Development of a bioassay to test the orientation behaviour of the honey bee ectoparasite, Varroa jacobsoni

A bioassay was developed to test various aspects of the orientation behaviour of the honey bee ectoparasite, Varroa jacobsoni. The bioassay arena consisted of a petri dish, 60 mm in diameter, in which live honey bee larvae and previously frozen adults were used as hosts. Bioassays were conducted in a dark incubator at 32 degrees C for 60 min. Greater numbers of mites parasitized worker larvae than drone larvae, but this trend was not significant. Mites of various ages given a choice between nurse bees and fifth instar worker larvae preferred nurse bees at all ages of mites tested, excluding newly emerged mites. When given a choice between a nurse bee and a pollen forager, V. jacobsoni did not show a preference, and similarly when given a choice between a nurse bee and an adult drone no preference was observed. Finally, when given a choice between a nurse bee extracted with hexane and a non-extracted nurse bee, V. jacobsoni preferred the nonextracted host.