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A shortage of pollen

Bee Brief bee

Many bees, including honey bees, collect multiple kinds of pollen and can adapt when a particular type becomes scarce. However, many native bees are completely dependent on a single plant species and cannot survive without it.

In addition, native bees feed their larvae in a different way. In most bee species, pollen is collected, moistened with nectar, and formed into a ball inside the nest. The female bee lays an egg atop the ball so that when the egg hatches, the larva can eat the sweetened pollen—the equivalent of bee bread—and the royal jelly step is skipped altogether.

A shortage of pollen is a relatively new concern for beekeepers. Once upon a time, pollen was taken for granted. But today, a bountiful and diverse supply of pollen is sometimes lacking. Habitat loss, invasive plants, monoculture farming, and herbicides are just some of the reasons.

A pollen grain is simply a small package containing the male genetic material of a plant, so a frame of bee-collected pollen is like a gigantic sperm bank, except the sperm is lost to the plants forever. Instead, it becomes food for bee larvae . . . kind of an odd menu item, when you think about it.

Help wanted: move pollen

Since plants can’t walk, jump, swim, fly, or bar-hop, they need a way of moving their pollen around. The most significant mover of pollen is the wind. The grasses—the family of plants that includes wheat, rice, maize, millet, sorghum, barley, oats, and rye—are wind pollinated, as well as most conifers and ferns.

But plants with showy flowers are often pollinated by animals. At least they once were, before mankind began tinkering with them. Today, some of the showiest blooms have little or no usable pollen—another reason for the shortage of bee food.

How to nurse a larva

Not all pollen is created equal, not even close. Just as human food varies in nutritional content, so does pollen. Some are higher in protein or amino acids, some have more lipids, some have a greater variety of vitamins or micronutrients. Go to a farmer’s market at the height of the season and admire the produce—all the colors, textures, shapes, and sizes. Just as you can identify a plant based on its fruit, you can also identify a plant based on a single grain of pollen. Each is unique.

As beekeepers, we know that pollen is necessary for brood rearing. But the youngest honey bee larvae do not eat pollen directly. Instead, the nurse bees eat the pollen in the form of bee bread. Such a protein-rich diet stimulates their hypopharyngeal glands to secrete royal jelly, which is then fed to the young larvae. After about three days, the worker and drone larvae are switched to a diet of pollen and diluted honey.

As older adults, honey bee foragers eat energy-rich honey almost exclusively. Because foragers don’t eat bee bread or pollen directly, when they need protein, they beg the nurse bees for it. That’s right, nurse bees feed both larvae and foragers.

Don’t ask me, I just work here

So the foragers that collect pollen don’t eat it, they just pack it home. Sometimes foragers will bring home other stuff—sawdust or coffee grounds, for example—that have a powdery consistency and the right particle size. This has led some researchers to believe that honey bees cannot determine the food value of pollen.

However, other research has shown that although foragers may collect inferior pollen or non-pollen, the nurses—the ones that actually have to eat the stuff—are much more selective. Think of mom coming home from the market with parsnips and rutabagas. The kids sneer: “Really? Where’s the food?” In the hive, the nurses may discard some of the treasures their sisters brought home from the field, including pollen with questionable food value and sometimes that pricey pollen substitute.

The need varies with brood rearing

When you understand how pollen is used in the hive, you can see why a colony doesn’t need a large supply during winter. In late autumn through mid-winter, when there is little brood production, a colony can get by with very little. However, heaps of good quality pollen are needed throughout the major brood-rearing periods, especially in late winter and early spring.

In highly built-up areas, or in places with lots of agriculture and herbicide use, pollen may be especially scarce in early spring and again in late summer or early autumn. Pollen substitute is often used at these times.

It’s a shame we spray roadside weeds with herbicides and then feed our bees soybean meal. In fact, we humans do so much stupid stuff, you have to wonder how we survive. I know, I know. You say that if we don’t spray for invasive weeds, they will overrun the landscape. I say, if we hadn’t sprayed the native weeds in the first place, the invasives wouldn’t have had an opportunity to start. Oh well, too late now.

Natural pollen is the best

If you are not a commercial beekeeper, if you are a hobbyist with just a few hives, you should seriously consider trapping pollen from your hives and feeding it back in times of pollen dearth. Natural pollen is superior to substitutes and trapping is fairly easy to do.

Some beekeepers don’t like to trap pollen because they fear that extra pollen foraging will cut into their honey production. Maybe yes, maybe no. But you have to ask yourself: Do you want healthy bees or do you want that extra jar of honey? Considering how difficult it is to keep bees healthy, and considering the price of replacement, a trap may be the answer.

Rusty
HoneyBeeSuite

Honey bee with pollen. Pixabay photo.
Honey bee with pollen. Pixabay photo.

Comments

Mariana
Reply

Rusty,
How do you view pollen needs for bees in warmer climes? I’m in coastal So Cal, and my bees are foraging all year. I have to assume that although they decrease the population over the winter (such as it is) they continually produce brood. (This is verified by the decreased but definitely present brood (all stages) this morning.) We do have a nectar/pollen dearth in late summer and fall, but right now I’m seeing good amounts being brought in. Should we be monitoring stores of pollen and supplementing now?
Thanks,
Marian

Rusty
Reply

Mariana,

The thing to remember is that honey bees don’t hibernate, and brood rearing goes hand in hand with the availability of forage. If forage is available and it is warm enough to fly, the honey bees will collect pollen and raise brood. Looking at it the other way, if you have brood then forage must be available. So if everything is working—that is, pollen is coming in and brood is being raised—I see no reason for supplementing their stores. As I explained in an earlier post, I think it is rare that hobby beekeepers need to supplement pollen, but it’s a good thing to be aware of in case the weather doesn’t cooperate and your bees run short.

Tammy
Reply

Fabulous post! Thanks for that!!

hg
Reply

Luckily ours never seem to need extra pollen. Always satisfying to see the bees bringing in loads: https://flic.kr/p/mFoTVP

willowcreekhoney
Reply

Thanks Rusty, I have been wanting to trap pollen for some time now. I guess this year would be a good time to start. Pollen flows from spring to fall, so when is the best time to collect it? Obviously, not in the spring as it is needed in increased brood production.

As always, I enjoy your posts.

Ken

Rusty
Reply

Ken,

After reading your question I added a link in today’s post that leads back to a post on pollen trapping. It doesn’t quite answer your question but provides more information. I think the best time to collect would be just after the spring build-up (or just after swarm season) when lots of pollen is still coming in but brood rearing is about to slow down. In truth, I haven’t done it in years because there seems to be plenty of pollen here where I live. I’m thinking that I might try one of the new top traps this year, just to see how it works and to keep some pollen in the freezer.

Nancy
Reply

Great article, Rusty! Sharing….

And is that honey bee on spotted knapweed? Here it’s considered invasive, but if bees can use it, well and good. Not the only introduced species they benefit from: chicory, dandelion, saponaria, sweet rocket and most of our food plants, not to mention that godawful Bush honeysuckle.

Nan
Shady Grove Farm
Kentucky

Rusty
Reply

Nancy,

It probably is spotted knapweed; I know honey bees love it. Another invasive for your list is Japanese knotweed, which grows all over the place out here. It makes sense when you think about it—old world bees love old world plants.

Guillaume
Reply

Thanks so much for this excellent blog, Rusty. When I finally do get bees, they will owe you for every mistake I manage to avoid!

There is one thing I don’t understand about pollen trapping, and I would be grateful for your lights. If the bees store pollen anyway (you mention frames of pollen), why would we need to trap their pollen to store it for them? Is it because they are not good at managing their savings, and we act like more responsible “bankers/insurers” in case of pollen dearth? Or do we have ways of keeping pollen fresh longer? Otherwise it seems a bit micro-managing, but I might be missing a crucial element, having no experience whatsoever.

thanks,
Guillaume

Rusty
Reply

Guillaume,

That’s a good question, and I think you’ve already answered it. We all know that honey bees hoard nectar, and they will store as much as they can possibly collect. But with pollen, they collect it more on an as-need basis. They store it around the edge of the brood nest. If you look at a single frame, which is a cross-section of the brood next, you will see a rainbow-shaped arc of pollen just outside the brood nest, and everything else is honey.

That amount of pollen is pretty much what they will use in the near future. They will store some for winter but not much. I’m not sure why this is so, but I think it has to do with “use by” dates. Pollen that is stored for long periods can get very hard and brittle, or it can get moldy and degraded. In either case, it is unusable by the bees. I’ve seen it last much longer, of course, but there are no guarantees.

I don’t think honey bees evolved in places where there was ever much of a pollen dearth. By moving them all over the world, we have provided conditions which aren’t the same as their native habitats. So in places where pollen can be short for a period of time, we can take some of that pollen and store it for them. They will work to make up the difference at the time you take it, which means they will have enough to raise the present brood. Then, if they should experience shortage later, you can feed their own pollen back to them.

Comprenez-vous?

Guillaume
Reply

Mille mercis, Rusty! It all makes perfect sense now.

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