138 Ron Spendal - The secret lives of mason bees (in English)

[00:00:00] Andony Melathopoulos: [00:00:00] All right, so, welcome to PolliNation, Ron. Finally!

[00:00:07] Ron Spendal: [00:00:07] Thank you. We've been talking about it for quite a while. 

[00:00:10] Andony Melathopoulos: [00:00:10] You were there actually, when I was hired. When I showed up to OSU on the very first day, Ron Spendal was there to meet me. 

[00:00:20] Ron Spendal: [00:00:20] Yeah, I was part of your interview panel. 

[00:00:24] Andony Melathopoulos: [00:00:24] Well, so many years later, finally got you on the show. Right now mason bees are still active they're still building nests. How are they doing this year? I know it's been a funny year for everybody because of the stay at home order, but, what have you noticed about mason bees? What's your experience been this year? 

[00:00:44] Ron Spendal: [00:00:44] Well, I've got thirteen research sites across Western Washington County and only one of the sites am I monitoring every day - at the same time every day. And this year at that one site is Jackson Bottom Wetlands. [00:01:00] And this year is much better than last year actually. Last year I ended up collecting about 906 cocoons from Jackson Bottom and so far this year I've gotten 2,878 nesting cells as of this afternoon. 

[00:01:24] Andony Melathopoulos: [00:01:24] Oh, wow. Do you have any sense of what happened last year? I know last year was a poor return where you were, and were you ever able to figure out what happened?

[00:01:37] Ron Spendal: [00:01:37] Most of it I would attribute it to a cool, wet spring going into it - heavy on the wet side. This year it's been a cooler spring, than historical for the time period, but much drier. I've only [00:02:00] been soaked twice since April 1st when I started doing the daily routine. So it's not too bad. 

[00:02:12] Andony Melathopoulos: [00:02:12] We are recording this May 1st, how far along in the cycle are your bees?

[00:02:24] Ron Spendal: [00:02:24] Basically they are cycling out. I think today I had thirteen new nesting cells built and that's all. So, it's on a very steep decline. So, the big time consumer right now when I'm doing my daily monitoring is, trying to determine when the eggs are actually hatching into larva. So, that takes a lot of manipulation on my part. Frequently in the nesting cells you won't even be able to see the egg [00:03:00] because the females smudge the plexiglass cover on the tray with some nectar and pollen and you can't see anything beneath it.

[00:03:08] But, frequently if you stare at it in funny angles and kind of stand on your head, you can see the egg in there. Even though it may not be totally obvious, you can kind of manipulate things around where you can see it - sometimes it's very clear. At Jackson Bottom Wetlands, for example, I have fifty-three nesting trays, each one has a clear plexiglass lid on it. So, I'm able to see the nesting as it develops through the whole season. For the most part, there are still some mason bees out and about, doing a lot of foraging and stuff. But nothing cell development right now, it's going really slow. At the beginning of the period, back towards the 1st of April it was [00:04:00] going very fast. There were a number of days where frequently a female mason bean would lay up to four eggs a day. 

[00:04:08] Andony Melathopoulos: [00:04:08] Oh, is that right? 

[00:04:10] Ron Spendal: [00:04:10] Which is really a lot of work. 

[00:04:14] Andony Melathopoulos: [00:04:14] Just to complete the timeline, when did your cocoons go out this year? 

[00:04:20] Ron Spendal: [00:04:20] I put the cocoons out, basically about the last week of March - third to fourth week of March. 

[00:04:32] Andony Melathopoulos: [00:04:32] Is that the earliest that you've put cocoons out? 

[00:04:35] Ron Spendal: [00:04:35] No, no. I've put them out as early as the Valentine's Day, and then just waited to see what would happen.  I've done different approaches. Sometimes I'll set them out early, like I used to a bit around Valentine's Day and then wait just to see how Mother Nature would warm up and when it got above fifty-five degrees for enough [00:05:00] days in a row, they would start to emerge from their cocoons. But then frequently, the pollen and nectar resources weren't at the right stage, even though they were emerging  there was nothing really for them to forage on. 

[00:05:15] So, now I've gotten to the point where I refrigerate my cocoons and wait for the pollen and nectar resources to show up. But once I'm convinced that they are in fact abundant in the environment, then I'll set the cocoons out of the cooler. And within 24 hours, they're pretty much, you know, ambient temperature and everything kicks into gear. I'm much more in control of when they emerge from this cocoons this way. And at Jackson Bottom they have a large banks of flowering currants and Oregon grape. Oregon grape is kind of the plant that I use to gauge things [00:06:00] by when it's, you know, busting open - I know it's fine. And the mason bees really like Oregon grape, so then I'll set the cocoons out and things will take off. 

[00:06:10] Andony Melathopoulos: [00:06:10] Okay, fantastic. I think listeners who are listening to you, are like, "those are all kind of peculiar practices, clear plexiglass, watching eggs." What a lot of people have mason bees for is to pollinate some kind of backyard fruit tree. For you, mason bees are a whole lot more. And in the interview I'd like to kind of get into all those things that they are for you, but one of the things they are is a intensive research project. You've been looking at mason bees for a long time. Tell us a little bit about what your mason bee blocks look like. Cause they themselves seem to be key [00:07:00] to what you do and they're peculiar. 

[00:07:04] Ron Spendal: [00:07:04] Okay, that's an opinion and I could respect that. Okay, to me, they're not peculiar, but basically when I got into mason bees, which was back in 2004, I did a lot of reading on mason bees and attended a lecture and went through the normal route that a lot of people go through. And, most people were talking about holes drilled in blocks of wood and paper straws. And, I tried that and they did work. Mason bees nested in the straws, they nested in the bee traps. To me it was kind of a failed attempt to understand more about the bee because everything it was doing was done where I couldn't see them. I wanted to know what they were doing in those straws and what they were doing in the drilled [00:08:00] holes and everything. 

[00:08:00] And so, I was researching different tray designs and trying out different things and I even tried clear plexiglass tubes that I would cut and put a cork in one end and watch the mason bees nest in those a little bit. But again, when they started nesting, you know, they're carrying a lot of pollen and nectar and they got smudged and it was hard to see. So that didn't work out very well for me, but it worked out better than the paper straws.

[00:08:38] And then I thought, "well, if I did wooden trays, I could put plexiglass over the top of it and really get a good picture of what's going on." And then I experimented with, what the channels could look like. I did it where the channels were pretty much rounded when you put one tray on [00:09:00] top of the other. I did it where the channel, had a rounded bottom, but straight sides and a flat plexiglass lid across the top. And tried different designs on the trays and figured out that basically the bees didn't care what shaped the dimension of the channel was. But the diameter of the channel was critical and needed to be five sixteenths of an inch.

[00:09:26] Because I made trays with different diameter channels ranging from an eighth of an inch up to a half inch and put twenty of those kinds of variable sized trays out across different sites in Washington County. And 87% of the time the mason bee used the five sixteenth of an inch channel - as opposed to the other options that were available to it.

[00:09:53] Andony Melathopoulos: [00:09:53] I remember that was one of the first things I noticed about work that you were doing was a very [00:10:00] nice kind of description of common bees, cavity nesting bees and their cavity preferences. Which I thought was really elegant, I hadn't seen anybody kind of do that in an area. 

[00:10:14] Ron Spendal: [00:10:14] Yeah, and it gave me an opportunity that I didn't anticipate, which is when I put out the variable sized channel trays I could see where the mason bees were nesting. But then as I left the trays out, other native pollinators would come and, make use of the smaller sized channels - even down to an eighth of an inch. I was getting Asynthica wasps nesting in there, which are very, very tiny, black wasps that prey on Apis. And they were so small that when they went into the eighth inch channel, they even got tree sap and made the entry only a sixteenth of an inch. [00:11:00] So, it would prevent anything larger than themselves to get in. So they were very protective of their environment. But that way I got to see, I think I ended up with a total of about twelve different native pollinators, and a few different kinds of wasps that were out there. 

[00:11:21] Andony Melathopoulos: [00:11:21] Okay, so through experimentation, you came up with a design that finally got you where straws and wooden blocks wouldn't get you - you could see everything. Well, apart from some smudges that were going on in the mason bee nest, why was that? What did you have in mind at the time? Cause you've done many, many experiments since that time. What was the kind of first questions that you had when you could finally peer inside the nest and see what they were doing?

[00:11:50] Ron Spendal: [00:11:50] I was curious as to what things they did first. Did they always build a mud wall at the end of [00:12:00] the channel? Some books said that they would initially go back and build a back wall and then proceed to make nesting cells as they exited the channel. And sometimes they did, sometimes they didn't. I can't remember what the percentage was of time. It was a high percentage where they usually put a back wall and and other things would happen that I would find curious. So I needed to do more research to figure out why that was happening. For example, in a wooden tray with a plastic lid on it, plexiglass lid, the bees can still perceive that there is a opening or a minuscule crack between the top of the wood and the plexiglass.

[00:12:55] So, frequently, like in the mid 90% of the [00:13:00] time, the mason bee will caulk that crack that it proceeds. So, I was looking at that and then, looking at straws and when I would carefully unroll the straw, the only mud used was for the partition between the nesting cells - there was a wafer thin little disc of mud. And if you look at the nesting tray that I built, there would be the dividers in-between the nesting cells, but also two lines of caulking at the top where it sealed up the crack between the wood and the plexiglass. So I had to weigh how much mud was within each cell given a straw as opposed to a wooden tray. The mason bee has to use 240% more mud in my wooden trays because they do [00:14:00] that caulking along those edges in there. Which means my bees spend a lot more time collecting mud than mason bees nesting out of straws.

[00:14:11] Andony Melathopoulos: [00:14:11] You know how there's this theory out there that retention of mason bees has to do with a number of factors, one of them being mud availability. It just struck me as you were saying that if it takes a lot less mud to do a straw, if retention would be higher? Did you know that? I'll just tell the listeners, this is what happens if you're from Washington County or anywhere on Portland, if you have a question about mason bees, you will ask it to Ron and he has likely done the experiment to answer it. So, Ron, what do you think? 

[00:14:56] Ron Spendal: [00:14:56] That may be true. There are [00:15:00] definite advantages for straws I will not debate that. When I put out straws next to the wooden trays - I made a series of six inch long wooden trays with five channels routed in them and six inch paper straws, and you put them side by side and the bees will fill up the straw in spurts every time. And then they'll go to the wooden tray and fill it up. But their first preference is the straw. And I would assume that would be because it is much more efficient for them to nest in that, they can use a lot less mud to make the divisions between the nesting cells and all of that. But again, you just can't see what they are doing in there. 

[00:15:50] Andony Melathopoulos: [00:15:50] So, I interrupted you. One of the first questions you had was just basically watching the nesting behavior and you started to generate new questions. [00:16:00] Subsequently you did an experiment where you looked at the mud effort that was required in different size chambers. What are some of the other questions that you've sort of posed using these really great observation mason bee blocks that you run?

[00:16:15] Ron Spendal: [00:16:15] Well, I'm kind of a natural skeptic, so even though I read as much as I can on mason bees, in different books in the literature - they will make a statement in the book that I will say, "well, is that really true, here?" They may have done some research or it could have been in Arizona in 120 degree heat, but not in Washington County, Oregon. So for example, I wanted to see how many nesting cells, in a six inch tray were going to be females and were they always located deeper in the channel and then the males out towards the front of the channel?

[00:16:59] And in [00:17:00] fact, that was true. Well that led me then to think, "well, why am I only doing six inch long tray?" Why is six inches considered what everybody has? At that time, if you went online to look at nesting trays, everything was six inches long. All of the companies were selling six inch long straws, and I couldn't figure out why six inches was such a magical number, and nobody really explained that very clearly. And that led me to calling some well respected entomologists like Jim Kane at the USDA Bee Lab in Logan, Utah. And talking with them about why six inches and then I decided to make longer trays [00:18:00] and would the mason  bees nest in channels longer than six inches?

[00:18:05] So I made wooden trays that were two feet long. The channels were two feet long, and then I did them at twenty-four inches, twenty-two, twenty, and then just worked backwards by two inches at a time and sat out piles of these trays. And, basically the mason bees can pretty effectively nest up to twelve inches. Anything longer than twelve inches is kind of a wasted effort on their part because it's just a lot of distance for them to have to cover. So they like, basically twelve inches would be the maximum. So any kind of a tray between six inches and twelve inches seem to be the ones that they were using in terms of volume, but nothing going on.

[00:18:55] So all of my trays now, except for a handful of experimental six [00:19:00] inch trays, like he, all of my trays now or are twelve inches long, which makes the channel about eleven and a half inches deep. That leads to other experiments you can run, for example, a lot of the literature says that, you'll probably get one and a half to two males per female and in a six inch straw, which I found to be true when I was looking at my six inch straws and opening them up and, and sexing the cocoons that were  inside. But in a twelve inch long tray again they make the last, you know, four, maybe five cells in the channel, will be males. But then they have a longer channel behind that but that they can basically construct [00:20:00] female nesting cells.

[00:20:02] Andony Melathopoulos: [00:20:02] You know, it does remind me. We had a previous episode with Weldon Hobbs who was talking about the emergence of the alfalfa leafcutting bee industry. And I always wondered there, I think they're four inches in depth and he said, "oh, there's a reason for that is because they moved to plastic and if you made them any longer you couldn't dry the cocoons down". And it was like you inherit these things, you never quite understand why they were the way they were. You might assume a four inch depth is optimal and the other part of it is research done in a far away place, which may not even apply. And so you have these received wisdoms that you just keep doing when you don't know. There are all these things that you never test. And I guess these blocks have enabled you to test a lot of these critical aspects of things like, [00:21:00] development that we were talking just before we got on the episode. You have a long standing interest in the development time with the bees.

[00:21:11] Ron Spendal: [00:21:11] Yeah, different pieces of literature that are available will tell you some, some studies, will just say it's a short period of time between the date the egg is laid and the date that the egg hatches into a larva. Others will give you a specific number of days and there's a wide variation. One of the things that a lot of the literature doesn't lay out, specifics for you is, exactly where was the research done? What was the average temperature during the research period? What was the humidity? Those kinds of things. So you can't really exactly replicate it. Which is why being a natural skeptic, I [00:22:00] tend to run a lot of experiments of literature that I've read to see if that holds true for our area.

[00:22:08] I'm finding that there are significant differences. Basically in 2019 I studied a 1,005 eggs, and on average they would hatch to into a  larva after ten days. This year, so far, I've looked at about 1,500 eggs that have hatched, and they're at about twelve and a half days.

[00:22:39] Andony Melathopoulos: [00:22:39] Really?

[00:22:40]Ron Spendal: [00:22:40] So, I'm assuming that the difference in that time may be related to temperature and humidity. And I 've got weather channel places I can go to and look at historical trends and patterns. And I'll do that to see, in fact, if there were significant differences [00:23:00] between last year and this year, during the same timeframe. To see if that was the factor, off the top of my head that makes logic to me.

[00:23:10] Andony Melathopoulos: [00:23:10] I do think these things are critical because it seems a lot of the times. I mean with mason bees, everything seems a mystery to people who are managing them. "Why did they do this?" "Why did they do that?" And people do come up with stories as to why they do things, but nobody ever really sets up the test.

[00:23:27] Ron Spendal: [00:23:27] Yeah, there's a lot of folklore which I find interesting at times. When I first started really getting into mason bees, I would talk to people that had been raising mason bees for decades and asked them, "what do they do?" And look at what they're doing and then go out and visit their sites. You know, some of them will take a nesting tray and with a sharpie, you put little geometric symbols in front of the channels, like a [00:24:00] square or a circle or a triangle. And they think that that helps the bee navigate to the channel, that they can memorize that their channel has a circle at the bottom of it, but it helps them figure out which channel is theirs.

[00:24:15] Basically they mark their channels with a pheromone that they emit, so that each female has her own pheromone, and that's what she goes to. But there is a learning curve to it, at Jackson Bottom, for example, I have four nesting stations that are ten feet apart from each other in a row. The stations are identical. And inside each station there's four stacks of three trays, so they all look identical. And at the beginning of the season you can watch the females come flying back. Sometimes they land in the wrong station and then they'll walk around, they can't pick up their scent so [00:25:00] they fly to the station, to the left of that one, or to the right of that one. And they'll walk around until they pick up their scent and figure it out. 

[00:25:08] And then if you kind of go back and sit and watch for hours, you can see the same female can now recognize which station to go to and she'll fly to that station, and then she'll learn which stack of three she needs to locate, you know, upper left, lower right. or whatever. And then eventually after about a week to week and a half, she will come flying directly into her channel. She won't stop and do any kind of checking out of any other landmark or anything, she knows exactly where she's going to. So navigation is a learned activity or learned process for them. And I would love to figure out how to measure the rate of their learning navigational skills. Well that would take a lot of expensive cameras. 

[00:25:59] Andony Melathopoulos: [00:25:59] Well, [00:26:00] I suppose, but you never know. Let's get some bee tags on them. Yeah, the little paint marks. Okay, I want to take a quick break, but before we take the break, what is it about this bee that you think sustains your interest? It seems like you have endless sets of questions. Is it just that there's so little known or it's observability? And you have other intersts you've done a little bit of work with the grass carrying wasps, but why this bee? Why is this bee really the center of your attention?

[00:26:39] Ron Spendal: [00:26:39] Basically because it's a solitary bee and I'm a fairly solitary person. I could relate to that, but the bee is different. You know, as a kid, I would not have recognized it as a bee. And like, most people, upon [00:27:00] their first sight of a mason bee, would probably think it's a fly. But to me it's a creature that just has tremendous capabilities and skills and, behaviors that I just want to keep learning more about. And the fact that it is so incredibly docile - during the peak of the nesting season when I'm out doing my field studies and picking up a stack of three trays and then looking through each tray and making my notes and everything and the bees are foraging, they're coming back and forth and they're looking and their tray is gone. 

[00:27:40] And, they see me, you know, standing in front of the station and I'm obviously an obstruction, they ping me, they will fly and hit me and fly off and come back and hit me again and kind of told me to hurry up and put the trays back. And frequently when I'm putting the trays back, they're still in my hand and the bees are flying, you [00:28:00] know, on my arms and hands, trying to get into the right channel cause they're in a hurry. To me it's just kind of a fascinating process so that I can be so involved in what they're doing in terms of - disrupting it, take my data and make my observations, and they seem to have extreme patience. 

[00:28:21] Andony Melathopoulos: [00:28:21] "Sorry, it's census time". 

[00:28:25] Ron Spendal: [00:28:25] Yeah. 

[00:28:26] Andony Melathopoulos: [00:28:26] Well, let's take a quick break and we'll come back. I want to ask you a few questions for people who are getting started. So we'll be right back. 

[00:28:35] Ron Spendal: [00:28:35] Okay.

[00:28:37] Andony Melathopoulos: [00:28:37] Okay, we're back. So, you've mentored a lot of people on how to keep mason bees. How many people do you estimate that you've trained, and what are some of the most common problems that people have?

[00:28:49] Ron Spendal: [00:28:49] I have no idea how many people I have trained. I teach about twelve to fifteen mason bee [00:29:00] classes throughout the year.

[00:29:01] Andony Melathopoulos: [00:29:01] Wow. 

[00:29:02] Ron Spendal: [00:29:02] Mostly to adults, although I'm getting more and more involved in teaching in schools, elementary schools in particular. And it seems that people's concept about bees and, invariably when you go into a group of people, it doesn't matter if I'm talking to kids in the first grade, or if I'm talking in front of a group of senior citizens - for a long, long time I would ask them to name three bees, and invariably it was a honeybee, a   bumblebee and a yellow jacket. 

[00:29:41] Andony Melathopoulos: [00:29:41] Yeah. 

[00:29:44] Ron Spendal: [00:29:44] And you know, you explain, the yellow jackets are wasps, so you're really only naming two bees and the two bees you're naming are highly social bees. And only 10% of the bee species in the world are social bees. [00:30:00] But it never ceases to amaze me that our limited knowledge of bees, is really only information about the minority of bees. Most of the bees, the 90% of bees that are solitary bees are just mysteries to people. As you explain some of the mystery to them, they seem to become more and more interested in what's going on. In particular, when you take care to explain that social bees live in hives, and if you live in a hive, you have an extremely high defense instinct and a fairly low survival instinct.

[00:30:44] And if you're a solitary bee, you're just the opposite. You have a very low defense instinct, an extremely high survival instinct. So working around solitary bees is a really safe activity. They're [00:31:00] not going to sting you, they'll just fly away. 

[00:31:04] Andony Melathopoulos: [00:31:04] Is that one of the first things you run into with people? They're just skittish, like when you're getting into the mason bee, you got to deal with their skittishness. 

[00:31:11] Ron Spendal: [00:31:11] Yeah, yeah. And I've developed an observational nesting station where the trays are vertical and all you have to do is walk up to a nesting station and slide a door back and you can see the nesting activity - you can get within a half inch of it.

[00:31:28] Andony Melathopoulos: [00:31:28] Can you send me images? Where is it located? So, can people go view this? It's quite remarkable. 

[00:31:34] Ron Spendal: [00:31:34] Sure, there's  a number of them at Jackson Bottom Wetlands here in Hillsboro. There's two of them on the campus at Portland Community College of Rock Creek Campus. 

[00:31:47] Andony Melathopoulos: [00:31:47] Oh, okay.

[00:31:47]Ron Spendal: [00:31:47] And there's one and there will soon to be three at the Jenkins Estate in Beaverton. But basically, even [00:32:00] though this is something that people can get so close to the bee to watch it, and the kids will get really, really close to it. When you're standing back and you're watching people and they don't know that you're involved with the mason bees, they are very skittish about using an observational tray. I mean, they seem the bee coming in and they kind of, "woah man! - back up, I don't want to get stung." And then you kind of say, well, these are bees that wont sting you, they can, but they won't - it's not in their best interest. So, you know, go ahead and just slide the door back and if they fly into their channel while you're looking, you know, they'll do what they need to do and fly out. You can watch what they do. You know, it's easy to calm people down once you explain it to them, but their initial skittishness is definitely there. 

[00:32:48] Andony Melathopoulos: [00:32:48] Okay. So after, you kind of work through that part of it, what are some of the common problems? Where do people get hung up and lack success [00:33:00] that you've observed over time? You must have people that come up to you and say, "Ron, it didn't work out at all." It must be a common thing you hear. 

[00:33:09] Ron Spendal: [00:33:09] Yeah, yeah, which led me to produce a lot of printed information that I try to hand out everywhere. But yeah, as you said, you give an hour  presentation, people usually don't come and take a lot of notes, they're just there to listen. Like at a nursery when you give a presentation and they're in the nursery and they'll sit down and listen to your presentation, but they'll miss critical things that to them may not sound that critical like - face your nesting stations so it's somewhere between the East and the South. That usually flies right by. 

[00:33:50] Andony Melathopoulos: [00:33:50] Put them in a shady spot that's convenient for them. 

[00:33:53] Ron Spendal: [00:33:53] Yeah, when you talk to them and they say, you know, "gee, you know I had terrible success", well, how did you set it up and which direction was [00:34:00] it facing? And was there the three critical elements that they need? You know, pollen and nectar resource and a mud resource. And did you have the right kind of cavities for them to use? And did you clean them?  

[00:34:16] Andony Melathopoulos: [00:34:16] Let's back up on each one of those. So the first one is, I can imagine this, that somebody doesn't have a very good garden, there's not a lot of spring blooming plants, and they put the block out. They heard the shade thing, the bees come out and there's just nothing for them to go onto, I imagine. That must be a common issue. 

[00:34:36] Ron Spendal: [00:34:36] It is. And so, luckily, a lot of the nurseries up here that I do classes  through have come up with lists of you know, early flowering plants and shrubs that are attractive to native  pollinators. So you kind of can point out to them that, you know, you need things like Oregon [00:35:00] grape and flowering currant, but Andromeda japonica, bluebells, some other kinds of things. So you're going to lay out what, what the flowering heather and flowering heath - you can lay out a kind of a list of things that people can start looking for.

[00:35:20] And if they don't have them in their immediate landscape for whatever reason, you can kind of say, "well, look over your fence and see what your neighbors have" because they, you know, they only forge for 300 feet. So if you can pretty much survey that football field around you, if there is foraging material in your neighbor's yard you may be still successful and able to raise mason bees. You don't have to get them to come nest at your site. And one of the features of a mason bee is they, like to nest close to where they emerge from their own [00:36:00] cocoons. So, if you've set out cocoons in your backyard and they emerge there, there's a very strong likelihood that that's where they will come and nest.

[00:36:11] Andony Melathopoulos: [00:36:11] Well the second thing you mentioned is mud. Tell us a little bit about how somebody can make sure that there's enough mud for them. 

[00:36:21] Ron Spendal: [00:36:21] Basically, Oregon or Western Oregon at least is blessed in that we have very clay like soil. So it's the right kind of soil for a mason bee to use, they need a certain clay content to construct the nesting cell. But they like the mud resource to be as close as it can be to the nesting site. Mostly because the mud weighs a lot, for them to fly with mud between their jaws is a fairly difficult task. And the photos that I've been able to take, or bees [00:37:00] at a mud collection site, when they leave that site to fly back to the nesting station they fly head down. Normally they fly a little bit heads up. So the weight of the mud is pretty significant for them in terms of their ability to fly. 

[00:37:18] But it's easy to provide the mud resource, at a couple of the sites that I've got, I mount the nesting station to a four by four post that's sunk in the ground. And I'll just take the post hole digger and then, you know, go about two feet away and dig an eight inch deep hole and once a week pour and a half gallon of water into the hole. The mason bees will find that hole and go down into the hole to where the moisture level is, the right moisture content, and they'll excavate caverns in the side of the hole.

[00:37:57] Andony Melathopoulos: [00:37:57] How wide does the hole have to [00:38:00] be? 

[00:38:01] Ron Spendal: [00:38:01] I just use a, it's about five inches wide. The other thing that they like to use for mud collection site is soil that has been recently uplifted, like a mole mound or, plowed activity and a field nearby. 

[00:38:21] Andony Melathopoulos: [00:38:21] I've got lots of moles!

[00:38:24] Ron Spendal: [00:38:24] Yeah, there you go. I've put a couple of nesting stations in, some community garden sites in the city of Hillsboro here. And they build their community gardens in usually poor land and then they will come in, and what they did at this site at least, they put in like a half inch layer of cardboard and then they put in like four or five inches of bark chips as a weed protector. And then they will make [00:39:00] small raised beds and bring in used nursery soil to fill the raised beds so people can plant vegetables and whatever in those. 

[00:39:11] And they wanted me to put in some nesting stations, but what I found was that, well, first of all, you got to get rid of the bark chips in an area, and that goes down four or five inches. And then there's a half inch of cardboard you have to get through. And then the soil underneath is usually real compacted or has the high gravel content, and didn't seem to be very good at all. So what I've done in a couple of these public garden places now, is I will build a a box that's two feet by two feet that's two feet tall. And at some of the sites that I use for my research are private farms - and so I asked the owner if I can just get a couple of buckets full of dirt from their field, and then I will go and [00:40:00] fill up this two foot by two foot by two foot box that I've built in the public garden. And the mason bees will use that for their mud.

[00:40:08] Andony Melathopoulos: [00:40:08] I'll be darned! Okay. The last thing you mentioned is a cleaning, that the other place that people get jammed up on - the first thing is they put the boxes in the wrong place, they don't have a spring blooming plants, if it's raised beds and it's kind of like highly managed garden they don't have mud resources. But the last thing you mentioned was they don't know how to clean or do the care on the box. Tell us a little bit about that. 

[00:40:41] Ron Spendal: [00:40:41] Yeah, basically if you're going to raise mason bees, there's certain responsibilities inherent in that activity, one of which is, keep them as clean as you can. So, after they've cocooned, which is usually around the first week of June into maybe [00:41:00] mid June - then you remove the nesting tray from the nesting station. Or the straws if you are using straws, and you put them in like a paper bag or a large Tupperware box, and then you put that into an unheated storage shed, like a garden shed. You move it out of the environment basically because parasitic wasps show up about the 1st of June. 

[00:41:25] Andony Melathopoulos: [00:41:25] And just describe these are not wasps, like people are used to wasps.

[00:41:30] Ron Spendal: [00:41:30] No, these are called monodontomerus wasps. They're only about a quarter of an inch long, but they are very destructive when it comes to mason bees. They're very, very hard to see unless you're really looking for them. So it's not, a typical wasp. So moving the cocoons into a protected area is, is one good step. And then around mid-November to the [00:42:00] end of December, the mason bees are in a condition, once they get inside their cocoon, they're kind of dormant. Some people say it's like hibernation, or it's called diapause. But in a six to eight week window from usually mid-November to the end of December, they're in a condition called true diapause, which is where you can take the cocoon and put it in a warm environment, but the metabolic rate of the bee inside the cocoon won't increase because of exposure to warmth.

[00:42:36] So that gives you a period of time where you can bring the cocoons indoors and take them out of the straws or scoop them out of the channels in an nesting tray. And then you can clean their cocoons, which helps remove a lot of the mites that may have collected on the outside of the cocoon. The [00:43:00] krombein mites, so that too helps clean the cocoons off. And then you can store the cocoons or put them in a cooler, the setup following spring so that then you've got clean cocoons that you put out. So when the bee emerges from the cocoon it's not going to be covered with mites that are sitting there. And it's just a good process to do that cleaning of the cocoon itself.  

[00:43:28] Andony Melathopoulos: [00:43:28] Finish the whole cycle, then come on back to the cleaning. 

[00:43:36] Ron Spendal: [00:43:36] And so after you clean the cocoon, then if it's a paper straw that you were using, you've unraveled the straw, so it's lost and you'll have to buy new straws. If it's a wooden nesting tray that you've done, and you scoop the cocoons out and clean them, then you need to clean the tray out. Which you can do quite easily. The channel that you've [00:44:00] got is five sixteenths of an inch wide. So I take a quarter of an inch wide strip of wood and wrap a piece of sandpaper around it, and then just run it up and down the channel a couple of times to knock out the any mud that may still be in there and then blow it out really good.

[00:44:16] If you're still concerned that there might be mites in the nesting tray, you can easily take care of that by freezing the trays. So if we've got cleaned wooden trays, then you want to make sure that there's no mites living in them. Just freeze the trays for like 24 to 48 hours, and that'll assure that they're mite free. And then reconstruct them when you put them back out. 

[00:44:43] Andony Melathopoulos: [00:44:43] One thing that I just wanted to ask quickly, we did have a previous episode - again we were talking about alfalfa leafcutting bees and the kind of conversion to lose cell management. Their concern mostly were diseases like chalkbrood. Do we have to worry about those diseases with mason [00:45:00] bees? 

[00:45:00] Ron Spendal: [00:45:00] It's very, very rare that I get chalkbrood in any of my nesting trays, basically, I've got thirteen research sites across the County and a total of about 500 testing trays out. And it will be an odd year if I got more than maybe one or two channels that have some mold in it, which is chalkbrood. And then to clean those out, basically I throw away the cocoons and then use a bleach solution to scrub out the channel to make sure I've killed the mold really well. 

[00:45:41] Andony Melathopoulos: [00:45:41] Okay, great. 

[00:45:43] Ron Spendal: [00:45:43] Rinse it out with water really good so it won't have any residue bleach in it. 

[00:45:47] Andony Melathopoulos: [00:45:47] Okay. So you're really focusing your cleaning on these mites. Tell us a little bit about how you do that. 

[00:45:52] Ron Spendal: [00:45:52] I use a dry process. To me everything that I was reading back when [00:46:00] said that when you wanted to clean your cocoons you woul collect them and then you would either put them under running water two or three different times and shake them around and swish them around in the water.

[00:46:12] Andony Melathopoulos: [00:46:12] Oh, so you would knock the mites off, presumably? 

[00:46:15] Ron Spendal: [00:46:15] Yeah. And then you'd put them under running water and then you'd lay them out on a paper towel to dry them. And a number of people recommended using a 5% or higher percent of a bleach solution and swishing your cocoons around in that and then putting them under running water two or three times to rinse that off and then putting them on a paper towel to dry them again.

[00:46:39] And then it never made sense to me because I went to great length all throughout the nesting season to assure that the nesting trays were dry. Or the straws were dry so that I wouldn't promote mold. So, why at the end of my putting these things that I've taken great care to keep dry, why would I put them through all of this water [00:47:00] process?

[00:47:01] And then there was a entomologist the University of Victoria that was using a dry sand process where he would get a big plastic jar, put a bunch of cocoons in it and put in a bunch of beach sand because he lived on an Island. And he would swing the jar around in the sand, and the cocoons would be swirling around in this jar. And it made sense to me that it was a dry process and I really liked that concept. And I told him, if you study the process it looked like there were a little bit of a problem because of the sand and the cocoons were moving at the same speed in the same direction. And it didn't seem like there was much scuffing going on. 

[00:47:54] So, I came up with this design where you could use [00:48:00] a wire grid comb or cylinder that you would mount into a mason jar. And it's a eighth inch hardware cloth. So that the screen is, an eighth of an inch opening in the screen cylinder that I make that goes inside of a mason jar. You can put up to a hundred cocoons in the cylinder and it goes down into the middle of a mason jar. You pour in a little dixie cup full of mason sand cause mason sand has a lot of grit to it, sharp angles - so it helps cut things really quickly. And then you put the lid on the jar and you turn it sideways and you shake it like a cocktail shaker. Shake it for about four minutes, and the sand is going back and forth through the cylinder. The cocoons are in the cylinder and they can't move very far, so they're pretty protected. [00:49:00] And the sand basically scuffs, all of the mites off the outside of the cocoons. So, if you look at them under a microscope before and after they are pretty much mite free.

[00:49:15] Andony Melathopoulos:[00:49:15] Oh and this is something anybody can do with a hand lens anyways. You can sort of see the mites on the outside surface - you can tell if it's working. 

[00:49:22] Ron Spendal: [00:49:22] If you have a little ten-power to handle it, it'll will work fine. And that way using a dry process your cocoons never get in contact with moisture and it seems to be really effective. And then basically you have two options with the dirty sand. You can either throw it away because it's got mites in it, or you can bake it in an oven at 250 degrees for 30 minutes, and that'll kill the mites that are in the sand if you want to keep reusing the sand over and over. [00:50:00] But you can buy a five gallon bucket of sand from a landscape supply place. Five buckets of mason sand costs you about $3. And for most people that will last you several years. 

[00:50:12] Andony Melathopoulos: [00:50:12] Fantastic. Cheap, easy and effective. Well, thank you so much for taking time to talk with us today. I really appreciate this and good luck with I guess the tail end of the Mason bee season.

[00:50:25] Ron Spendal: [00:50:25] Still a lot of data to collect.

[00:50:28] Andony Melathopoulos: [00:50:28] Well, keep collecting. Thank you so much for all that you do.