Stimulation of Varroa jacobsoni Oud. oviposition with semiochemicals from honeybee brood

The oviposition of female Varroa jacobsoni kept with worker larvae of honeybees (Apis mellifera) in artificial gelatine cells was stimulated when 5-larva equivalents of extracts of L5 worker larvae were applied on the inner side of the walls of the cells. Most of the stimulating activity was recovered in the most polar fraction of the larval extract. The corresponding fraction of an extract of pupae did not stimulate oviposition. Semiochemicals present on the surface of L5 worker larvae, but not on pupae, may play a role in the regulation of V. jacobsoni reproduction.