Understanding the contribution of the olfactory chemoreception processes to elicit the hygienic behaviour of the European honeybee Apis mellifera L. against the Varroa destructor

Honeybees of the hygienic line can unseal the wax cap and remove the brood infected by the Varroa mite more frequently than the normal bee line. They can open the infected brood cells before the completion of the reproductive cycle of the mother mite. This behaviour leads to a better control of the spread of the Varroa infestation inside the colony. Olfactory and / or contact chemoreception processes may play an important role to elicit this important social immune response probably when bees scrutinize the brood cells as a part of their regular in-hive activity. I am using bees of a specific hygienic line (in collaboration with Prof. Kaspar Bienefeld, Länderinstitut für Bienenkunde, Hohen Neuendorf, Berlin) to investigate the underlying contribution of the olfactory chemoreception components in mechanism(s) of recognising Varroa mites inside the brood comb. Honeybees of the hygienic and non-hygienic lines are tested using the differential olfactory Proboscis Extension Response (PER) conditioning with different hive components such as the wax caps of the brood cells, whole comb pieces and the intact pupae both from the healthy and Varroa infected colonies in order to understand whether bees in general can differentiate between the healthy and the infected hive materials and also whether the hygienic bees are able to discriminate better compare to the non-hygienic bees.

I am also searching for neural correlates of the chemoreceptive components by imaging the Calcium activities in the antennal lobe and mushroom body lip region in the bee brain.

This work is funded by the Forschung für eine nachhaltige Tierproduction (FUGATO), Bundesforschungsministerium (BMBF), FUGATOPLUS.