Wild bumblebees actively visit different flowers to balance their intake of protein, fat, and carbohydrates, according to a new study conducted in the Colorado Rockies. Over eight years, ecologists tracked eight species of wild bumblebees, collecting pollen samples from flowers to analyze their macronutrient content. The findings, published in the Proceedings of the Royal Society B: Biological Sciences, revealed that bees’ dietary choices are closely linked to both seasonal changes in pollen nutrients and the bees’ physical traits.
Researchers discovered striking differences in protein levels among flowers, with some containing as little as 17% and others as much as 86%. Seasonal shifts also influenced the bees’ preferences: spring flowers tended to offer more protein-rich pollen, while late-summer blooms were higher in fats and carbohydrates. Larger-bodied bees with longer tongues favored high-protein pollen, while smaller species with shorter tongues preferred pollen richer in sugars and fats.
Conservation and Nutritional Diversity
The study highlights how wild bees adjust their diets as colonies grow, reflecting changing nutritional needs over time. Lead author Justin Bain compared pollen diversity to human meals, saying, “Some are very high in protein like a steak. Others are more like a salad.” Senior author Paul CaraDonna emphasized that the findings reveal how varied nutrient availability is in natural ecosystems, showing that pollinators’ needs cannot be met with a one-size-fits-all approach.
Experts say these insights can inform conservation strategies and even garden design, helping ensure that a diversity of flowers continues to meet bees’ dietary requirements. With global pollinator populations under pressure from habitat loss, climate change, and poor nutrition, the researchers stress that protecting nutritional diversity in ecosystems is essential. Michael Walsh of The Urban Apiarist, who was not involved in the study, noted that the research shows bees do not forage randomly but demonstrate a kind of “collective intelligence,” underscoring the need to safeguard both pollinators and their habitats.
