Don’t Overlook Honey Bee Nutrition

How brief pollen shortages can weaken colonies weeks later

I was going to write about the so-called “June gap” – a period between spring and summer when, at least in my area, the available forage for honey bees can dry up. However, the phenomenon can occur anytime, and it connects to apiary site selection, migratory beekeeping, and weather patterns that can prevent bees from foraging or limit the supply of pollen and nectar for bees. There are plenty of challenges for beekeepers, with management of pests and disease foremost in the minds of many, but even the ability of a colony to deal with those things can be heavily influenced by nutrition – particularly pollen. So, don’t overlook honey bee nutrition. I said that in the title too, ‘cos apparently it helps SEO (Search Engine Optimisation).

Dangers of Dearths

Presently, in early March, my bees are bringing in great bundles of yellow pollen on the days when it’s warm. I think it is primarily from willows – an essential source of early pollen – but there’s probably other stuff too (crocus, plum blossom, hazel, gorse). The bees are making babies, and they need pollen for that. There are days when it’s cold and wet, and days when it’s warm and dry, so the pollen tap goes on and off frequently in springtime here. What are the implications for the colony of a prolonged period of poor weather (tap off) and how long before it starts to become damaging? Little or no nectar will be available until the dandelions are properly in bloom, so this is a time when the bees tuck into their stores of honey.

Impacts of Pollen Shortage

Luckily, there is research into this. In a study by Scofield & Mattila (2015)¹ researchers restricted pollen availability to nurse bees, which meant larvae were raised under nutritional stress. Bear in mind that larvae are only larvae for six days, so even three days of suboptimal feeding is a lot, from the larva’s perspective. The study found that workers resulting from larvae that were under nutritional stress were:

• lighter (weighed less)
• shorter lived
• less likely to forage
• less likely to waggle dance, and the waggle dances were less accurate
• those who did forage started foraging sooner, foraged for fewer days, and were more likely to die after only a single day of foraging
  

Thus, a pollen dearth (caused by unavailable pollen, or weather preventing foraging) of quite a short duration causes damaging effects to workers that emerge two weeks later. This matters not only for colony productivity but also for resilience to disease, since nutrition is known to influence immune function in honey bees.

In Di Pasquale et al. (2016)² researchers fed worker bees different controlled amounts of pollen – full pollen diet, moderate restriction, extreme restriction, and no pollen at all. The key findings were that pollen restriction affected nurse bee survival and development of hypopharyngeal glands (the glands that produce brood food). So, there is a direct link between pollen shortage and impaired ability to raise healthy brood.

Permanent Damage

In another study, Brodschneider et al. (2022)³, bees were restricted from consuming pollen during the first seven days of adult life, then allowed normal feeding afterwards. They found that the bees deprived of pollen for the first week of life tried to compensate by eating more later on. However, they only reached 51.1% of the lifetime consumption of unconstrained bees. Body mass and survival were reduced, as in the experiments on protein-deprived larvae. So, a pollen gap of just one week can permanently impact worker quality.

Signs of Trouble

At various times in the summer I have seen ominous signs on the comb; a lack of fresh pollen (normally placed on the comb between the brood and honey, if there is any honey) and larvae that are sitting in tiny puddles of brood food, rather than lakes. I have sometimes seen that when selecting a comb from which to graft. There is no point grafting larvae that are a little ‘dry’ as they will be substandard, and more difficult to graft anyway.

The timeline for a pollen dearth and its effects on the bees goes something like this:

Days	Effect on colony
1–3 days	colony increases foraging behaviour
4–7 days	nurse bees begin to deteriorate
1–2 weeks	brood feeding declines (quality and quantity)
3 weeks	weakened workers emerge
4–6 weeks	reduced foraging efficiency, weaker growth

Only in extreme cases does a dearth lead to starvation. Hopefully beekeepers would spot the signs before it happened, and feeding would be instigated to save the colonies. However, perhaps they would not notice those periods of a week or so when pollen is not coming into the hive. As we have seen, this can have consequences further downstream. Such an event in late May or early June (yep, that’s the ‘June gap’) could result in workers that are poor foragers and die sooner – not really ideal for when the main summer flow kicks in.

Stalled Development

What people often see with stationary (non-migratory) hives and a dearth of one to two weeks is that the colonies seem to stall. Brood nest contraction, ‘dry’ larvae, bees that become a lot more feisty, and maybe signs of robbing. As far as I’m concerned, I would rather not see that any time. Last season I suspect that bees were possibly suffering from nutritional deficits in late summer, which would have made them more vulnerable to varroa/deformed wing virus (or any other pest or disease), and could have led to low quality winter bees. In the end, that would cause higher winter losses.

Delightful Diversity

Another problem that beekeepers might encounter is a lack of pollen diversity, such as when bees are moved to pollinate crops. Bees need a range of different pollens from different flowers, and often this will come from wildflowers on the edges of fields or hedgerows. A recent study⁴ looking at this stated: “Monofloral pollen diets have previously been shown to have detrimental effects on overall honeybee health, specifically in their ability to combat pathogenic infection. This highlights the complex relationship between diet, health, and microbiome composition in honeybees — a lack of diversity in foraged pollen appears to drive dysbiosis and … reduces the host’s ability to suppress infection.” Dysbiosis means an imbalance in the gut microbiome (I thought I’d save you some time searching for that).

I think it can be a useful exercise to build a forage calendar for your particular area. This can help with identifying potentially good apiary sites, and bad ones. Being next to oilseed rape (OSR) might help your spring crop, but if there’s nothing but ‘green desert’ afterwards, that could be a problem. In my area, the OSR only appears in small patches every three years, and my spring honey comes from tree blossoms mostly. I have only had a significant crop of lime (linden) honey once in the last decade, sadly, and the summer crop tends to be from brambles, sometimes clover, and whatever they grow in those fields funded by the SFI initiative (phacelia, sunflowers, clover, vetch, etc.). Last season the brambles lasted about a week, which was unusually poor.

Feeding Bees

Even with well-placed colonies on great sites with good forage throughout the season, there is always the uncertain British weather. What should we do when the pollen stops coming in? Well, in my case, I feed a pollen patty of some description. I know that these are nowhere near as good as real pollen, and there is not, as yet, a commercially available ‘complete food’ for honey bees. Pollen contains sterols and many other goodies as well as protein, and it turns out that isofucosterol⁵ is essential (or at least critically important). I am more nervous about feeding syrup to honey production colonies, but I can see the merit of giving thin syrup during prolonged bad weather or a dearth. It would need to be thin and in small quantities, just to get them through to the next nectar flow.

So, this subject of nutrition is worthy of attention. Could it be that poor colony performance is not due to the type of bee you keep, or poor queens – maybe the bees are handicapped by gaps in pollen which have knock-on effects on foraging ability and resilience. Things to keep an eye on:

• amount of pollen on combs
• diversity of pollen (different colours and shades)
• amount of brood food given to young larvae (lakes not puddles)
  

References

1. Scofield HN, Mattila HR (2015) Honey Bee Workers That Are Pollen Stressed as Larvae Become Poor Foragers and Waggle Dancers as Adults. PLoS ONE 10(4): e0121731. https://doi.org/10.1371/journal.pone.0121731
2. Di Pasquale G, Alaux C, Le Conte Y, Odoux J-F, Pioz M, Vaissière BE, et al. (2016) Variations in the Availability of Pollen Resources Affect Honey Bee Health. PLoS ONE 11(9): e0162818. https://doi.org/10.1371/journal.pone.0162818
3. Brodschneider R, Omar E, Crailsheim K. Flight performance of pollen starved honey bees and incomplete compensation through ingestion after early life pollen deprivation. Front Physiol. 2022 Dec 9;13:1004150. doi: 10.3389/fphys.2022.1004150. PMID: 36569746; PMCID: PMC9780383.
4. Meehan DE, O’Toole PW. A Review of Diet and Foraged Pollen Interactions with the Honeybee Gut Microbiome. Microb Ecol. 2025 May 27;88(1):54. doi: 10.1007/s00248-025-02551-y. PMID: 40423805; PMCID: PMC12116653.
5. See https://thewalrusandthehoneybee.com/better-bee-food/