Addressing Deficiencies in Commercial Bee Feeds

Supplements are Meant to “Supplement” a Foraged Diet

Honey bees are generalist foragers, meaning their diet consists of a variety of nutrients and microbials. Bees also feed one another trophallaxicaly (“mouth to mouth”), resulting in further chemical and microbial processing of the foraged food. In times of dearths, there is a shortage of nectar and/or pollen, so bees utilise their hive stores to continue colony operations. If this dearth is accompanied by consistent decreases in temperature, then bees begin overwintering preparations.

The beekeeper may look to feeding hives with sugar syrup, homemade pollen patties or their commercial counterparts. If the dearth passes and flowers begin blooming again, the bees cease consuming the beekeeper’s feed, as they can sense it to be inferior to natural forage.

There is big money in producing a feed that bees would prefer over natural sources. Even if we produced “the sweetest multinutrient of them all”, the colony eventually “tires” of it and goes searching for something that’ll meet their newfound nutritional needs. What is lacking in these commercial feeds, and why would bees prefer their natural forage? Read on.

Examples of Commercial Product Formulations in Australia

A search for the current commercial feeds in my local beekeeper stores provides the following:

• Hive Alive EZ Feed Super: Sugar syrup enriched with the HiveAlive supplement (seaweed extracts, thyme & lemongrass essential oils).
• Honey B Healthy: Non-GMO essential oil emulsion (lemongrass, spearmint, etc.), proteins/vitamins in some versions; designed as a stimulant/additive to syrup or patties.
• AgriSea Bee Nutrition: Liquid nutritional supplement derived from seaweed (“brewed naturally”) plus trace essential nutrients, meant to be added to sugar syrup, pollen patties, or water.
• Vitahive Power Feed: A pollen supplement/ “powerfeed” sold as patties or powder; designed to boost protein, vitamins, minerals in times of low forage.

There are also the homemade varieties: plain sugar syrup & soy pollen patties (soy flour/brewer’s yeast & vegetable oil). All these products boost hive health, with their effectiveness depending on forage conditions: when plant pollens are low, the supplements are more likely to be beneficial. The second factor is current colony condition: if you have a strong hive that you’d like to strengthen further (e.g. before making a split), then the premium supplements are worthwhile. If the hive is weak and needs a boost, a plain 1:1 water to sugar mixture is enough to stimulate broodrearing.

What’s Missing in Supplemental Formulations?

Four descriptions of “what’s missing” in many commercial feeds relative to the natural forage:

1. A defined sterol (lipid) content,
2. The right lipid profile, i.e. the Omega-6: Omega-3 balance,
3. The many phytochemicals found in pollen & nectar which activate detox and immune pathways,
4. The nutrient complementarity (i.e. biochemical interactions) that comes from pollen diversity, as opposed a surplus of simple proteins or sugars.

As you can see, it’s more complicated than isolating key compounds and mixing them into one brew. There are complex interactions that take place in the digestive tract – Vitamin B alone is good for you, Vitamin B as found in say, sunflower pollen, may be even better for you. Alas, we don’t know which aspect(s) of the pollen makes the vitamin that much better.

A Defined Sterol Content: 24MC

In the article on royal jelly production in bees, Major Royal Jelly Protein 1 (MRJP1) received the spotlight as being… the major royal jelly protein. Another compound, the sterol 24-methylenecholesterol (24MC) interacts with the acidic MRJP1 complex (which includes the protein Apismin) to increase its viscosity, and holds the queen (or worker/drone) larva in its cell (Kruth et al., 2019). Since larvae only consume jelly, it makes 24MC a key sterol for their development.

Jelly proteins come from the hypopharyngeal gland secretions, whereas lipids are secreted by the mandibular gland. Sterols are incorporated in the cell membrane, regulating its permeability and fluidity, as well as hormone production (makisterone A in honey bees is one example; used for waxy cuticle [exoskeleton] synthesis & subsequent moulting).

From a survey of 122 plant species, Zu and colleagues identified at least 25 pollen-derived sterols, with 24MC, sitosterol & isofucosterol being the most common (Zu et al., 2021). A single plant genus could have up to twelve sterol types in its pollen, with tropical plants having a higher total pollen sterol content: “…tended to occur in locations with higher annual mean temperature, higher temperatures in the coldest quarter, higher precipitation in the wettest quarter, and lower temperature seasonality”¹ (Zu et al., 2021).

More recently, Moore & colleagues genetically modified yeast to produce the essential sterols required by honey bees (Moore et al., 2025). The yeast first produced 24MC, then those 24MC-producing strains were further modified to produce small amounts of other sterols like the aforementioned sitosterol & isofucosterol. They found that when hives are fed these artificial yeasts, they had better brood rearing capabilities than those on control or commercial feeds (as measured by the number of larval and capped brood counts per colony).

Such work is still in the early days, as “GMO” and commercial-level scaling are two heads of a (very big) hydra. For now, you can appreciate that work is underway to enhance the nutritional value of commercial feeds.

Pollen-Derived Fatty Acids, Sterols & Lipids Lower the Severity of Varroa Parasitism

Annoscia and colleagues fed Varroa-infested bees pollen that was manipulated to have either its polar or apolar (“non-polar”) components removed (Annoscia et al., 2017). Polar components include sugars, water-soluble vitamins and proteins, whereas the non-polar component were the lipids and sterols. If you’ve been reading along, you may exclaim “ah! The bees that were fed apolar pollen had decreased survival due to a lack of lipids”. Gold star, well done!

One reason for why these bees had decrease survival could be due to cellular damage, as they lacked sufficient fatty acids to repair their cell membranes following Varroa feeding or viral infections. Moreover, the cuticle of bees is their “first line of defence” against pathogens, akin to our skin, and is composed of wax and other lipids, all of which are synthesised from dietary sterols.

A lack of diet-derived fatty acids means a weaker cuticle that is easier to breach by pests and pathogens. The authors speculate that “bees receiving a complete diet can rely on a constant supply of lipids and proteins that could compensate for losses caused by the mite feeding activity, thus saving energy from metabolism and nutrient stores mobilization, in favour of immune system activation against the pathogen” (Annoscia et al., 2017)

Sidenote: Majority of Insects Cannot Synthesise Their Own Sterols

Cholesterol is the important sterol in animals, and insects (unlike us) cannot synthesise their own sterols de novo (“from scratch”), needing to acquire it from their diet (reviewed in Furse et al., 2023). The bulk of sterols are incorporated into the cell membrane and its organelles. The 2020 review of Jing & Behemer state that “This inability to produce sterols likely exists because insects lack the enzyme-coding gene that converts farnesyl pyrophosphate to squalene” (Jing & Behemer, 2020). It is thought to be evolutionary advantageous since the process is oxygenically-costly, and insects themselves are already lacking in oxygen supply due to their blind-ended tracheal system².

Bees Fed a Diet of Pollen Substitutes Had Reduced Immune Function & Microbial Diversity

Powell and colleagues tested three different diets (Powell et al., 2023):

1. Using canola pollen, which simulates monoculture conditions,
2. A pollen substitute mixture that matches the canola pollen profile, made of 50% sucrose, along with cellulose, and vitamins,
3. The same diet as 2), with additives: beta glucan, arabinan, pectic galactan, xyloglucan & polygalacturonic acid.

Individual bees fed on all three diets had the same survival rate, suggesting that the experimental diet has no short-term adverse effects. Perhaps if this was repeated over a season or two, we’d see differences at the colony level. For now, it appears that a diet formulated to match the macronutrient profile of a pollen source largely resulted in minor changes to the gut microbiome, and major differences in gene expression and immunity (Powell et al., 2023).

Micronutrient composition also matters. Bees in the pollen-fed group had the highest diversity of gut microorganisms, even when their diet was a monoculture. The effects of plant polysaccharides and other compounds are not easily replicated in a lab… it could be that these phytochemicals, or their digestion via the gut microbiome, is what contributes to normal hormonal function, as pollen-fed bees showed higher expressions of vitellogenin and juvenile hormone- two hormones that regulate behaviour in social insects (amongst other functions).

One more thing: the bees raised on pollen were also more resistant to infection by the opportunistic pathogen Serratia marcescens (Powell et al., 2023).This bacterial species is used as a model organism for demonstrating immune function & infection susceptibility; its presence in this study reinforces the notion that a pollen-based diet beats the artificial when it comes to withstanding infections.

Higher Vitellogenin Titres Results in a Stronger Immune Response

A higher vitellogenin count is indicative of stronger colony immunity and longer-lived workers. Vitellogenin binds to the molecular patterns associated with pathogens (e.g. lipopolysaccharide, peptidoglycan and zymosan; Salmela et al., 2015). When queens are exposed to these pathogenic molecules (via trophallaxis with contaminated workers, contact with the hive surfaces etc…), they are “captured” by the vitellogenin and taken into circulation, where that carrier vitellogenin molecule can be incorporated into the ovaries (remember, it’s called the “egg yolk protein” for a reason). As the vitellogenin is carrying a “foreign” molecule, it triggers the egg’s immune response, thus “priming” against this pathogen’s “molecular signature”, should it be encountered in the adult stages of life.

Pollen Lipid Profiles & Omega-3/-6 Balance

Dietary intake of linoleic and α-linolenic acids (Omega-6 & Omega-3 respectively), matter for honey bee cognitive development and energy provision (Arien et al., 2018). The ratio of the fatty acids matters more than their total amount, with higher Omega-6 levels having detrimental effects. Manning and colleagues found that when bees are fed Eucalyptus pollen “enhanced” with 10% or 16% linoleic acid (Omega-6), their survival rates were lower than those colonies fed on a control diet (25 days & 42 days survival respectively; Manning et al., 2007).

Bees with a diet deficient in Omega-3 had impaired learning performance in both probiscis extension reflex (sticking out the probiscis in response to smells associated with a sugary reward) and the tactile assay (whereby the bee’s antennae is stroked with a bit of sandpaper, followed by a sucrose reward; Arien et al., 2015). The authors suggest that it was not the antennae or receptors that were damaged by a lack of Omega-3, rather it is due to abnormalities in the brain’s higher processing centres.

The review of Furse and colleagues suggest that the negative outcomes occur when high Omega-6 content displaces (“outcompetes”) Omega-3 and prevents its metabolism (Fruse et al., 2023). This is based on the similar observations in mammals, as Omega-6 displaced other polyunsaturated fatty acids in cell membranes after it was consumed in excess. Beware the seed oils!

This tells us that the ideal pollen supplement should be one that’s higher in Omega-3, or α-linolenic acid and lower in the Omega-6/ linoleic acid. That said, Omega-6 is easier to pack into foods, and has a longer shelf life than Omega-3, so you’re less likely to find the latter in your average bee-lipid supplement.

Migratory Beehives are Exposed to a Higher Omega-6:-3 ratio

The same study of Manning and colleagues showed that Eucalyptus pollen is high in Omega-6 & low in Omega-3 (Manning et al., 2007). As such, the migratory beekeepers that follow Eucalyptus blooms would be exposing their hives to a monoculture that’s high in Omega-6. More edible-ly, the Rosacae plant family (almonds, pears, apples etc…) also show this high Omega-6:3 ratios (e.g. Dmitruk et al., 2023 in blackthorns). 

As hives forage on these monocultures for the purposes of commercial pollination, these plants become their major (or only) source of pollen during the brood rearing season, and since lipid ratios matter more than their individual values (Arien et al., 2018), this nutritional deficiency combines with other stressors (e.g. high use of agrichemicals in commercial orchards) to worsen the health outcomes of commercial beekeeping operations, no doubt contributing to the whole “colony collapse” disorder.

Phytochemicals in Pollen Stimulate Immune Activity

Pollen contains different levels of phytochemicals that stimulate various metabolic & immune pathways (the “eat a varied diet for optimal health” applies to bees too). One such combination are coumaric acid, pinocembrin, and pinobanksin 5-methyl ether (Mao et al., 2013). When bees ingest pollen containing compounds like coumaric acid (in this study, from soybeans and wildflowers in Illinois), there is an increase in detoxification gene activity via the CYP9Q enzymes.

They note that these compounds are “not reported from nectar but rather are abundant in bud exudates of poplars [trees]” (Mao et al., 2013). Additionally, honey itself upregulates detoxification activity, whereas sugar syrup does not, and this is unsurprising consider that honey is a blend of sugars, vitamins, minerals and other trace elements, whereas sugar syrup is… sugar.

Palmer-Young and colleagues fed bees with various phytochemicals (as isolates, rather than as part of a pollen package) and found greatly increased immune function in bees, along with a significant, short-term decrease in deformed wing virus levels (Palmer-Young et al., 2017). This was largely mediated via increased expression in the antimicrobial peptide hymenoptaecin, which primes bees against infections and helps prevent it from spreading throughout the colony. The seven compounds tested in their study are naturally found in the nectar and pollen:

• Amygdalin, from almonds
• Anabasine & Nicotine, from tree tobacco
• Aucubin & Catalpol, from white turtleheads, native to north America
• Thymol, from thyme and even fumigated hives (as a treatment for Varroa)

Nicotine, thymol & the white turtlehead-derived phytochemicals showed positive immune effects at naturally occurring concentrations. Beekeepers have been advised to add “a few drops” of essential oils like lemongrass and thyme to their sugar syrups to enhance the feed’s profile, and studies like these vindicates this friendly bit of advice.

Nutrient-Nutrient Interactions, or Why We Can’t Model Complex Systems

Nutrients don’t act in isolation as their effects depend on ratios, balances, co-factors, gut microbiota, host age, food freshness, what your mother cooked for breakfast, the weather, current economic conditions in Ulaanbaatar, feeding time, arousal state, microplastics, shmicroplastics…. The list goes on. My dear reader, what we call “protein, fats and carbohydrates” are not singular entities, rather a class consisting of dozens of amino acids, fatty acids, sterols, flavonoids, vitamins, polysaccharides and so on.

Interactions are not linear – if a bee consume pollen first and nectar second, it does not trigger the same response as nectar first and pollen second. Each honey bee caste metabolises differently; workers have differing metabolic capabilities based on their age (nurses are better digesters of pollen than foragers; drones can’t digest anything that isn’t highly processed). As you saw above, there is synergy and antagonism: excess Omega-6 displaces Omega-3 which results in abnormal development. Likewise, some micronutrients are better absorbed in the presence of another.

All this is to say that with our current tools and instruments, we cannot adequately replicate, package and sell the natural forage of bees. Even the genetically-engineered sterol-producing yeast mentioned above may encounter issues in the long term as pollen is a mixture of nutrients, not just sterol alone. Don’t let this deter for you from feeding your hives. Supplemental feeding works well in times of dearth or disease. Just put aside during a nectar flow.

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Footnotes

1. Note that the authors sampled plants from various greenhouses or in the botanic gardens “(e.g. tropical glasshouse, alpine glasshouse) or outdoors at Royal Botanic Gardens Kew and nearby areas”, which does not reflect real-world conditions. Like wine, the terroir of climate, soil, terrain, and human elements impact the plant’s growth – I wonder if further variations would be found if these studies were replicate in the plants’ natural environment? ↩︎
2. ”Blind ended” because their tracheoles end at the tissues, they do not loop back into circulation or go elsewhere like blood vessels. Each tracheole penetrates the tissue and stops there; oxygen diffuses in, carbon dioxide diffuses out. This works well when you’re small as oxygen can diffuse a short distance into the tissue… as you get larger, the inefficiency catches up to you, which is one reason why we no longer have those giant insects from the oxygen-rich carboniferous period. ↩︎