Calorimetrical and biochemical investigations on the influence of the parasitic mite Varroa destructor on the development of honeybee brood

The parasitic mite Varroa destructor is a serious pest to the western honeybee Apis mellifera. Here, we investigated the impact of mite infestation on the energy content, energy density, hemolymph volume and hemolymph protein concentration of drone and worker pupae. Mite infestation had a significant impact on the energy content of worker pupae at the end of metamorphosis, with an energy content of highly infested pupae 15% lower than non-parasitized pupae. The energy content of infested and uninfested drone pupae did not differ significantly. The energy density of drones and workers was not affected by mite infestation. Drones had a higher energy density compared to workers and lost more energy during metamorphosis. The heat production rates of drone pupae did not change due to mite parasitation. The total hemolymph volume of worker bees was significantly reduced in infested pupae, whereas the mites did not influence the hemolymph protein concentration. Although drones generally were less affected through mite infestation than workers, our results reveal a clear energetic impact of mite parasitation on honeybee pupae.