wild bees and native bees

European woolcarders: bees that attack honey bees

Wool carder bee examining a lemon balm flower. © Rusty Burlew.

Honey bees beware: A male European woolcarder bee will aggressively guard specific flowers so females can forage in safety and he can mate.

Inside: European woolcarder bees are aggressive to any insect that invades its territory, and that includes bumble bees and honey bees.

Fast, noisy, hairy, black-and-yellow bees

Earlier this week, Lisa from Oregon wrote to say some extremely aggressive black and yellow bees were injuring the honey bees that came to her yard. She likes the honey bees and wanted to know what bees would attack them.

At first, I thought they were probably wasps or hornets of some sort, but then I had another idea: European woolcarder bees. Lisa mentioned the right modus operandi, the right physical description, and the right time of year. I told her my thoughts and said it would help to have a photo. Truthfully, I never expected to hear from her again, but in no time she sent a photo: a European woolcarder, indeed.

Recent arrivals from Europe

Many people in western North America are unfamiliar with woolcarders and it is no surprise. We accidentally introduced them to the east coast of the United States prior to 1963, and they first appeared on the west coast in 2007. The most recent distribution map I saw shows an “H” pattern across the continent. They spread up and down the two coasts and in a narrow band that runs across the middle of North America. Based on their adaptability, I expect they will soon be everywhere.

European woolcarder bees (Anthidium manicatum) are in the family Megachilidae, closely related to the mason bees and  leafcutters. The females are solitary, carry pollen in an abdominal scopa, and build their nests in cavities. She scrapes the leaves and stems of downy plants and carries the wool back to her nest to be used as lining, hence the common name “woolcarder.” The woolcarders are generalist pollinators that forage on a wide variety of plants.

The bees are striking in appearance with bold yellow stripes on either side of the abdomen—interrupted in the middle—and yellow on the legs and face. The males are much larger than the females and can be quite aggressive when they hunt for females or defend their territory. Early in the day, you can sometimes find males asleep in the flowers, covered with morning dew.

Not a significant threat to honey bees

Are woolcarder bees a threat to honey bee populations? Certainly not. Woolcarders do not seek bees to kill. The males simply stake out their territory and then defend it from intruders. No matter what enters his stake—a bumble bee, honey bee, carpenter bee, hover fly, butterfly—the male woolcarder chases it off. Usually he just slams into it. Rarely, he will do more damage by pulling off a wing or antenna or even spiking the intruder with spines at the end of his abdomen.

Although the woolcarder may occasionally take out a honey bee, so do spiders, some flies, hornets, praying mantids, yellowjackets, birds, and frogs. And certainly humans. It’s just another hazard in a dangerous world. In fact, because our honey bees and woolcarders are both of European origin, you can bet they’ve dealt with each other throughout history.

How to attract woolcarder bees to your garden

Personally, I love to watch the woolcarders. They are quick, agile, strikingly beautiful, and they can hover in the air. They dart and stop, dart and stop with a characteristic buzz. Unlike honey bees, the couples mate in the flowers, and although the bees are hard to photograph, if you are patient they will rest on a flower or leaf so you can get a quick shot.

If you want to attract woolcarders to your garden, one of the very best plants is lamb’s ear, Stachys byzantina. It has both woolly fibers and attractive nectar. They also like salvia, catmint, lemon balm, birdsfoot trefoil, lavender, and plants in the Scrophulariaceae family such as Verbascum (mullein).

As soon as I got Lisa’s message, I went looking for woolcarders and found them in the chicken yard circling a patch of lemon balm. Although I have lots of pollinator housing, I’ve never seen them use it. I’ve heard they prefer offbeat locations, ones we humans can never predict.

Honey Bee Suite

Wool carder bee.
Woolcarder bee. © Rusty Burlew.
Wool carder bee nectaring. © Rusty Burlew.
Woolcarder bee nectaring. © Rusty Burlew.

About Me

I backed my love of bee science with a bachelor’s degree in Agronomic Crops and a master’s in Environmental Studies. I write extensively about bees, including a current column in American Bee Journal and past columns in Two Million Blossoms and Bee Craft. I’ve endured multiple courses in melittology and made extensive identifications of North American bees for iNaturalist and other organizations. My master beekeeper certificate issued from U Montana. I’m also an English nerd. More here.

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  • They “…mate in the flowers.” How romantic is that???? Kind of sounds like “…making love in the dunes on the Cape…” I have some lemon balm and bee balm growing. I’m going to have to get a chair and sit and watch who visits (but I’ll look the other way if there’s any wool carder hanky-panky going on!).

  • That explains what this strange looking bee is hanging around my lambs ear. It did not look like a honey bee, kind of wide and flat compared to a honeybee but it really does dart about and stop in mid air. Really fun to watch. What kind of nests or housing does it like?

  • I got lucky this year and a female nested in my “bee chalet” in one of the larger cardboard tubes, and another chose a sprinkler attachment. That one I managed to record on video, which is posted to my Tumblr: http://backyardbeehive.tumblr.com/tagged/Anthidium-manicatum

    Strangely, the day after that nest was completed, all wool carder bee activity ceased on my Lamb’s Ear. Finally the honeybees were able to partake. Where no honeybees dared approach before, now there are dozens, and bumble bees galore as well. 🙂

  • A somewhat unique quality of these bees is the strong role the males play. Males are equipped with three sharp protrusions on their hind end which they effectively and rather brutally employ on intruders; male can attack and sometimes kill “intruders” into their established territory. These bees really are quite aggressive, and a bee advocate friend whose identity I shall protect has retrieved enough bumblebee corpses to now systematically trap out these carder bees. They are EXTREMELY fond of germander, and woe be to any other bee attempting to feed from it.

    A couple of years ago I trapped out a dominant male from a stand of germander and watched. Shortly after the first overseer was trapped, a new dominant male appeared. I trapped 6 males and only then did I not see a new patrolling male. Meanwhile the females placidly fed on the germander, nonplussed by the ever-changing patrol.

    I maybe able to find some close-up photos and if I do I will send them. His armor piecing posterior is quite impressive. BTW, our nickname for this bee is The Mean Bee.


    • Glen,

      I’ve got a good close-up of the business end spines in an old post.

      But I think we exaggerate the damage they do. I agree with Eric Mussen (UC Davis) that, they are not the terrorist some think. I have watched them for hours, striking at bumble bees, honey bees, leafcutters and have never seen them damage one. I’m sure they do now and again, but I think we blow it out of proportion. They are damn good pollinators; I like to leave it at that.

  • I live in SC and have an organic garden that I share with numerous bees, wasp, hornets, frogs, lizards and hundreds of other critters. I have seen this bee many times and never seen it kill another bee.
    My garden is coming to an end, as the heat and weeds are taking over because I spend more time observing insects than working.

  • I was camping at Timothy Lake in the Oregon Cascades and watched one of these large black bees attack a honey bee and cone crashing from the roof of my tent to the ground, where they continued to wrestle foe quite a while, it appeared the black bee was trying to tear off the honey bees wing.

    I figured the honey bee was toast, and being decidedly for the underdog, I decided to put the honey bee out of his misery as well as punish that darn black bee! LOL

    I had never seen a bee like that before, nor had I watched a MMA match between different bees before either!

  • The behavior described for the wool carder very much describes the behavior I witnessed with honey bees in my flowers in Denver, Colorado but the pictures do not match. The insect I saw exhibiting this behavior did not have any yellow but was tan, brown with maybe a little black.

    I do have a photo of an insect that is similar to what I saw that day but I am not certain it is the same insect. I found it in an hibiscus blossom while picking out Japanese beetles and threw it in soapy water so it is probably a little discolored from its original coloring.

    If this is of interest to you I can forward the photo.

  • I purchased a bee house that came with 70 leafcutter bees. Been waiting and finally some action a few weeks back. These tiny little creatures darting around, then out came this big arse thing that looked like a fat wasp. Now there are 3 of them on my catnip plant that is in flower, defending it and attacking anything that comes near it! I was told by the person I got these bees from that they are gentle and get along with other bees. I think I was lied to. I love watching these wool carders, but man they are aggressively defending that bush! One poor honey bee was writhing around on the ground. How long will this go on for?

    • Tracy,

      Well, if they are wool carders, and it sounds like they are, that’s just what they do. The males will continue to defend their territory as long as they are alive. The females will behave much differently, docile and not intimidating. So it’s not clear to me, but are you saying you had both wool carders and leafcutters in the same set of tubes?

  • Rusty,

    I just found this article and read it. I am reading all I can about these wool carder bees as we have a hoard of them ‘patrolling’ our garden. I say hoard because I started noticing about a month ago, many injured honey bees crawling on our cobbles sans at least one wing. I have probably noted about 20 in a month’s time that are missing at least one wing, and some that are missing part of an antenna. I love the honey bees and I know they are not doing well so I was naturally concerned about what it was that was attacking them.

    After observing the lamb’s ear plants where I was finding all of our poor wingless honey bees, I noticed a bee looking creature that has since been identified by a CSU expert after my sending them a photo. So my experience with these wool carder bees is that they are most certainly causing problems with the honey bees in our yard. Apparently, we have many of their favorite flowers as well so now I am in a quandary. How do we preserve the honey bees in our garden while these wool carder bees are attacking and essentially killing them? A wingless honey bee is a dead honey bee, no?


  • Why on earth would I want to attract one of the wood carders to my garden? They are simply intimidating, violent and annoying just like the blm protestors.

    • Cate,

      For heaven’s sake, they are bees. They do not have ulterior motives but merely act on instinct.

  • Well, I recently pulled out all of our lamb’s ear and it was a lot! The honey bees loved it but I was sick of seeing the poor things dying or dead on our walkway due to the wool carder bees. So I pulled it all out and planted other bee-friendly flowers. I haven’t seen a dead or wingless honey bee since. Wool carders have been evicted from our garden!

  • I’m not a fan of wool carders. I suspect — but admittedly didn’t observe — that they ripped up a wing of a Gulf fritillary that visited my front yard daily. I saw the butterfly in a semi-disabled state. Amazingly, it was able to fly well enough with a partial wing to leave my yard. But it never visited again, so I assume that it died. Fortunately, the Monarch butterflies — which were also attracted to the many nectar and pollen plants in my front yard — were large enough to fend off the wool carders just by fluttering their wings. The wool carders body-slammed and chased off other Gulf fritillaries but didn’t manage to disable them

    Wool carders are also called “head bonking” bees. Now I know why. This spring, I’ll plant whatever they’re particularly attracted to in the hope of distracting them from harassing my guest butterflies.

  • Thanks for this post!!! I live in Sonoma County CA and my yard is full of them as well as some larger carpenter bees. Unfortunately I’ve noticed a graveyard of honey bees around one of the wool carder bees favorite plants (a flowering lamb’s ear) and have watched them attack the honey bees shortly before the honey bees then fall to the ground, wander around for a bit, then eventually die. The poor honey bees don’t seem to stand a chance in my yard against all these other territorial pollinators. I’ll leave them alone for now but I am sad to have so many dead honey bees on my patio.

  • I have a male wool carder in my somewhat large salvia garden attacking every kind of bee. I planted the salvia for the bees, but now I feel bad because many of them are dying because of the male wool carder. For such an aggressive bee, it’s weird how it steers clear of me. The female wool carder doesn’t bother anyone. Should I stop planting salvia? I also have lavender.

    • Heather,

      I think the damage wool carders do to other bees is overstated. However, if you think this particular one is overly aggressive, why not kill it? Just swoop it up in a butterfly net.

      Changing your plantings probably won’t help much. Wool carders are generalist foragers that are fine with a wide variety of plants.

  • Last year, wool carder bees in my front garden repeatedly chased away gulf fritillaries who were trying to feed on my Mexican sunflowers (Tithonia). The wool carders constantly tried but failed to chase away monarchs. The monarchs fended off the wool carders with a few wing flaps but the slightly smaller fritillaries had to fly away. This season, I planted 7 Tithonia, which one or two monarchs visit every day. I don’t know if I have wool carders because I can only identify them by their behavior. I don’t see any bees chasing off the monarchs but I’ve only had ONE visit by a fritillary since spring. I don’t claim that the wool carders are the reason for the fritillary absence but isn’t chasing off competitors from food….damage?

    • Jane ,

      Competition for scarce resources is the rule of nature. All animals and plants compete for food, water, sunlight, housing, nutrients or whatever else they need. If it wasn’t wool carders, it would be something else.