FÖDOPREFERENSER HOS BIN En jämförelse mellan pollenpreferenser hos nordiskt honungsbi och Buckfast

Abstract

The original honeybee in Sweden, the European dark bee (Apis mellifera mellifera), was lost form the wild during the 19th century. The subspecies survived through beekeeping but began to be exchanged for other honeybees from the beginning of the 20th century and was almost locally extinct a century later. The hybrid Buckfast is the most widespread honeybee in Sweden today. We lack knowledge about whether the European bee and Buckfast has got different feeding preferences and therefore different relations to the local flora. The purpose of the study was to examine if the two types of bees visited different flora and how the collection of pollen varied during the season. Pollen was collected from the bees from hives in the Gothenburg Botanical Garden. The pollen was identified using a light microscope at 400x magnification. The frequencies of visits to different kind of plants and to native and introduced species were analysed with a Pearson's chi-square test. Shannon's diversity index was used to compare the variation of pollen types during the season. 41 plant taxa belonging to 22 families was identified. Most abundant was pollen from the families Rosaceae, Ericaceae, Brassicaceae and Salicaceae. There was a significant association between type of bee and the distribution of pollen types as well as between type of bee and native/introduced flora. Native flora dominated the pollen from both the bees, but it accounted for a much larger proportion in the pollen from the European bee while pollen from introduced flora was five times as common in the samples from Buckfast. The results implies that there is a difference in the foraging preferences which could be of ecological significance for the local flora. The diversity index was lower for Buckfast in the beginning of the season but similar for the bees during late summer.