Bees that attack honey bees

Earlier this week, Lisa from Oregon wrote to say that some really 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 would attack them.

At first I thought they were probably wasps or hornets of some sort, but then I had another idea: wool carder bees. It was 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 pic: a European wool carder, indeed.

Recent arrivals

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

The European wool carder (Anthidium manicatum) is 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. The female 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 “wool carder.” The wool carders 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 threat

Are wool carder bees a threat to honey bee populations? Certainly not. Wool carders do not seek out 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 wool carder chases it off. Usually he just slams into it. Rarely he will do more damage by pulling off a wing or antennae or even spiking the intruder with spines at the end of his abdomen.

Although the wool carder may occasionally take out a honey bee, so do spiders, some flies, hornets, praying mantids, and yellowjackets. It’s just another hazard in a dangerous world. In fact, since our honey bees and wool carders are both of European origin, you can bet they’ve dealt with each other in the past.

How to attract

Personally, I love to watch the wool carders. 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 wool carders 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 wool carders 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.

Rusty
HoneyBeeSuite

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

Comments

Mary Powers
Reply

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!).

Bonnie
Reply

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?

HB
Reply

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. :)

Glen Buschmann
Reply

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

Rusty
Reply

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.

Terry
Reply

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.

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