For bees, diet isn’t one-size-fits-all
Most in-depth study of wild bee nutrition finds they need a balanced buffet
image:
A wild bumble bee (Bombus appositus) visiting a flower (Delphinium barbeyi) — both species were included in the study.
view moreCredit: Paul CaraDonna
Move over gym rats. Bumble bees are now the true masters of macros.
In the first long-term, community-level field study of wild bumble bee nutrition, a team of ecologists led by Northwestern University and the Chicago Botanic Garden discovered that wild bees aren’t just flitting from flower to flower, collecting pollen at random. Instead, they are strategically targeting flowers that enable them to carefully balance their protein, fat and carbs.
Focusing on pollen consumption, the study revealed 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.
The study will be published on Tuesday (Aug. 26) in the Proceedings of the Royal Society B: Biological Sciences.
“Despite the general importance of wild pollinators, especially bees, we know very little about their nutritional needs,” said Northwestern’s Paul CaraDonna, the study’s senior author. “Given widespread pollinator declines that have been observed around the globe, this knowledge gap is surprising and concerning. Our research provides some of the best information yet on the availability of nutritional resources found in wildflowers and how pollinators use these resources. We can incorporate this work into our thinking about garden design, so we can select the right flowers that best support the nutritional needs of wild pollinators.”
An expert on plant-pollinator interactions, CaraDonna is an adjunct associate professor in the Program in Plant Biology and Conservation, a partnership between Northwestern’s Weinberg College of Arts and Sciences and the Chicago Botanic Garden. Justin Bain, a recent Ph.D. graduate from CaraDonna’s lab group, is the study’s first author. This work was a part of Bain’s dissertation.
In the dark about diet
In the wild, bumble bees mainly consume two floral-based foods: sweet, syrupy nectar and fat- and protein-packed pollen. 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.
“We know that bees forage exclusively from flowers for pollen and nectar,” CaraDonna said. “Beyond that, we are in the dark. That is like humans shopping at a grocery store and assuming that all food items in the entire store have similar nutritional value. Clearly, that is a bad assumption.”
While other researchers have conducted short-term, lab-based studies on nutrition for single species of bees, the Northwestern and Chicago Botanic Garden team aimed to develop a more comprehensive nutritional map for how things play out in the wild. Instead of focusing on one bee species in isolation, the team examined a collection of bumble bee species in the wild to determine how species divide nutritional resources.
From steak to salad
To do this, the researchers observed eight different species of wild bumble bees at a field site in the Colorado Rockies. Across the span of eight years, the team meticulously tracked which flowers each bee species visited for pollen and then collected pollen samples from these plant species to understand their nutrient content.
The team took the pollen samples back into the lab, 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.
“All pollen contains protein, fats and carbs,” Bain said. “But each type of pollen has a different mixture of these macronutrients. Some are very high protein like a steak. Others are more like a salad. So, the nutritional profiles are very, very different.”
Who eats what and why
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.
“Queen bees emerge in the spring to establish their colonies,” Bain said. “They forage when the snow first melts, collecting protein-rich pollen for themselves and their first brood. Later in the summer, worker bees take over foraging, and half of the species shifted toward pollen with less protein and more fats. Seeing these clear transitions between queens and workers was especially striking, and it highlighted how differently species meet their nutritional needs across the colony life cycle.”
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.
Planning the perfect menu
In another surprise, the protein differences from flower to flower are larger than expected. In some flowers, protein only made up 17% of the pollen. In other flowers, however, protein comprised as much as 86% of the total pollen.
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.
“We now have a better idea of what bees are bringing home in their ‘grocery bags,’” CaraDonna said. “Although this work is from one ecosystem in the Rocky Mountains, it paints a very important picture for scientists to build upon. We found that not only is there a huge amount of variation in macronutrients available in natural ecosystems to wild pollinators, but our wild bees use those nutrients in distinct ways. The nutrient needs of bees are not ‘one-size-fits-all.’ But we also see that two distinct ‘nutritional niches’ emerge, suggesting that there may be some general hot spots in terms of what the pollinators are seeking out nutritionally.”
The study, “Nutrient niche dynamics among wild pollinators,” was supported by the Chicago Botanic Garden, the National Science Foundation, the Rocky Mountain Biological Laboratory, the American Society of Plant Taxonomists and the Colorado Native Plant Society.
Justin Bain, the study's lead author, looking for wild bumble bees at a field site in the Colorado Rockies.
Credit
Paul CaraDonna
A meadow near the field site with many different flowering plants, illustrating an example of a nutritional landscape for wild bees.
Credit
Jane Ogilvie
Journal
Proceedings of the Royal Society B Biological Sciences
Article Title
Nutrient niche dynamics among wild pollinators
Article Publication Date
26-Aug-2025
Busy bees can build the right hive from tricky foundations
Merging, tilting, and layering honeycombs allow bees to adapt to available space
image:
Bees building a honeycomb on the authors' 3D printed panels.
view moreCredit: Golnar Gharooni-Fard (CC-BY 4.0, https://creativecommons.org/licenses/by/4.0/)
There’s more than one way to build a honeybee hive, depending on the needs of the bees, according to a study published August 26th in the open-access journal PLOS Biology by Golnar Gharooni-Fard of the University of Colorado Boulder, USA, and colleagues.
Honeybees are renowned for their ability to build intricate hives where they can store their food and raise their larvae. Hive construction is the collaborative effort of thousands of hard-working bees, which also demonstrate a knack for adjusting their honeycomb structures to account for available space and resources. In this study, Gharooni-Fard and colleagues investigated the specific strategies that honeybees use to adapt to different building conditions.
The authors presented honeybee colonies with varying sizes of 3D-printed plastic honeycomb foundations upon which to build up their own wax-crafted combs. Using X-ray microscopy, the team was able to visualize and quantify the bees’ building strategies. When the foundation honeycombs were too small to accommodate worker bees, the insects would merge multiple cells to create overlying spaces of adequate size. If the foundation cells were too large, the bees built their honeycombs with slanted borders, effectively shrinking the opening of each cell while preserving depth for storage. And if the foundation cells were extra large, the bees simply built a new layer of regular-sized honeycombs on top, using the borders of the plastic foundation as support.
These results demonstrate that honeybee hive-building does not follow a fixed blueprint, but instead is a flexible process wherein a colony can apply a variety of strategies to adapt to different starting conditions. This study not only provides some preliminary insights into the complex behavior of bees, but also has implications for the design of bio-inspired engineering systems.
Corresponding author Francisco López Jiménez adds, “We have provided bees with 3D printed panels with a hexagonal pattern already imprinted, but with a size different of that preferred by the bees. We have found that they use at least three different techniques to adapt these foundations to a pattern more suitable to their needs, including complex three-dimensional arrangements.”
Co-corresponding author Orit Peleg notes, “These tiny builders seem to have an intuitive understanding of the physics behind collective construction. We're just beginning to understand the rich set of strategies they use - tilting, merging, layering - to shape structures that meet their needs in remarkably adaptable ways.”
López Jiménez concludes, “It is striking that the patterns that bees used to adapt to constraints due to irregular geometries are similar to those in very different systems. These include the cracks that appear in mud as it dries off, or the patterns in graphene and other atomic crystals.”
In your coverage, please use this URL to provide access to the freely available paper in PLOS Biology: http://plos.io/4kKsIlA
Citation: Gharooni-Fard G, Kavaraganahalli Prasanna C, Peleg O, López Jiménez F (2025) Honeybees adapt to a range of comb cell sizes by merging, tilting, and layering their construction. PLoS Biol 23(8): e3003253. https://doi.org/10.1371/journal.pbio.3003253
Author countries: United States
Funding: This work is supported by a grant from the CU Boulder Research and Innovation Office Seed Grant Program to O.P. and F.L.J., by NSF grant 2210628, both to O.P. and F.L.J., and by BioFrontiers Institute internal funds to O.P. The funders played no role in study design, data collection or analysis, decision to publish, or preparation of the manuscript.
Journal
PLOS Biology
Method of Research
Experimental study
Subject of Research
Animals
Pattern used when the bees are provided with a foundation of three times their preferred size, showing how they build smaller cells on the vertices of the provided pattern.
Credit
Golnar Gharooni-Fard (CC-BY 4.0, https://creativecommons.org/licenses/by/4.0/)
ByPaul Wallis
EDITOR AT LARGE
August 26, 2025
Pesticides have been linked to the deaths of bees around the world
A new bee superfood developed by the University of Oxford, Royal Botanic Gardens Kew, the University of Greenwich, and the Technical University of Denmark might just be the key to rebooting global environments. The superfood produces 15 times more bees. That’s good news all round.
You need to see how this works. Bear with some “explanations of the obvious” to clarify some major issues.
The world’s leading pollinators have been very much on the wrong side of the news for a long time now. Bee populations have been under attack from parasites, diseases, pesticides, and chronic environmental mismanagement.
The main reason for this unholy global mess is human activity. Agriculture promotes vast unnatural monocultures, which generate pests, parasites, and diseases on a huge scale.
Monocultures are, by definition, extra vulnerable to massive population crashes. They create their own problems and never fix them. Add to this the totally unnecessary, wasteful, and useless destruction of natural habitats which provide reliable counterbalances to risks, and it’s that much worse.
This collateral damage environmental disaster is largely responsible for what’s happened to the bees. Declining bee populations worldwide are a serious overall threat to food and natural ecologies worldwide.
Let’s spell it out:
The net environmental effect of the “bee deficit” in both natural and manmade environments is to reduce the biomass for future survival.
All populations of organisms are totally interdependent down to the soil biota levels in both human and natural environments.
All of the organic chemistry in an environment can be derailed by the loss of any component group.
Plants support the entire global macroenvironment, including the critical recycling of biomass by fungi, etc. The loss of nitrates alone can cripple an ecosystem almost overnight.
The bees, therefore, don’t just support the pollination cycle. They also support most of the world’s organic chemistry directly or indirectly.
Bees to the rescue? Yes, and you can prove it.
Given the pathetic state of most human-afflicted environments, adding bees and biomass generation potential is a good, safe option.
Bees can kickstart a lot of organic chemistry in the volumes required to generate positive outcomes. It’s not just honeybees, either. Many other types of native bees and pollinators could be used for local and macro-level regeneration and preservation.
You could generate some good, useful metrics, too. Adding bees is roughly the equivalent of adding energy to a power system. The metrics should show multiple increases in biomass elements, biota, etc.
In comparison to a biologically impoverished environment, you should generate an encyclopaedia’s worth of new phenomena.
To bee sure.
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Disclaimer
The opinions expressed in this Op-Ed are those of the author. They do not purport to reflect the opinions or views of the Digital Journal or its members.
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