COMPARISON OF THE RESPONSES OF SOME NEW-ZEALAND AND AUSTRALIAN HONEY-BEES (APIS-MELLIFERA L) TO NOSEMA-APIS Z

To determine whether the introduction of Carniolan stock may alter the impact of Nosema apis on New Zealand bees, the responses of Italian ( Apis mellifera ligustica) and dark (Apis mellifera mellifera) New Zeal and bees and Carniolan (Apis mellifera carnica) bees from Australia to dosing with N apis spores were compared. Newly emerged adult bees wer e individually dosed with 2 x 10(5) N apis spores, caged together in g roups of 50, and incubated at 33 degrees C. The longevity of each bee and number of N apis spores carried by each bee at the time of death w ere recorded. All bees dosed with N apis spores had significantly redu ced longevity compared with the undosed control bees. Furthermore, the re were no significant differences among the 3 stocks of bees in the d egree of this reduction in longevity. However, dark and Carniolan bees survived better in cages than Italian bees, whether dosed or not. The re were significant differences among the 3 stocks in the mean numbers of spores carried by each dosed bee at the time of death, with Italia n bees carrying the highest spore loads, Carniolan bees the lowest, an d dark bees carrying an intermediate number of spores. Thus, Carniolan bees from Australia may support a slower rate of N apis proliferation and thus have lighter infections than New Zealand dark or Italian bee s receiving similar doses of spores.