Washington State University

Ask Dr. Universe

We eat well because bees have hairs!

January 6th, 2012

Dear Dr. Universe,
Why do bees have stuff that looks like hair? The hair on their legs looks like a real hassle, what with all the crud that sticks to it.
Elliott

Dozy autumn bee. By John Spooner/Flickr

Dozy autumn bee. By John Spooner/Flickr

That crud is their food, Elliott. That’s what I learned from Steve Sheppard. He studies bees here at WSU.

In fact, these hairs (which are branched, kind of like feathers) are one of the main characteristics of bees. They use the hairs to gather plant pollen. As they crawl in and out of flowers to gather the sweet nectar that flowers produce, the flower pollen gets caught on the hairs. The bees use their legs to comb the pollen down and pack it in little pollen baskets on their legs so they can carry more.

Bees are vegetarians. Of course, they make that nectar they gather from flowers into honey, which is their food supply for the winter. But even vegetarians need protein, and that’s what the pollen provides. They use the protein they get from eating pollen to produce “brood food” in special glands in their heads. You can think of flowers as a bee supermarket—a place where they can get all their groceries!

And this brings us to another question I got, from someone who didn’t include her name: “…I would like to know why bees are important to apples.”

Great question, says Professor Sheppard. Bees love apple blossoms. And that’s lucky for the apple trees—and lucky for us. This pollen that bees collect is the “sperm” of plant reproduction. Some plants can reproduce without outside help. (We’ll get to this in the next column.) But apples produce best if they get pollen from other apple trees.

Well, someone needs to move the pollen from a blossom on one tree to a blossom on another tree so the blossom can turn into an apple. That someone, more often than not, is the honey bee!

A single full-grown apple tree can have as many as 100,000 blossoms on it. Only a fraction of those will actually develop into apples. But still, it’s fortunate for the apple tree that they have the busy little bee.

One bee will visit 10 to 15 blossoms a minute and up to 5,000 a day! In order to produce one pound of honey, says Professor Sheppard, bees have to fly about 75,000 miles, about three times around the Earth!

But here’s the key point of all this. When the bee crawls in and out of the blossom, pollen from that blossom collects on the bee’s hairs—and one bee can carry around as many as 100,000 grains of pollen. And some of the pollen already on the bee from other blossoms gets rubbed off, so the blossom gets pollinated. The bee collects nectar and pollen, the blossom gets pollinated, we get apples and honey, and everybody wins!

And it’s not just apples. Professor Sheppard says that as far as what bees do, the pollination is actually more important to us than the honey–if you can imagine. About 15 percent of what we eat—both fruits and vegetables—depends completely on insect, mostly bee, pollination. Also, a lot of things we eat depend PARTLY on bee pollination. For example, the alfalfa that cows and other animals eat is pollinated by bees.

As important as honey bees are, they are not native to North America. They were actually brought here by European settlers. Even “wild” honey bees are bees that decided to go out on their own.

So before honey bees got here, who pollinated everything? Professor Sheppard says that before the settlers and their bees got here, all sorts of pollinating insects were doing the job, including thousands of species of “solitary bees,” bees that do not gather in hives.

But at least a couple of things have changed. Much of our farming today is in “monoculture,” huge fields in one crop. This does not provide a very good place for all these other pollinators to live. Also, even if they did hang around, huge areas of one tree or crop are just too much for these insects to handle by themselves. So be kind to those honey bees!

One more thing. Professor Sheppard is very interested in how honey bees evolved and where they came from originally. In a couple of weeks, he is going to Kazakstan. He believes there might be an undiscovered species of bee that lives there that would help answer some of these questions. I’ll keep you posted.

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