172 - Theresa Pitts-Singer - Where next for managed solitary bees


Andony Melathopoulos: [00:00:00] There's increasing interest in using solitary bees in the pollination of major agricultural crops here in the Western United States. In some ways this has been going on for a very long time. If you recall an earlier episode with Weldon Hobbs and Jim Cane, as well, with the alfalfa leaf cutting bee. But more recently it has seen the increased use of blue orchard bees and to get a better picture of what is the status of these solitary bees and a Western agricultural crop pollination, but also what are some of the kind of horizons and challenges with increasing their use?

I reached out finally, we've been trying to get her on the show for awhile, to Dr. Theresa Pitts-Singer. Now, Dr. Pitts-Singer is a research entomologist at the USDA ARS pollinating insect research unit, known as the Bee lab in Logan, Utah. She's had over 18 years of experience and research into alfalfa leaf cutting bees and blue orchard bees, and so I thought she'd be an excellent person to address the broader picture of the solitary bees and where they are right now, and what we might expect from them.

And Dr. Pitt singer is going to be talking about a lot of these issues at an event this this week, March 10th at 10:00 AM eastern time, The Pollinator Report, Seasonal Bees at Your Service webinars series. I'm going to have the link in the show notes so you can check it out.

It's going to have everything that we're going to talk about today, but with some beautiful pictures; don't miss it. And without further ado, let's dive deep into the world of solitary bees and agricultural crop pollination in the West this week with Dr. Pitts-Singer.

All right. I'm so glad to have you on the show finally. I've been angling. I think I even chased you at an orchard bee association meeting with a mic and you ran away, but I finally pinned you down.

Theresa Pitts-Singer: [00:02:07] Yeah. Sorry. I don't even run that fast.

Andony Melathopoulos: [00:02:13] Welcome finally, to PolliNation. And we were talking a little bit about the show and I think we really want to talk about solitary bees and their role in agriculture. And to begin with, can you go through some of the managed solitary bee species that are available to growers in the West, and what crops that have they been used historically to pollinate?

Theresa Pitts-Singer: [00:02:32] Sure. I would say the most famous solitary bee that's used as a crop pollinator is the alfalfa leaf cutting bee.

That is a non-native bee that got introduced in the U S kind of at the ports of entry in the, I want to say the late 1930s, early forties, that's when they found it in museum collections. And then people like in the fifties, up in Canada and around here in Utah and Oregon Washington area saw that that it was in the alfalfa fields, but they didn't realize what a good pollinator it was until they started to really look into it. And what they realized was out in the West where it's nice and dry and alfalfa grows really well, and you can stress a crop of alfalfa so that it sets a lot of puts out a lot of flour and sets a lot of seeds, that when these bees visited the flowers, they tripped the flower, which kind of pops it open and releases the stamina column, which is the place where the pollen is. And so the pollen is released; they stick their heads down in to the flower to get nectar and wiggle around a lot and collect the pollen. They were three times better at pollinating or transferring pollen between the flowers and then within the flower itself, just popping it open and tripping it than honeybees.

And so people had been bringing honeybees into alfalfa to pollinate it, but we were like, wow, this other little bee does such good job. What is it? Where does it come from? How can we get it to stick around? And that's when the research all started back in the fifties. In Canada, I think Hobbs, I think you had Weldon Hobbs on, I think his dad was one of the pioneers of all of that.

And then Bill Stephen, he's in Oregon? And then Dan Mayer, I think he was in Washington, they were all kind of the major players. And then Ned Bohart in Utah, which had a different name, but the bee lab where I am now is where he started with all that.

And so it's been around for quite some time and it's a whole industry has developed around it. And the major source of the bees is from Canada, where they raise bees really well, like they can get three times the... so you put out X number of bees and they get in Canada about three times back, in the U S we get about half as many back because we farmed so intensively for the seed production versus the bee production. And they're more likely to use pesticides or just, we have a lot of disease and parasites and stuff in the U S too. So it's a one-way traffic from Canada into the U S for getting those bees. But that's been going on for a long time, and that's what my job was when I first came to Utah was specifically to work on that.

Andony Melathopoulos: [00:05:08] It is surprising to me because the last decade there's been a lot of attention on crop pollination, and I haven't heard a peep, it has not made the New York Times. The alfalfa leaf cutting bee is out there doing this job in it, but it's a huge pollination event in the United States.

Theresa Pitts-Singer: [00:05:23] It is, and it's magnificent at its job. And, in a way, probably the reason we haven't heard from it is because it hasn't had the crisis that the honeybee had. It doesn't have Varroa mites, and it doesn't have the colony collapse, or the pesticide that stored in the waxes and stuff.

So it's because probably it is saddled with the one crop, and a specific use. And the farmers also know that it's so valuable for setting their crop and making their crop profitable, that they take really good care of it. And a lot of the farmers are also bee managers, so they don't call in the honeybee people to drop off some hives; they do a lot of the management themselves.

I think it's just a different attitude about having the bees there on their farm. But they haven't really had a shortage of bees; the price has gone up from when I first started working at the bee lab there, the bees were say $15 to $25 for every 10,000 live bee cells, which is what's called a bee gallon.

And then the price jumped to $125 at some point, and maybe it's down to maybe $55 right now. So it just waxes and wanes with the need for seed production from the proprietary seed companies. And also how good the weather was in Canada and the supply of bees are. So all those things factor into the economics of the price of bees.

And sometimes the contracted seed production reflects that high dollar amount for the pollinators. And sometimes it doesn't; it's always just with anything in the economy, there's always like somebody's mad at somebody else because the price of whatever is different this year, but it's an interesting thing to learn about and to understand.

 I find it fascinating. And it also helps me understand why my job is important for having to figure out a way for American farmers to do a better job at raising their own bees. The more bees they get back, the less they have to buy to supplement in the next year, because the bees are only around for a little while; they're not around year round, like honeybees are, and so they're a one-shot deal.

Andony Melathopoulos: [00:07:26] Okay. And so you've done a lot of research and working out the emerging problems on alfalfa leaf cutting bees, but you've also worked on other solitary bees species. Tell us a little bit about the other actors in this Western pollination.

Theresa Pitts-Singer: [00:07:41] Sure. The other bee that I know, cause I don't know bees in general, but the other bee I know very well is the blue orchard bee, which is Osmia Lignaria. It's a native bee species, and it's prowess as a pollinator was probably figured out in the seventies, some of the papers started to come out. And that was a bee that people at the bee lab noticed were great pollinators and like apple orchards locally.

And then they realized that it's an early spring bee; it overwinters as an adult. It's a solitary bee, a cavity nester. It's just it's a bigger bee and it has some different qualities, which have been interesting to figure out from the leaf cutting bee. It's the same family of bees, but it comes out in the early spring with the orchard flowers and pollinates only for about six weeks.

And the adults are gone after that. It can be too hot for them, for sure. And we don't have an easy supply of them from Canada. We have a lot of people are getting them from trapping them in the wildlands where they exist freely, and then they bring them onto farms and try to propagate them on farms, and that never works out as well as anybody hopes.

So they're always re trapping them from the wildlands. So one of the main things we've been working on with that species is increasing their retention on-farm and production on-farm. Plus trying to figure out other ways to raise them besides trapping them from the wild lands. And understanding where if there's local adaptation to these bees where if you wanted to use them in California almonds, which they're great in, can you source them from Utah and Washington without consequence? And the answer is no. So how do you manage them so that you can keep them in California and use them there and not have most of them die before the next year?

Andony Melathopoulos: [00:09:26] All right. Let's see. We'll come back to challenges, cause I imagine this is a very different model than a beekeeping and it has all sorts of... each species seems to have its own kind of problems.

Theresa Pitts-Singer: [00:09:39] Yeah, it does. Yeah. There's some that are the same, but then they're unique in their own ways, which is fun.

Andony Melathopoulos: [00:09:45] But with blue orchard bees, you talked originally that people started to notice it in Northern Utah, on apples, but where's it primarily used these days?

Theresa Pitts-Singer: [00:09:58] Yeah. It's not used much in Utah. It is primarily being used and recently so, in almonds in California, And somewhat in cherries in California. And so I hear in cherries in Washington and maybe Oregon. I know my team has a research project we're on year three, introducing the system to people in Washington who are some big players in cherry production, and we're trying to show them that you can produce these bees in cherries.

We are showing that you can enhance fruit set, but we have not yet shown that you can increase fruit yield because these people are still using their full complement of honeybees. But what they're learning is that these bees work in the cherries and work well in the cherries, and maybe it offers them a little bit of comfort in knowing there's another bee that can be a pollinator in those cherries.

And what's interesting is the difference between osmia lignaria, the blue orchard bees and the megachile rotundata, the leafcutter bees is that when you add leaf cutting bees to alfalfa, it's way better than using honeybees, like three times the seed yield you get by using the leaf cutting bees.

With the blue orchard bees, it's just an either or situation. The honeybees do fine, but if you have orchard bees, instead, that does fine too. If you have orchard bees, half and half orchard bees and honeybees, you may have an increase because of some interaction that we don't quite understand yet. And that increase is usually in fruit set and not always fruit yield.

So for a crop like cherries and almonds, where you could set fruit from every flower as opposed to apples, where you might have to, if you want big fruit, you got to get rid of some of the flowers, so you don't need to set fruit on all of it. But if you could maybe manage the orchards to hold on to all that fruit throughout the whole season, so that it's completely ripe, mature fruit or nut at the end of the summer, then you've increased your yield.

What happens is you get more fruit set in the spring. So more of the flowers are turning into fruit in the springtime, but around June or so in almonds especially, the nuts drop because the trees can't handle them. So you lose that rich pollination you got in the spring time; it's not carried over into yield and late summer because around May or June, a lot of that fruit drops off the tree and doesn't mature and it's not available as yield.

Andony Melathopoulos: [00:12:31] I remember somewhere I read a study where they would look at the leaves after a heavy fruit set and they would change; they dropped their leaves quicker. There is a lot of stress on a plant to carry a huge crop. And so I guess what you're saying is that there's, if I just recount this, people are seeing these benefits that may not necessarily be a yield when they're combining the two bees.

So there's seems to be this kind of like magic that happens when two bees are around. People are not maybe realizing those benefits because they're getting this kind of super abundant pollination. And so the people haven't figured out nutrition management for those trees. It's like you maybe need to give them a little bit more juice.

Theresa Pitts-Singer: [00:13:20] Yeah. And one horticulturist I did ask about this very thing, because there's a lot of variation between orchards that we've worked in across Maine, across areas. And then year to year, they change so much. And so one was good in one year, in one, not in the next one.

They're not even on a schedule. It's not even every other year. It's some years it does. And some years it doesn't. But what they said was if you have spring come on so fast, especially in Southern California, the trees just can't handle it. But if summer comes on too fast, not spring, but if you have that nice transition from spring to summer, instead of instant summer, you can carry more of the fruit.

But also you think about California, the water stress. That'll alone has got to play into that. And there's probably some company trade-offs on knowing that they've got all these acres, they only have so much water, and they're regulating how much water they can use. They already know they're going to lose some crop, but they have it balanced out for the economics to work out for them, which is some formulation that I don't know. But that probably plays into why they don't, just say "why don't you water more? Why don't you do more?" It's maybe it's not economically in their favor to do it, these days.

Andony Melathopoulos: [00:14:34] Okay. Moving away from plant management, cause clearly there's a way in which, and I was thinking about this... we had a episode quite a while ag  on blueberry, and bringing stocking rate of honeybees up high and suddenly this kind of maybe changes things.

People have been adjusting nutrient management or water management to two colonies per acre or four colonies per acre, and suddenly you double it. And you may not see those full benefits under the old settings.

I wanted to come back.  One of the things I often think about when it comes to Mason bees or blue orchard bees, you see these little memes of 40 honey bees is worth one mason bee.

But I think what you're saying is the way in which this is actually coming about in agriculture is not replacing honeybees with blue orchard bees, but there's this refocusing on how you might hold these two bees together in this kind of magical thing that happens when, well not magical... it's very biological, we just don't know what it is. These two bees are working together, tell us a little bit about that two bees and why two bees might be a better strategy than one bee.

Theresa Pitts-Singer: [00:15:41] Sure. We all love diversity, right? So maybe that's just part of it. So I have a pretty slide I like to use where I have a honeybee visiting a flower and a orchard bee visiting a flower and the honeybee you'll see, putting her face very carefully into a flower, into the goodies, and honeybees are also very specific that they're collecting just honey or just nectar or just pollen. But this particular picture has a bee that looks like she's collecting some nectar at the base of the flower, and her hind legs are packed with pollen. So that pollen is nowhere near the ovial or the stigma that it needs to touch in order to deliver that pollen to where it needs to go so it can fertilize the ovaries.

Andony Melathopoulos: [00:16:28] Maybe because a honeybee is really trying to move that pollen off her body as quickly as possible to her corbicula in the back. So it comes off the body. Okay.

Theresa Pitts-Singer: [00:16:37] And she packs it wet, and there it is in those solid little pellets on her legs. And then my other picture is this blue orchard bee, and you can't even see all the anthers and the stigma on the flower because her body is all over it and she's wiggling around all over it, and she's collecting the pollen on her belly with all her hairs and it's dry and it's falling off all over the place. It's getting transferred all over the place. There are two different forging behaviors that may be helping in this system.

 A very wonderful person who has studied synergisms between wild bees and honeybees, Claire Kremen, once gave a talk where I was an attending, and she talked about that the interaction may be that the methodical nature of a honey bee going from flower to flower on the same plant or the same tree may be picking up some of this loose, crazy pollen that's left behind by a blue orchard bee that's collecting this pollen dry, dropping it everywhere, making a big mess, going all over  different trees and zooming around. And, but then that honeybee picks it up and gets it on her body hairs and methodically delivers that extra variety of pollen around on that same tree.

And so there does a very systematic delivery of the... You need two varieties for pollinating almonds and cherries. So you want from one row of trees to cross over to the other row of trees. And that's what a blue orchard bee also does. 

Andony Melathopoulos: [00:18:07] So she hypothesized that because the blue orchard bee is dropping pollen all over the place from different cultivars, it's just falling off. Then when a honeybee then goes in its regimented way of moving in each of its visits, picking up a little bit of that compatible pollen. And so her visits are better than they would have been all around.

Theresa Pitts-Singer: [00:18:27] And then delivering it within one tree, instead of pinging around like the way the orchard bees do it. So together they're doing like this cool job, as opposed to just each one doing their own thing.

Andony Melathopoulos: [00:18:39] Okay. That sounds like a really good system then. You've building on the strengths of both species and putting together into one pollination system.

Theresa Pitts-Singer: [00:18:47] Cause the other theory was that, say a solitary bee is visiting a flower and a honeybee comes along and it pisses off the solitary bee who flies off and it gets it to move around more, or the honeybee, vice versa. But you don't really see that often you hardly ever see the blue orchard bees in the orchards, you see a lot of honey bees, but not the orchard bees.

And so, where are they? What are they doing? But they're out there doing a lot. It's just you don't see them because they zoom around quickly. They just don't stay in one place long for your eye to catch up with them.

Andony Melathopoulos: [00:19:16] Interesting. I've often heard that and I've wondered how to explain that to a grower. You've bought these bees, but you won't see them. And I wasn't sure how to explain that.

Theresa Pitts-Singer: [00:19:27] Yeah. The other thing is if you've got a hive of honeybees out and the equivalent that we've come up with for management is 400 female orchard bees. You've got potentially 10,000 female honeybee foragers versus 400 female orchard bees out there.

Andony Melathopoulos: [00:19:44] Oh by virtue of numbers, you're always going to see honeybees. Yeah. Yeah. 

Theresa Pitts-Singer: [00:19:47] But they may be some are only collecting nectar, some are only collecting pollen, where the orchard bee is collecting both, but zooming around for whatever reason, she moves around a lot more. It's just her behavior.

Andony Melathopoulos: [00:19:58] I was thinking that this two bee thing, I was familiar with it when I was working with Dr. Shelley Hoover and in Lethbridge Alberta where there, the hybrid canola seed production always uses two bees. Seed industries there always used honeybees and they use leaf cutting bees, and the idea would be something along the same line. That's a compatibility issue that the honeybees you have to move from one bay of plants to another bay spatially, and that the honeybees tend to go up and down the rows.

Theresa Pitts-Singer: [00:20:26] They're little automatons. They're just very specific. I'm going to go in this direction until I run out, as opposed to just exploring everywhere.

Andony Melathopoulos: [00:20:37] Okay. So where we're looking right now with the blue orchard bees in the West, is this is the model that's starting to emerge. And I think the other thing I heard when you were talking, is that this is recent. This is not something that's been going on for, 50 years like Alfalfa leaf cutting bees. This is the last decade or so or 20 years. And so we're seeing that people have some honeybees. Do people typically take the rate of their honey bees down, or what's the kind of practice are you seeing out there?

Theresa Pitts-Singer: [00:21:03] So I'm hearing about the practices. I don't get to do the practices. We did have a couple of years where in doing some research, a collaborator allowed us to add orchard bees into places where they put half their stocking rate of honeybees. So we had that very situation and we saw that the yield was equivalent to other years that they had.

And I think that gave entrepreneurs who are trying to be suppliers and pollination specialists using the orchard bees, they have taken that model. And we actually got the information from someone else as well, so we just tested it. And then so people have gone with that with the kind of the backing of science to say, yeah, this should work.

And it keeps working. So that's what I hear as where we're at, and we're starting to get some testimony from real users and people who are making it practical for their systems, and trying to transfer over to that kind of system. It reminds me a lot of alternative fuels.  It's taken a while for people to make a decision that they want to change and invest the money in it, and the early investors have to pay a lot more than people who get at it later when the prices come down, when it gets all figured out and when all the bugs are worked out. So there's the early adopters. And then the people who can benefit from all of that as it becomes affordable for more people.

And more mainstream, and more testimony that it's worth having, and it works just as well.  I got a hybrid car and people are like, "yeah, but I bet you can't go up the hill." Of course I can. Better than your car, and you can't tell the difference. I forget to go get gas cause I do it so seldom, but it just kinda reminds me of that.

It's a change in attitude and how you go about things. And also you can't just call up and say, "Hey honeybee keeper, come into your thing, drop off some hives and feed them if they need it." It's, it takes a different level of management and a different type of management to do orchard bees.

These honeybees are the extreme different bee. It's not which is always funny. All the other bees are more the same than anything is like the honeybees. And so the honeybees are the weird one, but it is because it's transportable and lives in this man-made house.

The hive that we give it, it makes it a unique bee that it's a minimal to moving around as the pollinator. For the orchard bee and the leaf cutting bee, you can't just move them around like that and you can place them in a place so that they will pollinate, but you're one and done. You can't take that and do the next crop or truck them out somewhere else because they're done.

And you might have a different stock that you hold back and use a little bit later, so it's just a different mindset of how to do it. We do have a project where we're trying to overlap the two, where you can emerge orchard bees off of the top of a honeybee hive. There's a patented device that's available for doing that and we're field testing it right now.

But one of the challenges would be would a honey beekeeper let you mess around with their hives. And when you release the bees, are they being co-located with the honey bees will they still go out and visit all of the orchard, or will they want to stay close by, or where will they go?

Andony Melathopoulos: [00:24:19] The idea would be that on top of the honeybee colony it's warm. Okay.

Theresa Pitts-Singer: [00:24:23] Yeah. Yeah, because otherwise when you manage the orchard bees, even though they overwinter as adults, in the early spring, like in February, when almonds bloom, you have to heat them up artificially to get them to chew out of their cocoons and then fly out.

And if you just put them out in the orchard, like ready to chew out, they'll still take forever to chew out and bloom will be gone by the time they all get out and you'll waste them. So it's almost a hundred degrees on a honeybee hive. We've recorded the temperatures inside with this little box, that's a false top on a honeybee hive, and they do great. They come out really fast; within three days all your orchard bees are already hatched out and out in the open and, so it's fun, but we're going to field test it in Washington this year.

Andony Melathopoulos: [00:25:07] I suppose the last thing I just wanted to mention, or explore with you a little bit is, that I guess the fact that honeybees can be trucked around also you have to have a real good partnership with your beekeeper because delivery can be challenging.

I was thinking in situations where you have a cool spring in almonds and the Pacific Northwest that heats up, you can have a situation where the bees aren't quite done in almonds, but they need to be in cherries, pronto. And that with these other bees you they're yours and you can start them up when you want to start them up.

Theresa Pitts-Singer: [00:25:40] Yeah. Yeah, you can. Once you get them into cold storage, which happens in the fall, the orchard bees and the leaf cutting bees, you can bring them out of cold storage when you're ready for them. So you could use some of them that you overwintered in almonds, and you can use a different batch of them that you incubate later for cherries and or even into some cane berry crops.

Then you have the leaf cutting bees that can be used for canola and for alfalfa. And they foraged for about 11 weeks. Some of those do, and even in the leaf cutters, they will go through different generations in the summer in some hotter areas. And so that's like a whole o her meaning towards it.

I've never really gotten to see that because that happens like in Southern California. But that's another strategy that can be used. But once then they're into winter management, you can hold them quite, quite a long time beyond what you could like honey bee hives. Because they're always active and once they get active, they're gonna have to find food and eat.

Andony Melathopoulos: [00:26:38] Super. Wow. Let's take a quick break. We'll come back. I want to explore, I love that metaphor you have of like alternative fuels.  What are the challenges to the alternative fuels of crop pollination in the West realizing themselves? So let's take a break and we'll come back and explore that.

Okay. We're back. I want to think about this question of what are some of these obstacles to people using solitary bees in Western crop production at a higher level? One of the things that comes to mind is, are there some crops that you think are a really good fit for solitary bees that we're just not even thinking or using them? So what are the obstacles? What's holding us back?

Theresa Pitts-Singer: [00:27:18] Yeah, a little bit back to that attitude question. So it's having to try a new thing and not knowing if you have all the parts and pieces. I kinda started a new project. During this COVID stay at home stuff, I started doing some artwork and I was like, I don't know if I could do it and I don't know if I have all the tools to do it. And so I've had to challenge myself to go out and buy a few things to make an investment and some things that I didn't already have and to go online and read about it and learn about it and to take a chance and not even know if I was good at it.

Maybe I'm not no good artist at all. And so I found out a lot of things for myself and now I'm happy with where I'm at, and I could go a lot further. So with the orchard bee stuff or with the leaf cutting bee stuff, it's a whole different set of equipment. You have to have a whole different tool set compared to the honeybees.

And there's not a lot of people around who know exactly how to do it. For the leaf cutting bee there's more information there. If you live in the West and you have almost a family tradition of doing it because you have to have some specialized equipment that you can't just go to Home Depot and pick up. It's not just there.

 There are specially made bee blocks and puncher outers or scraper outers, or I don't even know if they have real names. And then you have to have big coolers to store bees in and incubators to heat them up in and then transfer them out. And there's not many companies that will come and do that for you. Actually, there's probably only two or three that will do it for you.

And it's the same with the orchard bees and they each have their own sensitivity about how to figure out their timing, partly because of how they overwinter. And then also on the crops you put them on, some crops go fast and some crops have a lot of flowering for over a longer period of time. So it's really important how you're able to manage them.

So it sounds really nuanced and a lot scary. There's a lot of things you could mess up. But then you also only have to be scared about it and worried about him for a short period of time versus honeybees that have to be managed the whole year around and they'd have to be split and you have to worry about the queen.

Whereas within the solitary bees, every female is her own queen and worker. She does everything herself. So it's a whole different mindset about how to work with them and also not be afraid of them. They don't really sting such that you have a bad reaction. And so it's hard to get stung. You don't get attacked or swarmed.

So I think it's about being educated. What to do with them. And knowing that they will work for you. And so that's where it takes researchers like myself and educators like yourself who can break down the science to the persons who want to use it and then ask all the right questions.

But it also takes the curious user. Reminds me of some Malcolm Gladwell stuff, like having people hit a tipping point and people who adopted, and people who like to talk about it, and then the people who eventually become the mainstream users.

Andony Melathopoulos: [00:30:28] I was thinking about with leaf cutting bees, that at the beginning of the section you talked about how there was intensive research, took years of development, and now it's pretty ubiquitous. You point out we've gone through this period of where honeybees have had a lot of difficulty, the supply chain and production chain is so resilient that there's just a lot of supply out there.

 I guess Mason bees being newer, is it useful to think about this timeline with leaf cutting bees as the kind of, in a couple of years it'll automate. Or is it really so different a system that making parallels to leaf cutting bees is a little misleading?

Theresa Pitts-Singer: [00:31:10] Yes. I think both things. The big differences that the leaf cutting bee is not a native species that we in a sense care about. In if we destroy the leaf cutting bees, we we've just destroyed... this is terrible to say in a way, we just destroyed an exotic species that was never intended to be here in the first place.

Alfalfa is exotic as well. But when we lose the orchard bees, we could wipe out or cause epidemics in a native species that could spread from commercialism back into the native environment, like what's happened with our native bumblebees.

And so that's a different kind of worry that I personally have. I don't want to see that happen, but also there's a n interesting thing about being a native species and a non-native species. I think when exotic species come and they are able to adapt to very disturbed, highly disturbed environments, they have some sort of characteristics that make it stick.

Not all organisms that get moved to a new place, get established, but some do. So what are those characteristics that make them amenable to that? They're trashy species, the fire ants and other bugs and stuff. They just can deal with the human environment. And I think that orchard bees have a little of that, like more nativism to where they're not so amenable to being manipulated.

They're not a trashy species in that sense; they are disturbed by us handling them and moving them around in ways that I don't think the leaf cutter bees are. And in my own research, I've seen that you can, by the odor cues that the bees use, the orchard bees are much more particular and can be much more disturbed if you mess around with where their nest holes are or if you take away their odors, they'll get so confused when they come home to their nest, if it's been messed with that they might leave. Or like when fungicides are sprayed and they get the smell odor or something going on with them, they'll leave. Whereas leaf cutting bees will be like "Something weird went on here, but oh yeah, whatever. I guess I'll just come on back and do this. I'll just stick a new hole." They're just, kinda like dogs and cats, like the puppies are happy to see you most of the time. And the cats are like maybe not. But, so I think those nuances are going to make it a little harder for the orchard bee to be to work out so well.

And they also are more keen to disperse from a release site compared to the leaf cutting bees. Oh, one other thing I'll say. So we put out say a thousand bees per acre. So that's 400 females and then a bunch of males. So a thousand bees per acre when we're working with blue orchard bees. When we're working with leaf cutting bees, they put out 40 to 60,000 bees per acre. That's a gazillion bees and they really just flood the landscape with them. And they want a lot of seed production. There's a lot of little tiny flowers out there for alfalfa seed production and canola too. But in my own research I've found that a lot of those bees don't stick around either, but you don't realize it because of the supply and the numbers you start with are so great.

And they're the way that they are so happy to nest in these huts with a gazillion little bee holes, and they can find their own nest and use whatever holes... they're just so much easier to deal with in that regard. We're blue orchard bees, they don't like the big city. They like to spread out and be in the country and have their little nooks.

Andony Melathopoulos: [00:34:29] I remember that with leaf cutting bees, almost every hole is plugged in. It's reliable. I remember growers would come in and they would replace the blocks halfway in and they could maybe fill another block up. And I was like, Oh, that's amazing. Yeah.

Theresa Pitts-Singer: [00:34:45] You don't have that problem. Air quotes... problem in orchard bees. So you don't really fill up blocks so much.  Because I don't think they'd like to, I think a lot of those holes are made by the same females. They kinda spread out a little. And so they're not that kind of aggregating species in the same way that leaf cutting bees are.

There is another bee that's been introduced. Another Mason bee that's introduced into us for crop pollination. It was intentional. Osmia cornifrons, and I think it has that kind of trashy personality in that I think it might do a little better because it's okay with all that disturbance.

Andony Melathopoulos: [00:35:22] Okay. So we've got there is this time factor of working the kinks out, which is going to take some time, and the automation bringing the price down. But there is also the fact that this species the blue orchard bee is a native species, and maybe it's just going to be a little harder to get to the same level of output and drop the price and supply as it has been for leaf cutting bees.

Theresa Pitts-Singer: [00:35:45] Yeah, that's my general feeling, although I'm still super hopeful. I mean I'm not naysaying whatsoever. I still think it's a great bee and a great compliment to honeybees. I just don't think it's not a direct comparison to the leaf cutting bees. The other thing is that. The mechanistic way that they punch the leaf cutting bees out of their nesting holes with machines, because the cocoon is hard. There's a larva inside. And then that cocoon is wrapped in a lot of leaf pieces. And then the orchard bee is the soft cocoon with no outside wrapping. And it's an adult inside that if you damage it, it's not gonna fly for you later. And so you can't just punch them out the same way you can't mishandle on them in the same way. So that's another little nuance that makes them extra special.

Andony Melathopoulos: [00:36:38] All of those things in mind, it has been remarkable. I n the short period I've been working with these bees just to see the price drop. There has been a lot more supply. It's remarkable. The amount of supply that's come online over the last five years have been.

Theresa Pitts-Singer: [00:36:55] Yeah. And that's what I feel like it's been a steady climb. My years of working with this bee, which is close to, I would say 15 to 20 years. And I think we're over the hump. And it's downhill from here, but it's not a steep downhill, it's a gradual downhill.

Andony Melathopoulos: [00:37:11] One last thing I wanted to ask you about as you're going to be speaking at a webinar this week. This episode is going to come out on Sunday. We're recording the week before, but The Pollinator Report, what are you going to be talking about at this event? And we'll plug it at the beginning, but what will people catch?

Theresa Pitts-Singer: [00:37:25] I'm going to show you some beautiful pictures of these bees. I'm going to talk about why these two bees are important in agriculture. What kind of foods that you get because they are at our disposal. I'll talk a little bit about how they are not like honeybees. I'll explain a lot more about their biology.

And also maybe what you can do to have them at your own home and how to safeguard them against, management practices, ruining habitat, or use of pesticides. So it's a very general and public talk, hopefully engaging. And so I'm really happy to be doing it.

I'm pretty excited. But the person who has asked me to do this, Justina Block, her company sells osmia bees and she has been spearheading a series of talks. The other talks that are available are a lot about bee diversity, and so I'm hoping that my talk will dovetail into there's all this great diversity of bees.

We only think of bumblebees and honeybees when people bring up the subject of bees. And to connect these two other bees that I study to our food supply is pretty exciting for me. 

Andony Melathopoulos: [00:38:27] I love your talks. They're always so great. There's always some detail there. You really know these bees inside out and the pictures are always wonderful.

So I would really, if you've had a taste of it this episode, we'll have it in the show notes. It'll be in the show notes showing you how to register. But let's take a quick break. We have one last segment we do. I'm really curious what your answer is going to be. We'll be back in just a second.

Okay. We are back. We were just talking to during the break and you've got great answers, so let's start them off. Do you have a pollinator book recommendation?

Theresa Pitts-Singer: [00:38:58] Yes. Can I give two? Because I have never managed my own honeybees and I'm not a honeybee person, there's two kinds of honeybee books that I really like, that I would recommend.

And one is Honeybee Democracy by Tom Seeley and it is about why bees form and then the swarm mentality and how they work together. I like to be introspective and it has that kind of feel for it. It's very sciency. But yeah, it has that human, anthropomorphic kind of connection to it.

And I was just really enthralled in the book. It was a great read for somebody who doesn't know a lot about honeybees and I've learned tons and it wasn't overly scientific. My other one is the The Beekeepers Lament: How One Man and Half a Billion Honeybees Help Feed America. I forget the author of that book. Have you read that one?

Andony Melathopoulos: [00:39:45] I have not. I going to look it up as we're talking here.

Theresa Pitts-Singer: [00:39:48] It's 2010 and a great friend of mine recommended it to me.

And it is a journalist who goes out with this crazy beekeeper guy, honeybee keeper guy from Blackfoot, Idaho, and he drives a Corvette and he has these wonky emails he sends to her. He's really an interesting character and he's just hard for her to interview, which makes it interesting.

But then he also talks about how his relatives started the movement of honeybees by train out to almonds from my hometown here in Logan, Utah. And I didn't know that was going to be in there, and then it was all these almond board people that I have met over the years are all mentioned in there, including Justin Schmidt, whose book is this The Sting of the Wild.

And I've known Justin for years. He studied bees his whole life. So anyway, it's got a lot of great characters in it, and the book itself is told really well. And you learn a lot about just the honeybee industry. And so I enjoyed that tremendously.

Andony Melathopoulos: [00:40:44] We'll put a link in the show notes, Hannah Nordhaus I see, as the author. The one thing I do remember, I'm old enough to remember this, is that there was a time when it was hard to rent honey bees for pollination, that there was a lot of investment and time to convince growers to even use honey bees.

Now we look back at it and it's "Oh, of course they would." It took, years of research and like the McGregor book really to make the case to growers that this was a useful.

Theresa Pitts-Singer: [00:41:10] There's so much we take for granted in there.

Andony Melathopoulos: [00:41:13] Absolutely. For sure. The next question I have for you, I'm really excited to ask you is, cause I always love going through your papers cause you've got so many great little gadgets that you've discovered.

Wow. She did that with that? That's so cool.

Theresa Pitts-Singer: [00:41:28] We haven't published the one where we use hair curlers, but...

Andony Melathopoulos: [00:41:30] I'm not even surprised. If somebody else said that'd be like, "huh, hair curlers." But I was like, of course she would. But are hair curlers your go-to tools?

Theresa Pitts-Singer: [00:41:38] You can use a big hair curler like a boll weevil trap to emerge bees in and collect them. So organza bags, hair curler, and the funnel like a boll weevil trap.

Andony Melathopoulos: [00:41:51] I have to say the one thing I've learned, because we've been emerging bees out of trap nest is you need really thick material because all these megachilidae they can chew through anything.

Theresa Pitts-Singer: [00:42:01] Yes, absolutely. Absolutely. We have bees all over the lab.

Andony Melathopoulos: [00:42:06] Anyways. It's not the hair curler that is your go-to tool. Tell us what you've got.

Theresa Pitts-Singer: [00:42:11] Okay. So we love the otoscope and I didn't come up with us. It was a tool being used by the bee lab people for years, but it's the thing that the doctor looks down your ear or up your nose in.

And we take off like a special tips on the end, but they're great for looking down into the cavities of these bees. You can see all the way to the back and you can see eggs and plugs and pollen and all that stuff in there. And we have a whole bunch of these rechargeable auto scopes in the lab.

But the other tool that I really love are hemostats which doctors used the clamp off your veins or during surgery and without the little locking mechanism, we cut those off, you can just slip your fingers in there and then grab the paper straws that we use as inserts into the bee board.

So we can pull out paper straws that have bee nests in them just efficiently and rapidly. They're just like the perfect tool for that. And so I love an otoscope and the hemostats, they're in all my bags.

Andony Melathopoulos: [00:43:04] I have to say, I remember emailing you years ago about the otoscope to get the model and everything.

And the thing I really loved about it is you can get the number of females that are nesting if you go there at night, then you can see the females. You can actually get a count of how many females actually are starting a nest.

Theresa Pitts-Singer: [00:43:20] Yeah. So you use your hemostats to pull out the paper straw, and then you hold the paper straw with the otoscope backlighting the whole thing. And then you can mark on the nest, how far along it's the nest, put it back in and then over time you will know exactly which were laid per day. You just date on the straw with your pencil, because you can backlight all of that too, instead of just look down the inside.

Andony Melathopoulos: [00:43:42] So amazing. I'll try that this year. Okay. The last question I have for you is you've talked about two species here today, and maybe this is not even your favorite species, but do you have a species of pollinator when you see it you just: I love that?

Theresa Pitts-Singer: [00:43:56] Yeah. I was thinking it really has to be, one of the two bees that I do study, but I think because it was the reason for my job and I fell in love with it first; there's something always about your first, is to love the megachile rotundata, my alfalfa leaf cutting bee. I just really love that a little bee. And its wiggly behavior and I love its attitude. It's just so happy go lucky. And so I just, and some of the pictures I have of it just make me happy to see I've got this great picture of the bee had just landed on an alfalfa flower and tripped it and this pollen is just bursting from behind the bee. It's just exploding. And that just brings me happiness. So I love that.

Andony Melathopoulos: [00:44:40] I always think of them as little tanks. They just seem like up for anything.

Theresa Pitts-Singer: [00:44:44] Yeah, I'm a rugby player. I love tough and I love teamwork.

Andony Melathopoulos: [00:44:50] That's awesome. You were just telling me that you coached the, I was surprised as one of the Pitts-Singer or things I didn't know about; you coach the university rugby team.

Theresa Pitts-Singer: [00:45:00] Yeah. Utah State University women's rugby club. Yeah. I'm there. I'm their coach. I love them to death. Yeah. We don't sing dirty rugby songs just in case you're wondering. I know them, but I don't teach them. I just teach them all the good rugs, smalls and tackles.

Andony Melathopoulos: [00:45:15] Oh, that's amazing. I'm so amazed. It's just another level of appreciation for it.

Theresa Pitts-Singer: [00:45:22] Yeah. Yeah. Be careful. I tackle.

Andony Melathopoulos: [00:45:24] Thank you so much. It was great catching up with you and good luck with your taco later this week.

Theresa Pitts-Singer: [00:45:29] Hey, thanks so much. This was fun.


Managed solitary bees have been a part of crop pollination in the Western US for decades, particularly in alfalfa seed production. But over the last decade, the use of these bees has expanded. We look at the recent expansion and where it might lead in this episode.

Theresa Pitts-Singer is a Research Entomologist at the USDA-ARS Pollinating Insects Research Unit in Logan, Utah. Her 18+ years of research on alfalfa leafcutting bees and blue orchard bees focuses on bee reproduction during crop pollination, on chemical cues that affect bee behavior, and on effects of certain pesticides on bees. She is co-editor of the book Bee Pollination in Agricultural Ecosystems, is co-author of 2 patents on bee-related products, and has published over 45 papers in peer-reviewed scientific journals, including her work with professional colleagues, postdoctoral associates, and graduate students.

Links Mentioned:

Book recommendation:

  • Honeybee Democracy by Tom Seeley
  • The Beekeepers Lament: How One Man and Half a Billion Honeybees Help Feed America by Hannah Nordhaus


Autoscope and hemostat

Favorite Pollinator:

Megachile Rotundata

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