By Dr. Tim Sandle
EDITOR AT LARGE SCIENCE
August 28, 2025
Bumble bee on a plant. Image by Tim Sandle
A new study looking at how to conserve bees has tracked eight bumble bee species in the wild across eight years. Scientists from Northwestern University and the Chicago Botanic Garden recorded which flowers bees visited and calculated macronutrients in pollen from 35 flower species.
It was found that bee species occupy two distinct diet groups: one prefers protein, and another prefers fat and carbs. This more nuanced finding could help conservationists design pollinator gardens with flowers that meet bees’ nutritional needs.
Such findings are important due to the decline in bee populations globally. With this comes a decline in pollinators and an impact throughout the food chain. As Digital Journal pointed out a decade ago: “The causes of this decline are multiple. Reasons include loss of habitat from intensive farming, pesticide use, urban development and climate change. Each of these environmental pressures carries equal weight.”
The new study focused on pollen consumption, indicating that coexisting bee species occupy two distinct nutrient niches. Larger bodied bees with longer tongues prefer pollen that’s high in protein but lower in sugars and fats. Bees with shorter tongues, however, tend to gather pollen that’s richer in carbs and fats.
The scientists also found individual bees adjust their diets as their colonies grow and develop, reflecting changing nutritional needs throughout the season.
By dividing up nutritional resources, wild bumble bees can avoid competition, thrive together and keep their colonies buzzing strong all season long.
In terms of the variations with diets, while adult bees sip nectar for a quick burst of energy, they also collect pollen for their babies, or larvae, to help them grow. Worker bees gather pollen from various flowers, pack it into special “baskets” on their hind legs and ferry it home to feed their young.
The researchers developed a comprehensive nutritional map by examining a collection of bumble bee species in the wild to determine how species divide nutritional resources. The researchers tracked which flowers each bee species visited for pollen and then collected pollen samples from these plant species to understand their nutrient content.
The scientists took pollen samples back into the laboratory, where they measured the macronutrient content of each pollen sample, specifically calculating the concentrations of protein, fat and carbohydrates. The full dataset included nutritional profiles for 35 different plant species.
After determining the macros for each pollen sample, the researchers compared each bee species’ diet with their physical traits (like tongue length) and with seasonal shifts in flower availability. Immediately, clear patterns emerged.
Not only did pollen’s nutrient content vary substantially among plants, but it also changed throughout the season. Spring flowers, for example, have more protein-rich pollen, while late-summer flowers are richer in fats and carbs. Interestingly, this shift in protein aligned with bees’ nutritional preferences across the season.
The researchers also noticed the eight bumble bee species naturally divided into two diet groups. Long-tongued species collected pollen with higher protein and lower fat and sugar. Shorter-tongued species collected pollen with lower protein and higher sugar and fat. These differences seem to be associated with how tongue length influences which flowers bees can access.
As global pollinator populations face threats from habitat loss, climate change and poor nutrition, these findings highlight the need for conservation efforts that focus on nutritional diversity — not just floral diversity. Providing a mix of plants with nutrition could help support the specific dietary needs of different wild bumble bee species.
The research appears in the journal Proceedings of the Royal Society B, titled “Nutrient niche dynamics among wild pollinators.”
Bumble bee on a plant. Image by Tim Sandle
A new study looking at how to conserve bees has tracked eight bumble bee species in the wild across eight years. Scientists from Northwestern University and the Chicago Botanic Garden recorded which flowers bees visited and calculated macronutrients in pollen from 35 flower species.
It was found that bee species occupy two distinct diet groups: one prefers protein, and another prefers fat and carbs. This more nuanced finding could help conservationists design pollinator gardens with flowers that meet bees’ nutritional needs.
Such findings are important due to the decline in bee populations globally. With this comes a decline in pollinators and an impact throughout the food chain. As Digital Journal pointed out a decade ago: “The causes of this decline are multiple. Reasons include loss of habitat from intensive farming, pesticide use, urban development and climate change. Each of these environmental pressures carries equal weight.”
The new study focused on pollen consumption, indicating that coexisting bee species occupy two distinct nutrient niches. Larger bodied bees with longer tongues prefer pollen that’s high in protein but lower in sugars and fats. Bees with shorter tongues, however, tend to gather pollen that’s richer in carbs and fats.
The scientists also found individual bees adjust their diets as their colonies grow and develop, reflecting changing nutritional needs throughout the season.
By dividing up nutritional resources, wild bumble bees can avoid competition, thrive together and keep their colonies buzzing strong all season long.
In terms of the variations with diets, while adult bees sip nectar for a quick burst of energy, they also collect pollen for their babies, or larvae, to help them grow. Worker bees gather pollen from various flowers, pack it into special “baskets” on their hind legs and ferry it home to feed their young.
The researchers developed a comprehensive nutritional map by examining a collection of bumble bee species in the wild to determine how species divide nutritional resources. The researchers tracked which flowers each bee species visited for pollen and then collected pollen samples from these plant species to understand their nutrient content.
The scientists took pollen samples back into the laboratory, where they measured the macronutrient content of each pollen sample, specifically calculating the concentrations of protein, fat and carbohydrates. The full dataset included nutritional profiles for 35 different plant species.
After determining the macros for each pollen sample, the researchers compared each bee species’ diet with their physical traits (like tongue length) and with seasonal shifts in flower availability. Immediately, clear patterns emerged.
Not only did pollen’s nutrient content vary substantially among plants, but it also changed throughout the season. Spring flowers, for example, have more protein-rich pollen, while late-summer flowers are richer in fats and carbs. Interestingly, this shift in protein aligned with bees’ nutritional preferences across the season.
The researchers also noticed the eight bumble bee species naturally divided into two diet groups. Long-tongued species collected pollen with higher protein and lower fat and sugar. Shorter-tongued species collected pollen with lower protein and higher sugar and fat. These differences seem to be associated with how tongue length influences which flowers bees can access.
As global pollinator populations face threats from habitat loss, climate change and poor nutrition, these findings highlight the need for conservation efforts that focus on nutritional diversity — not just floral diversity. Providing a mix of plants with nutrition could help support the specific dietary needs of different wild bumble bee species.
The research appears in the journal Proceedings of the Royal Society B, titled “Nutrient niche dynamics among wild pollinators.”
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