Protecting Our Pollinators – How to Support Our Solitary Bees – Episode 016

Join us as we explore the wonderful realm of Leafcutter and Mason Bees with our special guest, Thyra McKelvie. In this episode, Thyra sheds light on their unique behaviors, vital roles in pollination, and how gardeners can join in on protecting our pollinators.

We kick off the conversation by learning what sets solitary bees apart from other bee species, highlighting their distinctive habits and characteristics and the importance of their pollination services for our crop production. Thyra also provides insights into the intriguing nesting behaviors of these bees, including the use of leaves by Leafcutters and the use of mud by Mason Bees. 

Listeners will learn practical tips on how to nurture these bees in their gardens, with Thyra offering valuable advice on providing suitable nesting materials and creating a bee-friendly environment. 

• Rent Mason Bees – Release Bees Rent Nesting Blocks
• Life Cycle of a Mason Bee and How You Can Protect Them
• Planting Guides | Pollinator.org
• Planting Guide for your Native Pollinator Garden | Pollinator.org

[00:00:00] Erin Landon: Welcome to episode 16 of the Evergreen Thumb. My guest today is Thyra McKelvie. Thyra is the Managing Director and Pollination Program Educator for rentmasonbees.com. Thyra oversees efforts to help gardeners host solitary bees and engages in public outreach to teach more people about solitary bees and the importance of taking care of all of our pollinators.

In addition to writing feature articles for national publications, Thyra also produces educational videos that can be seen on their YouTube channel. Before Thyra joins us to talk about solitary bees, we’re going to talk about the March gardening calendar.

[00:01:00] For planning in March, it’s time to make sure that your vegetable garden is fully planned for Spring, Summer, and Fall vegetables. If you don’t have an in-ground gardening space or designated space, consider container gardening. For maintenance, compost, grass clippings, and yard waste. Unless your clippings are from lawns that have been treated with weed and feed or weed killers.

Spread compost over your garden and landscape areas.

Prune currants and gooseberries and fertilize with manure or a complete fertilizer. You can fertilize evergreen shrubs and trees if needed. If established and healthy, their nutrient needs should be minimal, and you shouldn’t need to fertilize. The same goes for rhododendrons, camellias, and azaleas. If they’re already established and healthy, then they probably don’t need fertilizer.

[00:02:00] But if you do need to fertilize, use an acid-type fertilizer specific for rhododendrons and azaleas. In Western Washington, you can prune Spring flowering shrubs after the blossoms have faded. For planting and propagation, it’s time to divide hostas, daylilies, and mums. You can use stored scion wood to graft fruit and ornamental trees.

Plant insectary plants like alyssum, phacelia, candy tuft, sunflowers, yarrow, and dill to attract beneficial insects to the garden. If the soil is dry enough, you can begin preparing your vegetable garden and plant cool-season crops. Onions can be started indoors by seed. In Western Washington, you can plant berry crops, such as blackberries, strawberries, blueberries, and currants. It’s a good time to get those in the ground.

For pest monitoring and management, you can spray trees and shrubs for webworms and leaf rollers if they are present in your trees and shrubs. Protect new growth from slugs. The least toxic options include traps and barriers.

[00:03:00] Use caution around pets and pollinators. As you will hear in this episode, slug bait can contaminate mud and is toxic to many pollinators, including Mason Bees. Learn to identify predatory insects that can help keep aphids and other pests under control. Prune ornamentals for air circulation and to help prevent fungal diseases.

For Western Washington, monitor for European Crane Fly and treat if damage has been verified. For houseplants and indoor gardening, it’s a time to start tuberous begonias. And you can take geraniums, begonias, and fuchsias out of storage for Western Washington. Water, fertilize, cut back if necessary, and you can move them outdoors come April.

[00:04:00] As you can see, things are starting to ramp up a little bit and it’s getting to be Spring. So, enjoy the nice weather, enjoy being able to get out in the garden if it’s warm enough and dry enough. Spring is coming.

Now that we have finished the March gardening calendar, let’s move on to my talk with Thyra McKelvie.

Introducing Our Guest

Erin Landon: Thyra, thanks for joining me today. Welcome to the show.

Thyra McKelvie:  Thank you so much for having me.

Erin Landon: It’s great to have you here. Why don’t we start off with you telling us a little bit about yourself and your experience with solitary bees?

Thyra McKelvie: Oh, thank you. So yeah, I got started with Mason Bees when my daughter was seven and my son was five. My daughter was paranoid about bees and I came home one day with a Mason Bee starter kit, hung it up in our yard and she fell in love with these little bees because they are super sweet, she called them mermaid bees because they have this green iridescent sheen on them and both my kids went out and they would count the holes in the Mason Bee block and we just did math with it and had fun with it and it’s just It’s taken off from there.

[00:05:00] And so then I’ve been working for the company for what, eight, seven, eight years now. So it’s just been, it’s been such a joy to be able to teach more people about Mason Bees and Leafcutter Bees.

What are Solitary Bees?

Erin Landon: So, to start off, let’s talk more about what solitary bees are and how they’re different from honey bees or other like colony bees.

Thyra McKelvie: Yeah. You know, before I started even knowing, I didn’t know what a solitary bee meant. I had never heard the word before. Everybody knows what a honeybee is, but I had never heard of a solitary bee, and it means alone by themselves. So I like to now coin it as each female is their own queen. So with a solitary bee, all the females lay all their own eggs, gather their own food, and find their own nest. So, she does it all by herself.

[00:06:00] She doesn’t have a hive or worker bees or anybody solitary bees alone by themselves. So she does all the work. Honeybees have the queen and the queen will lay what, I don’t know, 2, 000 eggs a day. And, uh, solitary bees, Mason Bees, will lay about 15 eggs in their lifetime. So it’s a much different life cycle than a solitary bee and a social honeybee.

So there’s a big distinction between our pollinators.

Erin Landon: What makes Mason Bees, um, great pollinators for the garden?

Thyra McKelvie: Yeah, so little Mason Bees have, little hairs on their belly called scopa, S C O P A, scopa. And when they belly flop onto these flowers, because they’re kind of those clumsy little bees, they just plunk along and they plop onto the flower, those little hairs collect all the pollen from the plant and its loose pollen.

When you look at a honeybee, you can see how it meticulously collects pollen on the back hind legs because it has to carry it back to its hive. But solitary bees, they just flop along, they land on these flowers, and that loose pollen gets spread all over.

[00:07:00] So they are actually Mother Nature’s best pollinator. Everything they touch, they pollinate about 95% of everything they land on whereas Honeybees only pollinate 5%. It’s a huge distinction between the Honeybees and the solitary bees. Solitary bees will get to about 2, 000 blossoms a day.

Because they are native, the Blue Orchard Mason Bee is used to our colder, wetter climate, you will see solitary bees out flying if it’s misty, not torrential downpour, but if it’s, if it’s rainy and it’s kind of cold outside, you’ll still see solitary bees out there working where the honeybees don’t like it when it’s really cold and wet. So, it’s a big, big difference.

Erin Landon: So, are there specific plants that are better or that they’re more attracted to than others?

[00:08:00] Thyra McKelvie:  Yeah, so that’s a really key distinction to, um, especially Mason Bees. So Mason Bees are your Spring pollinators. When you start to see dandelions pop up in your yard, that means that your temperature is starting to warm up for Spring.

I always consider, and a lot of people in our industry, you know, that dandelions are a bee’s first food. But it’s a pollinator’s first food. So all those early pollinators that come out in Springtime rely on those early Spring bloom flowers. Um, so it’s really important if you are hosting Mason Bees in your yard that you provide food that’s going to be blooming in early Spring.

Mason Bees will emerge when temperatures reach about 55 degrees. Now there’s a distinction with that. That’s daytime temperatures. So because we’re coming off of the Winter and it’s going to be cold at night, those daytime temperatures can dip between, you know, below, 55 degrees, but the daytime needs to be 55 in order for them to emerge and pollinate and do their thing.

[00:09:00] And they’re going to need food. So if you’re hosting Mason Bees, you need to make sure that you’re planting in your yard early Spring blooms. I always tell people in early Spring, go head to your nursery and what you see blooming is a really great thing to then plant in your yard. We’ve also partnered with pollinator.org, and they have these beautiful garden cards that will tell you exactly what to plant in your yard for Spring, for Summer, for Fall, to support all pollinators in your yard.

We have a link on our website up on our partners tab that you can go to and you can find that resource. Um, but yeah, it’s really important that Mason Bees have early Spring blooms and that they have a great habitat to support them.

Mason Bees’ Role in Fruit and Vegetable Yields

Erin Landon: So, what kind of role do Mason Bees play in fruit and vegetable yields?

[00:10:00] Thyra McKelvie: Huge. So Blue Orchard Mason Bee is their name because they have helped orchards, and apples, blueberries, cherries, almonds, like anything that’s a fruit blooming, uh, tree. Mason Bees will do wonders with it. So you know, I know around here, there’s a lot of Asian plums that bloom really early.

 So if you have Mason Bees they’re going to help with those early Spring blooms. But you know, there will be, you know, the 400 Mason Bees do the work of 40, 000 Honeybees. I mean, they’re amazing pollinators because of how well they pollinate with that loose pollen all over their little bellies. So they’re remarkable pollinators and you only need about three to five Mason Bees to pollinate an entire apple tree.

 I mean, they’re remarkable little pollinators.

Erin Landon: So, some of the early vegetable crops, too, then, that would be flowering, like peas and things like that?

[00:11:00] Thyra McKelvie: Well, good question because it depends on when those peas are blooming. I know some blueberries will bloom in Spring and then some blueberries will bloom in Summer, but Mason Bees only live six to eight weeks and they’re done after that.

So, if you’re, if you have things that are blooming later in Spring, then you’re going to want to release your Mason Bees later in Spring. Cause, I don’t know, I wouldn’t know what time your peas are blooming. But yeah, they will pollinate anything in your yard that’s blooming in the Springtime.

Mason Bees and Their Life Cycle

Erin Landon: Okay, well, that makes me think maybe we should backtrack a little bit on the life cycle of the Mason Bee and, you know, how they nest and, and things like that.

Thyra McKelvie: Yeah, yeah, so, Mason Bees, I like, when I teach a lot of kids at schools and education and, adults too, they can connect with it, but Mason Bees are like a butterfly. They spin a silk cocoon and they hibernate, hibernate in that cocoon all Winter long, and then they emerge in Spring when the temperatures reach 55.

[00:12:00] So a Mason Bee, she’s going to go out and she’s going to look for nesting chambers in your habitat. Whether that is Woodpecker holes, or reeds, or crevices and nooks, or you provide a bee hotel, um, Mason Bee mandibles are not strong enough to chew wood. So those are the Carpenter Bees. We get asked that a lot of times.

Mason Bees need to find natural holes in their habitat. So what mama Mason Bee’s gonna do is she’s gonna go fly around. She’s gonna go collect mud in your yard. And because she’s using mud in her nesting chambers, it’s really, really, important not to use slug bait or pesticides or anything in your yard that’s going to seep into that mud that’s going to harm her babies inside.

When we open up nesting blocks we can see the nesting chambers and there is a larva or an egg or a larva that hasn’t developed and it’s died, which sometimes means that it’s eaten. Uh, toxic pollen or has been contaminated by the mud and it kills the baby larva. So it’s really important if you’re hosting Mason Bees that you’re not using any pesticides in your, in your yard that’s going to harm them.

[00:13:00] Um, but what that Mason Bee is going to do is she’s going to go fly out. She’s going to find that natural hole. She’s going to crawl into the hole and she’s going to plug it with mud. And then she’ll go out and she’ll gather pollen. And she’ll put a loaf of pollen next to the mud cap. Then she’ll lay a tiny little egg and then she’ll cap it with mud.

So it’d be mud, pollen, baby, mud, mud, pollen, baby, mud, mud, pollen, baby, mud. We do a little song in school when we do the mud, pollen, baby, mud. Um, and there’ll be about five to seven little. And it’s a whole nest of full-grown Mason Bee cells in each one of those nesting chambers, nesting holes. And then that little egg will hatch into a larva.

The larva will consume the entire pollen loaf. And then it will spin a silk cocoon. It then hibernates in that cocoon all Winter long and will emerge as a full-grown bee.

[00:14:00] We just launched a video last year, in the Fall. That took us two years to film the life cycle of a Mason Bee, and it’s pretty remarkable. I used my macro lens to film it. We got bees up close, little larvae eating the pollen. I was able to capture a Mason Bee spinning a silk cocoon while it was inside the silk. It’s pretty fascinating. If you guys like that kind of stuff, I encourage you to go check out the video.

I also incorporate in that same video the predators that harm them and why it is so important to harvest and clean your Mason Bees every year.

How can we support Mason Bees as Gardeners?

Erin Landon: All right. And we’ll include a link to that video in the show notes. So, anybody who wants to check that out, you can find a link there. We kind of touched on this a bit when you were talking about Spring flowers, but are there other ways that gardeners can support Mason Bees in their gardens?

[00:15:00] Thyra McKelvie: Yeah, if you have it, Mason Bees are using crevices and logs and reeds and stuff like that in your yard. There was a whole campaign for not raking your leaves until after Spring because a lot of pollinators will go and use them. Moths or butterflies. They’ll go and they’ll use the leaf to wrap up and make their cocoon.

You know, Mason Bees are going to do the same thing. If you have those old, um, plants in your yard that you’ve trimmed and there’s Mason Bee holes in there, just wait till mid-Spring, to clean up everything as best as you can. Cause I know a lot of people want to maintain their Spring yards.

They get the Spring clean itch, and they want to go out and clean. But, you know, the key element for Mason Bees is just making sure that you have a really good source of mud for them that’s nice and clean and not contaminated with pesticides. And you know, they’re going to go out and find natural holes in your habitat.

Most of the time, Mason Bees aren’t going to go ground-dwelling. Um, those are minor bees and other types of bees, uh, bumblebees, but, um, Mason Bees will find little nooks and crevices, usually off the ground in your yard. 

Protecting our Pollinators

[00:16:00] Erin Landon: I guess we kind of touched on this, some of the threats and challenges to the bee populations that gardeners need to be aware of like you said, slug bait and contaminated mud.

 Are there other threats or concerns?

Thyra McKelvie: Yeah, I’m doing a really big awareness campaign, this year and we, we’re the largest solitary bee provider in the country. We partner with research teams and bee labs all over the country that are studying predators that harm Mason Bees and solitary bees.

And with our research and what we’ve, you know, we clean 3 million Mason Bees every season. It’s a lot of bees. I’m opening up a lot of blocks. We’re seeing a lot of predators coming through and that’s why it’s so important to harvest and clean your nesting blocks every Fall. I always get asked, well, why clean in nature?

[00:17:00] Bees don’t go out and clean. You know, we don’t have to clean in nature where they’re laying their babies in nature. They’re camouflaging their nesting chambers. It’s hard to find them, but when you’re sitting at a bee hotel, you’re, I like to describe it as, as you’re putting out a sign that says vacancy, come on in because you’re allowing really great access for these predators to just hang out at the nesting block or your reeds or whatever you have and just access those tubes at any time because their main predators are kleptoparasites.

So you have the Mono Wasp and the Houdini Fly that utilize the nesting chambers to lay their babies. So a Houdini Fly will wait outside the nesting chamber for mama Mason Bee to leave. And again, remember we have the mud, pollen, baby, and then mud. Well, Mama Mason Bee is going out collecting pollen and building stuff for her nest.

[00:18:00] Well, when the Mama Mason Bee leaves, that Houdini Fly waits for her to leave. And then she, the Houdini Fly crawls into that nesting chamber and will lay about 15 to 30 of her babies. Mama Mason Bee doesn’t know this. She’ll cap that cell with mud. And now you’ll have mud, pollen, tiny Mason Bee baby. 15 larvae of Houdini Fly and mud.

And I have lots of videos online showing what the inside of a cell looks like with a bunch of Houdini flies. The problem with this predator is it’s growing rapidly. So, people that aren’t cleaning or taking care of their Mason Bees, are going to have a complete overrun of predators in their habitat.

Cause when do you think those Houdini flies hatch? They’re going to wait until Spring. Their life cycle is the same as Mason Bees. So when the Mason Bees emerge, The Houdini Fly emerges at the same time. So if you’re leaving all those predators in there and now you have a one to 15 ratio of one Mason B to 15 Houdini Fly, and we’re talking about just one cell.

So you can imagine when we open up a cell and it’s completely full of Houdini Fly larvae or Pollen Mites or whatever, what other fun stuff that we get to find?

How Mason Bees Contribute to the Ecosystem

[00:19:00] Erin Landon: So, how do Mason Bees contribute to the ecosystem?

Thyra McKelvie: Yeah. So because they’re such amazing pollinators, they’re going to make everything they touch grow bigger and stronger.

You’ll get a lot more fruit on your fruit trees. You’re going to have a lot more healthier plants in your yard. And anytime you have a healthier plant, you’re going to have healthier soil, you’re going to have healthier air. And so they are remarkable pollinators because they just make everything in your yard grow bigger and stronger.

What are Some Behaviors of Solitary Bees that People Might Not Know About?

Erin Landon: Are there other interesting behaviors with solitary bees that people might not know?

[00:20:00] Thyra McKelvie: Behaviors. Well, they are super sweet little bees. You can stand right next to your nesting block and watch them. They’re so docile and sweet. They’re not going to swarm. They don’t, you’ll see, I have a video where I stand in front of a block of 1, 200 bees and we release a whole bunch. And they’re just, they just fly around and they don’t bother you at all.

They don’t attack. They don’t sting. The males don’t have a stinger at all. The females have a tiny little stinger, but they never use it. I actually got, if you want to say stung, for the first time after seven years because I was trying to do a video with a Mason Bee, and I dumped her out onto my hand and she wasn’t happy with me and it was just like this little zap.

It didn’t even have, what’s the shock, the venom? They don’t have the venom that’s gonna hurt people that are allergic to bees. They don’t have any of that. It was more like when you shuffle your feet and you touch something and you shock yourself, that’s what it felt like. It didn’t even hurt.

It just went away. But, you know, if you get one stuck up your watch or, you know, in your wristband, or you’re trying to get a cute picture of them for educational video purposes and you make her mad, she won’t be happy about that. So, I stand there all the time and I watch these little bees. Kids don’t have to worry about them in school.

[00:21:00] I will go around, and I’ll have all the kids sit crisscross applesauce. And they have to be really quiet. Then they get to hold a baby bee, which is a cocoon. They just find it fascinating. Sometimes they can sit there and listen to the cocoon. And if you hear a little crackling noise, like rice krispies, that’s the sound of the Mason Bee starting to chew through that cocoon.

If you’re in your yard and your garden and you have Mason Bees during the early Springtime, I encourage you to go out to your nesting block or wherever you’re releasing your bees and just listen for that crackling noise. It’s a really distinct sound. It’s very cool because those are the Mason Bees chewing out of the cocoons to emerge.

Once all of your Mason Bees have emerged, we do a whole science curriculum for schools. The teachers can go out to those. The white PVC tubes are how we distribute our bees. They can go and empty the cocoons and then the kids can study them in their labs under microscopes and really take a look.

[00:22:00] They can squish, they’re empty now, there are no bees left anymore. But they can now turn that project into investigating and looking at all the cocoons. You can squish them and they sound like a little Rice Krispie treat. So, there are a lot of things that parents can do and teachers can do to teach our kids about, about these little bees.

Other Predators: Pollen Mites, Houdini Flies and Chalkbrood Fungus

Can we talk about some other predators as well with the Mason Bees?

Thyra McKelvie: Oh, sure. I think is important to mention Pollen Mites because they are another predator that we see a lot and people wonder what a Pollen Mite is and what Chalkbrood Fungus is. Then we’ll jump over to Leafcutter Bees. ‘Cause um, I do wanna mention the other predators that harm our little bees, our little pollinators.

So Pollen Mites are these little tiny, little spider-looking things that the Mason Bees and Honeybees and all our bees go and collect on the flowers. So they’ll land on a flower belly flop. They’ll get that pollen, all them well. There’ll be a little Pollen Mite on that flower that they’ll carry back into their nesting chamber.

[00:23:00] Pollen Mites multiply crazy rapidly. It’s so fast. So I have a lot of videos on Pollen Mites. It’s in that one life cycle of a Mason Bee video as well that you’ll link. But what happens with Pollen Mites is just like the Houdini Fly and the Mono Wasp, the Pollen Mites will stay in that nesting chamber until the following Spring.

What happens is if you’re not cleaning your nesting material, that Mason Bee is going to emerge from the cocoon. He or she is going to crawl through the nesting chamber, is going to crawl through those Pollen Mites. Those Pollen Mites will stick on its back and it’ll get out of the nesting chamber and then that Mason Bee is now carrying the

Pollen Mites that are spreading all around your garden that are going to harm all your other pollinators. So it’s really important if you’re hosting bees in your yard that you’re harvesting and cleaning because you can get rid of all the Pollen Mites, you can get rid of the Houdini Fly, and the Chalkbrood. Chalkbrood is a fungus.

[00:24:00] It’s also on the flowers in your garden. It’s a tiny microscopic spore that when the Mason Bee goes out and collects pollen, she’ll carry it back to her nesting chamber. And then the baby Mason Bee will start to consume the pollen that mom left for it. Well, what happens is if there is a fungus spore in that pollen loaf, that baby will consume it, and then the spores will essentially dry it from the inside. You’ll see in some of the videos, they’re black, they turn solid black, it dries them up and they, they don’t survive. But what happens with Chalkbrood is the spores will burst in the nesting chamber. And so in that nesting chamber, it’s mud, pollen, Chalkbrood, baby, mud.

[00:25:00] Now that becomes contaminated with all these tiny little spores you can’t even see with your eye. But then again, if the Mason Bee emerges and crawls through that, now those spores are being spread in your yard. So, it’s really important before we move on to Leafcutters that if you’re having Mason Bees and you’re hosting Mason Bees, that you’re not using logs with holes drilled in it, or bamboo reeds because those are nesting chambers that cannot be opened and cleaned. And you have to be able to get to your Mason Bees and clean them every Fall. And then in the Springtime, you have to put out clean nesting material every Spring. Because again, the Chalkbrood spores.

The fungus will linger and the Pollen Mites will linger and the Houdini Flies. So you’ve got to sterilize your nesting material or replace it completely with brand-new nesting material every Spring. Sorry, I wanted to make sure to mention that because it’s so important for people to learn.

Leafcutter Bees

Erin Landon: Let’s talk about Leafcutter bees.

Thyra McKelvie: Yeah. So Leafcutter Bees are your Summer pollinators. They emerge when temperatures are about 75 degrees. With our program, we provide a Pollinator Kit with Mason and Leafcutter Bees, and the Mason Bees and Leafcutters are not out at the same time.

[00:26:00] So as I mentioned earlier, the Mason Bees only live six to eight weeks and are Spring pollinators. When the Mason Bees are done flying and are done pollinating, then you swap your blocks. You take the Mason Bee block out, you put your Leafcutter block in, and then you wait for the Leafcutter Bees to emerge when temperatures are 75. Leafcutter Bees have a different life cycle.

[00:27:00] Mason Bees hibernate in a cocoon and grow into a full-grown bee and are ready to emerge as a full-grown bee in early Spring. Leafcutter Bees need the temperatures to be 75 plus degrees and inside their little nesting, nesting chamber, they’re teeny tiny larvae. When they feel the temperatures of 75, they eat the pollen loaf that mom left and it takes them about six to eight weeks to grow into a full-grown bee depending on how hot it is, then they’ll emerge.

So Leafcutter Bees take a little bit longer because their life cycle is different. Sometimes if you live in a hot state, you can get two or three generations of Leafcutter Bees because they’ll lay the babies again. Then if it’s 75 degrees out, those babies will grow up and you’ll get another life cycle of baby bees.

Erin Landon: So interesting. I’m assuming Leafcutter Bees are native to Washington as well.

Thyra McKelvie: So, we get that question a lot. They’re not native, your Blue Orchard Mason Bees are native, but Honeybees aren’t native either. So Leafcutter Bees were brought over to help save the alfalfa crops.

They’ve been around for decades. So Leafcutter bees are amazing pollinators to pollinate all of your veggie gardens and anything blooming in the Summertime. I can’t say that they’re native, but you know, Honeybees aren’t either, but they’re not harming anything because they’re helping our ecosystem because of their pollinating. They also have the little belly hair scopa as well so they’re amazing little pollinators.

[00:28:00] Erin Landon: Okay. So, you said they, so say in like Western Washington, is it more likely we’ll get one life cycle?

Thyra McKelvie: Depending on, well, if you’re east of the mountains, you might get more because it’s warmer over there, but yeah. The Seattle, Everett, you know, on this side you’ll probably only get one life cycle.

I usually put my leaf cutters out in mid-July because it’s so cold. We don’t really warm up to 75 degrees until it gets, you know, later in the Summertime.

Erin Landon: So, yeah, I think I’m a little warmer down here, but not very much. Yeah. All right. Are there specific plants that Leafcutter Bees particularly like to feed on?

[00:29:00] Thyra McKelvie: Same thing with Mason Bees. They just like those Summer blooms and pollinator.org has great garden cards and references to plant what to plant in your yard. I mean, they’re just amazing little pollinators. You know, they’re really good with veggie gardens. They love if you have a veggie garden, they’re going to help you out there.

Predators to Leafcutter Bees

Erin Landon: So, what about predators or threats to the Leafcutter Bees?

Thyra McKelvie: Yeah, they have different types of predators, but not to the extent that the Mason Bees do because they’re so tiny, you know. You’ll see these little red looking, like they look like little red caterpillars, in their nesting chambers.

They’re a type of moth that’ll get in there. Um, they’ll have, uh, wasps. Um, so Mono Wasp, um, different types of wasps will impact Mason Bees and different types of wasps that will impact Leafcutters. So, another kleptoparasite.

Erin Landon: Okay. So how big is a full-grown Leafcutter Bee? Is it significantly smaller than a Mason Bee?

[00:30:00] Thyra McKelvie: Yeah, they’re teeny tiny. Yeah, so if you want to, I’ll send you a video link. I did a video where I was holding these little tiny Leafcutter Bees and they’re like half the size of my pinky. They’re so small. I can send you that video because I did a whole video and then I was able to get a macro lens of these Leafcutter Bees up close.

They’re remarkable. Their eyes are so beautiful. So yeah, I can send you that video if you want to share it as well. They’re such cute little bees.

Where do Leafcutter and Mason Bees get their Names?

Erin Landon: Okay, so where does the name Leafcutter, I’m assuming that means that they feed on leaves, come from?

Thyra McKelvie: Yeah, that’s a good question. I probably should have started with that. So Mason Bees get their name Mason because of mud masonry work. So they use mud for making their nesting chambers. Leafcutter Bees use tiny pieces of leaves and they cut out little tiny half circles of leaves. They don’t damage the plant; they use it for their nesting chambers.

What a Leafcutter Bee does is she’ll go out and she’ll find a teeny tiny leaf and she’ll cut it off and she’ll crawl into that hole. She’ll go in the back, and she’ll climb it into, she’ll chew it and make it really pliable, and she’ll push it up around the edges.

[00:31:00] She’ll go back and get a couple more leaves and she’ll do the same thing. So she’s chewing up these leaves, making them really pliable and soft. Then she’ll get pollen and she’ll lay a pollen loaf and then she’ll lay an egg and then she’ll go get more leaves, chew them up, and take these tiny little leaf cells and use them, and now it’s just leaf, pollen, baby, leaf, and she wraps them up. I call it like a little leaf sleeping bag.

We have a video online for the leaf cutter harvest. So you can see what these tiny little leaf cells look like. I call it nature’s artwork. They are so beautiful. I have a couple of pictures up.

Sometimes they use flowers, flower petals for their leaf, for their, um, leaf sleeping bags. And then you’ll get pinks and purples and whites. And it’s just so beautiful when you see a leaf cutter cell.

How Can Gardeners Encourage Healthy Populations of Solitary Bees?

[00:32:00] Erin Landon: So what are some things that gardeners can do to encourage healthy populations of solitary bees?

Thyra McKelvie: Yeah, we have these garden signs this year.

It says pollinators at work and it teaches people about solitary bees and where they can find them in their yard. I had a host one year contact me so upset. He went on vacation and he came home and all his Mason Bees were dead. His neighbor next door to him had sprayed pesticides in his yard and it trickled over to his bee house because they shared a fence and it killed all his Mason Bees. Mason Bees are really sensitive to pesticides, sprays, and anything like that in your yard.

Back in the Midwest, the hosts that we work with (because we’re able to send bees nationwide) say “You know, mosquito spray is a big problem”.

So if people are spraying mosquito spray, in their yards, that’s going to also harm pollinators.

[00:33:00] So yeah, it’s really important to, you know, keep those dandelions. There was a whole campaign last year, No Mow May. Get away with it. Don’t have to mow your yard in May. Keep those dandelions up. It’s a first food for all pollinators. Moths, hummingbirds, and bats, like they’re all amazing food for all your Spring pollinators.

Then, yeah, throughout the year, just make sure you’re not using pesticides and you have a pollinator-friendly yard and you’re planting amazing flowers and food for your bees. You know, the biggest thing is you’re out enjoying them. I think when I have my bees in my garden, I will go put a blanket out on one of my busy flowers and I will just sit there and I’ll watch and I’ll count how many species of bees and moths and butterflies.

Your garden comes alive with all these little pollinators.

You know, I just want to thank all of our hosts and everybody out there who supports pollinators because it’s so important to make sure we’re planting a great habitat to support our pollinators.

[00:34:00] Erin Landon: Yeah, I just recently heard a fact that they’re estimating there are over 600 species of bees in Washington state.

And they’re in the process of doing an actual catalog of all the different species of bees.

Thyra McKelvie: Yeah. So 90 percent of bees are solitary. Yeah. So we work with the USDA bee lab, and UC Riverside, UC Davis, Penn State, we work with a lot of bee labs that are studying bees and making sure that you know, we’re educating ourselves on how to properly take care of them.

Solitary Bee Information

Erin Landon: All right. Is there anything else you want to share about solitary bees?

Thyra McKelvie: You know, I get asked, you know, where should I hang my Mason Bee house? Where should I put it in my yard? You know, you want to have it in the morning sun, south, south facing, or whatever direction that is.

[00:35:00] Our houses are painted black to attract the heat. So that’s, I’ll say the black house. So our black houses are painted black. Um, and you hang them up in the south-facing morning sunshine. They need morning to mid-afternoon sun. You don’t want to hang them on a tree because that’s going to get shaded.

You’re going to want to put it on a fence post or the side of the house, or some people will take like a nice planter pot. They’ll fill it with rocks. They’ll put a two-by-four post in it, and then fill it with soil, plant little flowers on the bottom of it, and then they have their portable bee house.

Once you hang your Mason Bee house, you’re not going to want to move it. It’s got to stay up for that season, for that year. What happens when the males emerge from your emergence tube is they’re going to mark it with a scent mark. And you’ll notice it looks like mud. So the male bees will mark it with scents and they’ll come out. They’ll fly off.

[00:36:00] It takes the girls about a week or two later to emerge. So boys always emerge first. Boys have a white tuft of hair on their heads, and then the girls come out. Then the boys and the girls, as I say to my kids, give lots of piggyback rides. They have lots of fun. And then the girls will come back and they’ll start laying their babies. You know, they only lay about 15 babies in their lifetime.

So when you see little mud marks on your emergence tube. That means the boys are coming out and then the girls will soon follow.

Final Thoughts on Protecting Our Pollinators

Erin Landon: All right. Any last thoughts you want to share?

Thyra McKelvie: Make sure you have a mud supply nearby about 10 feet from your bee house, a nice clean mud supply hanging in a sunny warm spot, flowers for early blooms, and 55 degrees, um, to get them going for Spring.

And then they don’t stay out year-round. At the end of Spring when they’re done pollinating again, six to eight weeks when you stop seeing your Mason Bee activity, you’re going to want to remove that nesting chamber, those nesting cells, whether you’re using a block or you’re using cardboard tubes.

[00:37:00] You’re going to want to store them safely in a cool garage or shed over the Summer. They don’t stay out year-round. And then you open and harvest and clean them once they’ve spun that full cocoon. You’ll clean them in the Fall. Keep them in hibernation mode in a refrigerator. And I have a video

I can send you on how to clean your own bees. And then yeah, they’ll emerge the following Spring.

Erin Landon: Great. Well, thanks so much for joining us. That’s a lot of great information. I’ll link to your whole YouTube channel, but the life cycle of the bee specifically I’ll put on in the show notes. So there are lots of resources out there on Mason Bees.

Thanks for joining me today.

Thyra McKelvie: Yes. Well, thank you for having us. I just love teaching. So if anyone has questions, they’re welcome to give us, give me an email or pop us a call.

Erin Landon: All right. I will share that info.

Thyra McKelvie: Thank you so much.