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The role of pollen in honey bee nutrition

In the back of the feed store, where pallets of fifty-pound sacks rise to the ceiling, I watched two women obsess over brands of layer ration. From what I could hear, they were concerned about protein content and they were comparing the nutritional labels. It makes sense. If you want healthy chickens and many eggs, your birds need a balanced diet that includes the proper type and amount of protein. It works the same way for horses, pigs, dogs, cats, and even your kids.

Although we often speak of the protein content of foods, it is the selection of amino acids that is most important. Proteins are made from strings of amino acids. When an animal needs a certain protein, it can take the amino acids it ate and string them together to build the protein. Even more awesome, if an animal eats one protein, it can take it apart and re-string the amino acids to make a different protein—the one it actually needs. Conceptually, it’s a bit like Legos. You use single pieces (amino acids) to build the object you want (protein).

Honey bee nutrition

Honey bees, too, need the proper mix of amino acids to be healthy. Except for trace amounts in honey, pollen is the sole source of amino acids in the honey bee diet. And just as humans need a variety of foods to remain healthy, a honey bee colony needs a variety of pollen types.

Variety is important because not all the amino acids are found in a single type of pollen. Some have a greater assortment than others, so eating a variety of pollen types is the ticket to good colony nutrition. In nature, this would not be difficult. But in many modern settings, especially those containing a small number of flowering species, bees may come up short in one or more of the essential amino acids. Coming up short can mean diminished life spans, less resistance to disease, or poor foraging ability among other things.

Well-fed colonies do better

Only in recent years has honey bee nutrition begun to receive the attention it deserves. As colonies came under attack from more threats, including new pathogens, parasites, and pesticides, it became clear that well-fed colonies with balanced diets had the edge over those with nutritionally deficient diets.

I learned many things while writing my paper for the UM master beekeeper program. But the thing that bowled me over was discovering that honey taken from healthy colonies shows more antibacterial action than honey taken from nutritionally deficient colonies. Why? Because bees receiving a full complement of amino acids are more able to secrete the enzymes that give honey those properties, especially glucose oxidase. And why is that important? Because that is the same enzyme that, when secreted into brood food, keeps the larvae free of disease. It that cool or what?

A changing environment

It is easy to fall into the trap of thinking that since our fathers, grandfathers, and great uncles never worried about bee nutrition, we shouldn’t either. Back then, the bees gathered pollen on their own and thrived. No one gave two hoots about its source or amino acid content.

While that may be true, we have substantially changed our environment in the intervening years. No longer are urban areas separated by large swaths of natural vegetation. No longer do farms grow a large selection of crops. And no longer do roadsides provide a sparkling array of wildflowers. No. Instead we plant vast expanses of one thing and spray down the rest until the landscape is uniform and easy to manage. Bee nourishment? Who cares?

In this new world, beekeepers must be mindful of the pollen available to their bees. Ironically, if you live in an urban area with diverse plantings, your bees may be fine. But if you live in an agricultural area with monocrops, your bees may suffer. Most of us have something in between, but all of us need to be aware.

What can beekeepers do?

Depending on where you live, planting flowers or flowering trees may be the best solution. Others have worked at changing the spraying regimens in their local communities—simply changing the timing of maintenance can make a big difference. Other beekeepers use pollen substitutes, or they trap pollen for feeding when local pollen is scarce. Others use bee vitamins added to syrup.

Certainly these measures are extra work for the beekeeper, but I think the resources used to prevent a nutritional deficiency can be offset by healthier, more productive bees. Typically, when we think of feeding bees, we think of syrup. It’s high time we added pollen to the menu.

Rusty
Honey Bee Suite

Bee with pollen
Pollen plays a vital role in honey bee nutrition. Pixabay photo.

Comments

Charles Carlson
Reply

It should be noted that vitamins aren’t proteins and that a diverse array of pollens come a diverse array of plant blossoms. I love the description of amino acids as lego pieces that are assembled to make functional structures from the strung together amino acids. It’s a useful condensation of more than a century of human scientific endeavor, and one of the most remarkable stories we know.

Jennifer Godwin
Reply

Is it ok to feed bees pollen going into winter? I live in the mountains and it’s already 50º or colder during the day and no flowers and nectar now.

Rusty
Reply

Jennifer,

You can, but remember their pollen needs are low when the brood nest is small, so they don’t need a lot. I generally start adding pollen to their diet around the winter solstice, just when the days begin getting longer and the brood nest begins to expand.

Glen Buschmann
Reply

Rusty, Thanks
I’ll leave chemical analysis of pollen and nectar (and propolis) to the folks with big labs. BUT, while it seems complicated examining nectar from flowers (let alone bees) and examining it, collecting and identifying pollen seems relatively simple. It is on my “like to do” list to collect and then microscopically photograph pollen gathered from different flowers and then from bees. Obviously such a task requires some special optics (which I have not (yet) purchased), some microscope skills, and a trace of insanity. But from what I know, the physical uniqueness of pollen under a microscope is startling clear as one goes from one plant species to the next, and thus cataloging and recognizing pollen has got to be hugely more doable than nectar analysis. I figure that one only needs to chose a dozen or so plants of interest, at least to start with. (A full pollen catalog would require more insanity than I care to tinker with — what with so many of species of bees that I want to learn first.)
I’ve particularly thought that this is a doable project working with mason bees, because it can be very easy raiding their jumbo pollen pellets (with the right type of tunnel system), even if it makes me a bit predatory. What would reduce my sense of predatory guilt and pecuniary indiscretion is having a valuable research reason — I’m pondering it.
Cheers, Glen

Glen Buschmann
Reply

PS Why do I see typos AFTER hitting the SEND button. Oh well. GB

Rusty
Reply

Glen,

Because that’s the way life works. I sometimes do my final edit after I post, because I can’t see the errors before.

Rusty
Reply

Glen,

When you get going I will send you honey samples: I would love to know where it comes from. The honey I’ve looked at is loaded with pollen, but I don’t know how to recognize it.

Also, I used a pollen trap this year, so I have lots of pellets for you to examine!

Glen Buschmann
Reply

Sure Rusty — thanks (I think). I’ll also raise the question at the next Beek meeting. Glen

Dave Maloney
Reply

Rusty, this is a super explanation of the protein/amino acid factor as it pertains to nutrition. Thanks!

My question is this as it regards bee bread: I contend that the nurse bees do not feed bee bread directly to the larvae. Bee bread is stored close to the brood for the benefit of the nurse bees as opposed to the benefit of the larvae. I contend that it is the nurse bees who eat the bee bread – the protein from which enhances the nurse bees’ ability to deliver a high quantity of high quality excretions (royal jelly and brood food) to the larvae. In other words, the bee bread is fed “indirectly” to the brood via nurse bee excretions as opposed to being fed “directly” by dropping chunks of bee bread on top of the larvae (which, of course, I have never seen). Is this correct, of am I missing something?

Rusty
Reply

Dave,

Your explanation is correct. The only thing I would add is the larvae begin to receive some bee bread at about the end of the third day. By then their digestive systems are more able to handle pollen grains. But they don’t receive chunks. Some of the bee bread is chewed by the nurses, mixed with digestive enzymes, and fed along with the brood food to provide a transitional diet.

Nancy
Reply

Rusty, thanks for mentioning this:
“No longer are urban areas separated by large swaths of natural vegetation.”Isn’t it curious that colony collapse began to be noticed right around the time millions of acres of land were being lost to development? Often, it was so-called “marginal” farmland, rough pasture and hayfield, scrub woods, full of diverse vegetation, not “profitable”under current farming models. .
Well, speaking of marginal farmland, right now my acres are swaths of goldenrod, purple and white aster, and some persistent chicory. I wonder if bees’ protein needs vary with the seasons: certainly the available types of pollen do. You’re right, we all need to know more about pollen. Thanks!
Nan
Shady Grove Farm
Corinth, Kentucky

Rebekah Lee
Reply

Excellent topic. Sources for safe and affordable pollen? Any other avenues of providing the required aminos? Or stated another way, is it necessary for the required bee aminos to be supplied via flower pollen?

I’d love to read your paper. Is it available?
Best regards, Rebekah

Rusty
Reply

Rebekah,

I think the best pollen is that you’ve collected from your own hives and saved in the freezer. Other than that you can supplement the bee diet with pollen substitute, Amino-B-Booster, Hive Alive, or something similar. Pollen can carry AFB spores, so caution is warranted when purchasing from an unknown source.

I will try to post my paper by Monday.

drew
Reply

It was so gratifying to watch the bees bringing in legs full ‘o pollen back in the spring. Yes!!! They are doing their job. But obviously, this isnt the time of year for pollen in suburban Philly so Ive been feeding syrup with Honey-B-Healthy and MegaBee pollen substitute. What is your opinion of this technique, Rusty?

Rusty
Reply

Drew,

Do you mean you are mixing the substitute into the syrup? If so, you can certainly do that. However, I prefer to keep the two separate so that if the bees want just syrup, they can do that, or if they want just pollen sub, they can do that. Or they can have both. I don’t like to have them forced to eat the sub if all they want is the syrup. I think of it as self-regulated, free-choice feeding.

That said, there is probably no long-term harm done in mixing. When I’ve given pollen mixed with sugar too soon in the winter, I find my bees build up too early in the spring and then they plow through their food supplies really fast. When I feed the two separately, I get a more reasonable build up. Anyway, just something to think about.

Mark
Reply

Rusty,

What indicators exist to tell me my bees need more protein/pollen other than a visual inspection of the comb and seeing a dearth of pollen packed away in their cells? If I see enough pollen in their comb, what would tell me they need supplements?

Rusty
Reply

Mark,

I don’t know how to tell except for visual inspection. But I like to be aware of the brood nest. If it is small or shrinking, as in the fall, they don’t need much pollen. But when it starts to increase, such as after the winter solstice, they will need lots. If they are bringing in pollen during those times (depends on weather and location) they probably don’t need extra. But if the nest is expanding and they are not bringing any in, there is a good chance they will need a supplement.

In the past, I have seen huge jumps in population after feeding supplements, which tells me the lack was holding back their growth. But other than actually looking, you can only guess.

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