Where to Listen:
Imagine feeling not quite yourself. You don’t feel like taking care of your kids. You can’t find your way to work anymore, don’t want to hang out with anybody. It would be awful.
But it’s happening to bees all around us.
Turns out a pesticide used on virtually all of our corn and soybeans is harming our pollinators at very low levels of exposure in ways that are rarely studied.
On this episode, hear from a University of Wisconsin Madison researcher who’s been looking at the lives of bees and the impacts of a neurotoxin we put on our food.
Host:
Amy Barrilleaux
Guest:
Dr. James Crall, Assistant Professor of Entomology, University of Wisconsin
Resources for You:
Episode: Neurotoxins on our Plates
Episode: Wisconsin’s Vanishing Bee
Episode: No Mow May, Does it Work?
Understanding the Impact of Neonicotonoid Pesticides
Wisconsin Neonic Forum Video Series
Transcript:
Amy Hi there and welcome to The Defender, Wisconsin’s environmental podcast. I’m Amy Barrilleaux. The Defender is powered by Clean Wisconsin, protecting our air, water, and land since 1970. Imagine feeling not quite yourself. You don’t feel like taking care of your kids. You can’t find your way to work anymore. You don’t want to hang out with anybody. It would be awful. But it’s happening to bees all around us. Turns out a pesticide used on virtually all of our corn and soybeans. is harming our pollinators at very low levels of exposure in ways that are rarely studied. On this episode, I talk with a UW-Madison researcher who’s been looking at the lives of bees and the impacts of a neurotoxin we put on our food. That’s right now on The Defender. You’ve probably heard bees are not doing great. Hives and colonies are disappearing. Wisconsin’s native rusty patched bumblebee, for example, has seen population declines of more than 85% since the late 90s. They were the first insects added to the endangered species list. At the same time, farms have been using more and more of a class of insecticides introduced in the 90s called neonicotinoids that target the central nervous systems of insects. These days, farmers growing conventional corn can’t even find seeds to plant that aren’t already coated in the chemicals, which are neurotoxins. So yeah, it’s concerning. And all that information has researchers wondering how much is too much when it comes to the insects we don’t want to kill, our pollinators. I sat with UW Madison entomology professor Dr. James Crall to talk about his study that takes a rare and fascinating look at a bee’s life inside the colony. I guess we’re all kind of interested in bees. You know, we see them, they do so much. pollination so much in the background, but was it something where you kind of looked at insects, the thing that piqued your interest, I guess, where you kind of looked at insects maybe when you were little or growing up and thought there’s more here than just, you know, passing them by or what kind of was the hook for you?
James Yeah, that’s a great question. I was not, I think some people, I’m always actually even impressed here at UW. We have, you know, entomology major for undergraduates. There’s not that many left in the country, but we have one of them. And so we have, you know, folks that come in from high school with a sort of focused interest in insects and entomology in particular. I was not that, I was not that kid. I mean, but what I did love was being outdoors. So I had a real love for nature and sort of hiking and being outside and that turned into an interest in agriculture and sort of sustainability. So I always had that interest a bit but then actually during – I kind of took a sideways turn a little bit in undergraduate and spent a couple weeks thinking I was going to be an engineer and did some very different things but then really came back in sideways a little bit and it was really It was actually a project looking at these really fine details of dragonfly wings and how they work as sort of mechanical structures. It was really fun. And at the end of my undergraduate research project, really looking at these flexible rubber proteins in dragonfly wings and how it lets the wings bend in certain ways and not others. And kind of just caught me by surprise of how interesting I found it and really trying to think about, oh, there are these fascinating. creatures that we kind of take for granted and they have all this complexity, right? Even all these details of little tiny bits of, you know, morphology and the shapes of parts of wings. So I found that really fascinating. And also I got a little intoxicated with the idea of being like, oh, nobody knows how that thing works or why that thing is there when you look at these tiny details and on insects. So that was like that hooked me for sure. And then I think I’ve over time just increasingly come to appreciate in insects in particular right like what the phenomenal diversity of insects means just as a feat of evolution and ecology to have the you know who really knows because we haven’t described very many of them but the millions of different species of insects right that are on on the planet and so yeah some of my hook was kind of just fundamental amazement and curiosity with this group. But then also increasingly you know you come to appreciate the just critical importance of insects for our life as humans right whether or not that’s through crop pollination services supporting food production and especially sort of healthy fruits nuts and vegetables we depend on for pollination, understanding the role of insects in, say, either being pests or controlling pest populations in agriculture, movement of diseases. So like insects are really the small things that run the world. So I think they’re a fascinating group and they’re critically important too, so yeah.
Amy So speaking of insects that maybe we don’t know as much about as we think we did about bees, right? They, I think everybody kind of knows, okay, bees they have a colony and there’s a queen and then some things happen and they gather honey maybe if they’re honeybees and that’s about it. But you’ve been really looking at kind of inside the hive, the social structure. Why is that important?
James Yeah, it’s really, it’s such an important aspect of the biology to look at. But you’re totally right that, you know, what I always say is it’s sort of a black box of actually looking inside of the colony, not only sort of metaphorically, but also in the case of bumblebees, literally, right? Because that’s usually happening in bumblebees are social bees, but they tend to live underground. So they usually hang out and make their nests in old rodent burrows. So they’re like literally in the dark underground most of the time. So we’re, we’re so used to seeing, um, you know, bees out in the environment. We’re walking around nice prairies in the middle of summer. We’re used to seeing bumblebees flying around and they’re doing all of this amazing stuff, right? Like moving between flowers, um, keeping amazing memories and keeping track of what flowers are making, producing food when. They have like spatial memory of where there is food available. So they’re doing all this amazing stuff out in the environment where we see them. But all of that… that we see when they’re out of flowers is really just driving one thing. It’s all aimed at bringing food back to the nest and turning that food into colony growth, right? So all the social bees, which I should note are actually, we’re used to talking about bees as being social, but those are the minority. Only about 5% of species are actually social. Most bees are solitary, so they’re kind of like most other insects. They live alone, yeah. be, you know, single mom taken care of…
Amy Right.
James yeah developing young but those social bees even though they’re a minority of the species they’re critically important. So especially honeybees and bumblebees, stingless bees, which aren’t in North America or in the U.S. at least, but those bumblebees and honeybees are really really important both ecologically and also for agricultural production especially. So those social bees are really important for the basic functioning of ecosystems. And so the reason that we’re interested in, uh, understanding what’s happening inside of the colony is like, yeah, bees need to be able to bring back food, but they also need to do things like provision, like they take that food and feed it to developing larvae. They do some things that we often think of as very vertebrate things. Like they, they keep a temperature for the developing brood. So they incubate the, the young, right? So the larvae that are developing within the colony. They’ll do this amazing thing where they wrap their abdomen around the developing larvae and sort of heat them up so they actually run a temperature right so we don’t think of of insects usually as we think of them as you know cold-blooded but actually a whole colony sort of keeps a temperature that helps the whole colony develop quickly. So basically they’re doing all this amazing stuff within the nest, too. And all that. all that behavior is really, really important for successful development of the colony. And if we care about having bumblebees around, that is all those behaviors within the nest are totally critical for the colonies reproducing, right? Cause the workers that we see are out foraging are not actually the kind of reproductives. What we really care about are colonies being able to grow, make new sort of queens and males. and reproduce and sort of grow populations over the years.
Amy So let’s talk about then, I think what everybody started to notice maybe 10 or 15 years ago, which was the bees were under some stress, colony collapse I think is what you would hear about, and the thought was that it could be pesticides. And so researchers like you started looking at what are the impacts of pesticides on bee populations, particularly the neonicotinoid pesticides, which are really prevalent throughout agriculture in Wisconsin. And I think your research brought kind of an interesting lens because it’s not, OK, did this pesticide kill this bee? Is it dead or alive? It is, what is the impact on the colony, on that little nice home front description that you were giving us? And what did you find when you went in and you wanted to see what the impacts are?
James Yeah, that’s a great question. And you’re totally right. So basically, in the mid-90s, we introduced this new class neonicotinoid pesticides. And then what started with some sort of anecdotal observations of colonies not doing so well and seeing lots of dead bees in, for example, honeybee colonies, but then turned into really now a much broader interest in the whole research community trying to understand that only with these sort of direct lethal. effects are, so like actually killing bees. But one of the things we’ve learned over time with neonicotinoids in particular is they have what we jargon the jargon for it is sublethal effects but basically the idea is things that mess bees up without actually killing them directly is the the sort of key there. And one of the ideas is you know the analogy i use a lot is: There’s a lot of… ways alcohol might affect you before it has a lethal effect, right? So your ability to drive, to remember things, to pay attention. There are all these kinds of abilities of your everyday life that it might mess up. And the same thing might be happening with some of these compounds, right? So neonicotinoids in particular are neuroactive insecticides that target one of the key neurotransmitter sites in the insect brain. Now, you know, the details of that aside basically the idea is in the central nervous system of the bee what’s happening is these compounds are targeting the brains of bees so it’s probably not surprising that there might be some of these kind of subtle effects. So one of the things that we have found in our work is if you look inside the bumblebee colonies in particular what you see is all kinds disruptions even before bees are dying per se. Right so even though there’s no direct lethality we see things like disrupted interactions so bees are kind of less social with each other they move out to the periphery of the nest and associated with that they also stop taking care of of the developing right so what i was saying before i’m needing to turn all that protein and and carbohydrates that are coming in in the form of nectar and pollen the colony. Really what the colony needs to do is successfully turn all of that into larval growth and to do that they’re feeding larvae all the time. They’re incubating them. They’re doing all this sort of nursing care to help those larvae develop and we find that bees exposed to even these relatively low levels of neonicotinoids do less of that. So they reduce their amount of nursing. So we kind of see this whole suite of of effects within the nest that probably work in concert with also effects we know happen on bees outside of the colony so their ability to forage remember the locations of food like we were talking about before that’s disrupted and also the ability to kind of turn that food into colony growth within the nest seems to be disrupted so really we see this whole sort of suite of impacts, even well below lethal.
Amy So I guess the way to paint a picture for people would be if we were all exposed to some kind of a neurotoxin that kind of gave us or ruined our ability to work with each other, to care for our kids, to figure out where we were gonna do and what we were gonna do next. I mean, that would be devastating, right, if it happened to your community, something like that. And then we kind of look at bees and you’re kind of opening the door to look at the kind of devastating impacts of something like that.
James Yeah, I think that’s a great way to think about it, right, is that the way that we often we when we are deciding whether or not, for example, an insecticide is safe in the environment, most of that decision is focused on something that we call sort of lethal effects, right? So when the EPA is deciding like, oh, a particular neonicotinoid or other pesticide is safe to put in the environment, we do have tests to see, test, um, to assess the impacts on, on insects, usually focused on just honey bees, which is another important limitation, given that there’s, you know, 19,990 other, uh, uh, thousand other species of just bees. But those, even the species that we are testing in, we’re mostly looking at toxicity. So really this is like, what is the dose that will kill a bee within 48 hours? And what we see are these effects, exactly like you said, these sort of disruptions of all the every day-to-day tasks that bees need to be able to do to successfully grow. Those are disrupted way below we see these lethal, at the levels where we see these lethal effects show up.
Amy So why is it important to understand this? You know, you mentioned honey bees, I think people think bees, they think honey, and then maybe move on with their lives. Why is it important to understand these sublethal impacts on all kinds of bees?
James Yeah, it’s a great question. So one reason is honeybees are really important for agriculture, right, but the other bees are also really important for agriculture. So even just from a totally human selfish perspective, the ability to to grow crop, crops like apples and here in Wisconsin cranberries. We care a lot about about successful production of cranberries, right? There are a huge number of crops so actually the vast majority of crop species and about a third of total food productivity comes from plants that depend to some degree on animal pollination, right? So needing that visitation by animals, but especially bees and insects, is really important for food production. And the plants and the crops that depend on insect pollination are often actually the healthiest ones. So fruits nuts and vegetables super important for not only just feeding ourselves calories but feeding ourselves healthy nutritious and sustainable calories. So a lot of that value in the U.S. comes from honeybees but not all a huge amount comes from native bees throughout the U.S. So you know roughly maybe half of the existing amount of pollination we get is actually from native pollinators and also in certain crops the native pollinators are way better pollinators than than honeybees, so for example in cranberry and and many other crops bumblebees are much more effective pollinators there’s some crops that can’t really be pollinated by effectively by bees at all, like tomatoes, or really depend, they have depend on something called buzz pollination, which is basically like the pollen hides inside of anthers on the flower, and it needs to kind of be shaken to release the pollen. Bumblebees do that, honeybees don’t do it. So there’s certain crops that really depend on these other pollinators, right? So that’s kind of the selfish crop production, but really important to think about what the value that we… get out of having these different kinds of bees around, right. And also, you know, not only thinking about what do we get out of native pollinators right now, but thinking in the kind of like long-term, you know, there is a danger to having all of our, so much of our crop productivity depend on a single species, right? So if we only had just honey bees, for example, right? Well, you know, we’ve seen in a lot of places diseases can have negative impacts and there’s some insurance that might come with having other other pollinators around too. And beyond that, there’s just the fact that, you know, there’s not just our crops, but also all these wild wildflowers and so much biodiversity depends on on pollinators and especially those diverse native pollinators. So both for selfish and also sort of broad conservation reasons, it’s really critical to conserve those pollinators.
Amy So I mentioned that these neonic pesticides are, you know, used all across Wisconsin, on virtually every acre of farmland, and in fact, if you’re a corn grower and you’re growing conventional corn, that you don’t really have any option to buy seeds that are not coated with neonicotinoid pesticides. So you were part of Clean Wisconsin’s Neonic Forum that happened several months ago. Why is it important from your perspective to start working with farmers, working with our agricultural industry, and figure out how to get a handle on this neonic problem?
James Yeah, I think it’s a great question. And part of the reason that that collaboration, I think especially between growers and scientists interested in conservation and groups like Clean Wisconsin, I think that collaboration is so critical, because we do need to produce food, right? We need to produce a good, healthy food to feed people. And the real hard questions are in some ways, like, what might be the trade-offs, right? Like, where can we make gains in, say, reducing the amount of pesticides we’re inputting into these systems without negatively impacting food production, right? And what I think is really exciting and what was, I think, great about seeing some of the talks and topics at the Clean Wisconsin Neonic Forum is I think there are real opportunities for places where we can actually effectively reduce the amount of pesticide input without necessarily having big negative effects on crop productivity. So I think there’s a world in which we would say, oh, well, you know, neonicotinoids are bad or insecticides are bad, let’s just stop using them. But we also know that in some places and certain times, they’re really important for mitigating the risks, for example, of… know, potential pest outbreaks. So I think finding a way that can help us dramatically reduce the use of pesticides and in places where they’re not actually having yield impacts, I mean I think this is one of the other things we’re learning a lot more about, is you know actually much of the time the effects on reducing pest populations and increasing yields might not actually be as big as we thought, right? So I think there’s a lot of opportunities to find places where we really can improve environmental outcomes without negatively affecting crop yields or farmer bottom lines.
Amy When you were doing your research and you saw those instances where the bees were moving to the edge of the colony or the bees were not taking care of the young larvae, what went through your mind as you saw that?
James Hmm. Yeah, it’s a good question. Definitely some, you know, you have a lot of sympathy for you kind of come to love these creatures. I think, you know, I was a little surprised at first, honestly, that when we first did those experiments on, yeah, how dramatic some of the effects were even at concentrations that, you know, for example, when we first started running these experiments, we really do concentrations that would be the equivalent of if a seed from a particular crop is coated in neonicotinoids that those compounds get taken up sort of systemically into the plant and show up in all the different you know leaves and stems and tissues of the plant including nectar and down the line and so what we were looking at are concentrations that we might expect sort of months after a seed application. And kind of what you might think of is trace concentrations. So in the parts per billion range, like six parts per billion, and even at those concentrations that we think are happening all the time in the environment, we’re still seeing some some quite dramatic effects on behavior and sometimes really striking even to the eye. So I think that’s one that was a real perspective shift for me a little bit just thinking about how. least you know for certain compounds you can have these really dramatic effects that are probably happening quite frequently out in the environment but again in ways that have sort of been hidden from us potentially.
Amy And so you’re talking about, so a seed gets planted that’s coated in Neonics and it grows up and then that chemical, that insecticide, is all throughout its leaves and its pollen and then the bee comes to feed, you know, months later and gets an exposure. So this isn’t like bees being sprayed. I think when people think of insecticide, they’re thinking, okay, this bee got sprayed.
James Yes, that’s a great, yeah, and that’s an important route of exposure too. So you can get sort of direct exposure sometimes through, you know, if certainly if during a crop is blooming, if bees can get directly sprayed or some of that spray can sit on flowers and get into nectar and pollen. But no, and a lot of, so when you were talking about, you know, The corn grower is ordering seed that is often just coated and almost you know the vast majority of the time now that seed will come coated in neonicotinoid and the reason that seed coating is there is it gets taken up systemically so that compound as the plant grows the compound sort of spreads through and is taken up by all the different tissues so yeah you do definitely get sort of spray exposure. You can also get things exposure through a drift of dust, for example, over different environments, but also this sort of systemic. So seed coating then taken up systemically by the plant tissues. So it’s one of the complicated things too is even just thinking about the different ways in which we use these compounds and the different ways in which those can sort of lead to exposure of the bees and other insects. I mean bees are kind of a favorite they’re certainly among my favorite insects and they’re you know more charismatic than some of the other insects out there although they all have their fascinating beauty in their own way. Yeah but I mean all these insects are being exposed in potentially potentially different ways and a lot of these can be surprising too I think one of another area that we sort of learned is really important you know Clean Wisconsin is really focused something about water, rates and transfer, but you know we know that even when you if you say treat a field while flowers adjacent to that field can also take up some of that compound that might move through the soil for example so you can have a lot of these complex ways in which these compounds are initially put into the environment but then also get transferred to bees and other insects through a lot of different around.
Amy Yeah, and eventually they make their way to people because it’s all, everything’s connected. I think the way you just described all this sounds a little scary, you know, the thought that you can have seeds coated with an insecticide and then not only does the plant take it up and then potentially, you know, the bees and other insects are impacted but then the wildflowers could take it up and the waterways could take it up and the dust And then it’s sort of. when you see how many cornfields, conventional cornfields are around us, it starts to feel kind of uncomfortable. So when you talk about your research to people, what kind of reaction are you getting?
James Yeah, that’s a good question. I think, you know, some people look at me with an eye of cruelty to think about the poison.
Amy Well…
James in the lab. And there is, you know, there is the level of thinking about, oh, yeah, to study some of these impacts. Yeah. But yeah, I mean, I think I don’t want to, yeah, I think there’s a balance here between thinking about, yes, there are definitely real world negative effects that have been well demonstrated. So for example, you know, we have these kind of more lab-based studies that we’re doing these sort of controlled, you know, fine manipulations of exposure. Also out in the field we know from long-term ecological data sets that you know agricultural intensification in general but also neo-nicotinoic use in particular can drive declining bee populations. So for example there’s been some really nice work uh showing that uh neonicotinoid use at the landscape scale is associated with declines in some of our uh one of the species the western bumblebee that has kind of declined precipitously in the past few decades um so definitely there are real world negative impacts that are occurring and can continue into the future but also i think there are reasons for for optimism okay right so i think
Amy I’m ready for those.
James Yeah, and so I think one is we know that, you know, some species are doing okay, right? So understanding that, yes, we can have negative effects on these compounds, but also in certain or there can be negative effects of these compounds, but species are not totally across the board disappearing, right? So there is some resilience in these. And I think we can think about ways to promote that a little bit, right? So can we think about, oh, ways to, for example, help reduce other kinds of stressors that might, so one of the things that we found, for example, is neonics don’t always act alone, right? They can make bees more sensitive to temperature stress or nutrition. The flip side of that is for example like supplementing nutrition can help bee populations in general and maybe even be able to help them kind of deal better with the effects of neonics. So not only thinking yeah basically I think there are ways that can really help us try to make our landscapes more resilient for better and healthier for bees in general. But also, I think one of the big reasons for optimism is increasingly, it’s just really clear that there is a lot of scope for reducing the amount of insecticide use, while not negatively impacting yields for farmers. Right. So I think that’s one of the big reasons for for optimism. Right. It’s like these systems, the bees are holding on. They’re declining, and certainly some species have sort of declined precipitously. But I think there’s also, we know that with the right tools, they can hang on and they can rebound too, right, so we know that these systems can recover. And I think there’s a lot of opportunity for thinking about, oh, how can we sort of reverse the trend of making our landscapes less toxic for bees.
Amy Yeah, you know, it’s sort of that human nature thing. Well, if a little bit works, then a lot should work a whole lot. And we see it with salt out on parking lots. If a little salt works, let’s dump a whole bunch, and that’ll really work. And then not really understanding that too much is bad.
James Totally and I think and I think it’s all about balance, right and that there’s there’s huge. I mean, I think it is hard to imagine a system and it’s not you don’t have to say that there’s no role for Neonicotinoids, right? But for example moving toward what you might think of as sort of an integrated pest and pollinator management system, right where like Pesticides play a role, but they’re also combined with things like oh, let’s manage or let’s diversify our landscapes use other sort of natural enemy controls and then you know yeah we do have the safety valve of being able to use pesticides in certain places where you see the pest outbreaks that sort of responsive system that still uses pesticides as a tool in the tool belt, I think is is you know we don’t need to totally get rid of them. There’s also some emerging technologies that I think can be an alternative to sort of these broad spectrum insecticides that might yeah provide some exciting opportunities but really there I think the the key is that we can dramatically reduce the amount of insecticides and the dependence of our system on agrochemicals right and and with huge benefit to insect populations in general without negatively affecting the food that we need to produce.
Amy So if somebody’s listening to this and they’re thinking, well, I want to help these poor bees that are impacted or could potentially be impacted by neonicotinoidss or other pesticides or just want to help make a difference in this big issue, where should they start?
James You know, it’s one of the things that I think is so great about insects in general, right? Like the one of the things we talk about is, you know, they’re kind of everyday wildlife. You know, you’re not going to see a polar bear every day.
James You know, at least in the right month in Wisconsin, you’ll see an insect every day, right? So they are kind of like in our lives every day, which, you know, not everybody might love all the time. Do you have a honeybee colony nesting in your house? Not your favorite. But I think the flip side of that is you can actually impact these populations on a small scale in a way that’s not always true of other species. So, you know, from the pesticide perspective, thinking bad. Certainly being thoughtful about where you’re buying your food from. I think that’s a great set of, so we’re using the power of the pocketbook to support farmers and farms that are growing in a sustainable way, I think is fantastic. Reducing pesticide use on, for example, buying, when you’re buying plants, making sure that those are pesticide-free can be great. but also again doing other things beyond just sort of reducing pesticide exposure, doing other things that can promote the health of pollinator populations and help them sort of maybe cope with the stressors of the environment like planting, you know, mowing your lawn a little bit less and especially like planting native prairies, you know, one of the fantastic things about these small wildlife insects is you can see some impacts on biodiversity right in your front lawn, and that’s fantastic. And then those have real impacts. So I think all of those things, one of the things that is nice is you can really act locally with insects and have an impact on, that can help the sort of populations as a whole. So I think making decisions about what you buy, but also, you know, your front lawn, and there’s a lot of actionable. Local things you can do in your own.
Amy James Crall, University of Wisconsin-Madison, thank you so much for talking with me about the coolness of insects and what you’ve learned in your research. I really appreciate it.
James Thank you so much, it was a pleasure.
Amy And thank you for listening to the Defender podcast. I wan to note we have several podcast episodes that are about pollinators in Wisconsin and also about neonicotinoid pesticides, so I’m going to list all of those in the show notes so you can take a listen. And if you have something you want me to talk about or a question, send me an email, podcast@cleanwisconsin.org. I’m Amy Barrilleaux, until next time.
