Wednesday, April 11, 2012

Bumblin' bumblebees

photo by Jose M. Rus
On my walk home yesterday, I was so pleased to spot my first bumblebee of the season--she's a sure sign of spring.

Like all other bumblers out and about this time of year, she's a mated queen who spent the winter buried beneath duff or fallen leaves, and her plan is to build a big royal family.

Since we usually only see a single bumblebee at a time, it's easy to assume that they are solitary creatures. But like the honeybee, the bumbler builds a colony.

She'll seek out the abandoned burrow of a mouse or other rodent and line it with dried grasses, leaves, or moss. When she's satisfied with her cozy, insulated nest, the queen secretes wax from glands on her abdomen, and fashions it into small cups called  "honey pots." After visiting early-blooming flowers or trees, she regurgitates the collected nectar into the pots. In one pot she places the pollen she's combed off her fur using her feet. To this pot she adds her first eggs, usually eight or so. She seals the pot with wax and then presses her abdomen against it to brood her eggs like an old hen, and sip from the other honey pots when she needs more energy.

Larvae will hatch from the eggs, grow, and spin silk cocoons. When they emerge, these sterile females have work to do. The queen mum is already incubating more eggs, and these new workers need to find pollen and nectar for their sisters. At its largest, the colony may consist of two or three hundred sisters.

Bumblebees manufacture only enough honey to feed the family through the warmer months. They don't need to stockpile extra because, unlike honey bees, the entire colony will not live through the winter.

When summer wanes, the queen will start producing fertile offspring. Up until now, to each eggs she's laid, she added a sperm from a special sac. Now she withholds sperm from some of the eggs, and these hatch into male bees (drones), which have no stingers and do no work for the colony. They've got just one job to preform before they die: to leave the colony, find a virgin (or maybe not-so-virgin) queen and mate.
Meanwhile, the colony is feeding some larvae extra food for a longer period of time, and these develop into queens. At maturity the queens will go looking for drones, following the advertising pheromones the males leave on twigs and leaves.

A queen may mate with several males before heartily gorging herself on the last of the season's nectar. When it gets chilly, she'll tuck herself away for a long winter's nap. Come spring, she'll extricate herself from the duff and trundle off to being raising a whole big batch of daughters and a few sons.

Have you seen a bumblebee queen this spring?                                                                              


  1. Wow!  This is exactly what I wanted to know---and exactly what I think chased my chickadees out of their nest.  A bumblebee nest deep in the chickadee nest. Can that happen? 

  2. Yes!  I saw a bumblebee yesterday.  Go Queenie!  Are the worker bees big and fuzzy like the queen?  Does she get to flit about in the summer sun, or is she stuck down in her burrow, procreating incessantly?

  3. We have bumblbees out for about 3 weeks now. Very early spring and we escaped all the frosts so plenty of flowers for them. The bleeding hearts are up and already have flowers. Tree leaves seem to be the only things taking their time. Not enough rain, but it is staying cool so looks good so far. We are seeing a few brush fires, closest was about 20 miles.

  4. The queen is the biggest and fuzziest of all. The bumblebees we'll see later in the season will be a bit smaller. And yes, queenie will be busy procreating with no time for bumbling abroad.

  5. Yeah, as we sat in the rain, we PNWers were hearing that the rest of the country was experiencing a strangely warm/early spring.

  6. Wow is right! A bumblebee nest inside a chickadee nest?! Sounds possible to me. Chickadees are hole-nesters, and since they have little beaks, they tend to rely on abandoned holes created by woodpeckers or others (they'll also nest in birdhouses). I thought the queens looked for *abandoned* holes--wonder if she got there before the chickadees and was covered up, incubating her honeypots when the chickadees showed up... who knows... 

    So interesting--thanks!

  7. Oh! I just went over to your blog, and saw the photos. Yes, that  nestbox looks like prime nesting habitat for bumblebees! 
    Check it out, ya'll:

  8. I love your blogs, Pat.  Now I know a lot more about the bumblebee.  I haven't been outdoors too much of late but when I do, I'm going to keep an eye out for this attractive species.

  9. Boy, you are so filled with information.  I did nto know about the queen and the sitting on her "nest."  

  10.  I've posted some follow-up developments in the chickadee nest story.  And now that I've re-read your extremely pertinent post ( which still amazes me at its timeliness and that it so closely addressed my questions) I'm thinking you pegged it exactly– that the queen bee was likely already there, then the chickadees built their nest on top of the bumblebee's base—because of the way the nest fell apart in two distinct layers when I investigated.  So fascinating!

  11.  Oh, and once again, I took the liberty of linking your bumblebee post in my blog in case any of my readers want to know more.