Shelby Herbert
More than 40% of insect species are declining and a third are actually endangered — that’s according to a 2019 meta study by the University of Connecticut. And this isn’t just bad for the bugs. The resilience of the ecosystems we rely on and the food we eat suffers when pollinators disappear.
I’m Shelby Herbert, and I’d like to welcome you to Biotalks. I’m an environmental reporter and an audio storyteller. I got my start in public radio, and you can hear my work on NPR affiliate station KUNR and the Mountain West News Bureau. This episode is part of an ongoing series about connecting to the biodiversity in our own backyards.
In this episode of [biota]LKS, I sit down with Dr. Anne Leonard from UNR'S Leonard Bee Lab, so named for her. Her early stage observations identified that an ingredient in a common household pesticide can actually change the nutritional makeup of nectar, thus hurting bees. Listeners should check if the products they use in their gardens contain neonicotinoids, which you'll hear Dr. Leonard call: “Neonics.” Today, Dr. Leonard and I chat about bee brains, behavior, and how we can rethink “save the bees.” Enjoy.
Anne Leonard
I'm doing great. I'm here in my office on UNR campus and it's a beautiful fall day.
Shelby Herbert
Right on. Awesome. Well, can you tell me a little bit about yourself and what you're working on right now?
Anne Leonard
Yeah, so I'm an associate professor in the biology department here at unr and my research group, we generally focus on plant pollinator interactions and bee behavior. So we've sometimes asked really general kinds of interesting basic research questions like about how bees learn scent and colors and why flowers are the way they are. And more recently we've started to ask some questions that look at how human activities — like pesticides and climate change — may be affecting these interactions, which are sort of mediated by effects on bee behavior. So I'm trained as an animal behavior researcher and I kind of bring that perspective to these ecological interactions.
Shelby Herbert
That's awesome. What, what species are you guys working with right now at the Leonard Bee Lab?
Anne Leonard
Yeah. So right now, the species that we mostly work with are actually bumblebees and there are many species of bumblebees in North America, about 50 or so. There are a lot of native ones that we have access to here in Northern Nevada and Northern California. For our lab based research, we actually use a species that's not native here, but it's native to the East Coast to Midwest. And we actually get those colonies sent to us through the mail through UPS. They're very carefully sealed in a box and we do that because we usually want to use bees that are really naive, like they don't have a lot of foraging experience. We can sort of standardize one element of the variability that we would probably find if we went out and collected colonies here locally.
Shelby Herbert
So naive bees? I'm just gonna jump onto that. That is so fascinating. Are you telling me that bees learn foraging behavior, that it's not just innate?
Anne Leonard
Sometimes, when I talk to a public audience, they're surprised to learn that insects have brains. But, yes! They have amazing little brains and they are capable of learning really sophisticated concepts. So I'm more interested in understanding how they learn in a natural environment. Like how they might learn floral colors or floral scents or even what type of resource like nectar versus pollen a particular plant offers. I have colleagues in the UK and in other labs that are sort of interested in pushing bees to the limit to see what complex things they can learn how to do. And so far, there's good evidence that they can learn to accomplish a lot of really impressive feats. There are even just simple feats that I'm impressed by that we see in our lab.
I can train a bee to a particular color and test her a week later and she'll remember that that color was good or bad — that it gave her a nice reward or a poor reward. And a week is a long time in the life of a bee. So for the bumblebees that we work on — when they first emerge as adults, it's a time when they're learning about their environment: how, where, when to find food. And so they are pretty amazing learners. They do come out as adults with sort of quote unquote innate preferences. They tend to really like the color blue. It can vary with different colonies. But we generally detect that in our experiments that they like blue. They also like bright colors. So there are certain features of flowers that they're particularly attuned to, but you can train them to do a lot of sort of new tasks and they're, they're pretty adaptable. So, they've trained bees to pull strings to access rewards and to manipulate little balls to access awards. It got a lot of press attention because they look like soccer balls. For my personality, I'm equally as impressed by the sort of simpler tasks that they can accomplish. If you think about what bees have to accomplish over the course of a foraging trip, how they remember where to find resources that they can even remember what time of day to visit a particular plant. It's pretty dazzling to me — the amount of information they can remember, if it's worthwhile for them to do so.
Shelby Herbert
That is, that is incredible. And you know, say you were working with a colony of wild bees — would there be a marked difference between colonies of the same species?
Anne Leonard
Yeah, that's a great and interesting question. It's something that we have wondered about over the years. Sometimes we'll have just within the one species that we work with, mostly in the lab. This is an informal observation, but sometimes it’s as though you have a colony of really bright bees that are sort of on-the-ball about a learning task, and then sometimes you'll have a colony that takes a little bit longer to learn. And there has been research looking at colony level differences. So potentially genetic differences or differences at least sort of this family level in how quickly bees learn and how well they remember particular associations within a colony of bumblebees. There's also quite a big size difference among the workers. So you have some really large robust workers and some smaller workers that still try to forage. And we have definitely picked up an association between head size and how quickly they can learn certain tasks. We definitely noticed that variation among the sisters in our colony as well.
Shelby Herbert
That's so cool. Yeah. In your introduction, you mentioned these threats — these climate-driven, human activity-driven — those are different things, but they have a lot in common…
Anne Leonard
Yeah, they do.
Shelby Herbert
This podcast — we're all about biodiversity issues and you know, mass extinction. Can you tell me what's on your mind as far as threats go?
Anne Leonard
Yes. Bees have been in the news for a while. It's probably the most common comment I get when I run into someone at the grocery store, like: “How are the bees doing?” And we can answer that question better for managed bees like honey bees where we have beekeepers, we have a sort of annual census of colonies and what's happening to them. The wild bees that we work on, which is the majority of bumble bees, we have about 4,000 species of native bees in North America. It’s much harder to say what's happening to their numbers because they're not kept by humans, they're wild animals. So there's major initiatives to start monitoring programs. I think that that's something that agencies like the USDA are very interested in — in getting going so that we're starting to collect standardized data on population numbers and where bees are. And their ranges are changing as climate changes, et cetera.
So the big topic right now I think is in developing standardized monitoring schemes that will at least help us collect data in a way that we can have a better handle on what's actually happening to some bees. We expect with climate change there may be some winners, there may be losers as well. So it's important to get the full picture of what's happening with wild bees. Many bumblebees globally seem to be in decline and I think better monitoring schemes will help us answer a question about our local and regional bumblebees.
Here in Reno, we have a lot of variability between the years and years. It seems like it's a really good year for bees, but sometimes, it’s harder to find them. But, again, we don't have really well collected data for a long period of time to be able to say if the variation that we see is meaningful or not. But our region has been identified as one of the fastest warming regions nationally. Right. It's something I've been learning more about. I am not a climate researcher, but I think that like many biologists, psychologists — you start to feel like actually we are all becoming climate researchers in a way. Researchers in my lab group over the past five years have gotten really interested in nutrition. So when we see bees visiting plants, often the general public — people tend to assume that plants are sort of nutritionally interchangeable. I can just put out plants in my garden and it will make the bees happy.
Right. And the more that we study nectar and pollen chemistry, we realize, wait a minute, these nectars, and particularly the pollens vary chemically a lot in the type of nutrients they offer bees. So, some pollens are really rich in fats and lipids, and others are more protein rich. Bees seem to be really sensitive to that. Different bees may have different nutritional requirements. Some ornamental plants that people put out actually have been red to be beautiful or to smell wonderful, but actually offer no nectar or pollen at all. So they're great for it to look at in your garden, but nutritionally they're not so great. But then, also — as we have warming, there's been a little bit of research on this and it's an exciting area to look into how temperature affects the chemical composition of nectar and pollen. It's something that we don't know a ton about, but it seems really important given how important nutrition is to so many axes of health.
Shelby Herbert
Absolutely. Any specific like native plant species that come to mind that you're studying?
Anne Leonard
Hopefully, I have my fingers crossed. We just put a grant proposal where we would look at about maybe about five local species and experimentally warm them and look to see whether we see changes in things like pollen chemistry. But we have started doing some sampling across the region and a plant like the lupins that we have — they're a great plant, but they're a really important pollen source for bumblebees in particular. We're just starting to document geographic variation in their nutritional composition and, and try to at least correlate that with temperature. So just in terms of numbers, there's not a lot of scientists that study nectar chemistry or pollen chemistry. There's more and more as we realize how important this is. But even the question of: are the lupins growing in one Sierra meadow the same nutritionally as lupins growing in another Sierra meadow, the same as the lupins you could buy at a garden store here in town? We don't know. Or even on an individual plant level — does the temperature or the soil content affect the lipid or pollen composition of the pollen? We don't really know. And that's a really important question for bee health at the individual level and at the colony level. And so agencies like the USDA and the EPA are really interested in these questions and have identified climate change and its effect on nutrition as a really top priority for research going forward.
Shelby Herbert
Absolutely. Yeah. Thank you so much. And you also mentioned something about pesticides?
Anne Leonard
Yeah. So with pesticides — you walk into a garden center here in town in the summertime, early spring, and you'll see like a temple to plant protection products. So they're widespread across the landscape. My colleagues here at UNR, Matt Forrester and his research group, have done some really eye-opening studies. I think in his case, sampling milkweeds in California Central Valley and finding just multiple pesticides in plants. Even those that are, you know, bought commercially or are actually in sort of reserve areas or in people's backyards where if the person reports applying no pesticides. So depending on where you live, especially if you're in an urban or suburban area, these chemicals are being used quite a bit and they can transit through water and soil and reach plants where they're not intentionally placed. So we've been really interested in understanding what effects come with certain pesticides, and we've focused on really common pesticides called neonicotinoids. Or “neonics” for short.
We've done a variety of studies looking at their sub lethal effects on bumblebee behavior. And our findings correlate with a bigger picture, which is that these chemicals have a lot of subtle effects on bees' ability to learn and remember associations. We've identified a particular impact on bees olfactory performance. So their ability to learn and remember floral scents. Bees can encounter these chemicals in a lot of different ways. But the really common way is that they're taken up by the plant, and then found in nectar and poly that bees drink. So we've been documenting the effects of exposure. And then, more recently, we've been asking how the presence of these chemicals, these neonics — how do they work alongside the natural chemicals that are found in nectar and pollens to affect bee health. Most of the research into how pesticides affect bees just uses sugar water, which is a great starting point cause you don't wanna make things too complicated.
But real nectar is like a complex cocktail of chemicals. And we know that some of these chemicals — like caffeine, for example — can have their own effects on bee behavior and health. So we did a sort of ma recently a massive study where we maintained bees in the lab on a couple different natural chemicals found in floral nectar and then asked what happened when they got a little exposure to one of these neonic pesticides. And not an easy answer there except to say it depends on the natural phytochemical that's in nectar, and it depends on what you're measuring in the bees. Whether it's survival or immune performance. But I think the bigger picture there is that these pesticides and natural nectar chemistry can interact in ways that we think are important to bee health. We found some evidence that even just a single exposure to the pesticide could basically eliminate some of the health benefits of the natural nectar chemicals for bees. So our bigger argument is that we should be studying natural phyto-chemistry alongside pesticide exposures if we wanna really understand what's happening to bees because when they're out there forging in the world, they're consuming these pesticides alongside this host of natural plant chemicals that can have their own unique and sometimes idiosyncratic effects on bee health. It's kind of like a little bridge between two sub-disciplines of pollen research…
Shelby Herbert
Then it's also like what happens in a controlled environment versus how it...
Anne Leonard
Exactly, exactly. Real life.
Shelby Herbert
That's so cool. That's really complicated and it's…
Anne Leonard
It's complicated. I hate to do a paper and then just say like — it's complicated.
Shelby Herbert
Yeah, I mean that's what science is. And I guess that’s like the next step. I don't know if you guys are far enough into your research that you feel comfortable making these suggestions — but do you have any at the moment, like things you would caution the public on doing or not doing?
Anne Leonard
I don't know, sometimes I see people just sort of spraying them all around and I think if there was more awareness, that these pesticides definitely have a role. But there can be some really strong downsides for the animals in your backyard, or in your HOA or around your office complex.
Shelby Herbert
So, is it that agricultural broad scale commercial use or is the main problem, or, also like what you described — leisurely use for your average person?
Anne Leonard
So, some of the most commonly used pesticides in the US are on agricultural industrial side, but they're the major ingredient in some of the products that you'll see sold to the consumer as well as horticultural and landscaping uses. And their use in those latter contexts — where it's not large scale industrial agriculture — is not as well-studied. That's the research like that I mentioned earlier: we're going out in the landscape and actually analyzing plant tissues and seeing how ubiquitous these chemicals can be is a hint about how widely they're being used. And not just by professional farmers — they're popping up everywhere. In the study I referred to earlier, one of the selection sites was a Xerces Society employee’s backyard. And the Xerces Society is the major invertebrate conservation organization in the U. S. The person had not applied chemicals. So, yes, the consumer and the landscaper — if you're paying for yard care or your office park is professionally managed, there's a really good chance that neonicotinoids are being used. They're very effective chemicals and they have their pros.
Shelby Herbert
…But they don't discriminate which insect they're harming.
Anne Leonard
Right. Which is a difficulty. There is growing interest in more state level regulation on their use. There are some states, I think Maine and New Jersey have pretty heavily restricted their use. California seems like it's moving in that direction. I've had some inquiries from Nevada state legislatures over the years about the prospect of this for Nevada, but my colleague Matt Forrester might know a lot more about that. I think he's actually testified for some of these legislation as well. But yes, they're out there. If you go out to the garden store and look at the back of a plant protection product that's being marketed to you, just as a regular backyard gardener. You are very likely to see that neonic pesticide.
So it's good to just raise awareness of this. And I don't have a personal anti-pesticide stance or anything like that. My personal judgment is that if I'm not commercially growing crops — I'm just trying to plant native plants and I love to see insects and bees in my backyard — I don't personally want to use chemicals that are going to make it kind of a silent dead zone.
Shelby Herbert
Absolutely. So, this has kind of been the common refrain throughout this podcast: what is the public utility of native bees? When people here save the bees, they're usually thinking of domestic bees. Like my own parents — they are bee farmers. But why is conserving these species important?
Anne Leonard
So, I think depending on which member of the general public I was talking to, I might try to ask them some questions or suss out their background and understand what's important to them. For some people, they may see value in preserving our natural heritage. And biodiversity deserts are hotbeds of bee diversity for reasons that I don't think are super well understood. It's kind of the opposite pattern of many animals on this planet. But Nevada and Utah — these are hotbeds of bee diversity. We don't even know how many native bees we have in Nevada because we don't have a long history of good monitoring schemes and identification of specimens. So we should have some local regional pride. I think about our bees for someone who maybe they're not a big fan of insects, but they enjoy going on hikes and seeing wildflowers.
I also just wanted to say that I served on a workshop that the USDA and EPA put on jointly where they take input about research priorities and funding priorities.
They involve industries. They often have professional beekeepers sharing their perspective. But this last year they are rethinking things a bit and they invited, alongside the industry folks, representatives of sort of tribal interests to talk about the value of native lands and indigenous culture and medicine and the value of pollen for some of those specialized crops that have a real importance. So, if I were talking to that audience, I might emphasize that angle as well. And then, if I was talking to somebody who didn't care at all about the natural world, but wanted to have access to fruits and vegetables, I would just point out that there are a lot of crops where even honeybees…
Shelby Herbert
Tomatoes, I've heard…
Anne Leonard
Yeah. Okay. So tomatoes are pollinated by bumblebees. Honeybees can't perform the behavior called buzz pollination that's required to pollinate them. But even in open agricultural fields where honey bees are being brought in, there has been research observing who is actually going to these flowers. And often if there's a healthy population of native bees, they're there pollinating for free as long as they have habitat to live in. And so I would say that they're incredibly economically important in an agricultural context. And if all the native bees were to disappear tomorrow, we could not get by with just honey bees. Or if we did, we would lose some major crops and or the price of your fruits and vegetables and everything would explode.
Shelby Herbert
What? Oh my gosh, that's a good stinger and that's a great note to end on. Annie, thank you so much.
Folks, I hope you enjoyed this episode. No shade to the beekeepers in my audience — my parents are some of you! I've linked Xerces Society and Pollinator Partnership in the description. Check those out to find out more about native pollinators and what you can do to promote them in your area. And while you're there, feel free to check out my coverage for NPR affiliate station, KUNR 88.7, which is about a former postdoc researcher in the Leonard Lab. Her name is Felicity Muth and she authored a children's book about wild bees.
I'm Shelby Herbert and this is your cheerful reminder that you inhabit a dying planet. Don't stop talking about it.
Episode III: Native Bees