Tricolored Bumblebee

2010 April 10

I found this bumblebee on her back by the side of the road, waving her legs feebly in the air. So, I popped her into a collection bottle and brought her home. She’d probably had a near-miss from a car that roughed her up and stunned her a bit, but doesn’t seem to have done any permanent damage.

For scale, that thing she is standing on is the eyes from Mrs. Potato Head. She’s a big bee, around an inch long. The orange patch on the abdomen is pretty distinctive, and we see a lot of bees like her every year. There are a number of bumblebee species in the genus Bombus with that orange patch, particularly in the subgenus Pyrobombus. I think this one is the Tricolored Bumblebee, Bombus ternarius, mainly based on where she is: it looks like most of the other orange-rumped bumblebee species live exclusively further west and south, while BugGuide has reports of the Tricolored Bumblebee all through the Midwest and Canada.

One odd thing when I was taking the pictures is that, unlike most bugs I photograph, she flinched visibly every time the flash went off. She got progressively more agitated every time the flash triggered. After a time, she got so agitated that she took off and started flying around my head, finally landing on the floor[1]. Well, at least that proved that she hadn’t been badly injured when I caught her.

Looking at the size of her, and the small wings, it is easy to see how the old story about “physicists proving that a bumblebee can’t fly” got started[2]. Just looking at them, one’s first impression is, “that can’t actually fly, can it?” Of course, they obviously can fly, which just shows that the aerodynamics of a full-sized airplane with rigid wings is quite different than the aerodynamics of an insect with flexible wings being driven at an outrageous rate. Or, to put it another way, you can make anything fly if you put a powerful enough engine on it. Which is why bumblebees are so intimidating: this furry little ball of barely-pent energy, buzzing like crazy as it drags itself through the air, just gives an air of general annoyance with the world. I always get the impression that bumblebees are just this close to popping you one if you give them any guff.

That said, I’ve never been stung by a bumblebee, and they are evidently less inclined to sting than a lot of other bees, wasps, and ants. So, it might be all bluster. Or, it might be that the buzzing and the bumbling just makes me more aware of where they are at any given time, and so I subconsciously give them a bit wider berth.

I’d like to point out that her antennae have an elbow joint in the middle, which is pretty common among the females of bees, ants, and wasps. Interestingly, I understand that male bees, ants, and wasps generally don’t have an elbow joint in their antennae[3], so that’s one way to tell the males from the females.

Of course, at this time of year there is an even better, pretty much foolproof way to tell male bumblebees from female bumblebees: if it exists, it is a female. Specifically, if it exists, it is an overwintered female that is looking to establish a nest and become queen of a new colony. Until the overwintered queens hatch out and raise up some new bees, they are the only ones that are going to be around. So, that’s how I know for sure that this one is female.

Now that I’ve let her go, she’s gone off to look for a new nest site, probably a hole in the ground. They like pre-existing cavities like abandoned mouseholes, where the queen builds a wax nectar pot and a cell to lay her first eggs. When the eggs hatch, she feeds them pollen (for protein) and nectar from the nectar pot (for energy). Once the larvae mature, they become worker bees and take over the pollen collection, nectar collection, and nest construction duties, while the queen settles down to laying eggs. At its peak, the nest will have probably 50 or so workers, a number of nectar pots, and numerous larvae being raised. Bumblebees don’t exactly make honey, they don’t evaporate the nectar all the way down to the thick, long-shelf-life syrup that honeybees make. Instead, they just evaporate it down partially and only store it for a relatively brief period. It will probably keep in the nectar pots for a couple of weeks before it ferments seriously, which is enough to get the nest through dry periods in the summer where nothing is blooming.

They don’t need to save honey for winter, because the nest doesn’t last through the winter. When fall rolls around, the last batch of eggs is raised up to be males and fertile females. Once these reach adulthood, the organization of the nest pretty much falls apart while the fertile females go off, mate with the males, and look for a place to hibernate through the winter.

In some ways, bumblebees are better pollinators than honeybees. They are active at cooler temperatures, have longer tongues so that they can properly deal with plants like alfalfa and red clover, and can “buzz pollinate” things like tomato blossoms, which need vibration to knock the pollen loose. Their colonies are also small enough that they can actually be used inside greenhouses, and they are evidently mild-mannered enough that they don’t tend to sting the people working in said greenhouses. The fact that bumblebees evidently don’t have as much tendency as other insects to beat themselves to death against windows is also a big plus for use in a greenhouse.

[1] I was taking the pictures early in the morning, before everyone else was up. Probably just as well. I can imagine the excitement we would have had if a bumblebee was in the house buzzing two small children, one of whom might have been trying to catch it and put it in her mouth.

[2] Of course, the whole story about an aerodynamicist proving that bumblebees can’t fly is something of an exaggeration.

[3] Since writing that, I’ve been looking at pictures of male bees, ants, and wasps, and it looks like it is not so much that the males don’t have the antenna joint, as that they don’t hold their antennae with the joint flexed. They hold the antennae straight out, probably to improve their odds of scenting a female.

13 Responses
  1. Ellen permalink
    April 10, 2010

    Terrific photos! And a good piece – I’ve been “into” bees lately, mostly because I’ve been discovering all sorts in my flowering willow during the spate of summer weather we recently enjoyed. I’ve had some of my insects identified over at BugGuide, but had no idea how they could tell male from female – I presumed it had to do with size. Now that I know about those bent antennae, I’ll take another gander at my photos and see if it holds true on these species as well!

  2. Margaret B. permalink
    April 10, 2010

    Oh, I love bumbles. Petted them when I was young. Had to move the remnants of a nest that fell off of the bare insulation in the garage far more recently (we were gone for a week and a half and they built _then_). Didn’t expect they’d survive once moved, but knew they’d not if I didn’t.

  3. April 11, 2010

    A Piper Cub is loud, slow and clumsy, yet lots of people spend serious money to buy them and enjoy them. They realize in advance they’re not getting a P-51 Mustang, yet they’re perfectly happy to bumble around in the things. Maybe bumblebees are like that. Maybe they really don’t care that they’re slow and loud and clumsy (if they know it at all) and they just love the feeling of the wind in their faces and the sight of a field of delicious flowers beneath them.


  4. April 11, 2010

    A question for anyone:

    There’s another similar kind of bumblebee that’s a wood-borer. It’s one where (I think) the females bore out a small tube in any nearby chewable wood, and they lay eggs there. And I’m pretty sure we have those around our house, *and* I was led to believe that the wood-borers are pretty docile, despite their angry buzzing.

    1) Is the bumblebee on this page more aggressive than its wood-boring cousin?
    2) How can you tell them apart?


  5. April 11, 2010

    Very pretty critter!

  6. April 12, 2010

    Andy: The wood-boring bumblebees in Michigan are generally Eastern Carpenter Bees. They are actually solitary bees only distantly related to the colony-forming bumblebees, and have hairless abdomens rather than fuzzy abdomens. They tend to disturb people a lot because the males are territorial and will come to check out anything that moves. They will hover around nesting sites and buzz around people who approach. They are perfectly harmless, though, because like other bees and wasps, the males do not have stingers.

  7. April 12, 2010

    KT: I agree that the important thing isn’t how well one flies, but whether one can fly at all.

  8. April 15, 2010

    Hey – I saw this in the Guardian and thought of you:

    a Polish photographer by the name of Miroslaw Swietek taking bug pictures with the bugs all covered in dew.

  9. April 15, 2010

    Hello Tim,

    I am a student from University of Wisconsin-La Crosse. I am making a website for a biology project on ‘toe biter’. I saw interesting and beautiful pictures on

    Is it possible for me to use some of the pictures for my website project? The pictures will be linked to your website so that visitors are able to come to your website by clicking the pictures on my website.

    Thank you!

  10. April 16, 2010

    Edward: Thanks, those pictures are quite beautiful! And sneaking up on the insects at night while they are torpid certainly would be a solution to the whole running-around problem.

  11. April 16, 2010

    Ka Wai Hui: You have my permission to use the giant water bug photos, thank you for asking first.

  12. ashley permalink
    September 22, 2010

    I was attacked by one of these exact bees today. it flew in the car to my head so i opened the door to get out but was buckled. asd i tried to unbuckle i felt a terrible prick under my arm and swated away one of these. the pain was so great i screamed and jump out of the truck. my boyfriend soon killed it and got it out of the car but 6 hours later my arm is still swollen

  13. September 23, 2010

    Sorry to hear that. Normally these bees aren’t very aggressive, but if something had happened to rile it up (like the car being parked on top of its nest, or a near-miss by a passing vehicle), then that’s another story. It sounds like you’ve been stung a few times before, which is why your arm is swelling so much. I know it’s not much comfort, but if you get stung regularly, eventually you’ll get to the point where you can shrug off the immediate pain and there is no long-term swelling.

    Incidentally (and I know you didn’t ask this, but I think it’s important to know), the swelling (which is not dangerous) is completely distinct from anaphylactic shock (which can be life-threatening). They are different reactions, and just because you have the swelling doesn’t mean that you are in increased danger of anaphylactic shock.

    In general, I find that the best thing to do when a single stinging insect is flying around you is to move very slowly and deliberately, and resist the temptation to swat at it – that just makes them madder. If they land on you, hold still until they fly off again, and if they are specifically buzzing around your face, cover your eyes with your hands. They might sting you anyway, particularly if the reason they are buzzing around is that somebody just stumbled into their nest, but the odds go way down if you just avoid sudden movements.

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