A team of ecologists from Northwestern University and the Chicago Botanic Garden spent eight years studying eight species of wild bumblebees in the Rocky Mountains of Colorado. The researchers aimed to create a comprehensive dietary profile for these insects, which belong to the family of true bees and are closely related to honeybees.
The researchers identified which flowers each bumblebee species visited for pollen. The team also collected pollen samples from those plants to measure protein, fat, and carbohydrate content.
What Did the Scientists Discover?
The results showed that pollen nutrient content varied by season. Pollen from spring flowers contained more protein, while pollen from late summer had higher levels of fats and carbohydrates. That seasonal shift helped explain the insects’ changing preferences.
The researchers were surprised by how much protein differed among flower species: some pollens had as little as 17 percent protein, while others were around 86 percent, according to The Guardian.
“All types of pollen contain protein, fat, and carbohydrates, but each has a different mix of micronutrients. Some types are as protein-rich as steak. Others are more like salad,” said Justin Bane, lead author of the study.
The team also found that larger bumblebees with longer proboscises preferred pollen that was high in protein but low in sugar and fat, while bees with shorter proboscises selected pollen higher in carbohydrates and fats.
“We now have a better understanding of what they’re bringing home in their food bags,” said Paul Caradonna, a senior author of the study. The research shows a wide diversity of macronutrients in natural ecosystems, and bees’ nutritional needs vary by species.
Caradonna says the findings provide the most reliable field data yet on the availability of floral nutritional resources and how pollinators use them.
Why Is This Research Important?
Global pollinator populations continue to face threats from habitat loss and declines in floral resources. The authors emphasized the need to preserve plant diversity so bees can meet their nutritional needs.
Michael Walsh, founder of the London beekeeping service The Urban Apiarist, who was not involved in the study, said, “Bees demonstrate a kind of collective intelligence. We need to protect both them and their ecosystems, as our food systems depend on them.” Therefore, conservation measures are necessary to ensure a diverse diet for bees.
The study’s findings were published in the journal Proceedings of the Royal Society B: Biological Sciences.
Photo: Unsplash
