Why Are Honey Bee Colonies Collapsing?

IRA FLATOW: This is “Science Friday.” I’m Ira Flatow. Later in the hour, we’ll talk about how to think about risk as life under COVID-19 stretches on and the unusual story of a man who can’t see numbers. But first, we’re a big fan of pollinators here at team Sci Fri. There are even some hobby beekeepers among us.

And this year was a strange one for US beekeepers. According to a survey from the nonprofit Bee Informed Partnership, beekeepers lost more than 40% of their honeybee colonies since April of last year. And that’s quite a bit more than normal. So what does this mean for our beloved pollinators? Producer Kathleen Davis is going to tell us all about it.

KATHLEEN DAVIS: The vast majority of beekeepers deal with honeybees. And they’re responsible for pollinating a lot of the food that’s grown here in the US. If honeybees are in trouble, we are in trouble.

The Bee Informed Partnership has surveyed professional and amateur beekeepers for the past 14 years to find out how their colonies are doing. They reach more than 10% of beekeepers in the US. So their survey is thought to be a pretty accurate look at what’s going on across the country.

That’s why these latest results are so important. And they raise a lot of questions for honeybee researchers. Joining me today to shed some light on these questions is Nathalie Steinhauer, research coordinator for the Bee Informed Partnership. She’s based in College Park, Maryland. Welcome to “Science Friday,” Nathalie.

NATHALIE STEINHAUER: Thank you for having me.

KATHLEEN DAVIS: So losing more than 40% of honeybee colonies in one year sounds like a really big deal. How does this compare to years past?

NATHALIE STEINHAUER: Yeah. It is a big deal. Unfortunately, it’s something that we have got accustomed to. So we have been running the survey for 14 years now. And every year, we document the turnover rate of colonies, right? We call it the loss rate. It’s really how often do colonies need to be replaced, so that the beekeepers can keep their operation size. So it’s really similar to a mortality rate.

And it’s basically meaning that, on average, in the country, about 40% of the colonies will be lost at some point and will be need to be recovered. So it is high. And it is higher than what beekeepers themselves consider acceptable. But it is something that we have seen for a number of years now.

KATHLEEN DAVIS: Now just to clarify, does losing 40% of colonies mean that we lost 40% of honeybees?

NATHALIE STEINHAUER: It does not. So we are really talking about turnover rates. So the population in the US has actually been relatively stable for the last 20 years. And we know this from another survey, which is independent to ours, organized by USDA, which is called the honey report.

And we estimate that we have about 2.5 million colonies in the country, and that has been relatively stable. There was always fluctuation from year to year, but relatively stable overall. So that means that beekeepers are able to make up for their last colonies by making new colonies, right? It’s kind of like the similar mortality versus natality for humans. We have the loss rate on one hand. And then beekeepers can recover by making new splits by increasing the size of their apiary, on the other hand, to maintain the total population relatively stable.

KATHLEEN DAVIS: So if we’re not facing a huge drop-off in the honeybee population, why is it still such a concern that so many colonies are being lost?

NATHALIE STEINHAUER: So it is a concern that we are losing so many colonies every year because it comes at a high cost for beekeepers. So losing colonies, having to replace them means that you’re going to have to invest more time, more effort, more money into making up those loss. Usually, colonies that survive or barely survived a winter, it doesn’t mean they’re healthy.

Just we know that this is a good metric of honeybee health. And we think this is a better metric of honeybee health than the total population size because we actually see how many colonies have been struggling. And we can try to keep track of it. So this is the objective of the survey is to really try to keep a pulse on how they’re doing and seeing if there are some zones that are at higher risk than others, or operation types that are higher risk. And the concern that we have is that this is highlighting issues in honeybee health. And it means it’s harder for a commercial beekeeper, in particular, to maintain their operation in a sustainable way.

KATHLEEN DAVIS: You mentioned that, with the survey, you can look at how this is playing out in different zones. How does this play out geographically? Are there some areas of the country that seem to be hit harder by this colony loss? Or is it pretty even across the nation?

NATHALIE STEINHAUER: Yes. So the estimate that we have at the national level is really an average, right? And like every average, it really hides a lot of the variability behind that one number. So we actually see everything on the spectrum, right?

We see operations that lose 0% of their colonies, other that are completely wiped out that lose 100% of their operation, and everything in between. So we see variation, as I said, by operation type and by region. We are actually trying to analyze right now the geographical patterns and to see if there are some zones that are constantly at higher risk year after year.

Because also, one year out of context is really not terribly meaningful on its own. What we are really interested in is looking at the trends over time. So we’ve been doing this survey for 14 year now. And we are basically seeing the cyclical nature of losses.

We always see some worse years, some better years. But overall, what we see is that the situation is not getting worse. It’s also not getting better. But we’re trying to get into some of the more refined region by region risk. And we do see some patterns, but we are at the beginning of that analysis.

So generally, we say it’s typically higher losses in the North than in the South. But all of the state results of the past years are available online. So if people want to know the loss rates in their own state, they can look on our website to find pass result for their states.

KATHLEEN DAVIS: Do bee researchers, like yourself, know why this level of colony loss is happening across the country?

NATHALIE STEINHAUER: The reason why honeybee colonies can be lost are really multiple. And we usually refer to the drivers of honeybee loss as the four P’s of honeybee health. It’s pest, pathogen, poor nutrition, and pesticides. And unfortunately, it’s really hard to identify one single cause of loss for a colony because it can be a combination of factors. We know that there are interaction.

So a colony that is nutritionally deprived will resist infection less well. So they might be more susceptible to infection by parasites and pathogens. We also know that some pesticides can impact the nutritional status of the bee. So those are all factors that are interacting, so that it’s very hard to single out one specific cause. It also means that we have to act on all of those factors together to try to improve the situation overall.

KATHLEEN DAVIS: I would imagine that losing so many colonies would change the experience of being a beekeeper. What are you hearing from the people behind the bees about this level of colony loss?

NATHALIE STEINHAUER: Yes. So that is a good point. So what we hear from beekeepers is they tell us it’s worse than it used to be. Unfortunately, we don’t really have good historical data, so before we started the survey. Before that, we really do not have a good estimate of mortality rates of colonies.

So it’s hard to judge because it’s only word of mouth in which beekeeper tell us that it used to be better. But we don’t know how much worse the situation is now compared to then. What we know is that this level of acceptable loss seemed to be creeping up year to year. So it seems like it’s getting more not accepted, but beekeepers are realizing that the situation is not getting better and that they have to make do with the higher level of loss in their operation and just try to make the best they can with the situation.

KATHLEEN DAVIS: Right. Right. It’s my understanding that some scientists are trying to make tougher bees that are resistant to certain pests, for example. What’s going on with that kind of research right now?

NATHALIE STEINHAUER: Yes. So there are a couple of labs that are actually looking into trying to improve the stocks of honeybees, right? So for example, certain universities of Minnesota and Baton Rouge USDA lab are some of the efforts of researchers try to breed more hygienic, more resistant parasites and pathogens. And those efforts are really important because, in the long term, this is what’s going to make beekeeping sustainable again is to try to improve the stocks of the bees.

In the meantime, unfortunately, those lines of bees are not yet available to everyone. They’re still trying to improve those lines because it’s very tricky to improve only certain behaviors while maintaining all of the other aspects of the bees that we want to keep, right? We want to keep them productive and good pollinators and non-aggressive. And so trying to maintain all of that while selecting for hygienic behavior is tricky.

So they’re doing great efforts, and this is a very interesting area of research. But in the meantime, it means we have to deal with the pests and the pathogens that are attacking the bees now because selecting for bees is not something that you can do on a small scale. So really, you need those larger effort to drive the movement. And in the meantime, the rest of us need to try to keep the environment free of pests as much as possible.

KATHLEEN DAVIS: Is there a rift in the beekeeping world between people who want to keep these bees natural, I guess, for lack of a better term, and people who are more in favor of these maybe modified bees? It almost feels to me like an organic versus GMO situation going on for bees right now.

NATHALIE STEINHAUER: Yeah. That’s not completely wrong. What is one thing for sure is that beekeepers are usually people with strong opinions, one way or another. And there is merit in both aspects.

As I said, we want to go for a better bee that is intrinsically more resistant to pests. But in the meantime, leaving colonies untreated is just spreading the problem to your neighbors. And so that’s usually how we convince people. They say, if they don’t treat their own colonies, they’re just putting more pests in the environment, contaminating their neighbors.

And if they want to collaborate into breeding programs, they should do so. But it’s very hard at a very small scale to do that. So we have to have a coordinated effort to do it. And in the meantime, before we have that more resistant bee, we all have to do our part to try to minimize the infections of the bees we have now.

KATHLEEN DAVIS: Nathalie Steinhauer is the research coordinator for the Bee Informed Partnership. She is based in College Park, Maryland. Thanks so much for joining us, Nathalie.

NATHALIE STEINHAUER: Thank you. It was a pleasure.

KATHLEEN DAVIS: If you’re interested in more details about the Bee Informed Partnership’s latest survey, you can find it on their website, beeinformed.org. And if you’re a beekeeper having trouble with your honeybees, that website has some resources for you as well. For “Science Friday,” I’m Kathleen Davis.

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