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May 9, 2022

Pol-Line VSH Honey Bees with USDA-ARS Drs Frank Rinkevich and Mike Simone (S4, E47)

Drs. Michael Simone-Finstrom and Dr. Frank Rinkevich, are research entomologists at the Baton Rouge Honey Bee Research Laboratory in Baton Rouge, LA. They have completed an extensive set of tests in commercial beekeeping operations on mite resistance,...

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Mike SimoneFrank RinkevichDrs. Michael Simone-Finstrom and Dr. Frank Rinkevich, are research entomologists at the Baton Rouge Honey Bee Research Laboratory in Baton Rouge, LA. They have completed an extensive set of tests in commercial beekeeping operations on mite resistance, overwintering, honey production and virus loads of the varroa sensitive hygiene (VSH) P0L Line of honey bees bred there since the 1990s.

The line, called the Pol-line is drawn from the original line to be used as pollinator bees, have as a basis for mite resistance, the VSH trait, where mites in brood cells are removed by nurse bees before they are able to complete development.

Over the season these bees were subjected to moving to almonds, and from almonds to other pollination jobs or to honey production areas in MS, CA, ND and SD to sample a wide variety of environments.

The results are definitely encouraging. Listen to learn more!

Next on their agenda? Getting these bees into the hands commercial beekeepers so they can take advantage of the money saving, and honey bee saving attributes of these bees.

Dr. Dewey CaronAlso in this episode, Jeff meets up with Dr. Dewey Caron and receives an update from on Dewey’s PNW Honey Bee Survey.

Finally, before the main interview with Drs Simone and Rinkevich, Kim delivers his review of Brother Adam’s book, “Beekeeping at Buckfast Abbey”, presented by Northern Bee Books.

This is one packed episode!  Let us know what you think by leaving comments for this episode above. Start a discussion!

Thank you for listening!

Links and websites mentioned in this podcast: 

Honey Bee Obscura


We welcome Betterbee as sponsor of today's episode. Betterbee’s mission is to support every beekeeper with excellent customerBetterBeeservice, continued education and quality equipment. From their colorful and informative catalog to their support of beekeeper educational activities, including this podcast series, Betterbee truly is Beekeepers Serving Beekeepers. See for yourself at

This episode is brought to you by Global Patties! Global Patties is a family business that manufactures protein supplement patties for honey bees. Feeding your hives protein supplement patties will helpGlobal Pattiesensure that they produce strong and health colonies by increasing brood production and overall honey flow. Global offers a variety of standard patties, as well as custom patties to meet your specific needs. Visit them today at and let them know you appreciate them sponsoring this episode! 

Thanks for Northern Bee Books for their sponsorship of Bee Books: Old & New with Kim Flottum. Northern Bee Books is the publisher of bee books available worldwide from their website or from Amazon and bookstores everywhere. They are also the publishers of The Beekeepers Quarterly and Natural Bee Husbandry. Check them out today!

Thanks to Strong Microbials for their support of Beekeeping TodayStrong MicrobialsPodcast. Find out more about heir line of probiotics in our Season 3, Episode 12 episode and from their website:

We want to also thank 2 Million Blossoms as a sponsor of the podcast. 2 Million Blossoms is a regular podcast featuring interviews with leading bee and insect researchers in the world of pollination, hosted by Dr. Kirsten Traynor.


We hope you enjoy this podcast and welcome your questions and comments in the show notes of this episode or:

Thanks to Bee Culture, the Magazine of American Beekeeping, for their support of The Beekeeping Today Podcast. Available in print and digital at

Bee Culture Magazine

Thank you for listening! 

Podcast music: Be Strong by Young Presidents; Epilogue by Musicalman; Walking in Paris by Studio Le Bus; Original guitar background instrumental by Jeff Ott

Beekeeping Today Podcast is an audio production of Growing Planet Media, LLC

Growing Planet Media, LLC


S4, E47 – Pol-Line VSH Honey Bees with USDA-ARS Drs Frank Rinkevich and Mike Simone



Jeff:Welcome to Beekeeping Today Podcast presented by Bee Culture. Beekeeping Today Podcast is your source for beekeeping news information and entertainment. I'm Jeff Ott.

Kim:And Kim Flottum.

Global Patties:Hey, Jeff and Kim today's sponsor is Global Patties. They're a family-operated business that manufactures protein supplement patties for honey bees. It's a good time to think about honeybee nutrition. Feeding your hives protein supplement patties will ensure that they produce strong and healthy colonies by increasing breed production and overall honey flow. Now is a great time to consider what type of patty is right for your area and your honey bees. Global offers a variety of standard patties as well as custom patties to meet your needs.

No matter where you are, Global is ready to serve you out of their manufacturing plants in Airdrie, Alberta, and in Butte Montana, or from distribution depots across the continent. Visit them today at

Jeff:Thanks, Sherry and thank you Global Patties. Each week we get to talk about how much we appreciate our sponsor support, and we know you'd rather we get right to talking about beekeeping. However, our great sponsors are critical to help making all of this happen from the transcripts, the hosting fees, the software, the hardware, the microphones, the subscriptions, the recorders, they enable each episode. With that, thanks to Bee Culture Magazine for continuing their presenting sponsorship of this podcast. Bee Culture has been the magazine for American Beekeeping since 1873.

Subscribe to Bee Culture today. Hey everybody, thanks for joining us. We're really happy you're here. Before we get started, just a quick reminder to subscribe or follow Beekeeping Today Podcast and give us a five-star rating. It really does help. Also, we are now adding complete transcripts of each episode on the website after the show notes, check them out. You can also leave questions and comments online under each show. You can leave a comment, ask a question, reply to a question ours or our listeners. Click on, leave a comment at the top of the episodes show notes to join the discussion.

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Hey everybody, thanks for listening. I hope your spring is going well, no matter where you are, Kim is joining us in just a few. We have a big episode set for you today. Later on, we have Dr. Frank Rinkevitch and Dr. Michael Simone talking about their work on the USDA RS line of Pol-line honeybees. It's spread with the Varroa-Sensitive Hygiene or VSH as well and testing its viability as a honeybee for commercial beekeeping.

It's a fascinating discussion you will want to hear. Recently, I met up with Dr. Dewey Caron at a local beekeeper meeting and was able to talk to him briefly about his Pacific Northwest Honeybee Survey. We'll hear about that in just a few minutes, but first Kim is joining us with a review of Beekeeping at Buckfast Abbey,an old book by Brother Adam. Let's get to that right now.

Kim:Hi, this is Kim Flottum again with another session of bee books old and new kindly sponsored by Northern Bee Books, publishers of hundreds of books on bees and beekeeping, plus they have available a huge collection of used and antiquarian beekeeping books, check them out at

You've probably heard of Brother Adam, a monk who lived in Buckfast Abbey in the very South-Central section of the UK, located very close to the Southern Coast of the island and heading west towards Land's End.

He was introduced to bees and beekeeping when he took residence at the Abbey and was taught much of the craft by the Abbey's resident beekeeper Brother Columbine who had been in charge of the bees since 1895.

In 1915, Brother Adam was appointed to assist Brother Columbine. As it turns out, the timing was either terrible or extremely fortunate, depending on your perspective. The Isle of Wight Disease was at its height throughout all of England, and all predictions in the fall of that year were that there would be no bees left in the country come spring.

For background, the disease had been discovered, though the cause was not yet identified on the Isle of Wight, a small island just off the coast of South Central England, very close to the Abbey. It spread to much of the UK fairly rapidly because of unrestricted bee movement and was rapidly causing the collapse of beekeeping in the country.

It was this event in the UK that led the USDA to forbid the import of any honey bee from anywhere in the world to avoid unknown diseases and pests from coming here. It worked for a while, I guess, but the winter of 1915, '16, though difficult, did not see the end of beekeeping, at least at the Abbey as 16 of the Abbey's 46 colonies survived.

However, those that perished were all native black bees, not native in the sense they were originated in the UK but were the dominant strain in the use there for many years. While those that did not perish were all a fairly recently imported Italian origin, this fact was not lost by the resident beekeeper. That summer, using the Italian stock, they made good their losses, and the next year increased numbers to 100 colonies.

Finally, in 1919 Brother Columbine retired, and Brother Adam was put in charge of the Abbey's bees. It must be noted that the focus of this book is not nearly so much about the whys of the management techniques described, but simply the wens and the hows of their management.

The reason the Abbey had bees was to achieve maximum yields of honey per colony, entailing a minimum effort and time. As brother Adam states in the preface, when all is said and done success and beekeeping is in its final analysis, determined by our ability to ensure that every colony is at all times in the best condition to make the most of a honey flow when one comes along.

This book has three sections. Part 1 deals with general observations, looking at the bees used by Brother Adam, the hive and the apiary and the reasons for keeping bees. He sums this up nicely. He needed a bee that was able to withstand the demands of modern beekeeping, a hive of sufficient size to allow a colony to gather as much honey as possible, and a beekeeper smart enough to keep out of the way of his bees.

Section 2 is simply seasonal management in great detail, but simply what he did in each season and what tools and equipment he used to accomplish what needed done. If you are rather new at bees, these sections are fundamental and you will gain insight into good seasonal management.

However, the last section is on breeding. The skills Brother Adam is best known for. He carefully explains the need of isolation of breeding colonies, the production of drones needed to ensure nearly pure crosses, and much of the rest of what is needed to raise good queens with desirable traits.

It is his enumeration and detail of these traits that should be noted here, especially. These include fecundity, or how many eggs can a queen lay. Industry is simply how much of, what kind of work will workers do? Disease resistance absolutely must be on this list, but care must be taken so resistance to the appropriate diseases are chosen. A disinclination to swarm is indispensable along with longevity, which both the bee and the beekeeper play a hand.

Wing power means how far will workers fly for food coupled with a keen sense of smell. Defense is important, but our experience here with African bees may have some role here. Winter hardiness for those of us with winter is important, but no less important is spring buildup. Some colonies are thrifty, that is resource conservative while some are not, which also covers self-provision or how much will they store for winter. Comb-building, both speed, and skill is critical as his pollen collection.

Less important to Brother Adam, but important enough for him to mention were having a good temper, meaning calm on the combs, little proboscis collection, and little brace comb construction, but attractive cappings, white better than wet, are needed and a keen sense of orientation is needed for those foragers who travel further than most. All of these traits will note are good for the beekeeper first and perhaps good for the bee in the long run and that's only a perhaps.

The value of this book lies not so much in what strains of bees to use to accomplish this art, but importing bees is essentially impossible, but rather gaining the full understanding of what traits are needed by beekeepers to develop a strain of bee needed, where you are.

One other thing Brother Adam mentioned was to never forget that the bee is in charge of this, not the beekeeper. We far too often forget that important point, but one wonders if that is completely correct. This book is published and available from Northern Bee Books and is available on Amazon. That's it for today folks, we'll talk to you next time.

Jeff:All right. This is Jeff, I'm at the Olympia Beekeepers Association Meeting and who do I run in today is Dr. Dewey Caron. Dewey, I'm glad to see you actually, and not on Zoom.

Dewey:Thank you, Jeff. It's this is I think the first live meeting of this group, that's exciting. I like that.

Jeff:It's the first time in a long time but it's good to actually see people around. What brings you up to Olympia?

Dewey:I was doing a bunch of talks coming North, so I had arranged to have one trip to get meetings in several different of the club groups. This group lost their meeting so I ended up having to come back just to do this meeting tonight. I'm up and down, up and back in a real quick trip.

Jeff:All right, that's really generous of you, especially considering the price of fuel in the Pacific Northwest.

Dewey:Oh indeed and the fact that we're in one of our still our wet rainy seasons. We have to travel in the rain.

Jeff:Absolutely, hey and it's great I really enjoyed talking with you because I’m always whining as our listeners know about the Pacific Northwest honey beekeeping and how difficult it is for me to get used to coming from Ohio and Colorado, and tonight's you talked about your Pacific Northwest Bee Survey that you've been doing and you compare the management practices of so many beekeepers in the area. That's really fascinating. How long have you been doing that?

Dewey:I had started doing survey work in the East as we have mites. One of the issues is what are people doing? It's a way for-- surveys are one way to look over your beekeeper's neighboring fence. When I move from the University of Delaware with retirement to live in the Portland area I started doing a survey here so I’m now in my 13th year of this survey.

I’m looking at both the backyard and beekeepers so individuals that have fewer or 50 or fewer colonies as well as in a different survey at the larger scale, the commercial beekeepers.

What then I do with the information is not only what level of loss are we experiencing by our types of hives, by our hive origination, whether it's an overwintered colony or a new colony we started but I’m also looking some key managements. If you do some sort of a management, you feed them let's say a dry sugar, what level of survival do you have, so I compare the individuals that do feed, let's say a dry sugar, I split it by fondant or dry Verde or sugar candy, their level of loss, then I’m comparing it to the overall level of loss.

It's a pretty conservative look in terms of, can some of these managements make a difference in overwintering, and indeed we find that a number of them do make a difference. It's not necessarily just what's going to work this year, so now I have a good database, so I’m actually looking at the past several years. I’ll say that, let’s say, using a sugar candy over winter, in the last seven of eight winters, that made a difference in individuals doing that management, having a better survival, in other words, a lower loss rate.

Jeff:That's really fascinating and this is all available on your website, what's that website?

Dewey:This is available on, you can take the survey there or then look at these past results. For clubs such as the club here that have a return of roughly 20 or more surveys, I generate an individual club report, so it’s immediately looking over the beekeeping fence of your immediate neighbors here in this club plus those in Pierce County and in Lewis County, the immediate counties close by here, as well as your other Washington beekeepers that are included in the survey and Oregon survey back-yarders as well.

Jeff:Well, that's really cool, and it's great to have that as a beekeeper, it's great to have the information readily available. It helps me manage my bees to see what other beekeepers in the area are doing that works in this location. As they say, beekeeping is all local, so that's really great work.

Dewey:It is local, and it's timing and you might know one or two other beekeepers, but this is giving you a look at another 20 people in your immediate area, that are doing this, or not doing this, and how, what level of success they had.

Jeff:What else are you working on?

Dewey:I am the overall representative for the whole region for the organization called WAS, Western Apiculture Society. We have not yet gone back to our live annual meeting, so we are having monthly meetings of a mini-conference. We're featuring two speakers, sometimes on the same topic or related, sometimes not.

This month, myself and a beekeeper who has an interesting project in British Columbia are looking at bees in cities and urban areas. It's come on very strongly and there are companies that are selling corporations the idea of saving the bee, doing something of benefit for the environment, and educating their own employees about pollination and the importance of working and to help save bees by having colonies of bees be on rooftops of their city buildings, their campuses where they're doing their research or their development work, or their headquarters.

Well, what is happening is, we're finding that we're getting an awful lot of bees in the urban area, so we'd like to get a dialogue going in terms of what are the necessary supports that need to be in place, where we're moving from bees in an agricultural area, to having as many located in urban areas?

Jeff:Wow, that's really good work. You've been doing that for this year, you started this year, or have you been doing it for a couple of years?

Dewey:I’ve been doing some of the tracking for a couple of years, we have some of our associations that have more members in a city, we also ask the location. So we're actually doing some mapping, so we're separating out from our database with the PNW Honeybee Survey, those that are in urban settings versus those that are in more rural areas. Those in urban settings are not doing as well as those in more urban settings as a general rule.

There, of course, are some exceptions but it does appear like we are overloading the carrying capacity for the cities and the resources that are available for the bees by bringing in so many bee colonies. Whether it's for corporations or individuals that are just--

What I talked about tonight was colony creep where you start with a couple of colonies but all of a sudden, with divides and capturing swarms, you end up with really more colonies, your numbers of colonies have creeped upward and more colonies than you care to take care of or really wanted to ever do.

Jeff:More of a challenge especially on rooftops.

Dewey:Especially on rooftops yes, present a whole new challenge for getting your equipment there, getting the honey back down off that roof et cetera, yes.

Jeff:There's entertaining stories about beehives in elevators and the looks people get. Dewey, I know you need to get back down the road, I-5 and it's getting dark, so I’ll let you go. I look forward to having you back on the podcast here soon and talking with Kim as well.

Dewey:Thank you, I appreciate it. I’m a faithful listener for the podcast. You always have some of the very, very good guests, very interesting guests on, it's always an interesting topic, so it's time well worth spent, and I appreciate the effort that you and Kim are doing to put out those regular podcasts. Thank you.

Jeff:Well, I really appreciate those kind words, and I do agree we have great guests and it’s especially fun when I get to see them face-to-face like I am now. Thanks so much and have a great trip home.

Dewey:Thank you, Jeff thank you, take care.



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Jeff:Thanks a lot, Strong Microbials, and right back to the show, sitting [chuckles] across the virtual Zoom table right now, are Dr. Frank Ranko, Rank-- Rankovic [laughs]

Frank Rankevich:It's Rankevich.

Jeff:Rankevich, sorry oh boy, I knew I was going to-- We practiced this before we started recording and I still messed it up, sorry folks--


Jeff:Dr. Mike Simone Finstrom, did I get that right? I know NPR will never hire me now. Welcome guys to the Beekeeping Today Podcast.

Frank:Happy to be here.

Mike Simone Finstrom:Thanks for having us.

Kim:Well, Frank and Mike, this is the first time I’ve had the opportunity to meet you in person such as it is. I know about your work, you are both scientists at the USDA Bee Lab in Baton Rouge. You have been working on something called the Pol-Bee or the Pol-Line of Bees, and I have not heard that phrase before this, maybe it's because I wasn't paying attention or you went up and changed the name on me.

Tell us what your Pol-Line of bees is, a little bit of the history certainly, so people know where it came from, and then your recent research and some of the results. I’m probably going to interrupt you and ask some questions during all of this, so I don't know, who wants to start? [laughs]

Frank:The Pol-line bee is one that yes, you might not have heard before because the more common iteration or version of it have been VSH, so these are mostly VSH which means varroa-sensitive hygiene, so these are bees that have been bred for the specific trait where they remove varroa-parasitized brood and this is a selection that's been going on at Baton Rouge lab well before either Frank and I started at the labs, there's a strong history of that breeding program at the lab.

And then the iteration that got into Pol-line was led by Bob xxxx who's now retired but involved with this project that we're talking about and what they did as part of that effort is they bred or outcrossed these VSH bees into several different commercial operations to make sure that the bees that are expressing this VSH, this varroa resistance trait at a high level, that they can also be productive colonies in commercial operations, and so the Pol-line is really bees that are well suited for pollination services.

That's where that name came from and then after that happened and there was one large paper of the production of those Pol-line bees, we brought them back to the USDA lab in Baton Rouge and really further refined that breeding and so then this recent study that came out is really the first big test of that really well-developed line expressing both this varroa-sensitive hygiene trait at a really high level and consistent level along with these other productivity traits that beekeepers are interested in and really that's what the industry needs.

Kim:Does it make honey and stay alive basically is what it comes down to, it sounds like. You study, you brought in commercial beekeepers and a significant number of colonies-- I don't see the numbers, but if you're working with commercial beekeepers, I bet you, it isn't two out in the backyard. How many were involved in these experiments about?

Frank:I think we started with close to 400. Is that correct Mike?

Mike:Yes, between the two years, I think if it was 100 and-- it was at least 150 per year or a little bit upwards of that and so this is a large scale but in terms of the commercial beekeepers, it's still a small number but we were really going with these sample sizes that were going to be relevant to the beekeeping industry.

So we filled up four different apiaries in this commercial operation and then they traveled through the circuit to really give them a real test of what's happening in the real world. We partner as much as we can with commercial beekeepers in particular, because if what we're doing doesn't work for them, we're not doing fully what we need to do for the industry.

Kim:Well, also, I wasn't aware of it saying that you overwintered these bees in Mississippi, California, North and South Dakota, certainly large honey-producing states, but what I also wasn't aware of is that these were actual, real-world working bees.

You put them on trucks and you pollinated them and you split them and all the things that commercial beekeepers do and you started them in the spring, went the whole season.

Frank:Yes, so basically we made splits with the beekeepers, so we used the splits from the beekeeper so that everything was being done exactly as they would do. We naturally made it our queens in an area with our drones. Again, similar to what the beekeepers do and what the beekeeper we worked with, he made it and his queens in his standard way.

We mated them naturally in a drone saturation area so that they were mating with our Pol-line drones. Then we put all the splits in the same spot. He loaded them up and their team loaded them up on the truck and brought them to the Dakotas and then dispersed them in the apiaries until October and then in October, they moved to California to the holding yards.

There was a subset that just went back to Mississippi and stayed there as a control for the ones that didn't go to California. Then they pollinated almonds after making honey all summer, and then they made it back to Mississippi to be splits for the new year.

Kim:Well, real-world beekeeping and the results then are going to reflect what a commercial beekeeper could probably expect doing whatever it is he does during the course of a year. That would add from my perspective, that I do have a lot more confidence in the results of this study because you made them work.


Kim:Yes, that's good.

Mike:I was going to say because a scientist because we like to be in control and have every factor accounted for, but in commercial beekeeping, sometimes things are out of your control and you have to just roll with it and that's why we use these big sample sizes.

As we all know beekeeping can be unpredictable at times, so a lot of colonies make it on into the study and then just keep track of them, that's a challenge and it takes us a lot of places, so working with people, like I said, in the Dakotas where honey being made, in California, where almonds are being pollinated. The relevance is very high to the commercial beekeeping industry for sure.

Kim:I bet you guys spend a lot of time biting your tongues, right? Saying don't do it that way because, and they went ahead and did it that way anyway because that's what they do.

Frank:Yes and no, really this test was do these bees work with what beekeepers are doing and so we want them to treat them as they're going to. To a degree, obviously it's like-- and the ones, the beekeepers that we work with are really great about understanding that balance of, well, this is science, and so we need some more data.

Unfortunately for them, they have to leave colonies that they would normally combine. In the holding yards in California, they would combine them before almonds or even after almonds, but so they're not combining them and so then they have somewhat weaker stuff.

Some of the stragglers might still be persistent when they would've removed them. So they work with us and we work with them and we know that we're confident in the data that we're getting back is really applicable to what's going on.

Jeff:I want to go jump back to the beginning real quick because I'm just intrigued by the name the Pol-line, and Michael, you had mentioned something that they were an originally developed specific or with pollination directly in mind or it was it pollination first, honey second, was there a preference in the selection?

Mike:Unfortunately, we weren't part of the naming process, right? I think some of the naming process came and I believe it was even one of the suggestions of one of the beekeepers that was working with this line when they were developing with combining the bees from here with their bees and one of the suggestions was to make the name so it's not necessarily pollination but it's the idea that they will work for pollination services. That pollination services is what's driving the industry, not necessarily honey production, right?


Mike:They need to produce honey and they need to be effective for pollination services, whether that's going up and down the East Coast or to California and almonds, so that's where that name came from, that it's for pollination services and really that means that they're going to be big in early spring and be productive, strong bees and that's ultimately what that name means.

Jeff:It would've been confusing to call them worker bees because that name's taken well, that's really, that's really fascinating. So, and Kim had asked earlier, and I don't, maybe I missed the answer, what was the original stock for these? You selected for the VSH but were they more the Carniolan or were they more Italian, more--

Mike:Yes, so the Pol-line, the original VSH population was largely derived from Italian bees, so that's the base population and then certainly, there's some mixture in there but the Pol-line then had been bred mostly just within insemination, within the population, so then it closed the population again, especially after they were in the commercial operations and then brought back.

But it's largely an Italian-based stock however-- That's one of the things that I think is important to express about these Pol-line bees and really that we're talking about these mite-resistant traits is that there's varroa-sensitive hygiene is expressed in Carniolan bees, Italian bees, Russian bees and that's something that a number of beekeepers and queen breeders are selecting for the varroa-resistant traits and so it really doesn't matter if they're Italian or not from that perspective.

Jeff:Okay, let's take this opportunity to hear from our great friends at Betterbee.

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Kim:Part of this experiment was to treat some of these bees and to not treat some of these bees and you had some spectacular results. I think the bees that you treated, what was the treatment?

Frank:The treatment went on in the fall after honey gets pulled off, they really needed to treat for varroa because up till that time when those boxes of honey come off, that's the longest time the varroa has been able to develop within the absence of a miticide treatment.

The beekeeper that we work with, they're treating right after that event occurs and this is this treatment goes on and that's usually what they do for the fall treatment and then in the wintertime, they'll do another treatment as well. In that process with our experiment, we had it designed to set up to see does Pol-line need that fall treatment in order to have very low varroa?

In some of the colonies, we skipped that fall treatment and when I say fall, I mean late August, when they pull honey. Some of them got that treatment, and some of them didn't get the treatment but then they all got treated in the wintertime when they went to either California or Mississippi for holding. We have the high treatment and a low treatment.

The high ones got both the fall and winter and the low treatment only got the winter treatment. In that case, the commercial stock that got the low treatment only, the skip-the-fall only winter, they had really poor performance. I think the final total was under 10% survival. Have I got that correct, Mike?

Mike:No, it's between 10% and 20% total for sure.

Frank:When Pol-line only have the low treatment, they skipped that fall treatment, survivorship was over 50% so a very big difference in the commercial versus Pol-line treatments. But when both stocks got the high treatments fall and winter, they performed similarly, Pol-line had a little bit higher survivorship but the commercial really needed that fall treatment in order to have high survivorship around 50%.

It just shows that Pol-line can perform pretty well without that fall treatment. The fall treatment definitely helps but it doesn't have that dramatic effect like it does in unselected stocks. That was what we almost expected that, because when we work with these bees at the lab, we know that they could maintain very low varroa levels without any miticide treatment. To see that without any miticides in the field, they still performed quite admirably. That was very good to get that data, for sure.

Kim:The treatment, whether either one or two treatments, the product applied to these bees was the choice of the commercial beekeeper or you did that? Were all of the treatments using the same product, or were there different products being used?

Frank:Yes, so it was all the same product, all the colonies, a lot of commercial beekeepers like to treat all their colonies the same. That was actually really good for part of the experimental design, that they all got treated the same in terms of miticide application so yes, same product, same timing, all that stuff was very consistent across the treatments.

Kim:Would you recommend this product to other beekeepers to use and can I ask you the name, just so folks have an idea?

Frank:Amitraz-based products are what most beekeepers are using and so we actually study amitraz resistance in varroa because a lot of beekeepers rely on amitraz as the miticide of choice, if you only are using that to control varroa, it tends to lead to higher treatment rates and because if a little bit works, maybe a little bit works even better and so what we've been finding out is that these varroa are being selected for resistance and that's a whole another aspect of my research that we're working on.

What's really interesting about this VSH behavior and these Pol-line bees is that we could hopefully reduce some of our reliance on these miticides to really mitigate the development of resistance. If we could get away with that one last fall treatment perhaps, it's really good for delaying the onset of the potential of resistance.

The other thing is that if you've maybe missed a treatment, or you forget to treat an apiary in a certain limited time, this VSH behavior acts as a little bit of redundancy in your varroa treatment program. I think that going forward there should be-- I think that i also helps to build a more robust, resilient varroa management program by incorporating these bees with VSH behavior, for sure.

Kim:Well, like I said before, the states that the bees that you were working with were from Mississippi, California, North and South Dakota, did you see a location difference? I know winters in Mississippi are significantly different than winters in North Dakota, and I'll just throw a tail end on there. Were any of these beekeepers wintering their bees inside so location and location, I guess?

Mike:Sure. One of the things that we did look at in terms of the Mississippi perspective, so all of the bees went to the Dakotas and that was really just for honey production, then a large portion of them went to California and so then they stayed there for the winter.

When it started snowing, they get out of the Dakotas and then they go and sit in California. The other subset went to Mississippi and those stationary ones, we had another set that really just stayed in Mississippi and that was the biggest location difference.

That was because in all honesty, there wasn't the management that they're getting in the Dakotas and so they ran out of food because there wasn't great food for them in the summer in Mississippi, which is one of the reasons why they leave and so the biggest location difference was that when you're not properly managing colonies, they can starve because they don't have enough resources in certain places and particularly in the South.

When I was in North Carolina, we often had to feed colonies, and in August too, because they're not getting the resources because it's not a good location and that's one reason why we have to do the bees' route. We don't really have I wouldn't say, great locational evidence in terms of overwintering from this particular experience but we have worked and collaborated with others that are working with these Pol-line bees around the country and they overwinter just as well in the Midwest, as they do here in Louisiana, which is really nice to see.

Kim:That's even more real-world in this experiment. Were any of these people wintering indoors?

Mike:Oh, sorry. No, we didn't do. This was all done with one commercial beekeeper in this particular case and so we haven't done any indoor overwintering here.

Kim:Okay. I was just curious about that.

Frank:That's actually interesting you bring that up because I'm working on this grant with a bunch of other people from across the country to do this holistic varroa control program. One of them is to use different stocks of bees in these overwintering facilities like you're mentioning to see if there's any stock interactions with this overwintering because there's this idea that some bees are adapted to the local environment and selective how they're brought up and so we want to check to make sure that these Pol-line bees or the one that we run here, can survive in these cold overwinter climates just because Louisiana doesn't get too cold here even in the winter but we want to see how they perform in those cold overwintered environments.

Because I know that a lot of people are interested in the benefits that an overwinter indoor storage can have on their bees. We want to make sure that these bees are performing well under all conditions. The more that we can study it, the more that we can see if they're applicable across the board.

Kim:The other half of the varroa problem of course, are the viruses and I know you look at-- don't want to say the three major viruses that you were looking at, the question would be between treated and non-treated and then treated once and not treated, did you see three different-sized piles of dead bees from virus from this?

Frank:Yes, sure. Most of the virus difference that we see is really between unselected stock of a mite-resistant stock. We see that it tends to have less viruses in Pol-line bees and in large part the viruses do correspond to mite levels, right? When you have less mites reproducing and feeding on offspring that generally tends to reduce the viruses overall in the whole population, particularly with deformed wing virus and in this case, chronic bee paralysis virus too, which has a mild association with varroa.

Interestingly, we didn't find a difference in the amount of black queen cell virus between the two populations and that one is not transmitted by varroa. There's something else going on there. We definitely see pretty clear differences in deformed wing virus, which we've seen now several times with VSH bees, but a lot with the Russian bees, too. They tend to carry less deformed wing virus and we think that's also in part because of keeping the varroa in check. There's definitely a good thing. If you're keeping the mites in check, you're keeping the viruses in check too.

Kim:That makes perfect sense. Which one of you was the lucky person who got to do all those virus samples?

Mike:Thankfully, all that virus work gets done in my lab, but Thomas of O'Shay- Weller, who is the postdoc who led all these analyses. He has a wonderful task of mashing up bunches of beas and doing all the extractions and viral analysis.

Jeff:One of the things I was interested in knowing is how sticky is the Pol-line in a given group? How often would a beekeeper need to re-queen his operation to maintain that breed line?

Frank:The genetics of VSH in Pol-line is quite tricky because this is a complicated behavior where they have to first detect these infested cells, then uncap it, remove it. It's a stereotypical behaviors, that they have to be coordinated. There's probably a lot of genes involved, exactly how many, we're not too sure, but we have some ideas.

What's interesting is that since it's such a polygenic trait covered by many different genes it seems like after you cross one of these highly selected queens with a non-selected drone the offspring tend to have some level of VSH behavior. When those daughters then reproduce to make their granddaughters, they tend to have very low levels of expression. After about two rounds of outcrossing to non-VSH drones they tend to dilute the behavior.

That's what's really tricky is to maintain this in a population, we have to create this genetic momentum. That way, when they are mating they are outcrossed and mating to open drones that those drones are also VSH. So they can maintain it. That's what's really trick is we have to find out what level of penetrance in the population, we have to get these genes, that way it maintains itself without constant infusion of this genetic material.

Jeff:Whether that those traits while since it's multiple genes expressing it so that wouldn't be multiple recessive traits.

Frank:The good thing is though we demonstrate that we can do this because initially with this Pol-line, it was maintained by instrumental insemination, so very highly controlled breeding but the ones that we did for this experiment, we just let them open them in drone aggregation areas like Mike said, we saturate it with Pol-line drone.

If a breeder is working with this, they can maintain this phenotype with open mating which is actually a really big important step to making this commercially viable. I don't know how many queen producers are going to instantly inseminate every queen. It's a lot easier to open-mate them for sure.

Mike:I think to me, that was one of the most exciting things about these results because this was really that first big-- This was the first time that we had naturally made it Pol-line into this kind of drone saturation area. That's a big step in terms of moving this breeder stock forward.

The other thing is, we really need to continue to work on tools for selection that beekeepers can use for these traits. There's groups led by Kara Reigner, who's working on a chemical assay, then there's a group in France, that are working on different assays that can be used like a freeze-kill brood assay for more general hygienic behavior that would then help everybody be able to assess this trait and really increase it and then that can lead to these genes being more widespread.

We also have other projects with other collaborators looking more specifically at these genes with the idea of being able to do marker-assisted selection down the road. These are all things that we're actively working on and we wish that we could give you these tools right now but they take a long time to develop.

Jeff:It leads to the ultimate question that I'm sure our listeners are having is how soon can I order one from my local queen breeder and get them into my yard? Is that something that's going to happen or is this intellectual exercise?

Mike:For sure, the USDA and our lab has had different partners over the years working to try and work with getting the VSH bees out. That's mostly been focused on getting breeders out and those partners making breeders that they can then sell.

Again, we're worried about that trade diluting over time, or even in one generation. Right now, there's the agreement that we have for these Pol-line bees or a Pol-light bee is that the Hilo bees out of Hawaii and that's the only agreement we have right now. The Hilo stocks, it's as close to the Pol-line a any others. But there are other bee breeders, people that sell bee queens, honey bee queens that are producing bees that are at least somewhat VSH or have resistance to varroa via VSH or other mechanisms.

I think the important thing is if people are advertising varroa resistance in their bees, or in those queens is to actually talk to them and say, "Okay, how are you selecting for it?" If they have sort of the date of the backup that their bees are resistant to varroa then that's what you want to go with.

It's just like any other thing that you buy, you want to know if the product that you're buying if it's made in this certain way or whatever. The same thing should be true for queens, I thin,k that we can be responsible consumers and producers for getting the products that we want.

Frank:Evaluating these colonies for varroa resistance is quite labor-intensive. It's you have to inspect brood cells in each colony, and then check for mite reproduction and things like that. It's very involved just to evaluate each colony and to do this at the commercial scale.

It does take a significant investment of time, but like Mike was saying is that just knowing those criteria that beekeepers, the producers are using would be really important. Like I said, selection, what criteria and things like that are critically important to making that viable because the trick with this or any honeybee stock, in general, is to make sure it lives up to his claims is, if you say your bees make tons of honey let's hope eventually they make tons of honey.

With VSH it's no different is that we want to if you're going to be selling them, let's make sure that they are producing bees with very low varroa populations.

Kim:Here's a quick question. If I was a queen producer selling queens to beekeepers anywhere and everywhere, both breeder stock and general working stock queens and I wanted to convince people that I was doing things right and that the queens that they were going to be buying met certain standards, is there some way, could you put together something or could a queen breeder put together essentially a cheat sheet that said, "virus load this much, varroa this much, we're overwintering this percent." List the things that beekeepers are interested in and rate your bees to, compare your bees to how those things that beekeepers are looking for.

Am I making any sense here? I think you just said it right. I want to know what you're producing, and if I'm buying a car, I want to know it gets this many miles per gallon and all of these things, or this many miles per charge, maybe that's the new one. Is there some way to do that?

Mike:I don't know. Ultimately, it is tricky. If you're going to say that you're measuring honey production, for example, you would have to have some sort of standardized measure, is it over a season? Is it in Louisiana where they're going to make a ton of honey in May in June? Or is it two-week weight gain? I don't think we have great standards, in terms of some of those measures that then could be widespread across the board, and not often environmentally dependent.

I think in terms of mite resistance, one of the things would be is your breeding population, are they treated for mites? Is that part of your selection? If you're treating for mites in that population, then it's hard to assess mite population growth, potentially. Are you looking at how the mites grow in those breeder colonies over a three-month time period? That's a really good example of an easier metric that could be done as long as colonies are a similar size and make sure they're clean.

If you're looking at that mite population growth over time, your sugar shakes, your alcohol washes every month, and then is that number increasing? That can be one metric. Now, if you have low mite population growth, especially from that spring season and summer, especially over winter, does that mean you're selecting for a varroa-sensitive hygiene? No, it means you're selecting for low mite ovulation growth from some mechanism. You don't know what that is.

I think it's more of like, if a breeder is saying that they are producing varroa-sensitive hygienic bees, how are they measuring it to know that that's what it is? If they're selecting just mite-resistant bees, what is that metric? I don't think it necessarily has to be the same and I don't think we need all, necessarily VSH bees. I think we need bees to have a variety of traits that they use to defend themselves against all of their various parasites and pathogens. I think that's what makes a healthy bee population.

Frank:As Mike has mentioned, there are many different ways to get low varroa population. The mite reproduction is one way that they can enter, keep varroa populations low. Then another scientist at the lab found that there's this programmed death in the larvae in this one stock that also prevents mites from reproducing, it's called the term social apoptosis. It's a behavior that's seen in the original host of the varroa, the Apis cerana, but this was one of the first demonstrations that yes, an Apis mellifera, they can also undergo this sort of programmed social apoptosis, where they self-sacrifice the larvae to prevent the varroa from reproducing.

A lot of different ways to get at it. Under the low verroa population umbrella, there's many different ways to get to that endpoint.

Kim:I'm throwing the gauntlet down to the queen production industry to develop a set of standards that I can essentially put an ad in a magazine and say, "These are my bees." I bet it can be done. I bet somebody somewhere can figure this out.

Mike:The other interesting thing is that some people have different definitions of what's acceptable to them. Our one beekeeper, they say that my definition of resistance is that I don't have to do two treatments for miticide applications. To them, it's more of a functional operational level of resistance, where if he doesn't treat for verroa in the fall, he still gets good survivorship. He doesn't know how exactly that happens, but why he doesn't need it, whether it's VSH or the social apoptosis or what the mechanism is, to him functionally, that's his definition of resistance.

Kim:It's the end result that counts. What have we missed? You guys have done good work here. I'm excited about being able to go down and get some mite-resistant queens. Week after next when I have to re-queen. What have we missed other than what we've talked about this level of research?

Frank:For me, I think that this is really just demonstrating that the importance of varroa in honeybee colony health, we clearly demonstrated in our study that these bees with VSH behavior that specifically remove varroa-- That's the major difference between this and the commercial stock.

All other things being equal, same landscape, same regulatory pathway, same management style, same potential pesticide exposures, all that stuff is the same, but the major difference here is varroa. I think that's what's really important.

I think it also really underscores the need for diversifying our varroa management options. We have VSH and Pol-line, that's really good. Miticides, when you don't have resistance to varroa, tend to work quite well. There's also things like cultural control, like we mentioned, the overwintering and then the management programs when the strategic splitting things and all the different ways.

I think we need to think about varroa management as a system as opposed to, "Oh, we're just going to use one thing. We're going to use miticides. We're going to use this one thing," because once you only rely on one thing, then nature has a way of overcoming those barriers. Like in the case of amitraz they develop resistance. I think building redundancy in the system makes a more robust varroa management system.

Kim:I think you said something that lots of times comes true, Mother Nature bats last. I think that's true. However, you're beginning to show that there's a lot of ways to, if not control that, at least make it manageable. I like your term varroa control management system. That's a good way to end this.

Jeff:Michael, do you have any closing thoughts?

Mike:No. I totally agree that oftentimes we think of, there's a lot of talk of integrated pest management and learning how IPM works for honeybees, and oftentimes that just means rotating chemicals, and we often lose sight of the bee.

We really should be promoting all of these great bee defenses that they have against their parasites, the bees can do it, if we let them and if we work with them to it. We have to remember the bees there at the heart of it all.

Kim:Oh, that's excellent thought for closing. Gentlemen. Thank you very much. This has been enlightening, and I look forward to being able to find some Pol bees somewhere the summer. I'm kidding. Somewhere soon, how's that? Stay warm down in Baton Rouge, and I hope we can talk again.

Mike:Thanks. It was great.

Jeff:Thanks, guys.

Frank:Thanks for having us. This is great.

Jeff:Thank you. I enjoyed talking with you and look forward to having you back.

Frank:Right. Cheers.



Jeff:Well, that about wraps it up for this episode. Before we go, I want to encourage our listeners to rate us five stars on Apple Podcast wherever you download and stream the show. Your vote helps other beekeepers find us quicker. Even better, write a review and let other beekeepers looking for a new podcast know what you like. You can get there directly from our website by clicking on reviews along the top of any web page.

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Finally, and most importantly, we want to thank you the Beekeeping Today Podcast listener for joining us on the show. Feel free to leave us comments and questions at Leave a Comment section under each episode on the website. We'd love to hear from you. Thanks a lot, everybody.

[00:59:28] [END OF AUDIO]

Dr. Michael Simone-FinstromProfile Photo

Dr. Michael Simone-Finstrom

Research Molecular Biologist

Mike Simone-Finstrom is a Research Molecular Biologist at the USDA Honey Bee Breeding, Genetics and Physiology Research Unit in Baton Rouge, LA. He earned his PhD at University of Minnesota where he pioneered a line of research with Dr. Marla Spivak regarding how and why bees collect plant resins and use them as propolis in the hive, questions he still continues to study.

Prior to joining the USDA, he worked with Dr. David Tarpy at NC State University on topics ranging from queen quality to migratory beekeeping to social immunity. The overarching goal of all of his projects focuses on how honey bees can be made stronger, healthier and more productive using their own natural defenses and traits. His current work aims to understanding how these traits work in concert in order to promote them within the beekeeping industry and identify components of viral resistance in honey bees.

Mike's USDA website is:

Dr. Frank RinkevichProfile Photo

Dr. Frank Rinkevich

Research Entomologist

Dr. Frank D. Rinkevich is a Research Entomologist at the USDA-ARS Honey Bee Breeding, Genetics, and Physiology Laboratory in Baton Rouge LA. Frank has extensive training in insect toxicology, biochemistry, molecular biology, and genetics. The goal of Dr. Frank's research is to provide a basic understanding of pesticide toxicology that is relevant to field conditions in the commercial beekeeping industry.

Current research interests in Dr. Rinkevich's lab include evaluating the effects of pesticide exposure on colony survivorship in commercial beekeeping operations, assessing the capacity and dynamics of metabolic detoxification of insecticides, understanding the genetic, behavioral, and social factors that affect insecticide sensitivity, determining the breadth, depth, and mechanisms of amitraz resistance in Varroa, establishing the effects of fungicides on colony health, and evaluating the performance of honey bee stocks selected for low Varroa populations in commercial beekeeping conditions.

Frank's USDA website is:

Dr. Dewey CaronProfile Photo

Dr. Dewey Caron

Author, Professor Emeritus

Dr Dewey M. Caron is Emeritus Professor of Entomology & Wildlife Ecology, Univ of Delaware, & Affiliate Professor, Dept Horticulture, Oregon State University. He had professional appointments at Cornell (1968-70), Univ of Maryland (1970-81) and U Delaware 1981-2009, serving as entomology chair at the last 2. A sabbatical year was spent at the USDA Tucson lab 1977-78 and he had 2 Fulbright awards for projects in Panama and Bolivia with Africanized bees.

Following retirement from Univ of Delaware in 2009 he moved to Portland, OR to be closer to grandkids.

Dewey was very active with EAS serving many positions including President and Chairman of the Board and Master beekeeper program developer and advisor. Since being in the west, he has served as organizer of a WAS annual meeting and President of WAS in Salem OR in 2010, and is currently member-at-large to the WAS Board. Dewey represents WAS on Honey Bee Health Coalition.

In retirement he remains active in bee education, writing for newsletters, giving Bee Short Courses, assisting in several Master beekeeper programs and giving presentations to local, state and regional bee clubs. He is author of Honey Bee Biology & Beekeeping, major textbook used in University and bee association bee courses and has a new bee book The Complete Bee Handbook published by Rockridge Press in 2020. Each April he does Pacific Northwest bee survey of losses and management and a pollination economics survey of PNW beekeepers.