey bee (Apis mellifera) brood cel ls was studied in three initially mite-free colonies. Frames with emer ging worker brood, heavily infested with mites, were introduced into e ach colony and removed the next day. During the experiments ample work er brood was available for the mites to invade. Invasions into brood c ells started immediately after the introduction of the mite-infested c ombs, showing that mites do not necessarily have to have a period on a dult bees before invading a cell. However, as most mites stayed on the bees for several days or even several weeks, the average rate of inva sion was rather low. In addition, replicate experiments in the three c olonies showed much variation: 50% of the mites invaded brood cells wi thin 2.0 days in the first replicate, within 8.3 days in the second re plicate and within 4.3 days in the third replicate. Possible causes fo r the low and variable invasion rates are discussed.