Active defense against Varroa mites in a Carniolan strain of honeybee (Apis mellifera carnica Pollmann)F. Ruttnera and H. Hänelb
a Universität Frankfurt, Institut für Bienenkunde (Polytechnische Gesellschaft), Fachbereich Biologie, Karl von Frisch-Weg 2, D-W-370 Oberursel
b Hoechst AG, PO Box 800320, D-W-6330 Frankfurt/M, Germany
Abstract - Out of 700 hives (A m carnica) owned by a commercial beekeeper 12 colonies were selected which showed slower Varroa population growth, high mite mortality and good overwintering without treatment. Thirty to 50 percent of the dead mites had damaged legs and (rarely) cuticle of the idiosoma. The damage rate increased significantly with mite mortality level. By investigating freshly killed mites it was concluded that the damage was caused by the mandibles of worker bees. SEM photos of the mandibles indicate that they act like sharp scissors and that no substantial differences exist between A mellifera and A cerana.
Key words: Apis mallifera carnica / Varroa resistance / amputation / mandible / defensive behavior