Pollen has a surprising problem — and honeybees have found a way around it

A recent study by researchers at the University of Oxford has revealed an unexpected behavior in honeybees. These insects can regulate their food intake based on the essential amino acids present in their pollen diet. The findings, published in Current Biology, indicate that many types of pollen lack the ideal balance of these amino acids for bees.

Essential amino acids are proteins that animals must obtain from their diet as their bodies cannot produce them. Bees rely heavily on pollen, which is primarily a protein source, to support their growth, survival, and reproduction. However, pollen is the male reproductive material of plants and does not naturally provide the optimal nutritional mix for bees.

To investigate this issue, researchers compared the amino acid composition of honeybee tissues with pollen from 99 UK flowering plant species. They also created artificial foods that matched these compositions. Worker honeybees were fed these diets in controlled laboratory experiments. Bees fed a diet more closely resembling their own body tissue consumed more food, gained more weight, and consumed a higher protein proportion.

The researchers suspect that histidine, an essential amino acid needed in small amounts, plays a crucial role in this response. When the relative amount of histidine in the diet was high, the bees reduced their overall food intake, including protein and carbohydrate. This behavior may be due to a post-digestive feedback mechanism that prevents bees from consuming excessive amounts of certain amino acids.

Honeybees gather pollen from various flowers and store it as bee bread inside the hive. Nurse bees process this pollen into glandular secretions, including royal jelly, which is fed to developing larvae. The researchers found that bee bread contains a more balanced amino acid profile compared to individual pollen sources. Royal jelly has the closest match to the amino acid composition of bee tissues.

The study suggests that honeybees may have evolved a way to compensate for the nutritional shortcomings of individual pollen sources by combining pollen from different plants and processing it through nurse bees. However, this nutritional system is not available to all bee species. Wild bees, including bumblebees and solitary bees, feed pollen directly to their offspring.

In habitats with limited flowering plant variety, these bees may struggle to obtain the appropriate balance of essential amino acids for themselves and their developing young. The results suggest that pollinator-friendly planting schemes should consider not only the number of flowers but also the diversity of plants producing pollen.

A varied diet may be essential for bees to obtain the right balance of nutrients. The research involved scientists from the University of Southampton, Lancaster University, Newcastle University, and The Hebrew University of Jerusalem.