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July 18, 2022

The Small Hive Beetle with Drs. Morgan Roth and Aaron Gross (S5, E05)

The Small Hive Beetle with Drs. Morgan Roth and Aaron Gross  (S5, E05)

On this episode, we learn share everything you ever wanted to know about Small Hive Beetles, with Drs. Morgan Roth and Aaron Gross, from Virginia Tech. Small hive beetles cause about $3 million dollars damage to US beehives every year. Today we...


On this episode, we learn share everything you ever wanted to know about Small Hive Beetles, with Drs. Morgan Roth and Aaron Gross, from Virginia Tech.

Small hive beetles cause about $3 million dollars damage to US beehives every year. Today we explore their life cycle, how they find your hives, the damage they can do if you don’t interfere, how they spread, and most importantly, what you can do to slow, or stop them from destroying your hive and killing your bees.

They eat honey, pollen, eggs and larvae. And they bring with them a fungus that turns their fecal waste into a slime that may be the worst thing imaginable in a bee hive.

There are several ways to attack this creature and stop them from spreading to other hives. You can trap them inside your hives, you can make the area around your hives dangerous for them to burrow in when they leave and pupate outside the hive or you can provide pesticides or bacteria outside the hive that will stop them.

Also in today’s episode, Ed Colby returns with a story from his book, “A Beekeeper’s Life: Tales of a Beekeeper”, titled Staying Cool. Ed has a great tale on how to keep cool on while working bees in the heat of the summer!

We hope you enjoy the episode. Leave comments and questions in the Comments Section of the episode's website.

Thank you for listening!

Links and websites mentioned in this podcast: 

Honey Bee Obscura

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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 help Global 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 http://globalpatties.com and let them know you appreciate them sponsoring this episode! 

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

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

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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

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Transcript

S5, E05 – The Small Hive Beetle With Drs. Morgan Roth And Aaron Gross

[music]

Jeff Ott: 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 Flottum: I'm 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 honeybees. 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 www.globalpatties.com.

Jeff: Thanks, Sheri, 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 be cultured today.

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Hey, everybody. Thanks for joining us today. We have a great show all queued up for you. In most parts of the country, beekeepers must deal with the small hive beetle. It is a widespread problem. On today's episode, we've invited doctors, Morgan Roth and Aaron Gross from Virginia Tech's Department of Entomology College of Agriculture and Life Sciences in Blacksburg, Virginia, to this show to talk about their recent paper on the small hive beetle. If you've never had to deal with a small hive beetle, be grateful.

If every time you pop open the cover of a colony and you see them scurry off, you will want to listen to what Morgan and Aaron have to say. They'll be right up, but first, it's a hot, hot summer across the country. With climate change a reality, this is going to be a seasonal fact of life. Unless of course, the political and industrial leaders around the world can start making meaningful long-term decisions and lower global temperatures. In the meantime, working your bees in the heat of the summer is hard, finding a way to keep cool is critical.

Storyteller and commercial beekeeper, Ed Colby, joins us again with a chapter from his book, A Beekeeper's Life. Tales from the Bottom Board, on how he fights the heat, working bees along the Western slope of Colorado. Let's hear from Ed now, and then onto our talk with Morgan and Aaron about the small hive beetle.

[music]

Ed Colby: Hi, there. If it's hot where you live this summer, I have a story for you that might cool you down. In fact, it's called staying cool, and this is from August of 2003.

[singing]

The king was in the counting house, counting out his money,

The queen was in the parlor, eating bread and honey.

My beekeeper boss, Paul, loves the summer dog days because he gets to start extracting honey. He doesn't talk about it, but we all know with honey prices hovering in the stratosphere, in his mind, he's already tarpon fishing in the Keys. The sheet metal honey house heats up above 100 during the day, and probably a lot hotter, although nobody actually checks the temperature. I guess you want a hot honey house, so the honey spins freely out of the comb.

Paul cranks up the radio and works alone all day extracting. He sends the crew to work the bee yards from out South of Silt, to Rifle, to Parachute, to Meeker, to the Flat Tops, to Steamboat Springs. Temperatures sore to the upper 90s most days. Of course, none of the trucks has an air conditioner that works. The July issue of Bee Culture ran a letter and photo from Dick Crawford of Morrisonville, New York. The picture shows three beekeepers in their bee suits and veils standing shoulder-deep in a swimming pool.

Dick wrote, "We jumped into the pool with our bee suits on, then we went and took our honey. Our clothes kept us cool, while the temperature was 95 degrees. I got the idea while working construction. Jump in about noon, and work in cool clothes all afternoon." Stay cool merely by staying wet? This is too simple. On the way to the Zeiner bee yard outside of Hayden, Colorado, Derek and I laugh about Dick's picture. Later, loading honey supers onto the truck, I feel so hot. It occurs to me I might actually get sick.

Afterwards, I park by the Yampa River. Derek says, "What are we doing?" I say, "We're going into the river with all our clothes on." He says, "We are? You never saw a kid jump out of a truck so fast. Arms outstretched to the side, I walk across the stony river bottom in my long sleeve shirt, jeans, and Converse All Stars. Maybe some stern-faced preacher will push me under and baptize me. From waist-deep, in the current, I plunge head first into the ripple, and the cool river gently sweeps me away. When I come up for air, I'm 12 years old again, and the world looks new.

Now we go to the river every day, even Mark succumbs to its siren song. He sits hunched over on the bank, struggling to remove an upturned boot, just like the cowpoke in corny cartoons. Then he steps gingerly into the river, grinning as the sun illuminates his ghost-white cowboy shoulders. Swimming with your clothes on as an energy-efficient personal cooling system, totally changes my outlook on hot weather. A noon plunge keeps me chilled for about two bee yards.

When I'm almost dry, I put on my spare pre-soaked shirt, and it's October again, no matter how hot the day. Derek and Mark don't buy into the, wear all your clothes soaking wet idea. They take their shirts off when they go in, that's their problem. Mark's pretty careful in the river. Everybody knows, "Cowboys can't swim."

Derek basically works bees naked anyway. He wears shorts, shoes, and a veil, that's it. He does stay pretty close to the smoker, and he sometimes says a bad word, but who doesn't? People stop alongside the road to take his picture. I don't get it. I can't understand why everybody doesn't walk around fully clothed and dripping wet all summer.

The other day when I climbed out of the river, I almost tripped over an old bison skull half buried in the sand. Mark knows his Western history and Indian law. He said, the Sioux used to come down here from Wyoming to chase Buffalo. The skull had a hole in one eye socket, and we speculated about that. Mark finds arrowheads and spear points all the time. Whenever we look together, he always finds stuff, at least chips, but all I ever see are rocks of dirt and sagebrush.

After I found that bison skull, he kept saying, "That's an unbelievable find, how'd you get so lucky?" Lucky finds never happen when you put your head down and grind it out. We drive right past this spot all summer, we could have almost seen that skull from the road. I had never found it if I hadn't been swimming in the river. Thank goodness for hot weather, an air conditioner that doesn't work, and a picture in Bee Culture magazine.

[music]

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Jeff: Hey, and while you're on the Strong Microbial site, make sure you click on and subscribe to The Hive, their regular newsletter full of product facts and information about bees. Hey, everybody. Welcome back to the show, sitting across the virtual Zoom table right now are two great guests, Dr. Aaron Gross and Dr. Morgan Roth, both of the Virginia Polytechnic Institutes and State University in Blacksburg, Virginia. Thank you, you too for joining us. We're here to talk about small hive beetle.

Dr. Aaron Gross: Good to be here. Hi.

Dr. Morgan Roth: Great to be here. Thanks for having us.

Jeff: Thank you so much for being here.

Kim: Nice to meet both of you. Morgan, you just said that you have just finished your PhD congratulations.

Morgan: Thanks so much. Yes, I was doing projects on small hive beetles for the past five years. It's exciting to be finished with that part of it.

Jeff: I hear some relief in your voice, "I'm so glad to have that behind me."

[laughter]

Morgan: Certainly, but it was also really fun too. I learned a lot, and small hive beetles are fun if you're not a beekeeper.

[laughter]

Kim: That's one way of looking at it, I suppose.

[laughter]

Kim: Aaron, you are a professor there, assistant professor?

Aaron: Yes. I'm an assistant professor, more of a toxicologist. Just working on pesticides and ways to control pests.

Kim: Here's one you can control, small hive beetle. [laughs] Jeff, did you get a chance to read the paper?

Jeff: Oh, absolutely. Yes, Zoe brought us to our attention of Dr. Gross and Dr. Roth about the small hive beetle. You are our first guests talking about small hive beetle. It took us five years, but we're finally here talking about small hive beetle.

[laughter]

Morgan: It's exciting.

Kim: Probably what we should start with then is to have one or both of you give an overview of-- not in great detail. We'll get into detail later, but an overview of the small hive beetle lifecycle. Where do they come from? How did they get into my hive? What do they do when they get there and how can I get rid of them? How's that for a summary?

Morgan: Great. The last one is a little trickier but the other three are doable. Small hive beetles have life stages that take place both in and outside of the hives. The adult beetles are attracted to your hives through volatile chemicals from the hives, including alarm pheromone, which is a really interesting aspect of hive location.

Adult hive beetles will come to the hive about two to three weeks after they emerge from pupation in the soil. Once they reach the hive, they will congregate in dark crevices and areas in the hive, usually on bottom boards or long frames, and then they'll mate.

There's about a 2 to 1 or 1.5 to 1 female to male ratio, so there are a lot more females than male beetles. Each female can lay 1 to 2,000 eggs approximately.

Kim: Oh god. [laughs]

Morgan: Even just a few beetles means you could have a really big infestation in a pretty short time. The main damage-causing stage of this beetle is the larval stage. These larvae will eat pretty much everything in your hive. They'll eat the honey pollen, wax, brood, just pretty much everything. Actually, when they eat pollen, it leads to a lot of fermentation. They have a symbiotic fungi that lives in their digestive system that will then release more attractive compounds that will draw more beetles to the hive.

It's this really bad feedback loop of infestation, and then once larvae reach their third developmental stage or instar, they will go back to the soil outside of your hive and then they'll burrow and pupate, and then it will just repeat the cycle. That's an overview of the lifecycle of a small hive beetle.

Jeff: I think I've heard enough.

[laughter]

Kim: Going back to the beginning of that, you say they can find my hive through pheromones emitted by my hive including alarm pheromone?

Morgan: That's correct.

Kim: How far away do they have to be before they can't find my hive by that?

Morgan: They are very strong fliers. It's known that they can fly over 100 meters to find hives. I don't know that there's an exact perimeter that is well known as far as where they can sense your hives from, but they can sense really tiny trace amounts of these chemicals so they will find your hive.

Also, one thing I didn't mention with the lifecycle is that small hive beetles don't need a hive to survive. It's just more optimal for their reproduction. They can still survive on various types of fruit or in stored hive products as well. You have to be really careful with where you're storing your hive products because they can get into that and reproduce if it's warm enough.

Kim: That's promising. There's a hive down the road here about half a mile, and a bunch of them have pupated, they are leaving the soil. They start to look around, don't they automatically go back into the hive they came out of?

Morgan: Not necessarily, but probably if that's the closest one to where they came from. It would make sense that they would find their way back but they can go pretty far distances, they can crawl pretty far distances as well. There's no guarantee, but it's likely they'll probably go back to the hives that they came from if they're close.

Aaron: They are strong fliers too. They're good at flying good distances.

Kim: How far can they crawl? If they leave the hive as a larva and then they drop onto the ground but the ground is inhospitable, let's put it that way. It's concrete or blacktop or bed of a truck or something, how far will they crawl to get to a place that works for them?

Morgan: I believe it's 50 to 100 meters they can crawl. I'd have to double-check on that, but just from having them in the lab, we occasionally would have one where I would see it drop on the floor and would crawl for probably 30 feet, they would crawl. They can make it a long ways. Just having concrete or inhospitable surfaces directly around your hives doesn't necessarily mean that they're going to die, which is why people will use things like slaked lime and diatomaceous earth, which will actually desiccate the cuticles and abrade the cuticles as well. Just having something that's not hospitable directly around your hives isn't necessarily going to guarantee that you'll kill those larvae.

Kim: 50 to 100 yards. Holy cow.

Morgan: I think it might have been meters actually. I'll double-check on that.

Jeff: Two questions. Where are they from originally, a small hive beetle? What is their range in the United States, in Canada today?

Morgan: They are originally an invasive beetle from Sub-Saharan Africa. They were discovered in 1967, I believe by Murray. They weren't so much of a pest in their native range because A. mellifera or subspecies in Africa do abscond more frequently, it's a little more of a warm climate and those bees are better adapted to defend their hives.

Really, infestations only happen in hives that are already weak, but they were discovered in the U.S. in Florida, in 1998. In our climate when bees are absconding in late winter to late summer, that's pretty rough going into winter, they can if the infestations get severe enough. Also, our bees here are not quite as well adapted to defend the hives because they haven't really interacted with the small hive beetle before about 20 years ago. That's where they came from.

Kim: Are honey bees their only host?

Morgan: No, they can also live in bumblebee colonies. They're attracted actually also to Bumblebee volatiles, and also various species of stingless bees. There's actually one species in Australia because they're also a really big pest in Australia. This is Trigona carbonaria is the species of stingless bee that will actually mummify small hive beetle adults when they get to the hive to keep them from infesting the hive. They'll coat them in mud and resin and wax. That was a paper that came out a few years ago. There are few species that have adapted ways to deal with them, but our bees aren't so good at that yet.

Kim: We've got beetles who have found my hive and now they're going to start doing what they do. The first thing they're going to do I would imagine is start laying eggs. The classic question, eggs per day eggs per female. How does that work?

Morgan: Eggs, they generally lay clusters of about 30 eggs, and the eggs are really small, they usually will lay them in cracks and areas where they wouldn't be disturbed in the hive, but the females throughout their reproductive cycle can lay approximately 1,000 to 2,000 eggs. You can have lots of eggs very quickly. The beetles can live for quite a long time. It's estimated up to 16 months, especially in a lab setting, but in the wild, it wouldn't be necessarily unlikely that they'd live for up to a year.

Kim: 16 months.

Jeff: What a mess.

Kim: 10 To 30 eggs in a cluster, and the clusters are well hidden in the hive. When I'm looking for small hive beetle I'm probably not going to find egg clusters?

Morgan: No, no, the eggs are very tiny. The adult beetles and larger larvae are probably your best bet for just locating infestations within your own hive. Especially the adults, you can generally see them running around. They have a lot of defensive things that they'll do like drop and fall when bees come towards them or they'll huddle into a little turtle shape, they'll pull their legs and heads in so that the bees can't really do very much about them. They have a lot of little techniques to avoid being attacked.

Kim: One of the things that I heard, Jeff, was that the bees would build a propolis prison on metallic, the top bars, and circle several or one or several adult small hive beetles but then the small hive-- is this correct? Somebody told me this that the small hive beetle then would actually beg for food and the bees would feed them?

Morgan: Yes, that's correct. They will try to induce bees to do trophallaxis with them. They'll touch their antennae to the mouth parts of the bee, and then the bees about 50% of the time will actually feed them, even if they are in a propolis prison.

Kim: Unbelievable.

Jeff: Wow.

Morgan: They're smart.

Kim: Yes, very smart. Very smart. How big do the larvae get? I'm going to back up. Where I live, we don't have enough small hive beetle for me to have seen all of this. I'm the new kid on the block here. I'm just asking basic questions. How big do the larvae get?

Morgan: They get up to a centimeter in length.

Jeff: That's pretty big.

Kim: Well if they get that big, then they're going to look like small wax moth larvae.

Morgan: A little bit, but there are some really key differences. They are a yellowish color and they also have little spines that go down the back, the dorsal side of the larvae. They're pretty easy to distinguish. There's yellowish-looking spines that go along the back and they have a strong head capsule that's a little bit darker too.

Kim: The thing that you hear the most about small hive beetle damage is the slime. Where does that come from and why?

Morgan: Slime is basically beetle waste that has fungi growing in it, that's what makes it. Also, pollen feeding is really important in slime production. The symbiotic fungi, it's called Kodamaea ohmeri, and it's found on the surfaces and in the digestive systems of small hive beetles both larvae and adults. That will ferment the waste products of small hive beetles and that's what creates that really bad-smelling slimy substance that you'll find in your hives.

Jeff: Here, I always thought the Varroa was the nasty one, but this is not sounding very much like a picnic. Where are they located in United States and Canada?

Morgan: They're pretty widespread throughout the US and Canada, especially in the South and Southeast. One of the problems is because Varroa is so much more well-known and prevalent and does kill colonies so quickly. Small hive beetle populations in different areas isn't necessarily as well studied, but we do know that they are prevalent across the US and Canada. Also, Australia actually has a lot and there are some in Central America and the Philippines and some places in Europe as well.

Jeff: Then it must be a matter of time that we get them here in the Pacific Northwest, and I should say, my backyard because I cannot guarantee they're not down the street or down at the bee yard where the commercial guy drops his bees, but I've never come across them in my colonies and where's that wood I want to knock on because this does not sound enjoyable.

Kim: Yes. Keep up the good work, Jeff.

Jeff: Where is it? There we go.

[laughter]

Kim: When the larvae then go through several instars, I would imagine getting a little bit bigger in each one. What, four or five instars probably, something like that?

Morgan: They actually have three larval instars, and then they'll migrate back to the soil in the third instar.

Kim: That sounds like a weak point is when they leave the hive. Is this an opportunity for beekeepers to do something?

Morgan: It is an opportunity for beekeepers to do something, but part of the problem is by the time those larvae leave the hive, they've already done their damage. It is a good opportunity to maybe stop that next generation or attempt to stop that next generation, but you will already have suffered the consequences of that larval feeding. It's more ideal to try to target the adults before they have the opportunity to cause as much damage within your hives.

Kim: Okay. Controlling adults in your hive. I bet you're not going to spray Raid on those beetles when you open up the hive, are you? What do you use to control adult beetles in a hive?

Aaron: There's not a lot of products that are available right now for those beetles that are adults. We have a tendency to borrow from what is available for Varroa mites. Some of the registered products that are out there are going to be like your Coumaphos as far as chemical control, but Morgan knows a lot more about the mechanical and cultural control that's available.

Morgan: Yes. There are a lot of different products that are available for mechanical and cultural controls. One of the big things though is just keeping your hive as clean as you can, not leaving excess pollen patty or feeders when they're no longer necessary because small hive beetles love to eat pollen patty, that's actually how I raised my lab colony. It was just completely fed on pollen patty, and they very much enjoy it.

Just be careful not to leave your food on there for too long, and just making sure your bottom boards are clean, trying to get any areas small hive beetles would like to congregate just cleaned out so they don't get easy food in the hive. Then, there are various traps that you can use for adults. There are several different kinds of in-hive traps. There are entanglement traps which are fabric. There are some downsides to all of these methods, of course, but it is a way to at least get an idea of how many beetles might be in your hive.

There are traps that are inserted between frames where beetles-- you can use them. They're basically pitfall traps where you put oil in the bottom and beetles crawl in and get caught in the oil and eventually die. There are fabric entanglement traps, where they'll get snagged on fabric, but again, those types of traps can also catch bees so it's a little difficult sometimes to make that call, but it is better than necessarily using a chemical right away on your hives if you can help it.

There are also traps that you can put outside of the hive entrance, and then again that lime and diatomaceous earth can be spread around your hives to target those wandering larvae. There are also soil drenches, but again if you can avoid using chemicals in your apiary, it's best to maybe start with some of those mechanical and cultural methods.

Jeff: This is a great opportunity, we're talking about products, that we take a quick break and hear from our friends at Betterbee.

Sheri: Hey, have you thought about helping your bees protect themselves as you head into fall? Yes, it's that time when robbing frenzy start and your local nectar flow ends. If you add a robbing screen, it stops unwelcome bees from entering your hives. It can prevent the spread of Varroa mites and the transmission of Varroa mite diseases. For podcast listeners only, Betterbee has teamed up with Bee Smart Designs to offer a free Bee Smart Designs robbing screen with any product purchase through October 1st 2022. Simply use the code, protect, at checkout to get your free robbing screen.

Kim: Well, you mentioned a pitfall trap. When I was working at Bee Culture magazine, a lot of people who produced these would send me samples. I've had them in hives just to see how they look, work, and whatever. Is there some kind of an attractant I can put in that it fits between frames and it still got a slit in the top big enough for a beetle but not for a bee? Is there some attractant I could put in there that would just draw all the beetles in the hive right into that?

Morgan: I know there is an attractant that's being patented or it went into the patent process a few years ago.

Aaron: There are attractants out there that are currently being investigated. Those are primarily for outside of the hive, but I believe apple cider vinegar has been used to get some of those beetles towards that trap. There is also synthetic molecules that are looking into a PVC type trap that are primarily deployed outside of the hive.

Kim: I could put vinegar in one of those traps? Not only would it attract them, but when they got in, they'd fall in and drowned.

Morgan: That's the idea behind oil too.

Aaron: Yes. Some of that mineral oil in there to take care of those beetles too.

Jeff: It doesn't sound like that's going to be a cure, that's really as a way to monitor infestation levels.

Morgan: Yes, somewhat. It's complicated because unlike Varroa where we have economic thresholds of how many mites per hundred bees you could have, we don't really have a good number for that with small hive beetle. It's hard to know how many you really have. Even if you catch say 50 beetles, there could be a lot more in your hive that you're not seeing. That is one of the big issues with small hive beetle management. It is more a monitoring device that does end up catching some of your beetles too, but it could just be a little bit random chance that they're getting caught in those traps in the first place.

Aaron: As Morgan said before, once you have the adults, you probably already have the eggs and the larvae, so you already have a problem on your hand with that too?

Jeff: Yes, this is not an uplifting conversation.

[laughter]

Kim: With Varroa, you can do a sticky board on the bottom board and then check it after three days and count the mites and say, "Okay, I got no mites, I got a hundred mites, I got a thousand mites. You said one of the things that the adults do when they're attacked by bees is drop. Would a sticky board on the bottom that would capture adults give you some economic threshold, do you think?

Morgan: It's hard to say really at this point. There's a potential maybe, but those would just be the ones that maybe were unfortunate enough to get caught in the first place. If a beetles is dropping from closer to the top of your hive, it may just catch itself before it reaches the bottom. It's hard to say.

Kim: If you see one, you're in trouble?

Morgan: Yes. I would say so.

Kim: Well, that's comforting.

[laughter]

Kim: If I see one, I take the top off and there's one on the top arm in the middle of the hive, I can guess that it's time to put a trap in yesterday.

Morgan: Yes. I think that'd be a good choice.

Kim: How many traps?

Morgan: I don't know that there's necessarily a number that you need to put into your hives. Definitely, I would double check the instructions for that, but usually, I believe it's just one per hive body. It depends on the type of trap you're using as well. I know with corrugated cardboard, there was a study where they put traps. They compared a trap on the bottom board versus higher in the hive, and the bottom board was more successful in catching more beetles in that trap. It depends on which type of trap you're using, and there are a lot of different traps out there. A couple per hive or at least one per hive is a good place to start.

Jeff: Kim brought this up early on, I can't remember if we were recording at that point or not, but is there a preference for the beetle for soil types? If you were like Kim and you're sitting on top of clay, the infestation levels may be less than if you're sitting on top of sandy organic soil. Has there been any kind of studies along those lines or understanding of the lifecycle?

Morgan: I, for my beetles, used a one-to-one sand soil mixture, which worked really well in the lab for burrowing. I think one of the big things with soil is that there's enough humidity that they don't desiccate. I would think a sand soil mixture would be probably ideal. With that clay, they're probably having a difficult time actually burrowing down to start with. I'm guessing that's maybe what's going on there. A sand soil mixture is probably ideal.

Jeff: Can it be too wet?

Morgan: I'm sure it could be too wet. I've had problems just in my lab colony where I was raising beetles, where if the soil I put them in was too wet, fungus would grow on the small hive beetles' bodies, and they would eventually die and wouldn't be able to successfully pupate. A very, very saturated soil probably wouldn't be ideal either.

Aaron: They prefer that loose sandy soil in a moderate moist environment.

Kim: All right.

Jeff: Well, there is benefit for living here.

[laughter]

Kim: What I'm thinking of is the other thing that like Varroa and other pests is that I could be clean and safe and somebody moves in just down the road, and suddenly, I've got all of the pests that they have. I think I read once that a stressed hive is going to be more attractive than a strong healthy hive, and if a beetle has a choice, they're going to go to the stressed hive A because the pheromone signal is going to be stronger. Does that make sense?

Morgan: Yes, absolutely. They're attracted to honeybee alarm pheromone, actually. The more stressed your bees are, the more attractive that's going to be.

Kim: One of the keys is to keep strong healthy hives and not have them send out that pheromone and to stay away from people who have small hive beetles. There I've solved the problem, right?

[laughter]

Morgan: Hopefully. [chuckles]

Jeff: That brings up a good point, the increasing popularity of nucs, and how the transmission of both varroa and now small hive beetle through people buying nucs every spring from established colonies from the south or from wherever. How can I as a buyer of nucs in a northern tier of states, be sure or protect myself from small hive beetles being imported in nucs from the south? All packages for that matter.

Morgan: I guess it's always a risk you're going to take with bringing in new packages, but I would definitely just do visual scouting to start with. The small hive beetle adults are fairly easy to see, and just get your hive tool and start crushing them if you see them. It is just something that you just want to be really vigilant and keep monitoring because if you can keep them in check, you can still do okay with just a couple, but when they start really multiplying and you're not keeping an eye out for them, that's when you start encountering some problems.

Morgan: And if you know your supplier. If you know your supplier well and you have a good supplier, you're happy with your supplier, without having those infestations. If you're buying often, then you should be pretty good there too.

Jeff: Is there a difference in frequency of small hive beetle transmission or transfer packages versus nucs?

Morgan: I'm not sure that that's necessarily no, and I don't know. If Aaron you have any ideas on that? I don't.

Aaron: I'm not aware.

Morgan: As far as I know, I haven't seen anything detailing that. There's not quite as much research that's been done into small hive beetle as with varroa mites. There's still a lot of unknowns I guess in regard to transference of them from colonies and such.

Jeff: Varroa, of course, transfer on adult bees. I have never heard of that happening with small hive beetle. They seem like they're more equipment focused as opposed to bee-focused.

Morgan: Yes, they're not really taking risks. They're going to go where they're safest and least likely to interact with the adult bees that are trying to kill them. They're going to try to go to those places where they can hide, hiding in cells, hiding and things like that. Not so much hitching rides on adult bees or anything like that. I've never seen that.

Jeff: No, that's something to consider in the springtime when you're just trying to decide whether to go with a cheaper nuc or more expensive package, or it's the other way around, the more expensive. Anyways, the value of one over the other.

Kim: Once you get an infestation in a colony, you said that they eat everything, pretty much both the larvae and the adults. They're eating honey and pollen. Do they get into the nectar, eggs, larvae, all of those things they eat?

Morgan: They'll eat anything. Yes.

Kim: A big infestation could kill a hive, literally.

Morgan: Yes, they'll mainly kill it through making the hive so nasty that bees won't want to live there anymore, then your colony would end up absconding, and that's when they'll probably die. You'll lose the colony either way, and the colony probably won't live.

Kim: If that happens, my neighbor doesn't do anything, has small hive beetles, doesn't do anything. They get to the point where the colony absconds, and then what happens to the small hive beetles? Do they just die there or do they leave? What do they do? Do they stay there until all the foods eaten?

Morgan: Yes, they would stay in that resource until it's not providing them with enough food anymore. It depends on the climate a little bit as well. If it's getting closer to winter, they might try to find a different more protected source, but if they are protected and have plenty of food, they're just going to stay where it's easiest. They're really just scavengers. Making your hive as the least hospitable place for them, it's one of the best ways to keep them out.

Kim: Well, you just mentioned something, winter. To survive Cleveland's winter here or Wisconsin's winter, they're going to have to be in the middle of the cluster, right?

Morgan: That's correct. Yes, they'll steal heat.

Kim: But in the middle of the cluster, there's essentially no food or very little food.

Morgan: Yes, generally, it would be the adult beetles that would be going into winter. They won't necessarily need all those resources as much. They're going to try to keep warm as best they can, and steal food when they can until the spring, more than likely.

Kim: I suppose that triple axis in the middle of the cluster would be probably very successful then. I don't see a good way out of this, Jeff.

Jeff: No, I agree. I was really feeling good coming into this discussion. Now I'm like, "Oh, my God, now I got something else to worry about." Just kidding. A lot of people or beekeepers are working being very successful with small hive beetle in their colonies and managing for them just a part of the beekeeping life right now, in all seriousness. Where's the current research?

Aaron: There's interest in looking for new control tactics. I can speak much more to the control side, where there's an interest in looking at RNAi and can use turn off genes that are necessary for life. If we can do that, we can make it very specific towards the small hive beetle so we don't have to worry about that harming of the honeybee that we see common with chemicals.

Other control has focused on Bt, making Bt or seeing what's available for different Bt, that would be targeted a little bit better towards the small hive beetle. With that, those are some of the control tactics that may have avenues within the future. Also, really, and Morgan stated this earlier, with integrated pest management, right now what we're missing is what that economic threshold is. That is something that needs to be looked at here sooner rather than later.

Jeff: Before, you mentioned Bt, and that refers to what?

Aaron: Yes, Bacillus thuringiensis. We see it a lot right now within our crops, these cry proteins that essentially can tear up the gut of a beetle and kill the beetle.

Kim: There's a chemical on the market that's legal to put in a hive for the control of wax moth larvae called Certan. Are you familiar with that? A and B, do you imagine it has any effect on small hive beetle larvae?

Aaron: I'm not familiar with that. What is it again?

Kim: It's called Certan. It's applied to a hive and it attacks wax moth larvae. It's very effective on wax moth larvae. I'm just suddenly wondering if there's a cross chemical here that might help.

Morgan: I think that's Bt, isn't it? Certan.

Kim: Good question. It's Certan. [laughs]

Jeff: Everyone's wildly searching Google at this minute. [laughs]

Morgan: I think it's Bt toxins.

Kim: That's something we'll have to find out, Jeff, and talk about a little bit later. If it is a Bt, is that going to help?

Aaron: Yes. If it is a Bt, it could have the potential to help. Now if you're going to make a specialized Bt, again, it really goes into the economics to have a company to produce that and make it available. Certan is a biological though.

Kim: What does that mean? It's a biological.

Aaron: It looks like it's a naturally occurring compound, similar to Bt, where Bt is isolated and it can be modified, but it's isolated from soil-dwelling microorganisms.

Kim: I think somebody needs to look at Certan and small hive beetle larvae. It sounds like there's a project there for somebody. [chuckles]

Morgan: One other thing I was looking at too for maybe potential use in the future, it's not quite there yet, but just the use of potential repellants in keeping small hive beetle maybe from entering apiaries. I did a few projects looking at the effects of different heterocyclic means on insect antenna and then behavior.

I did see some nice preliminary results with that where some of these compounds were repellent to small hive beetles, and then when I'd mix attractants and repellants that would also repel the small hive beetle so those repellants could overcome an attractive source, at least in a lab setting. That's one potential area in the future that could be promising in just keeping those beetles outside of the hive in the first place.

Kim: Well, that would be good. Just slather it on the entrance, and small hive beetle aren't going to come in.

Jeff: Kim, if you put that on the front of your hive along with your cow poop, you can keep out small hive beetle and Asian giant Hornet.

Kim: There you go.

Jeff: Just saying.

[laughter]

Kim: Okay.

Jeff: On that note.

Kim: Well, we've covered a lot here on the life cycle and the damage and the things that you can do to control small hive beetle. What have we missed that you think that we should know? We've been pretty thorough I guess, that's good.

Morgan: Yes. I mean, we do have some fact sheets out through Virginia Cooperative Extensions. If you would like to see more photos and just get some more facts on small hive beetle lifecycle and some management tips, you can always check that out too. I can send you all a link for that as well if that would be helpful.

Jeff: We'll put those in the show notes.

Kim: That would be very good. Yes. All right.

Jeff: Well, this has been very enlightening. I came into the meeting or into our call knowing I knew how to spell small hive beetle and had no practical experience with it. I come away still knowing how to spell it and knowing I definitely don't want to have any practical experience with it. It doesn't look like something I would enjoy, but I appreciate the fact that so many beekeepers have to on a daily basis.

Kim: Yes. 2,000 eggs a day, there's going to be a lot of small hive beetle somewhere tomorrow.

Jeff: Yes. Well, Aaron and Morgan, we appreciate you joining us today on Beekeeping Today. Good luck in the rest of your research and enjoy the rest of your summer.

Kim: Thank you, Aaron. Again, Morgan congratulations on finishing your PhD. Good luck in the future.

Morgan: Thank you. Thanks so much, and thanks for having us.

Aaron: Yes. No, thank you for having us.

Jeff: I'm still at loss. I knew about small hive beetle, but boy, hearing about the details, it just does not sound like fun.

Kim: No, it doesn't, and being where I'm living, I haven't had any experience to speak of with them. I don't know if other people around here have or haven't heard about it. As a result, and they've been here, I don't know, 14, 15 years, something like that, they're almost an acceptable pest because A, there's no real control. You put a trap in and hope you can find some, but that's about it. There's not much you can do. If you get it bad and if you're not paying attention, you can lose hives to them. I guess, pay attention, and when you see one, you get a trap in. That's the economic threshold, I guess, is one.

Jeff: Well, that does bring up the point. I think one of the reasons why we don't hear so much about it is because the economic threshold is so high that it's not causing losses yet. The losses haven't been quantified to the point that someone says, "I'm losing X number of dollars because of the small hive beetle." It's been manageable up to this point.

Kim: Although Mike Hood who was at Clemson for a long time, did a lot of initial research on small hive beetle, and his estimate was just a couple of three years ago, about $3 million a year damage is done to hives in the US by small hive beetle. Over the total number of hives in the US, that's not a whole lot, but if it's your hives, it gets slimmed and dies. It's a lot.

Jeff: Slimes and dies. Well, that about wraps it up for this episode. Before we go, I want to encourage our listeners to rate us five stars on the 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 webpage.

As always, we thank Bee Culture, the magazine for American beekeeping for their continued support of beekeeping in today podcast. We want to thank our regular episode sponsor, Global Patties. Check them out at globalpatties.com. Thanks to Strong Microbials for their support of this podcast. Check out their probiotic line at strongmicrobials.com. We want to thank Betterbee for their long-time support. Check out all their great beekeeping supplies at betterbee.com.

Thanks to Northern Bee Books for their support of Bee Books: Old & New with Kim Flottum. Check out all of their books at northernbbooks.co.uk. Finally, and most importantly, we want to thank you the Beekeeping Today podcast listener for joining us on this 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.

[00:45:24] [END OF AUDIO]

 

Ed Colby Profile Photo

Ed Colby

Beekeeper, Author

Sideline beekeeper. Columnist, Bee Culture magazine "Bottom Board" column since 2002. Author, A Beekeeper's Life, Tales from the Bottom Board. (https://www.amazon.com/Beekeepers-Life-Tales-Bottom-Board/dp/1912271885)

Actuarial tables indicate I should be retired, but I continue to be obsessed with Apis Mellifera. I live in western Colorado with the gal Marilyn, the blue heeler Pepper, 15 chickens, three geese, four lambs and way too many bees.

Dr. Morgan Roth Profile Photo

Dr. Morgan Roth

Entomologist

After completing my B.S. in zoology I started working for Dr. Aaron Gross as a research assistant and M.S. student at Virginia Tech. Throughout my M.S. program I studied varroa mite acaricide resistance in the state of VA and also tested several known and novel insecticides against small hive beetle larvae and honey bees. I was interested in spending more time researching small hive beetle physiology and behavior, so after my M.S. I started another set of small hive beetle projects as part of my Ph.D. research.

My Ph.D. projects included testing small hive beetle antennal responses to a series of repellent and attractant compounds and testing small hive beetle behavioral responses to these compounds through olfactometry experiments.

Through this work I have been able to discover which repellents were most effective against small hive beetles and found that repellents could obscure responses to attractants in behavioral testing. I hope that this work can some day be applied in apiary settings in the form of repellents that keep small hive beetles from detecting and entering apiaries in the first place.

Dr. Aaron Gross Profile Photo

Dr. Aaron Gross

Assistant Professor

Dr. Gross is an Assistant Professor in the Department of Entomology at Virginia Polytechnic Institute and State University (Virginia Tech). He received his Bachelor of Science degrees in Biochemistry and Biomedical Sciences from St. Cloud State University (St. Cloud, MN, USA). Graduate training was performed at Iowa State University of Science and Technology where he received M.S. and Ph.D. degrees in Toxicology (minors in Neuroscience and Entomology). Postdoctoral training was at the Emerging Pathogens Institute, University of Florida.

At Virginia Tech, Dr. Gross’ lab, the Molecular Physiology and Toxicology Laboratory, focuses understanding the molecular mechanisms that are involved in insecticide resistance. Discovery and mode of action of synthetic and biorational insecticides. His lab also focuses on the molecular mechanisms that are involved in the ability of ticks to evade the mammalian immune response during blood feeding and the tick-associated red meat allergy. At Virginia Tech, Dr. Gross is affiliated with the School of Neuroscience, Fralin Life Science Institute, Virginia Tech’s Center for Emerging Zoonotic and Vector-borne Pathogens, the Molecular and Cellular Biology Graduate Program, and the Virginia Tech Center for Drug Discovery.