Inside: Has this noisy, fast, and aggressive summertime guest chased after you? Male woolcarder bees are a bit over-the-top assertive, but the females are superb pollinators and fun to watch.
Table of contents
Female woolcarder bees collect fibers by “carding”—or scraping—them from a plant surface. She wads the fibers into a ball, tucks the ball under her body, and carries it back to her nest. Once home, she lines her nest with the fibers, making a nice cushy spot to raise her young.
Audacious, aggressive, and quick
These large and noisy bees in the genus Anthidium appear in early summer. You can often see the males jealously guarding a patch of flowers. The males aggressively fend off any interlopers by darting and chasing. If necessary, he will wrestle a competitor to the ground—even bees much larger than himself, such as bumble bees and honey bees.
The only bees allowed inside his territory—female woolcarder bees—can enter and forage in return for the chance to mate.
North America has more than one species
The native species in North America is Anthidium maculosum. The bees are small, measuring one-half to three-quarters of an inch long. They are black to brown with white or yellow patches on their abdomens. The female carries pollen on the underside of her abdomen in a patch of hairs called a scopa.
A similar species, Anthidium manicatum, came from northern Europe and has spread across the continent. The male of this species is even more aggressive and is reported to actually kill bees competing for his territory.
Woolcarder bees are summertime pollinators
You can expect to see woolcarder bees in early summer. They will readily use nesting blocks with holes drilled 7-10 mm in diameter. Favorite forage includes sage, mint, catnip, lavender, Russian sage, and hedgenettle (Stachys).
As a general rule, bees are difficult to identify down to the species level, but with a little practice, you can become quite competent at the genus level. The woolcarder bees are a good group to start with because both their behavior and their coloring are striking.
Rusty
Honey Bee Suite
About Me
My love of bee science is backed by a bachelor’s degree in Agronomic Crops and a master’s in Environmental Studies. I have written extensively about bees, including a current column in American Bee Journal and past columns in Two Million Blossoms and Bee Craft. In recent years, I’ve taken multiple courses in melittology and made extensive identifications of North American bees for iNaturalist. My master beekeeping certificate issued from U Montana. More here.
So I think I found my first wool carder bee. Kinda excited about it. Found it to be a very adorable little bee. She was so very busy working over the spearmint with the other honey bees.
I was standing there watching the activity in some kind of stupor of awe. Then I saw her! Her little legs packed to the brim with pollen and waddling around like some kind of Sumo wrestler. Having never seen her before I whipped out the smart phone to grab a quick picture of her. And of course she took to flight—buzzed me and left. It would be so much easier if they would sit still and say cheese before taking off.
I am wondering if they are located here in the Eugene area of Oregon? Before I take the time to put them on my native bee list and make provisions for them, I had better figure out I have the right bee first. It’s fun trying to figure out who’s who, but it is a lot harder than one would think.
Thanks
Monica,
Yes, native bees are super hard to identify. That said, I know that your bee is not a wool carder because wool carder bees do not carry pollen on their legs. Instead they carry pollen on the bottom of their abdomens in a patch of hair called a scopa. This is just like the masons and leafcarders and, in fact, they are all in the same family, the Megachilidae.
Wool carders do appear in your area and they do like spearmint, but this is something else. When you say “Sumo wrestler” I immediately think of the Melissodes bees. They are also active this time of year and they have huge pollen scopae on their rear legs. Your image is perfect. They are also known as long-horn bees, but it is the males that have really long antennae.
Of course I can’t identify your bee with that description alone, but look up Melissodes on the web for pictures. I have some to post, but haven’t done it yet . . . will do it soon, I hope.
Yesterday I had my first sighting of the wool carder bee. Three of them at least, enjoying the rosemary which is in full flower. I understand it is the European carder bee. I live on Waiheke Is. just off the coast of Auckland N.Z.
Do they produce honey? Are they a threat to our current honey bee? Will they take on a wasp?
Sandy,
Wool carder bees do not produce honey. They live singly, one female to a small nest that houses a few eggs, so they are in no way a threat to honey bees which live together in the thousands. They may butt into a wasp to get it to leave their foraging area, but I doubt they would harm it.
Yesterday I was working in my pottery studio and noticed a little bee coming in and out of the studio. She was carrying little balls of fluff and cramming them into a hole in the hollow leg of my Potter’s wheel. She’s so cute! I don’t mind her making her nest there, but I’m wondering how long it will take for the eggs to hatch and leave. I don’t want to leave the studio door open forever!
Laurel,
It sounds like a wool carder bee. Most bee eggs overwinter and hatch roughly ten months later, so don’t leave the door open.
Hi Rusty,
My 7 year old son has picked up what looks like a carder bee nest. Does this bee sting? He has a very sore hand but didn’t see what bit him. I can’t see a stinger? Thanks Lucia
Lucia,
1. Wool carder bees nest in things like hollow reeds and stems. The holes are about 3/8-inch in diameter.
2. Like most bees, the females can sting. The males cannot.
3. A sting comes from the back end, a bite comes from the front end. Many types of bees can do both.
4. The vast majority of bees don’t leave behind a stinger. Only honey bees do that.
Thanks Rusty 🙂
Saw what I believe is a wool carder bee on my bachelor buttons, taking fuzz off of the stem and leaves. It was so fascinating to watch! On the second day I was able to get a couple photos, they arn’t great but show the ball of fuzz she was carrying underneath. I can e-mail them to you if you want. So thrilled to watch this wonderful native (?) bee. Saw one again just this last week. I house mason bees and have been pretty successful, not much luck with leafcutter though. Just trying to make my whole yard bee friendly!
Jennifer,
I have been trying for years to photograph a wool carder carding wool, but I have never succeeded. I have photos of them mating (!) but not carding. Please, I would love to see your photos!
Um, not very techy so not sure how to get it to you, can send in an email if you can let me know the address.
I am new to beekeeping but found the wool carder bee here in Northern California. I would like to argue that this bee IS an impact to local honey bees, at least here. I have watched one male cripple at least a dozen honey bees in a 10 minute period defending a nectar source. I know a dozen bees is nothing in the grand scheme but man I hate my girls getting taken out right in front of my eyes. 🙁
Doug,
I still think the impact is paltry compared to the take by birds, robber flies, yellowjackets, hornets, beewolves, etc. Sometimes we don’t notice these others, but they are out there doing their thing. There’s a reason a queen can 2000 eggs in a day.
I am near Lake Simcoe in Ontario and have noticed these bees around my flower garden. They chase away the larger bees, which i think are males, and let the smaller bees go to the plant and then do what bees do. LOL. I put cardboard tubes out this spring to attract mason or leafcutter bees to nest but i haven’t seen any of those bees and these wool carders don’t seem to be using the tubes either. I will keep trying.
Thanks Jim
Jim,
So far, I can’t get them to nest in tubes either. I keep trying.
I am pretty sure I found a wool carder bee after looking up all the bees that it could be. When I read about them they mentioned lamb’s ear flower, and this little guy was only on my lamb’s ear which I have a ton of. So cool finding out about all these bees I have in my yard. So far I’ve found a honey bee, a drone fly, an Agapostemon sp. bee and now the wool carder bee. Love me some bees, almost all my flowers are for them, butterflies, hummers and all other kinds of different flyers and some nasty ones of course. Do they really make wool, it wouldn’t surprise me as the lamb’s ear is so soft and fluffy. I also noticed that the bee hovered and was very quick to go in and out. I was able to take a couple of pics but it was very hard as it never stayed still for long. I am on the Northshore Montreal Quebec.
Karen,
Yes, it certainly sounds like a wool carder. The females scrape the fibers from the lamb’s ear leaves and use it to line their nests. Nice and cushy. The behavior you describe, hovering and quickly sipping from flowers, is male behavior. They are staking out their territory and keeping it safe for the females. Once the females arrive, you can often see them mating in the flowers as well.
Thanks Rusty,
I went out a couple more times and took some more photos, it is very difficult with a cell phone and how fast they move. I was able to get one exposing her underside so that you could see the cotton ball just below her neck. I also witnessed the way they peck on the flower with their mouths almost in a chomping way. At one point about 4 flew in and a bumblebee was having a snack on same flower and one of them attacked it and it flew off, so the territorial thing rings true. Now I know that the females grab the fluff and the males go in the flowers. I did have to be careful somewhat because they would fly around me and I must say I was a tad uncomfortable! They also went on the flower beside the Lamb’s Ear which is a tad fuzzy as well (sorry can’t remember names of the flowers). I have to say I am so excited being on these insects and bee boards because I am learning so much and I’m paying a lot more attention with the critters in my garden 🙂 My bee balm is exploding now so all the bumbles will be coming to my house lol. Now to get my Nikon body replaced so I can zoom and macro these little guys 🙂
Karen,
The females will go to the flowers, too, for collecting pollen and nectar. They collect the pollen under their abdomen, and like the males, they drink the nectar for energy. Although the males will butt into you to try to scare you away, male bees have no stingers. I’ve had them crash right into my camera to get me to go.
If you get a decent photo, please sent it along in an email (rusty@honeybeesuite.com). I’ve never gotten one of the cotton ball, although I keep trying.
Just had a customer bring a carder bee “Wool Clump” in to the shop, with a little observation I found some cocoons inside. This bit of “wool” was not inside a tube but stashed behind her mason bee block in a flat clump. Wondering if these are about to hatch or just formed for next years batch? we are at 3600 ft elevation and our leafcutters hatched 2 weeks ago. Do you know the time frame for these bees? Seems that having a cocoon as of now they would be early spring pollinators (just forming cocoon) or a later summer variety (soon to hatch)? I just opened a cocoon to see the development stage and appears to still be quite early (large white grub like pupae)….. SPRING hatch time? Does this sound like a native carder or of European sorts? Please help. Cheers!
Kendra,
As far as I know, wool carders only have one reproductive cycle per year. The larvae you found will turn into a pupae and spend the winter in the nest. Wool carders seldom use the tubes, instead they find long, often flat, cavities to fill up with wool and eggs. European wool carders are coming out right now. I can tell when mine emerge because it coincides with lemonbalm bloom here in western Washington. In the warmer, deserty areas they came out several weeks ago. I might be able to tell species with a photo, and maybe not, but it sounds like the European variety.
After months of research, I have just found your site and am hopeful. I live in Flagstaff, Arizona, at 7,000 ft. I have old gambel oak trees all around my back patio. I am very allergic to the most common (7) species of bees, wasps, etc. For the second summer in a row, I’m trying my very, very best to co-exist and appreciate the huge amount of bees, that up until now, have lived up high in my trees. Last summer they didn’t come down low to where we were sitting, so I kept an epi-pen by me, never had food or drink outside, and enjoyed the beautiful view. This summer I’ve researched and thought I had leaf cutter bees. They seemed small and not easily seen, buzzing around up high. The trees literally buzz with all the activity. Now things seem to be changing. The “bees” are coming down to the ground level occasionally, and more frequently, they are falling out of the tree. A couple of times two would fall out that looked like they were possibly mating. Once, when I was in the hot tub, two fell out that looked like they were mating, hit my shoulder, fell into the water, and died right away (instead of floating around and then dyeing). I took pictures of this “new bee” and it doesn’t really look like what I thought I saw up high. It looks a little more like the colors of a hornet. I tried to read if an enemy of the leaf cutter can move in and take over their territory, but haven’t had luck. Right now I’m only using the porch and hot tub at night (to be safer). Nothing seems to be flying around or falling out at night. Before I call a bee keeper or exterminator, I thought I’d see if you have any opinions based on my long story. Thank you! Melissa
Melissa means “bee” in Greek; so sad you are allergic to them. I have no idea what the 7 most common types of bee and wasp would be, except the honey bee. There are 4000 species of bee in North American and maybe three times as many wasps, so I think it would hard to say.
Bees in trees are just looking for pollen and nectar. Wasps are more likely to snoop around your food, although both may be interested in the hot tub water. With a few exceptions, neither bees or wasps are active at night. Once the tree stops blooming, the bees will move on to something else unless they have a nest up there. If they are mating and falling out of the tree, they are probably solitary bees of some sort and unlikely to be aggressive toward you.
Hi guys,
I have what I believe to be a wool bee nest in my roof. Living in Spain, and noticed this single bee filling the roof cavities with a cotton wool type substance. She has two full and is now filling a third one.
My question is should I be concerned? Will my apartment be swarming with bees of I don’t remove these, or will only one or two pop out and fly away?
I love bees and so want to leave them undisturbed, unless it will take over the apartment. Would appreciate any advice
David,
They are solitary bees. Don’t worry about large numbers.
I think I’ve come across my first wool carder bee. My sister saw it fly into my mason bee release box on the table on my porch. I opened it to find a huge clump of cotton with little dig outs. I do have a picture and the fb bee group on it said it look like a wool carder. I’m interested in larvae cycles. Should or can I store the box like I do mason bees but not harvest them, just store them somewhere safe over winter. I won’t move the little box until she plugs the hole or instructed otherwise. Any more info would be a great help. I’m in Colorado. I’ll gladly send the picture.
Colleen,
That sounds so interesting. For years I’ve been looking for their nests and I’ve never seen one. I have lots of the bees, though. You can send a photo attached to an email. Send to rusty@honeybeesuite.com.
I think you could just store the entire box, although harvesting the cocoons might work. I have no experience with this.
I put up a bee house filled with cardboard tubes on my 6th floor, south-facing balcony in Minnesota last fall. About two months ago, in June, I noticed one of the tubes filled and sealed off with tiny white hairs. Based on that, I looked at some pictures of female wool carder bees, and I think I saw several of them on my balcony plantings. I was so thrilled to have bee-babies that I’ve looked at it daily, even though I wasn’t really expecting anything to hatch until next spring. Today, the outermost cell has a hole in it, about half the size of the cell. I really thought there would be no predators on my protected balcony, and there are bits of the cell wall lying in front of it, as if something hatched OUT, rather than broke IN. Is it possible that a bee hatched in only 2 months? Or has my little nursery already failed? If it was a predator, are all the babies dead? Or only the outermost one?
Pat,
There are so many possibilities it’s hard to say. But it does sound like a predator, perhaps a small parasitic wasp hatched out of the tube. Many of those have two generations per year, so it’s possible. Also many of them look like fruit flies, so it’s hard to see them. However, I would say all is not lost. You will probably have some bees in spring. It’s just nature doing her thing.
Recently I purchased a bee house with 70 bees in it. They are supposed to be gentle leafcutter bees. I have seen the leafcutters flying around with leaves under them. But after a few days, I have what i think are wool carder bees hatching out! The male has taken over a catnip bush and is body slamming any other bees. I had a female hatch out today so i guess they might mate soon? They are cute little bees. Managed to get a good picture of it as well. My question is – they all seem to be going back into the ‘hive’ where they were born for some reason. Will the bossy carder bees hurt the gentle leafcutters if they are inside together?
Tracy,
It would not be unusual to have different bee species in different tubes, but it would be unusual to have more than one species in one tube.
Only the females go back to the tubes and the female wool carders are not aggressive like the males. The males will stay out there in their favorite plants to guard them, and they will sleep out there at night.
The females do often reuse the tubes they emerged from for the next generation of bees. But the species will not fight inside the tubes, fighting will only happen out in the forage where the males are.
Hello, I live in the northeastern US. I have a wreath on my front door that a bird started making a nest in and abandoned it. A large bee moved in and filled it with fibers in about a 3-inch ball. It seems to look like a bumble bee, not quite like the pictures I looked up of a carder bee. Is there another species that would make a nest like this?
Thank you, Sharon
Sharon,
If you send a picture of the bee, I will take a look. Send to rusty@honeybeesuite.com.
Good morning! We live in the northern panhandle of Idaho and last summer I noticed small bees swarming our front windows. They appeared to be stuffing the sides with cotton. I finally got them identified and left them alone since they don’t sting and seem to have run off our wasps. However, by the end of the summer, they had started crawling in through the window frames. I have resealed everything this spring, and they just ate right through it. Just our sunny side, but I don’t want to lose insulation or have it spread further. Any suggestions? I like them. I just don’t want them in our walls. Thank you!
Joan,
I don’t know. Perhaps you could provide them with some similar housing that they could use?
Please how do I either move them on or kill them?
Kel,
Why? What are they doing to bother you?