VITELLOGENESIS IN VARROA-JACOBSONI, A PARASITE OF HONEY-BEES

Reproduction in Varroa jacobsoni occurs only in cells of the capped ho ney bee brood. Female mites were sampled at different times after cell sealing and ovaries containing a vitellogenic oocyte of the first gon ocycle were examined under an electron microscope. It was found that t he cytoplasmic connection between the lyrate organ and the oocyte pers ists far into the vitellogenic growth phase. In addition, a large amou nt of yolk material is taken up from the haemolymph. All ultrastructur al features characteristic of vitellogenesis, such as microvilli, coat ed pits, vesicles and growing yolk platelets, are present. If more tha n four Varroa females live in an overcrowded brood cell, they appear t o be in stress conditions and their vitellogenic oocytes may become at retic. Alterations typical for oocyte degradation and oosorption were observed in such situations.