An online resource based on the award-winning nature guide – maryholland505@gmail.com

Pollen Baskets

Due to their tolerance of cold temperatures, bumblebees can still be found foraging on late-blooming flowers such as New England Asters (Symphyotrichum novae-angliae). Most worker bees collect and carry pollen in a dense mass of elongated and often branched hairs (setae) on their hind legs called a scopa.  Honeybees and bumblebees, however, have pollen baskets, or corbiculae, in which they place and carry pollen back to their hive. Pollen baskets consist of a polished cavity located on the tibia of each of their hind legs which is surrounded by a fringe of hairs. Pollen is pressed on to the pollen basket when it has been collected by the combs and brushes on the inside of the bee’s legs. The bumblebee moistens the pollen with some nectar to make it sticky and stay in the basket. The pollen is loaded at the bottom of the pollen basket, so the pollen that has been pushed towards the top is from flowers the bumblebee visited earliest on her foraging trip. When a pollen basket is full it can weigh as much as 0.01 gram and contain as much as 1,000,000 pollen grains.

Only queen bumblebees overwinter, and they must start a new colony in the spring.  When the queen first emerges you can tell whether or not she has started a nest by looking at her pollen baskets. If she is carrying pollen then she has found a nest site.

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7 responses

  1. What a fascinating discussion of pollen baskets, how they work, and when she fills them. I never knew. Their cold tolerance means they are out foraging early in the spring too. They were all over my Solomon’s Seal this year.

    October 5, 2020 at 7:47 am

  2. Ginny Bradford

    Waiting to go in. Weather looks good at Brandreth this weekend!!’ Want to get started on the bureau tomorrow.

    Sent from my iPhone

    >

    October 5, 2020 at 9:55 am

  3. Alice

    Little miracles of nature. So interesting.I have seen & watched & photographed many bumbles this year. I love the way they land under drooping Andromeda flowers.

    October 5, 2020 at 10:03 am

  4. Wonderful and fascinating, Mary!! I never knew most of this, and I am about to go out to my lovely New England asters to look for bumblebees! and see what I can see about their pollen baskets. (We do not have honeybees on Isle au Haut.)

    October 5, 2020 at 10:50 am

    • Alice

      No one has hives on the island?

      October 5, 2020 at 8:53 pm

  5. Wallie

    Would you please do a little story about hoverflies also known as flower flies? I have only learned about them recently and I’m fascinated but find it hard to identify them-some of them resemble bumble bees- any help would be appreciated
    Thank you!

    October 5, 2020 at 1:32 pm

  6. Peter Luquer

    Hi, Mary;

    When you say that only queen bumble bees over winter is it not true that the queen honey bee does as well?

    Peter

    Sent from my iPad

    >

    October 6, 2020 at 4:09 pm

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