74 Lila Westreich – Mason Bees and Landscapes (in English)

Speaker 1: From the Oregon State University Extension Service, this is Pollination, a podcast that tells the stories of researchers, land managers, and concerned citizens making bold strides to improve the health of pollinators. I'm your host, Dr. Adoni Melopoulos, assistant professor in pollinator health in the Department of Horticulture. Hi dear listeners, this podcast is a little bit on the run.

I'm at the Vancouver, British Columbia International Airport. I am just departing from the Entomological Society of America meeting where I've heard a lot of amazing talks and I'm hoping to convey to you in the next couple of weeks. But today I'm going to be bringing you an interview I had with Lila Westreich, who's a PhD candidate at the University of Washington in Seattle. This is a really interesting conversation where she's talking about her work using mason bees to evaluate different habitats, very much like the episode we had with Sarah Gallbreath a few weeks ago. But there are some really interesting twists to this research and I think you're going to really enjoy it. Okay, I got to go catch a plane and I hope you enjoy this episode of Pollination.

Welcome to Pollination. Thank you. Thank you for having me.

Now, we're at the Entomological Society of America meeting in beautiful Vancouver, British Columbia. Yes. And you delivered a talk yesterday talking about your research. Tell us a little bit about sort of the underlying questions. Why you're working with Osmeal, Igaria and looking at the sort of seasonality and you know, when they're active in the season. Tell us a little bit about why you chose this area of research.

Speaker 2: Yeah, that's a great question. So I originally came out to Seattle to work with the entomologist at the University of Washington and at the time he didn't have an entomology program set up, a pollination specific study area. So what we did was he allowed me to do whatever I wanted so I could figure out what species I wanted to work with. So I started, I've always loved bumblebees and I really wanted to study bumblebees.

I thought it was an easy system to get into and it turns out when I moved here and I did some research, the only guy who bred bumblebees. The guy down in Olympia. She passed away.

Yeah, that was tragic. Yeah, so right on the cusp of me starting grad school, I found out that the only place where I could get a native source of bumblebees was no longer a system I could enter. So from there, it was kind of like a hop and a skip and a jump to Osmia because they're really easy to work with. They're really easy to buy, which is kind of rare for a native bee source and they're really easy systems to put in different places.

So it was almost easier than bumblebees. I think I got lucky. But that got me into Osmia and then I started to talk to more people. I learned that they're really a cool native system to study. They're really easy to manipulate in many different situations, which is what we ended up doing.

Speaker 1: Yeah, I guess we often say, oh, 70% of the bees are ground nesting, but they're really experimentally intractable. They're hard to work with and here's a system. It's native and it comes in a, people have already kind of worked at the kinks of rearing them so it's a really good system for asking questions around.

Speaker 2: Right, right. And, even at these talks, I've heard a lot of talks about native bees and a lot of them are talking about ground-nesting bees as the native species in a landscape. And, interestingly, there aren't as many people studying them, at least at the entomology conference, but there is an orchard bee conference in Davis, California this year. So there'll be a bunch of orchard bee growers and...

Speaker 1: What a great plug. Yeah. Yes, there's an orchard, there's the Orchard Bee Association is having its meeting in Davis. It's like the beginning of December. Yeah, first weekend. It's kind of like a hidden secret. Like, people don't really know about it, but you get all the kind of like people who've been in this industry for a long time go there.

Speaker 2: Yes, for sure. You get people who've been breeding the bees for decades and there are a lot of USDA researchers coming. So a lot of really interesting work to be shared and there's tons of grad students across, you know, the United States using these as a model system. So it'll be really fun.

Speaker 1: It's an intimate little meeting. You get really good access to people and the food is good.

Speaker 2: Yes, and your talk is 20 minutes instead of 10 minutes. Yeah.

Speaker 1: Which is wonderful. Okay, so you were constrained today, yesterday to 10 minutes. So lay out sort of the, you know, what's the overarching question that you wanted to ask with these bees?

Speaker 2: Yeah. So my talk was on specifically one portion of my study. So we are looking at the effect of landscape composition on the Osmea Lignaria. So what we do, the basic setup of the study is we take the bees, we put them in a variety of different systems, and then we study the landscape of those systems and then we pull pollen from the bees. System.

What do you mean by system? So we have a couple of areas that are really easy to talk about in Seattle. There's a huge urban park system in Seattle.

It's beautiful. It ranges from places like Magnuson Park, which are really, really disturbed. There are a lot of invasive species there. There's a lot of non-natives. It's not as well kept up as a lot of other places. And you've got places like Seward Park where they're super, super native. People are coming in and pulling out non-native species all the time. They care really deeply.

Not that Magnuson doesn't, but there's a whole group that cares deeply about Seward Park. So what that means is that you have one landscape where there are a bunch of native plants. It's really beautiful. Big open spaces, lots of flowers. You have another landscape where it's mostly non-natives and a lot of invasives. So what we do is we place the bees in each of these landscapes and then we take count of everything that's on the landscape. So we write down every plant that's within a 100-meter radius of the box. We take how many flowers are on that plant.

We mark if it's native or non-native. And then we also analyze the bees inside of the box. So the bees that we use, we really only use them to get the pollen. We're trying to accumulate a bunch of different pollen to see what's available on the landscape to the bees and what do they prefer, right? Because they can go anywhere they want within about a 600-meter range of the box, but they'd prefer to go closer to the dust.

Why would you go really far away when you could go next door? And the pollen that they collect can be really easily analyzed for nutritional value. So the bees are going on the landscape and picking what flowers they're going to, probably based on nutritional value. They want really high-protein pollen. So they get the pollen, they bring it back to their nest and they create this perfect little pollen ball and then they lay their egg on the pollen ball, the egg hatches and the larva consumes all the pollen. And then once they're done, they spin themselves into this pupa and they overwinter that way. So they need the pollen to grow. And they're solitary bees. There's only one mother. They're going out and collecting all the pollen they'll need for all of their children and then they're passing away. So that one bee is dependent on the forage material for all of her next generations. Okay.

Speaker 1: So let me get this straight. So you've got these various sites that probably are more or less favorable to mason bees because of the floral diversity, the number actual, just standing number of flowers. And so they're coming back and again, you know, the number of offspring they have is going to be, or there might be some measurable difference. But the one thing that you're interested in is somehow getting the pollen off them before they go in or taking a little sample of it and then analyzing that pollen to sort of confirm the choices they're making. Are they choosing pollen that's of high quality and are they bringing the more in? All right.

Speaker 2: Yeah. Yeah. And we also, so with a box, it's really easy to see it. Obviously, it's harder to talk about, but we have a bunch of these light reeds. They're like paper reeds that the bees can nest in. So we provide the nesting material. We provide the bees on the landscape. We get them from a local breeder and we put the bees out, allow them to forage, and fill up their nesting tubes. They're mason bees, so they cap their tubes with mud

Speaker 1: that they'll collect from the... That tends to be Mason. ... Mason Bees. And so you get these really nice covered nesting tubes. And what you can do is you could take half of them, pull them open, destructively sample, so you stop the development of the bees and you pull out that pollen ball that they've created. Okay. So you have a ton of pollen to work with. We have vats of pollen back at the lab. It's like, I just pictured these vats. Giant vats.

Speaker 2: They're awesome. It's so much study material, which is really unique, I think, to a lot of native bee systems. Usually, it's diversity studies, right? You're walking out, you're counting how many native bees there are. You're taking samples of their pollen from their scopa and their legs, and then you're analyzing that, usually under a microscope. So we're able to take all of this pollen away from the bees, allow some of them to finish development so that the other half that we didn't touch, they finish their development. The next spring, they'll emerge, and we'll see what emerges and how many of them emerge.

So we get an idea of how they're doing on the landscape in terms of how many eggs are they laying, how well are those eggs doing, whether are they surviving through adulthood, and then we have the pollen as a separate study group. Okay.

Speaker 1: Wow, fascinating. Well, this does remind me of a conversation we had about a month ago with Sarah Galbraith. And the same kind of thing. It's like you can look for the bees and you don't really get any of this other additional life history information, but if you use a system like the mason bees, suddenly you can really get the mechanism in ways you can't just by catching bees.

Speaker 2: Yeah, yeah. It's a wonderful system just for accumulating information. And so with the pollen, what we're doing, we're trying to get information out of it by sequencing the DNA within the pollen. So pollen comes from plants. All of the DNA within pollen is going to be the same as the plant DNA of the species. So if you took a sample of a leaf versus a sample of a single pollen grain, you should get the same match.

Oh, I suppose, right. Everything's DNA, right? So what we can do, it's becoming cheaper and easier to do these days just with how much technology has benefited us in its steepness, but we're able to take the pollen, sequence it, and then get a bunch of DNA sequences back. And it doesn't necessarily tell us what abundance is there, right? So it doesn't tell us if it only went to one species on the landscape because we'll just get one copy of that plant and one copy of everything else that ended up in that sample. There's a chance that there could be something like a conifer species that blew into that pollen sample.

Speaker 1: And then you get a reed.

Speaker 2: Yeah, you get a reed. So we're just getting a basic idea, but what's helpful is that we have all of this data from the landscape. We know exactly what's growing there. So if we get a fluke hit of maybe a conifer, like a Douglas fir, and then we look into our sample size and see if there were Douglas fir in that sample, we can know that, okay, that made sense. They're foraging around Douglas fir, it fits. So we can identify the flukes, but we can also identify exactly where they're going on the landscape. And so we hypothesize that there will be all of these wildflowers on the landscape, and we'll get to see exactly where they're going.

Speaker 1: Well let's take a quick break. You can tell us what you found. Yeah. Or what you're finding so far. Yeah. Okay, so we're back. So tell us, so you've got the system, you've got these bees, they're going into these different landscapes, they're bringing pollen back, and you're looking at that pollen. You told us about this DNA way of sort of making a list of the plants they're visiting. What did you see?

Speaker 2: So it's tricky. So all of the DNA that we submitted the first time failed, which is like a nice part of science where everything fails on you, and then you have to start over from scratch. Oh really? Yeah. So we submitted it, we overloaded the library with preparation, and it was a whole mess. Really? So what happened was we got it back, we decided

Speaker 1: to try again. This is where in science journalism they say, how did you feel about that? No, we won't do that.

Speaker 2: This is what doesn't get published, right? So we sent it again, it was actually just sent in like this past weekend. So we haven't gotten the data back, but we have done a lot of protein analysis of that pollen because it's quick and it's dirty and it's easy. So we ran a bunch of protein analysis tests, and what we found was really interesting. So across the landscape, we had basically the same concentration of protein at almost every site. So there were totally different plants at different sites. Some parks do tend to have similar native species to others because if it's highly restored to the native idea, you're going to have a similar list of species being planted, but we do have all of these disturbed areas and very intricate disturbance matrices of native plants and non-native plants mixed. So the sites had different plants, but we were getting the same concentration of protein at every site. So what this tells us is that the bees are specifically choosing pollen on that landscape that has higher protein levels, and they're only working with that pollen. Isn't that interesting? Even if all the plants are different, they're still picking the right pollen for their offspring. Oh, nurse, they have no idea.

Speaker 1: So cool. Okay, this is good science. It opens all these questions up. Right. All right, was your list very short? The one thing I think is that mason bees are at a time of year when you're just starting to see in the Pacific Northwest a lot of flowers come on.

Speaker 2: Yeah, yeah, that's a great point because, at the end of the season, we also work with leafcutter bees a little bit, although that's, it's a much trigger system to work with in some senses. The leaf cutter bees have almost nothing at the end of the season because the end of the season in Seattle is like August or September. There's almost nothing blooming. Queen Anselace is kind of the biggest bloom in most of our sites.

But in the beginning, you get a weird mix. A lot of the non-native species aren't blooming. So Himalayan blackberry, we usually miss with the early bees. Same with a lot of the invasive crawling ground covers. You do have a lot of dandelions and a lot of small ground cover species that will pop up. Our bees that we've been analyzing came out at the end of May, the very beginning of June.

They only live four to six weeks and these bees wake up beginning of May so they're foraging middle of May to the beginning of June. Gotcha. So you hit a lot of species actually. A lot is blooming at that point. There are still spring species, but we had a range of diversity at our sites. So we were looking at species richness, so the number of species per site. We had a site that had only eight total species blooming within a 100-meter radius of that box. And they were all non-natives.

They were all invasive species actually. So that was our really low site. And then we had a couple of sites where there were like 35 to 40 species blooming. So it's a total range across the board. Of what's blooming, what they have access to, and then who knows where they're going, but that's coming in soon.

Speaker 1: You sometimes hear people who propagate mason bees as like, you need Oregon grape and maple. They just need a site that has those things in abundance. Is that the case? Are you finding that it's actually more complicated than that?

Speaker 2: I haven't seen them at Oregon Grape. And I've heard that too. We have obviously a lot of Oregon grapes across Seattle.

Speaker 1: The maple is really- Why do they call it Washington grape, eh? Yeah. Yeah, okay, all right.

Speaker 2: The maple is an interesting thing because there were a couple of sites with maple and they did seem to do well there, but I see this variation across the board. I've learned this lesson that when I first started with mason bees, everyone said that they were very finicky. They need this exact placement. They need to be within this range of a resource.

They need to be my maple or Oregon grape. And what I found is that you kind of get to know how they work the more you work with them. And I can look at a site now, I think I can look at a site now. And I can say, yeah, if I point the box in this direction, they'll be happy. No matter if it's covered in trees or if it's two degrees cooler or if the sun doesn't hit the box at exactly the right angle, you really learn how they manage on their own and you get to know them. So I've seen a total variation across the landscape. I've seen them on everything. So it'll be really interesting to connect all those visual observations with what they're actually doing.

Speaker 1: You also, before we talked, you talked about a bit of research that you're doing where you're looking at whether the bees go out early, regular time, like can you talk a little bit about those findings?

Speaker 2: Yeah, definitely. So this is all preliminary. I have no results for any of this, which is another great science.

Speaker 1: Listeners, don't come back and...

Speaker 2: Yeah, don't harass me. No, no, I don't know yet.

Speaker 1: Preliminary research update. Okay, go ahead.

Speaker 2: Yeah, so what we're doing is we have the bees out at what I consider their normal, think of normal in quotation marks, right? Normal can change all the time. But when the bees would naturally emerge, we're putting them out. At the same time, we're trying to put them out really early in the season and then really late in the season. And it's tricky because when you're overwintering them, bees are just like bears. They need fats to store in their bodies to survive this hibernation period. So if they don't get the right fats, or if you keep them too long within that hibernation period, they won't be able to survive the entire time.

Speaker 1: Oh, but on the flip side, that's when all the flowers are out.

Speaker 2: Right, right, exactly. So you can't push them into, especially breeders, you can't always push them deep into the summer when there's actually things blooming that they can survive on. And it's tricky with almond pollination. You have to time them perfectly with almond pollination. So that's been really interesting to talk to growers about with this synchrony idea of you need to have them out when the things are flowering, but they may not survive until that point. So by putting them out early and then putting them out late, we're kind of testing this idea of like, if we push them, right? If we push them to their limits, and if the potential for a climate change scenario is that we have this flower de-synchronization, so we have everything blooming at the wrong time, either we get a really warm spell or a really cold spell and it pushes everything back. What'll that do to the bees? Right. So how will climate change affect the bees? That's such a great question. Yeah, yeah, it really is.

Speaker 1: So this is really starting, so we're not gonna, you don't tell us how it's going.

Speaker 2: Yeah, I have no clue. We're doing it. And what we're getting is, we're putting them out early in the same systems, or putting them out late in the same systems, and then we're really not accumulating too much pollen, which makes sense. So the preliminary results I can tell you, or at least what I've seen, is that in the very beginning, the early bees, so these are going out in February, which is way before their time.

They're like emerging in February if they emerge, and then they're foraging in March. And we talked a little bit about this, but in Seattle, it rains all the time, especially in March, you get these off-and-on showers. So if it rains while the bees have woken up and are waiting to go forage, they'll starve, because they're just waiting in their nests for the rain to end.

Rain also washes pollen off of flowers, because that can have a detrimental effect. And at the same time, it's also cold, right? They need warmth to survive. So the bees in the beginning aren't doing so hot, which makes a whole lot of sense. And the ones that are surviving, they're foraging, but they're getting a lot smaller pollen groupings.

Their pollen provisions are smaller, and they're laying a lot fewer eggs. So it all fits, right? The late season is interesting because they've been doing okay. We've really been getting pretty high numbers. And I think that's because we're not hitting the really hot part of Seattle.

That's a relative term. It doesn't get hot in Seattle, but we're hitting the warm period, right? So there's this point in maybe late June, early August, that it gets really, quote-unquote, hot in Seattle. And we're missing that because we're only pushing them to maybe July 1st.

Speaker 1: But I've heard people say this. The last couple of years have been weird years. It was just a little bit wet. And if they just waited a couple, the people who held some back and let them go loose seem to have done okay with those.

Speaker 2: Yeah, yeah. It's a tricky balancing act, right? I think you could say that every year, especially in Seattle, where it might just rain one day. You might just lose all your bees.

But there are definitely a lot of people delaying their timing because we have had a lot of really weird years, really, really wet years, and then really dry years, just a mess. But that just helps my synchrony experiment, right?

Speaker 1: Well, I guess going back to it, it's not just the management, but you know, Osmeal Ignari is a good example, an exemplar of a native Spring Bee. And with climate change shifting, obviously, as managers, we can come up with these schemes to move things forward-backward, but the wild populations.

Speaker 2: Yeah, yeah. And I think there's this really interesting question of, especially in park systems, right? And we're coming through it and we're laying down a bunch of development. And then sometimes as a second thought, sometimes not, we're saying, okay, well we should put a park in. We should create a nice green system for this. And we plant a bunch of species. We probably look at a native plant list because we wanna be good to the restoration ecologists.

Of course. We plant all these native species, but we're planting species that we've seen bees on, right? We're planting things that, yeah, we know bees visit them because we've seen them on there, but we don't really know the effect it's having on the bees. Whether one plant that we see them on, it's better than another plant that we see them on, or if they're foraging on things we don't even think about, like clover, a ground cover that we usually pull out. They've shown that that's vital for a lot of honeybees in between the big blooms. So it's this really interesting question of, what should you be planting on that landscape? What's the best?

Speaker 1: It's good. When you think about apiculture, they've kind of worked this out. It's like they go in, they measure sugar concentration, they can tell you how much honey you'll, but really when it comes to native bees, visit constitutes a check mark.

Speaker 2: Exactly, exactly. And you see that a lot with a lot of these studies. A lot of diversity studies. And it's really cool, but it's cool to create a connection between the landscape and the bees too.

Speaker 1: Yeah, you can actually see what the outcome is. Exactly. All right, we'll take another break and then I got a couple of questions to ask you. Great. So, okay, we're back.

I ask all my guests these questions, well, most of them, sometimes I let them off the hook, but I'm not gonna let you get off the hook. So first thing is, do you have a book that you would recommend?

Speaker 2: Oh, okay. Well, I am a grad student, so I have no time to read books. I barely have time to read papers, let alone books. I can recommend a paper. Let's do it. Is that too drastic?

Speaker 1: No, no, no, people, a lot of these papers people can get. It's often like it's behind a paywall, but oftentimes people subvert the paywall and put it on their research net thing.

Speaker 2: Also, you could just email me and I'll send it to you. I'll sneakily send it to you because I don't wanna leave anyone out in the next. Okay, great. So this is totally not what I'm studying exactly, but within the Osmia system, there has been a lot of talk about the mud that they use between their segments. Oh my God.

Speaker 1: Everybody talks about the special mud.

Speaker 2: Everyone has like, they'll sell you a thing of mud and like, which I understand for people live in like Arizona, you know, the desert. There are so many different types of mud that people recommend for this. And there was a paper that came out in 2018 and it was looking at what exactly that mud was made up of. So what actual soil types were in the mud?

And it was like a total mixture. And basically, what they were, their hypothesis was, well, sand is really hard to pack together. And the bees are probably not using sand because they're trying to make these perfect little walls and they're, you know, they're expending a lot of energy to go get the mud. Why would they get sand when they could get clay? So they expected there to be these really high levels of clay and really low levels of sand. And what they found is it's a total mix. They're just taking from everything. A lot of loam, a lot of sand, a lot of clay, just these interesting mixtures, and in different landscapes it changes and...

Speaker 1: Because sometimes you see the cocoons are all flaky. Yeah. It's like, you know, it's like, they use tender flake or something. It's like, it's like, it doesn't look,

Speaker 2: I don't know if they do it. Yeah. So the mud is really cool. It was really a great paper and it was like these tiny little pieces of data, right?

Like these tiny little caps on the nest and they just collected a bunch of these and tested them. Do you remember the name of the author? I don't, but I could look it up.

Speaker 1: Okay, so we're gonna link it on the show notes and you guys can take a look at it and we'll not tell anybody. We're gonna sneak you a PDF. There'll be a link to a PDF on there. Okay, awesome. Okay, do you have a go-to tool for working with pollinators?

Speaker 2: Well, what's nice about my pollinators is that they don't sting. They're really gentle. They'll just crawl all over you. So I don't have to worry about any devices or anything. Honestly, the genetic stuff is kind of the newest tool. That's been really exciting.

Yeah, that is cool. Yeah, and being able to pull so much information out of such a small thing with the pollen is kind of insane. I went to school for plant breeding and genetics and then I decided to never go into that route and then I found myself in grad school doing genetics. So it's been interesting because it's forced me to become an expert on something that I really didn't expect to ever touch again. But it's awesome. There's so much information that you can gather and people are really excited about it.

Speaker 1: That's a really, I have to just comment on the last thing, it's really great when you learn something. I was a medical, I did medical genetics when I first started and it's like, I'm never doing this again. It's so specialized. I can't see the bigger picture. And then I started doing the bigger picture and I look back and it's like, oh, I can use that tool.

Speaker 2: That's a great way to go. Yeah, I think in undergrad you think none of this is ever gonna matter or I'm gonna go, right, I'm gonna go so deep into it. Grad school is cool because it allows you to zoom out on everything, especially PhD programs. You can build your experiment, right? So everything matters to you really deeply. Oh, PhD is a magical time. Yeah, yeah, I hear that.

Speaker 1: Painful. Yeah. Okay, last question I have for you. Is there a pollinator group that when you see it fly by you're like, oh.

Speaker 2: Yeah, so this goes back to the bumblebee thing. I love bumblebees. I'm dying to work with them even though I don't study them. We have a lot of Bombas Vasanacensky in Seattle, these giant bumblebees and they've got some white on them and they have like this yellow strip across the back two ends and they're just, they're so cool and they're huge. Like you can hear them coming. They just fly by your ear and you kind of duck. And I've seen a lot of the females, the moms out on flowers and on leaves and they just like, they take up the whole leaf. Huge.

Speaker 3: So I still have such a. I own this leaf. A love in my heart for Bombas and the native Bombas in the Pacific Northwest are so unique and so cool.

Speaker 1: Yeah, and we were talking about this. They make really big nests. Of all our bumblebees, they tend to have like, they grow and grow and grow.

Speaker 2: Yeah, yeah, you see them everywhere. Like every bumblebee basically that you see in Washington is the boss.

Speaker 1: Same in Oregon. Yeah, yeah. They're really predominant. Well, great, well I'll let you get back to ESA. Thanks for taking the time to talk with us.

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