The difference in pollen harvest between Apis mellifera and Apis cerana in a Tibetan alpine meadow

Abstract

To explore the difference in pollen harvest between the western honey bee Apis mellifera and a native eastern honey bee A. cerana in the Zoige alpine meadows in the northeastern part of the Qinghai-Tibetan Plateau, we investigated species diversity of the harvested pollen and the amount of harvested pollen per bee for both species, and calculated the niche overlap (in terms of similarity in harvested pollen) between the two bee species during the flowering season from June to August 2016. Results showed that the species diversity of the harvested pollen was indistinguishable between the two bee species. Nevertheless, A. mellifera carried more (although not significant) pollens per bee than A. cerana. Moreover, pollen composition differed between the two bee species: A. mellifera mainly foraged on Anemone rivularis, Saussurea nigrescens and Anemone trullifolia, while A. cerana foraged on Anemone rivularis, Stellera chamaejasme, and Pedicularis longiflora. Consistently, the niche overlap between the two honeybee species was particularly small in several observations. Our results indicate a niche separation in pollen resource between the two honeybee species in a Tibetan alpine meadow.