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Dryad

Data from: Bumblebee flower constancy and pollen diversity over time

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Mar 27, 2023 version files 638.02 KB

Abstract

Bees often focus their foraging effort on a few or even a single flower species, even if other equally rewarding flower species are present. Although this phenomenon – called flower constancy – has been widely documented during single foraging trips, it is largely unknown if the behavior persists over longer time periods, especially under field conditions with large spatial and temporal variation of resources. We investigated the pollen diet of individuals from nine different Bombus terrestris colonies up to six weeks, placed at either 0, 300 or 1000 m from nearest autumn sown oilseed rape. Adjacency to oilseed rape affected constancy, with a higher flower constancy in colonies far from fields. Overall, 23 % of the pollen foraging trips were flower constant, and the fraction of constant pollen loads did not change over time, although repeatedly sampled individuals that were flower constant once often showed different preferences at other sampling occasions, and the similarity between pollen loads collected by the same individuals dropped over time. This suggests that flower constancy and other learnt foraging strategies likely change in response to shifting floral resources. How rapidly it changes in response to changing resources, and if this differs between species as well as within species depending on e.g. size, should be the focus of future research. The average diversity of pollen from single foraging trips was around 3 pollen types, and we found indications of resource partitioning within the colonies resulting in higher colony-level pollen diversity. Keywords: flower fidelity, Bombus, foraging, seasonal shift, foraging preferences, Brassica napus.