Pollen variety and bee health

Yesterday I wrote that bees need a continuous supply of flowering plants such that something is always in bloom. I also mentioned that different types of bees prefer different types of flowers. What I didn’t discuss was the importance of pollen variety in the bee diet.

I think it is easier to understand bee nutrition when you compare it to our own. So, just now, I went to the pantry and reached for a can. It happens to be Trader Joe’s 100% pineapple juice in an 8.45 fluid ounce (250 ml) single-serve container. Good enough.

The nutrition facts printed on the side of the can tell me that one serving (the entire can) provides 2% of the daily vitamin A needs of a person who eats a 2,000 calorie-per-day diet. (Those are actually kilocalories, but that is a separate subject and a different blog.)

So, assuming I’m such a person, to get enough vitamin A by drinking just pineapple juice, I would have to drink 50 cans (422.5 ounces) or 3.3 gallons of the stuff. I like pineapple juice, but there’s a limit.

The 3.3 gallons also provides 7250 calories which is 3.63 times more than I need (assuming 2000 per day.) But it doesn’t supply any fat—which is necessary for good health—and doesn’t supply many of the other vitamins, minerals, and trace elements which keep us going from day to day. I certainly would not be very healthy living on pineapple juice alone.

You can think of a pollen grain as a “can” of food. It contains many of the amino acids, lipids, vitamins, minerals, and trace elements a bee needs, but different types of pollen contain different types of “ingredients.” The label on a can of beans will look very different from the label on the juice, just as the “label” on a grain of maple pollen looks different from the one on a grain of aster pollen.

Research has shown that when bees are forced to consume pollen that is low in nutrients they respond by eating more of it. But just as in the example above, they reach a limit. They’re full. They’re stuffed. They simply cannot eat enough of the inferior pollen to satisfy all their nutritive requirements.

Bees lacking in nutritious food are more prone to disease, don’t live as long, and can’t maintain a strong hive. Brood production falls off and eventually a colony will die. So when planning the placement of your hives, remember that the admonition to “eat a variety of foods” applies to them as well as us.

Rusty

Comments

Chelsea
Reply

In this light, it’s absolutely a wonder that bees manage to pollinate mono-crops and survive. I’ve heard that blueberries are especially poor for bee nutrition.

Hey, Rusty, have you heard of anyone inter-planting companion plants with any of the big bee crops (almonds, blueberries, etc.)? I’ve been daydreaming about some way to increase the plant diversity of monoculture fields such that it gives the bees something else to forage on and provides a benefit to the crop (i.e. fixing nitrogen).

Rusty
Reply

Chelsea,

I know some under-cropping of almonds is being done, and some inter-cropping of wildflowers in vineyards. Most of the current research involves habitat borders and bee pastures adjacent to mono-cropped fields. It makes an amazing difference in the number of and diversity of pollinators.

I just gave a lecture about this last week at The Evergreen State College. Wish you could have been there!

Chelsea
Reply

Ooh – wish I could have been there too. Let me know when you publish your North American Guide to Bee Forage; I’ll be first in line to buy a copy.

It makes practical sense to use borders rather than inter-cropping, I suppose.

PS – We have some wicked blood-red pollen coming in right now, and I think it’s from Purple Dead Nettle.

Rusty
Reply

Chelsea,

Way cool, red pollen! Do you have a picture I could use on this site?

Phillip
Reply

I’m totally hooked on all this pollen info. The bees in my backyard are bringing in mostly yellow-orange pollen, but some of them bring in blue pollen. So I had to look it up and discovered Siberian Squill is the most likely source.

I’m checking out flowers everywhere in my neighbourhood (not many at the moment). I want to know where the bees are going out for dinner.

Is there a book that catalogues the nutritional value of the nectar and pollen from various flowers? That’s a book I’d buy.

Rusty
Reply

Phillip,

I am also really interested in pollen. Many times in my research I ran across references to particular pollen sources and comments about their quality, but I never found a compilation of it. There are some references out there about the color and source of pollen, but most are from the U.K.–hardly anything from North America. Maybe this is the book I need to write.

Jeff
Reply

I found a nice PDF with pollen sources containing crude protein and amino acid distribution but if was written for Australia. It did have reference to some North American flora (fireweed, etc) but very little. As of right now the bees are bringing in four pollen sources, pale yellow, bright yellow, orange and rusty red. I have been able to identify three. The Rusty red is Daphne mezereum, the bright orange is Colts Foot, one of the yellow is pussy willow. I cannot identify the other. There is very little daphne pollen as it is only flowers in my yard and the rabbits ate all the crocus.

Does anyone know the crude protein content of Colts Foot. There are frames of that in the hive already this year.

Rusty
Reply

Thanks, Jeff. I’ll see what I can find out about Colts foot. You’re doing well to identify three of four pollen sources.

howardski
Reply

Good job. It sure makes it much easier to put into perspective when you say it like that. I remember Reagan telling us in a press conference once something like the American deficit is something like several hundred billion dollars and to illustrate his point he said if you stacked $1 bills on top of each other they would reach to the moon and back 3 times or something like that. The point is like your blog you have created visual pics that make your point easy to understand. Thank you.

petra
Reply

I forgot to mention I’m in Seattle, WA. Normally this time of year I have a ton of bees in my yard, this year I have seen all of 6-7 bees and only 2 honey bees. I have a small city lot and would like to know if there is more I can do.
Thanks

Rusty
Reply

Petra,

I have noticed the same thing exactly. I think it is the abnormally cold temperatures we are having here in the northwest.

Normally I have dozens of different kinds of wild bees in my yard. I have a lot of plantings designed specifically to attract bees, but I’ve seen very, very few this year. I’ve also seen few bee flies, hover flies, sawflies, and butterflies. Even wasps seem to be scarce.

I was especially looking forward to bee season this year because I wanted to take a supply of pictures for my website, but it just hasn’t happened. Perhaps some will show up when the weather warms, but I wouldn’t expect to see large populations this year. There is probably very little you can do.

Mark
Reply

Rusty, I am writing a book on planting for pollen and nectar for Australia and finding it very difficult to find much about pollen value other than the Aussie sources, some basic info in Crane. Do you have any info, anecdotal or otherwise on Rosemary pollen. Its a big unifloral honey in Europe but I haven’t been able to track anything down on its pollen value. Cheers Mark

Rusty
Reply

Mark,

It’s interesting that you ask this question. With the help of two beekeepers in Canada, I’ve started to assemble information on the nutritional quality of various pollens. We’re not doing any original research, just trying to assemble what is out there so North American beekeepers can have an idea about the pollen values. We’ve found that information is really hard to come by.

One of the complaints I’ve heard from the other two is that all the good information is coming from Australia. That’s funny. In any case, I don’t have anything on rosemary pollen but I will see what I can dig up since I’m digging anyway. The only thing about rosemary pollen I know is that my bees love it.

Your book sounds interesting. Let me know how it goes. I’ll be the first in line to buy a copy.

Jeff
Reply

Hi Rusty,

I am thinking about doing some grafting next year to help make a few splits/queen replacements. I know of one frame in one hive that is blocked with pollen/bee bread. What can I do to preserve this bee bread until spring? Can I place it in the freezer? Will the bees cap it? I’m hoping to have a few frames of capped honey and pollen available next spring to get one colony off to a good start and to allow for grafting in early June.

Any suggestions how to proceed to develop the healthiest queens possible?

The residual colony that swarmed this year is queenless and I have no options but to recombine it with this year’s nucs. So in light of that I’d like to have a few nucs for emergencies next year. But I’d rather not feed nurse bees sugar syrup to develop queens with.

Thanks

Rusty
Reply

Jeff,

To preserve the frame of bee bread I would wrap it in plastic wrap, freeze it overnight, then store it in a cool place. Bees will not cap it. Bee bread is a mixture of pollen and honey. The honey acts as the preservative.

Your questions concerning raising queens is long and complicated. I will try to answer them, but it will have to wait a bit. I plan to do a whole series on queen rearing, but haven’t had time yet.

Jeff
Reply

Thanks Rusty

Jeff
Reply

Rusty,

Are Black Eye Susan’s anygood as a pollen source? Is there any value in Hygerangea’s for pollen or nectar? the golden rod is coming to an end and asters will not much last longer.

Thanks

Rusty
Reply

Most asters provide some nectar and black-eyed Susan’s are in the aster family. However, I have no particular information about black-eyed Susan’s in particular, nor hydrangeas. I will let you know if I find anything.

Rusty
Reply

Hey Bruce, thanks. That is exactly the kind of document we need to develop for North America. I downloaded it and will be reading it from front to back. Good information.

owl farms
Reply

Hi guys, great site here!! thanks!

What sort of lab analysis are people using to analyze pollen? I have access to some equipment that may help.

Thank You

James
Reply

There are some interesting research theories that the pollen nutrients are not accessible to the bees except through beneficial microbiota in the hive and the bees’ gut. These fungi and bacteria penetrate the hard shell of the pollen grain and make the proteins available to the bee. Therefore fungicides and bactericides on the plants, including systemic ones, can be brought back to the hive where they effectively destroy the hive’s balance of microbiota and render the pollen useless.

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