A team of researchers led by the University of Oxford has developed a breakthrough food supplement that could help reverse the alarming decline of honeybees.
Working with Royal Botanic Gardens Kew, the University of Greenwich, and the Technical University of Denmark, the scientists engineered a diet that mimics the key nutrients bees normally get from pollen.
When tested, colonies fed this supplement produced up to 15 times more young. The findings were published in the journal Nature.
Honeybees rely on pollen as their main food source. It contains essential lipids called sterols that are critical for growth and development.
But climate change and intensive farming have reduced the variety of flowers bees depend on. As a result, bees are increasingly missing key nutrients.
Beekeepers often use artificial pollen substitutes made from protein flour, sugars, and oils. These provide calories but lack the sterols bees need, leaving colonies nutritionally deficient.
To fill this gap, researchers engineered the yeast Yarrowia lipolytica to produce a precise mix of six essential sterols.
They added this yeast to bee diets and tested it over three months in controlled glasshouse experiments. The enclosed setup ensured bees ate only the experimental feed.
The results were dramatic. Colonies receiving the enriched diet produced up to 15 times more larvae that reached the pupal stage compared with those on standard diets.
They also continued raising brood throughout the entire study period. Colonies without sterols stopped producing brood after about 90 days.
Even more striking, the nutrient profile of larvae matched that of bees feeding naturally, suggesting the supplement closely replicates real pollen nutrition.
Senior author Professor Geraldine Wright (Department of Biology, University of Oxford), said: "Our study demonstrates how we can harness synthetic biology to solve real-world ecological challenges. Most of the pollen sterols used by bees are not available naturally in quantities that could be harvested on a commercial scale, making it otherwise impossible to create a nutritionally complete feed that is a substitute for pollen."
Lead author Dr. Elynor Moore (Department of Biology, University of Oxford at the time of the study, now Delft University of Technology) added: "For bees, the difference between the sterol-enriched diet and conventional bee feeds would be comparable to the difference for humans between eating balanced, nutritionally complete meals and eating meals missing essential nutrients like essential fatty acids. Using precision fermentation, we are now able to provide bees with a tailor-made feed that is nutritionally complete at the molecular level."
To figure out what bees actually need, researchers analyzed tissues from pupae and adult bees. This required extremely delicate lab work, including dissecting individual nurse bees.
They identified six key sterols that dominate bee biology: 24-methylenecholesterol, campesterol, isofucosterol, β-sitosterol, cholesterol, and desmosterol.
Using CRISPR-Cas9 gene editing, the team programmed Yarrowia lipolytica to produce these sterols efficiently.
This yeast was chosen because it naturally produces lipids, is safe for food use, and can be scaled up for industrial production. The final supplement is made by growing the yeast in bioreactors and drying it into a powder.
Honeybees help produce more than 70% of major global crops. But their populations are under severe pressure from poor nutrition, climate change, parasites, disease, and pesticides.
In the U.S., annual colony losses have ranged from 40 to 50% in recent years and could reach as high as 60 to 70% in 2025.
This new supplement could strengthen bee health without increasing competition for limited wildflowers. It may even evolve into a complete nutritional feed.
Co-author Professor Phil Stevenson (RBG Kew and Natural Resources Institute, University of Greenwich) added: "Honey bees are critically important pollinators for the production of crops such as almonds, apples, and cherries and so are present in some crop locations in very large numbers, which can put pressure on limited wildflowers. Our engineered supplement could therefore benefit wild bee species by reducing competition for limited pollen supplies."
Danielle Downey (Executive Director of honeybee research nonprofit Project Apis m., not affiliated with the study) said: "We rely on honey bees to pollinate one in three bites of our food, yet bees face many stressors. Good nutrition is one way to improve their resilience to these threats, and in landscapes with dwindling natural forage for bees, a more complete diet supplement could be a game changer. This breakthrough discovery of key phytonutrients that, when included in feed supplements, allow sustained honey bee brood rearing has immense potential to improve outcomes for colony survival, and in turn the beekeeping businesses we rely on for our food production."
Larger field trials are still needed to confirm long-term benefits. If successful, the supplement could reach farmers within two years.
The same technology could also be adapted to support other pollinators or farmed insects, opening new paths for sustainable agriculture.
