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Leafcutting bees in action

Leafcutting bees are everywhere. Dozens of them nest in my backyard, and I’ve seen alfalfa fields served by massive leafcutting domiciles containing millions of these little bees. I’ve photographed them drinking nectar, collecting pollen, carrying leaves, and building nests, but I have never—ever—seen one cutting leaves.

But a few days ago, I happened across this YouTube video of a leafcutting bee doing what she’s known for. The video is about four minutes long, but the first minute is the best.

I was amazed at how fast these little bees cut out what they need. The circles have smooth and clean edges, but it’s the speed that fascinates me. The other odd thing is that they sit on the piece they’re cutting out. You would think they would drop to the ground as the disk breaks loose, but no. They have everything well under control.

The photo beneath the video is one I took at home. The leafcutting bees here prefer to nest in the hollow spots between the mason bee tubes, even though tubes of the proper size and shape await just a few inches away. They usually use leaves to line their nest, but some prefer petals.

After watching the video, I’m tempted to plant a Thunbergia (black-eyed susan vine) just to see if the leafcutters will slice away. I’m not sure how picky they are about the things they use. In the alfalfa fields, even though I don’t see them cutting, the domiciles smell thickly of alfalfa, an odor that reminds me of barns and silage and horses . . . heavenly.

I hear leafcutting bees love roses, but I’m not into roses because of all the deer we have here. So tell me, what do leafcutting bees cut in your area. Any suggestions?

Rusty
HoneyBeeSuite

Leafcutter-with-petal
The leafcutting bees at my place like the empty spaces between mason bee tubes for their nests. This bee has a piece of yellow petal, but I don’t know what it came from. © Rusty Burlew.
Leafcutting-domicile-2
A domicile like this contains tens of thousands of leafcutting bee holes. The domiciles are placed at regular intervals throughout the fields. © Rusty Burlew.

Comments

Cindy
Reply

Terrific. I have seen these bees around but didn’t know what type they were. And while I haven’t seen them leaf cutting I have certainly seen the evidence of their labors. I blamed it on the slugs – with whom I am not happy to share – now I will have to rethink my assumption. These bees are welcome to all they would like.

HB
Reply

They go nuts for the late lilacs (Syringa villosa) in my yard. Second choice is wisteria.

Bry
Reply

I’ve seen one cut a circle out once only but it was truly a privilege to see! I held my breath hoping it wouldn’t get spooked with me standing two feet away.

Didn’t know they nest in mason bee houses. Will get some.

Here on Vancouver Island, I have only seen them on our Saskatoon berry bushes, which they almost defoliate without ever doing damage to the plants.

Glen B
Reply

Leafcutter bees generally prefer smaller (1/4″ diameter, some even smaller) holes than the holes most commonly marketed / used by spring mason bees (5/16″ to 3/8″). If you have lots of spring mason bees around, wait until mid / late May before setting out the nest holes for the leafcutters so that the holes don’t get all mudded in by the masons. (This advice is for western USA.)

Rusty
Reply

Bry,

Glen is correct. The commercial guys use 1/4-inch holes for the alfalfa leafcutting bees, but there are many different species in the wild. When I’m drilling holes, I use both 1/4-inch and 3/16-inch bits for leafcutters, or else I look for bamboo tubes with appropriately-sized holes. Even so, bees have minds of their own, so they may elect to do something totally different, like mine did by moving in between the tubes.

Sonja
Reply

I live east of Denver in the high prairie. I’ve seen the holes cut out of the Evening Primrose flowers in our field. I didn’t know what it was either until one day I was lucky enough to witness a leafcutter bee in action. I thought it was going to fall off the edge too! Very cool to watch. Thanks for posting this!

Bry
Reply

Yet another comment sorry… I have almost thirty different cultivated rose varieties and have never seen these bees be interested in them. The wild roses (rosa nutkana) here do have the odd leaf cut but as the leaves are really pungent I don’t think the leafcutters favor them.

Tom
Reply

They like lilacs, roses, peonies primarily in my yard.

Glen B
Reply

Lilac, roses, and Hypericum formosa(?) I’ll email you a photo of the Hypericum.

Glen Buschmann
Reply

The Hypericum is H. forrestii, not H. formosa. Similar to H. hidcote, a 3′ tall shrub that is not invasive, attractive 3 seasons a year. Definitely different from invasive groundcover H calyxcinium and weedy invasive medicinal H. perforatum. Don’t know if it has any medicinal properties nor what sort of nectar and or pollen value it has but it does look nice and the leafcutters do seem to like harvesting it.

Glen

Rusty
Reply

Thanks Glen . . . and the photo tells the whole (hole?) story.

Samantha
Reply

They love my neighbor’s baby Redbud trees!

I alsonsaw an article recently where they found pieces of plastic bags (that must have blown into their areas…) to make pieces to line their nests. That made me sooooo sad 🙁 To think that littered plastic bags are becoming that prevalent, and that plastic promotes moisture/mold, which isn’t good for bees.

This is a wonderful post, thanks for sharing.

dan smith
Reply

Love reading your blog Rusty …. I’m in So CA and we have a lot of eucaliptus trees out here, mostly “blue gum” variety i believe, and many fallen leaves have semi-circular, picture-perfect cut outs along their edges, typical of what i’ve seen in this post, but its such a tough, hard leaf i wonder if its due to leafcutters or to something else, anyone have thoughts on this ? Do leaf cutters like eucaliptus leaves ??

Rusty
Reply

Dan,

I don’t know about eucaliptus leaves. Does anyone else know if leafcutters will cut eucaliptus?

lydia
Reply

I have been observing, for the last couple of years, leafcutter bees building their nests in an area where the earth is dry and I do not mulch. They dig tunnels in the earth and fly back and forth with the leaves they cut from some tender leaves close by.

Today I was emptying two pots that had dried out soil and, unfortunately, I found I had disturbed several “nests”. The bees were buzzing around the empty pots. It was as if they were looking for their half-finished nests. One of the green leaved tubes had been closed. I wondered if I could somehow “save” this. I punched a hole in one of my pots that had the dried soil and gently put the “tube” inside that hole and covered it loosely with soil. I will never again empty pots at this time of year. But when do they hatch in the spring?

I found it interesting that although I had moved the pots to a different location, the bees found the empty pots. I could almost hear them say “what happened!”. So now I will leave a few pots untouched so they can lay their eggs in them.

Rusty
Reply

Lydia,

Lots of people tell me they don’t have room in their gardens to leave space for ground-nesting bees. I always tell them to put flower pots filled with soil wherever they find a small space. And it works! What it is about flower pots, I will never know.

Most of these ground bees spend about ten months in their nests and two months actively building the next nest. That gives you a rough idea when they will emerge. It is different for every species, but you can estimate from when you last saw them.

Scott D.
Reply

I hope this isn’t a dead thread. I have a question for any bee afficianados. I’ve got a couple leaf cutter bees building a nest in the frame of my sliding screen door. I’m pretty sure having bees in my back door is going to cause problems at some point, especially with my kids coming and going so much. But I don’t want to kill them.

Anybody have any suggestions for moving them?

Thanks!

Rusty
Reply

Scott,

The leafcutters will not bother your kids. They are totally uninterested in them and probably couldn’t sting them even if they wanted to. I have mason bees in the frame of my sliding door as well, so I know what you are talking about, although I am elated to have them there. The eggs they are laying now will hatch next spring. You can take a knife or other tool and scrape the nests away. Of course, that kills the next generation but it gets them out of the door frame. Tape up the groove and then the current bees will have to find another place to nest.

Mommalala
Reply

I am having the same problem. I am assuming they are leafcutter bees after researching. Smaller than a house fly, white and black striped abdomen, and they want nothing to do with me. They completely ignore me. But I am concerned about them nesting in my door frame. I can’t access the nest because it is an enclosed frame with screw holes they are entering in and I’m not sure what to do. I feel eventually it will cause a problem and maybe get into the house?

Rusty
Reply

Mommalala,

They like door frames. I have them nesting in mine, too, year after year. So far, they haven’t gotten inside. I think they don’t want to go inside and will avoid it. It’s not their kind of place.

Jessica
Reply

I have recently found a leaf cutter bee making a home right next to my door. I would like to move the towel she is nesting in but am afraid she wont be able to find it again. Could I move her at night and does she sleep in there?

Rusty
Reply

Jessica,

Moving it at night is probably your best bet, although I don’t know how well it will work. Yes, she most probably will sleep there.

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