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Floral fidelity makes honey bees special. While many pollinators flit from one plant species to another, honey bees doggedly pursue flowers of a certain species.
So when the new day dawns, worker bees Sue and Marianne, Betsy and Josephine grab their flight plans and wing out the front door. Sue is visiting dandelions, Marianne and Betsy are working on apples, and Josephine has cherries in mind. They each collect just one species of pollen. This is great for plants because the pollen that lands on the stigma is the type needed for fertilization. How this benefits the honey bee is less clear.
Nevertheless, an entire foraging trip will be spent on that single flower type. In fact, individual bees are likely to keep collecting the same pollen for many days. Only when the source dries up does the forager switch to something else.
This fidelity to one pollen type at a time means the plant has a better chance of being completely pollinated. Bees that forage on any plant they come across have mixed pollen types on their bodies, so the chances of a plant receiving the right type of pollen are less.
Floral fidelity requires large numbers of flowers
Floral fidelity is the reason you seldom see honey bees on small plantings. If you have just a few flowers of several different species, the flowers are more likely to be visited by native pollinators than by honey bees. A honey bee forager wants to see at least two basket-loads of pollen—probably more—before she starts to collect.
Much research has gone into floral fidelity. Examinations of pollen loads show that only about six percent of the pollen is inconsistent with the rest of the load. And some of the six percent may have been introduced accidentally. For example, pollen could have been deposited on a flower by the wind—or perhaps by a different pollinator—where it remained until it was inadvertently picked up by a honey bee.
You can clearly see the results of floral fidelity
You don’t need a laboratory analysis of pollen pellets to know floral fidelity exists. Instead, just take a look. Pellets have distinct colors—sundry shades of white, yellow, orange, blue, and gray. Each pellet is made from one color, not mixed up like M&Ms.
However, this is not true of all bee species. You can often see loads of pollen on bumble legs that have layers of different colors. It’s apparent that when they finished with one plant, they went on to a different species of plant with a different color of pollen.
The advantages of floral fidelity to the bee are less clear
Probably the biggest benefit to the honey bee is the efficiency of pollen collection. Instead of flying here and there and everywhere, randomly searching for pollen, the bee keeps working the flowers on one plant until the supply of pollen is used up.
By staying on one plant, a honey bee needs to fly less distance, and flying is an activity that requires lots of energy. If you watch carefully, you can often see honey bees walking, rather than flying, from flower to flower on a blooming tree or shrub.
Each honey bee unloads the pollen from her own legs
Whereas nectar is transferred from bee to bee before it is stored in a honeycomb, pollen-carrying bees must store their own pellets. Somehow, the foragers feel their way around inside the dark hive and find an available cell. They back up to the cell and scrape one leg with the other until the pollen pellet drops into the cell.
The photos of brilliantly-colored pellets were graciously provided by Phillip Cairns at MudSongs.org.
Honey Bee Suite
Fantastically interesting, as usual. If “they” ever find out what benefit this has to the bees, I’m sure you’ll let us all know! As you say, the benefits for the plants (and for beekeepers going into pollination) are obvious. Hmm.
I have not had any luck getting a photo of the red pollen. If I had known that it was unusual, I would have taken advantage when I saw it! Our weather has been too bad for the bees to be flying much. Blueberries are already 3-4 weeks behind.
On the subject of floral fidelity, though, I have a super interesting photo for you to check out. I’ll email it along.
Now you’ve got me all curious. Can’t wait to see the photo!
“…back at the hive the pellets are packed into cells according to type. Although there are some exceptions, the cells are as distinctly colored as mosaic tiles.”
Get out. Are you serious?
I have seen some pictures of this that blow me away. Unfortunately, I don’t have one–at least not one I have permission to use. If I can find the one I have I will send a pm.
I’ll try to take some pics the next time I tear the roof of the hive that brought in the multi-coloured pollen.
Тоже наблюдал фиолетовую обножку. Правда только во второй половине лета. А сейчас несут пыльцу оранжевую, белую и светло-коричневую.
When you say they carry orange, white, and light brown pollen, do you mean they carry it separately or all mixed up?
They bear all of them together. Now at us the bird cherry, a willow, a mespilus, apple-trees, a currant, pears, steppe almonds blossom.
The first chapter of T. D. Seeley’s ‘Honeybee Democracy’ has an excellent picture. See this example chapter: press.princeton.edu/chapters/s9267.pdf
The colour we see when we look at the comb is that of the last pollen load. A longitudinal section through a cells clearly shows all the different colours of the pollen loads in that cell.
good information about bee pollen.