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Honey bees cannot survive on dandelions alone

A lot is written about how important dandelions (Taraxacum officinale) are to the honey bee. Indeed, honey bees flock to dandelions both in the early spring and in times of dearth when little else is in bloom. But unlike some other pollen plants, dandelions are only a mediocre food source.

The problem, it seems, is that dandelions are missing some of the amino acids needed to manufacture protein. You can think of amino acids like letters in the alphabet–you need all 26 letters if you’re going to form all the words. Likewise, a bee needs a full complement of the necessary amino acids if it is going to make all the proteins it needs to raise young bees.

Of the set of amino acids that bees need, dandelion pollen falls short of four: arginine, isoleucine, leucine, and valine. Researchers have found that honey bees fed dandelion pollen alone have low success at raising brood. In fact, some researchers found that that honey bees fail to raise any brood when fed dandelion pollen alone.

Remember, dandelion pollen is not toxic, it’s just not complete. Potatoes are not toxic either, but if you ate only potatoes you’d be missing important parts of your diet.

Bees, like humans, need a varied diet from a number of sources to be healthy. The dandelion problem is a good example of what can happen if bees are fed a single pollen (monoculture) diet. Although some pollens are better sources than others, the best thing for the bees (or us) is to eat a wide variety of foods.

Rusty

Bee rolling in dandelion pollen. Creative Commons photo by Guerin Nicolas.

Comments

Jeff
Reply

Do you have any ideal of the pollen content of Colts Foot. Bees forage heavily on Colts Foot early in the year and store a good bit of it. I have tried to find amino acid content and overall protein content and cannot seem to find anything. Any thoughts?

In my neck of the woods the first pollen source is the common alder, which I think is a low quality protein source as it is wind pollinated. But the colts foot the bees hit hard and fast just after the alder, followed by pussy willow, then red maple. At that point there are multiple pollen sources for the bees to feed on.

Rusty
Reply

Wow, Jeff, colts foot isn’t one of those plants that people run out and analyze all the time. I’ll have a look around but I doubt there’s a lot of research on it.

Phillip
Reply

I don’t know anything about Colts Foot, but the bees in our backyard are bringing in pollen all over the place — a rainbow of pollen. Yellow, orange, green, blue, purple. At least that’s what my colour blind eyes tell me. Foraging in an urban environment, my guess is they’re getting it from crocuses and other early-blooming planted flowers. The bees show little interest in the pollen patties I’ve given them.

What I’m more concerned about is reversing our boxes too early. I know the earlier the better is often a steadfast rule, but I don’t know. I still see plenty of bees in the bottom boxes of all my hives. I wouldn’t want to split up the brood nest.

Still no dandelions around here. Maple buds are just starting to show. I looked around too much at flowers on the ground last year. I hardly ever looked up into the trees. Do regular nothing fancy maples trees have flowers that attract bees? If so, I think our bees will do alright. This city is packed with maple trees and other coniferous trees.

I wish I could stay home and watch them all day.

Rusty
Reply

All the maples that I know about attract bees; they have loads of nectar.

Gabriel
Reply

A extract from Australian thesis: “Fatty acid composition of pollen and the effect of two dominant fatty acids in pollen and flour diets of longevity and nutritional composition of honey bees”.

There have been relatively few studies on honey bee longevity following the consumption by bees of pollen from different species (containing different protein and lipid levels). A few studies on longevity exist where artificial diets have been tested (Winston et al. 1983). Schmidt et al. (1989) found that the longevity of bees fed pollen from wind-pollinated species was less than those fed sugar-only diets (no protein), perhaps indicating the absence of pollen attractants, presence of pollen deterrents, toxic compounds (e.g. in Typha latifolia) or poor nutrients balance. Honey bees fed other pollen had increased longevity. For example, bees feed dandelion (Taraxacum officinale) pollen had life-spans of 6.4 days greater than diets containing only sugar, whilst bees fed from Rubus sp., Populus sp1 and sp2 had life-spans of 28.4, 38.0 and 28.6 days greater than sugar controls, respectively. These differences were significantly correlated with the amount of pollen consumed, protein concentration of the pollen and the total amount of pollen protein consumed (Schmidt et al. 1987).

Then as Rusty said, the best thing for the bees is to eat a wide variety of foods.

Disappearance of Bees | Craig A. Schmidt
Reply

[…] a huge food source for bees, and they are not that ugly if maintained right. Although, just keeping dandelions in our yard is not something that will help bees. While it is nourishing to bees, only going as far […]

lizzie
Reply

But is it still a good idea to NOT mow ones dandelions?

Rusty
Reply

Lizzie,

Dandelions are an important part of the bee diet, but they cannot be the only thing in the bee diet. Yes, let the bees have them.

lizzie
Reply

Thanx, Rusty!

Davey
Reply

I leave as many dandelions on my yard then cut them when they are turning to seed… there’s no ‘goodness’ at that point anyway. IOW in early spring I don’t cut my lawn anyway so the bees can have a ‘hayday’ at my ‘lions’. 😉
I have other flowers that bees love in my garden like bee balm, crocus, sedum, etc.

jeannie
Reply

Even though dandelions are not a great food source for honey bees, I think they are essential for the health of the bee population. Pre 2,4-D and glyphosate, dandelions thrived in parks, along roads, vacant lots, and even suburban lawns. Let’s face it they are (were) tenacious. Now spring brings the strong scent of 2,4-D and there is nary a dandelion in sight. A holistic health practitioner might prescribe dandelion tea to replace trace elements like magnesium and zinc or for detox. So maybe think of dandelions as spring detox after a long cooped up winter. It’s worth study to determine the importance dandelions in the ecosystem and in turn bee health. An analysis of trace elements present in honey from the 1970 or 1980’s and honey post dandelion extermination (now) could provide such insight. See Nat Geo Documentary: Zombie Alligators of Lake Griffin. This film illustrates the importance of trace elements role in a healthy ecosystem.

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