Pollen and nectar quality drive the major and minor floral

To investigate whether floral resource quality impacts on bumble bee floral choices, we determined the pollenforagingconstancyandfloralchoicesoffourbumblebeespeciescommonlyoccurringinpeaty,wetmeadows in South Belgium. We subsequently analyzed the chemical contents of pollen and nectar, as well as the nectar production of the major host plant species. Individuals of B. lapidarius and B. pascuorum collected high-quality pollen (i.e.,having high essential amino acid and phytosterolcontent)onComarumpalustreandTrifolium pratense, whereas individuals ofB. terrestris s.l. and B. hypnorumenlarged their diet breadth to less valuable pollen resources (Cirsium palustre and Valeriana repens). Since Persicaria bistorta and Comarum palustre offer abundant and concentrated nectar, these plant species might represent major nectar sources for bumble bee species in peaty, wet meadows. The present study demonstrated the role of pollen composition on differences in foraging strategies among bumble bee species.