Global patterns in bumble bee pollen collection show phylogenetic conservation of diet

1. Bumble bees (Bombus) are a group of eusocial bees with a strongly generalised feeding pattern, collecting pollen from many different botanical families. Though predominantly generalists, some bumble bee species seem to have restricted dietary choices. It is unclear whether restricted diets in bumble bees are inherent or a function of local conditions due to a lack of data for many species across different regions.

2. The objective of this study was to determine whether bumble bee species displayed specific patterns of pollen collection, and whether patterns were influences by phylogenetic relatedness or tongue length, a trait known to be associated with structuring floral visitation.

3. Bumble bee pollen collection patterns were quantified from 4,132 pollen loads taken from 58 bumble bee species, representing 24% of the pollen-collecting diversity of this genus.

4. Phylogenetic trait mapping showed a conserved pattern of dietary dissimilarity across species, but not for diet...