Multiple infestation of Apis mellifera L. brood cells and reproduction in Varroa jacobsoni Oud

Abstract

Infestation by adult Varroa mites and offspring numbers were recorded in worker brood cells (day 14—20) and drone brood cells (day 17-23). The numbers of offspring likely to develop to adulthood were calculated according to a scheme based on the developmental stage of each pupa and the time interval to uncapping of the brood cells. With increasing numbers of Vanoa infesting a cell, the numbers of female offspring per Varroa decreased within both cell types. Apparenffy, this decrease was based on fewer offspring produced per Varroa rather than by complete nonreproduction of some mites. Reproduction within combs, calculated according to the mite distributions, was even lower. This density-dependent reproduction is likely to influence population growth considerably. With increasing cell infestation, the proportion of males increased, thus reducing the bias of the sex ratio towards females.