Leafcutter bees are small to medium-sized, fuzzy insects that play a crucial role in our natural ecosystem. They provide essential pollination services to numerous plants, setting them apart from other bee species.
Unlike honey bees, leafcutter bees lead a solitary existence and do not form colonies. Each nest is created solely by an individual female bee. These remarkable creatures have a unique life cycle, wherein they overwinter as larvae within cells made by the parent bee and have one generation per year. Their nesting habits are also quite interesting, as they typically choose soft, rotted wood or large, pithy plants like roses to establish their homes.
Leaf Cutter Bees Life Cycle Overview
Life Cycle Stages
Leaf cutter bees go through four distinct stages in their life cycle:
- Egg: Female leaf cutter bees lay their eggs on a bed of pollen and nectar inside leaf-lined nest cells.
- Larva: The larvae hatch from the eggs and feed on the pollen-nectar mixture provided by the mother bee.
- Cocoon: After consuming enough food, the larva spins a cocoon within the nest cell to develop into an adult.
- Adult: The fully developed adult bee emerges from the cocoon, ready to mate and begin the cycle again.
The life cycle of leaf cutter bees is typically one generation per year, with the bees becoming active in late June and July. They overwinter as larvae within the cells created by the parent bee, emerging as adults ready to mate the following season1.
For example, nests typically consist of less than 12 cells, and can be found in the soil, in wood, or in hollow plant stems2. Leaf cutter bees are known to cut circular pieces from leaves of plants such as Eastern redbud, rose, and azalea, using these pieces as a lining for their nests3.
Table: Leaf Cutter Bees Lifecycle Comparison
|Egg||Short||Female bee lays eggs|
|Larva||Variable||Larvae consume pollen/nectar|
|Cocoon||3 weeks||Develop into adult bees|
|Adult||Variable||Emerging, mating, nest building|
- Pros: Leaf cutter bees are important pollinators and contribute to a healthy ecosystem.
- Cons: They can cause minor cosmetic damage to plants from cutting leaves for nest cells.
Mating and Reproduction
Leafcutter bees are solitary insects, and their mating behavior reflects this. Males actively search for females, trying to mate with them in flight. Once a successful mating occurs, the male moves on to seek other partners.
Egg Laying and Nesting
After mating, female leafcutter bees lay their eggs in individual nests. They create these nests in soft, rotted wood or the stems of large, pithy plants, such as roses 1. The bees cut leaf fragments to form nest cells, providing a safe environment for their offspring.
- Nests typically have less than 12 cells.
- Females lay one egg per cell and provide it with pollen and nectar.
- The offspring (egg, larva, and pupa) develop in these cells.
Female and Male Roles
|Female Bees||Male Bees|
|Construct nests||Focus on finding mates|
|Lay eggs||Do not participate in nest building or offspring care|
|Collect pollen and nectar for offspring||Shorter lifespan than females|
Both female and male leafcutter bees have specific roles in the reproduction process. Females are responsible for constructing the nest, laying eggs, and provisioning them with food. Males, on the other hand, primarily focus on finding mates. They do not participate in nest building or taking care of the offspring and generally have a shorter lifespan than their female counterparts.
Over the years, our website, whatsthatbug.com has received hundreds of letters and some interesting images asking us about these insects. Scroll down to have a look at some of them.
Letter 1 – Leafcutter Bee Nest Relocation
leaf cutter tragedy
Location: western Washington
August 15, 2011 8:33 pm
This year I planted hanging buckets of tomatoes and peppers. One of the planter types turned out to be disasterous as they failed one, after the other. The last one, with pepper plants well along, exposed one dead bee and around ten little cigar tips. I recovered the plant, then scooped up the (mostly peat) filling and cases into a ceramic planter. Is there anything I can do to encouage the larva to continue?
We are sorry to hear about both the loss of your produce garden and the resulting tragedy of the Leafcutter Bee nest. You have probably done all that you can do. We would suggest keeping the peat and the nest in a sheltered location and ensuring that it does not dry out and desiccate the nest. As long as the individual cells were not damaged, there is a chance the bee larvae might survive. Even if your well intentioned intervention fails, we are awarding you a Bug Humanitarian Award for your valiant efforts.
Before I accept this award, I’d like to thank all the little bees……
For providing me with beautiful flowers, tasty fruits, a myriad of grains, and hours of enjoyment in my garden.
We love short and sweet acceptance speeches.
gardening blog update: August 18, 2011
In our opinion, peppers and tomatoes should not be planted in hanging baskets except for ornamental purposes. Do not expect the kind of harvest you will get out of tomatoes planted in the ground in a favorable location.
Update: August 29, 2011
You said (re:Leaf cutter Tragedy)
gardening blog update: August 18, 2011
“In our opinion, peppers and tomatoes should not be planted in hanging baskets except for ornamental purposes. Do not expect the kind of harvest you will get out of tomatoes planted in the ground in a favorable location.”
Normally I would agree with you. Living on the Western side of Northern Washington, it is often tricky, to get tomatoes to ripen. This year was especially hard because unlike the rest of the country, we were very cool well into the middle of July. So I’ve been pretty pleased that I am getting ripe tomatoes and, in fact, I’ve gotten two peppers off the plant that tried to suicide with the leaf cutters nest. I stuffed it into an other (fabric) hanging pot and it has recovered better than I expected. There are other pepper varieties in that planter, and while they have done fairly well vegitatively, I suspect I won’t get any peppers off them. But, hope springs eternal, and if we get decent weather through October, there could be some.
The hanging planters have enabled me to place multiple plants in a small corner of the yard which achieves maximum sun exposure. I’ve been religious about watering them solidly every day.
Thanks for the update Kim. Watering a hanging basket would be an important factor in getting a yield out of plants. We did not mean to imply that vegetables should not be grown in hanging baskets, just that planting in the ground will most likely give larger plants and a better harvest. Did you get positive results with the Leafcutter Bee nest relocation?
Update: August 31, 2011
All I can say regarding the nest is that some of the tubes are still intact. I sort of assumed that they may not hatch (fledge? emerge?) until next spring, or at all. The peat was disturbed right after I picked them up by the squirrels in the yard, and a couple of the tubes were ripped open but I’ve now inverted the bowl and propped it to provide both cover and ventilation… It is in a brick planter, under an evergreen. So, it’s not being dried out, and it doesn’t get enough direct light to bake… But I haven’t disturbed it since to inspect the tubes. Maybe this weekend I’ll work up the courage to look and see if I can identify any changes….
Thanks for the update. Let us know if there is any activity next spring.
Update: September 9, 2011
I said I would look, so I did. What I found was… not much. It appears that most of the wonderful cigar tips were just gone, although I did see an occasional hint of a tube or the lacy leftovers of one of the cut pieces. I also found the little beads you see in the picture. Again, not knowing enough about the life cycle, I’m not sure at what I am looking.
I know in some of the the original tubes which were destroyed, there was a definite layering effect visible which I took to be piled up pollen with an egg or larva on top. I should have attempted a picture of that. These don’t seem to be the same, is it a pupa?
If so, I would surmise at least some of the original group are already out there pollinating again.
We are not certain what your new photo depicts, but we will post the photo and try to do some research. This might not even be related to the Bees.
Letter 2 – Leafcutter Bee Stings Child in Canada
Subject: Wasp like bug that stung my daughter
Location: Winnipeg, Manitoba, Canada
September 7, 2014 6:02 pm
Hi there! Tonight I went for a walk with my kids and my daughter put her hand on a chain and was stung by this little guy. We are in Winnipeg, Manitoba, Canada. any idea what this bug is?
This is a solitary bee in the family Megachilidae, commonly called Mason Bees or Leafcutter (or Leafcutting) Bees. According to BugGuide: “Most are leaf-cutters, nesting in ground, in cavities, wood. Tunnels are bored in wood or in the ground. Cell is provisioned with pollen (and nectar?), an egg laid, and cell is sealed over with circular pieces of leaves that fit tightly into cavity.” According to Featured Creatures: “Most leafcutting bees are moderately-sized (around the size of a honey bee, ranging from 5 mm to 24 mm), stout-bodied, black bees. The females, except the parasitic Coelioxys, carry pollen on hairs on the underside of the abdomen rather than on the hind legs like other bees. When a bee is carrying pollen, the underside of the abdomen appears light yellow to deep gold in color.” WE are sorry to hear about your daughter’s sting, as this is not typical of encounters with Leafcutter Bees.
Thank you so much for the info! I am sure it just felt threatened as it would have been squished if my daughter grabbed the chain any harder. Thanks again!!
Letter 3 – Male Leafcutter Bee
i found this is looks like a boxing bee
it was pretty sweet. but weirrrrrrrrrrrd. it has spider legs, a bee body, an ants mouth (opens sideways) and claws in the front it used to try to shoo me away. i live in denver, and i found it in my yard. thanks!!!
We are requesting Eric Eaton’s assistance with your unusual Bee.
Hi, Daniel: Sure, the bee is a male leafcutter bee in the genus Megachile. Some species have the front legs modified with feathery hairs like this, though I have no idea why. Something having to do with courtship and mating, no doubt.
Letter 4 – Mining Bee
Andrena mining bee
Mon, Jun 8, 2009 at 10:41 PM
Hi bugman – long time reader, first time writer. I’ve recently become quite enamored with the (what I believe to be) andrena mining bees that live in my garden. I’ve accidently dug up their burrows a few times doing spring gardening, and I’m sad to say that not all of them survived. They were always very groggy, but some of them were able to dig back down into the loose dirt when they were disturbed. This year I’ve spotted at least two burrows and have put reminders around them so I know not to dig there. Anyway, I was digging around your site, and didn’t find any close-ups of these utterly charming bees, and thought I would send along a nice one that I shot last week. Bugguide advises that identification to species level is best left to professionals – I’m happy just calling them my cute mining bees.
Thank you for your very kind letter. We are happy that you have finally written after being a longtime fan. Because of the extreme furriness and because of an image posted to BugGuide, we are more inclined to think your bee is a Leaf Cutting Bee in the genus Megachile, possibly the subgenus Xanthosarus, and quite possibly Megachile perihirta which if found on the west coast. BugGuide has this to say about the family Megachilidae: “Most are leaf-cutters, nesting in ground, in cavities, wood. Tunnels are bored in wood or in the ground. Cell is provisioned with pollen (and nectar?), an egg laid, and cell is sealed over with circular pieces of leaves that fit tightly into cavity.” Eric Eaton has indicated that he has settled in and is ready to assist us again. We will contact him to see if our ID is correct.
Correction from Eric Eaton: Mining Bee
In this case the submitter is right. Remember that leafcutter bees collect pollen in a brush on the underside of the abdomen. This female bee, likely an Andrena species, clearly has pollen collected on her hind legs.
Sun, Jun 14, 2009 at 12:10 PM
Thanks Daniel – and Eric by way of Daniel. I’ve had Eric Eaton’s help a few times on IDs on BugGuide. Being from Portland originally, he has a lot of familiarity with my backyard bugs. It’s an honor and a privilege to have one of my letters on your site!
Letter 5 – Male Leafcutter Bee from Canada
Subject: Bee with Huge Mandibles
Location: Courtice, ontario CANADA
August 12, 2015 7:54 am
Found another type of Bee. This one I have no idea but it was so fuzzy like a teddy bear, really cute until it woke up and it has huge mandibles. Kind of scary but so beautiful.
Seems to be alot of different types of Bees living near this Arena (courtice), Courtice , Ontario off of Prestonvale road.
As usual, your images are stunning. We are having difficulty identifying your Bee in the limited time we have this morning, so we have put our energy into creating a posting. We will contact Eric Eaton to see if he can assist in the identification and meanwhile our readership may weigh in with comments.
Knowing us, we decided to give it one more try this morning. The golden color and very furry front legs are interesting features, and we believe we found a matching image on the News Today blog where a similar image is identified as Megachile melanophaea and the following information is provided: “HE MAY look soft and furry – but don’t be fooled. ‘Out of all the species of bees that I’ve photographed during this project, this little guy was the only one that actually looked up at me and bared its mandibles,’ says photographer Clay Bolt. … Female leafcutter bees chew small circles from the edge of leaves, and use these to form tubular cells. Into each tube, she deposits a ball of pollen and an egg. The larva will feed on the pollen when it hatches. And the flamboyant gold leg manes? “Some males in this group have very furry front legs, which are used to cover the eyes of females during mating,” says Bolt. He speculates that this is to stop the females being distracted by other males during copulation.” BugGuide indicates you live in the range of the Broad Banded Leafcutter Bee.
Eric Eaton Provides Input
Wow, spectacular images! All I know is that it is a MALE Megachile sp. I’ll leave it to John Ascher to determine what subgenus or whatever. Males of some megachilids have those “fluffy” front legs.