The Underground Heroes: Earthworms

Earthworms. They may elicit memories of digging through the dirt, probably as a child, and picking them up to discover what they are. But what do they do other than slink around and bury themselves in the soil?

To help us explore this fascinating invertebrate are Jennifer Hopwood and Stephanie Frischie. Regular listeners will remember Jennifer — she’s been on Bug Banter before to talk about beetles and wasps. She is a Senior Pollinator Conservation Specialist with Xerces, providing resources and training for pollinator and beneficial insect habitat management and restoration in a variety of landscapes. Stephanie is Xerces’s Agronomist and Native Plant Materials Specialist. Stephanie works to improve the supply and growth of important plant species for the restoration of insect habitat. Additionally, and most pertinent to today’s conversation, she leads the Xerces Soil Life project that focuses on soil invertebrate ecology and soil health.

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Photo credit: S Shepherd Schizoform, CC 2.0

Thank you for listening! For more information go to xerces.org/bugbanter.

Transcript

Matthew: Welcome to Bug Banter with the Xerces Society where we explore the world of invertebrates and discover how to help these extraordinary animals. If you want to support our work go to xerces.org/donate.

Rachel: Hi, I'm Rachel Dunham in Missoula, Montana.

Matthew: And I'm Matthew Shepherd in Portland, Oregon.

Rachel: Earthworms. They may elicit memories of digging through the dirt, probably as a kid—maybe not—and picking them up to discover what they are. But what do they do other than slink around and bury themselves in the soil?

Rachel: To help us explore this fascinating invertebrate are Jennifer Hopwood and Stephanie Frischie. Regular listeners will remember Jennifer—she’s been on Bug Banter before to talk about beetles and wasps. She is a senior pollinator conservation specialist with Xerces, providing resources and training for pollinator and beneficial insect habitat management and restoration in a variety of landscapes. Stephanie is Xerces’s agronomist and native plant materials specialist. Stephanie works to improve the supply and growth of important plant species for the restoration of insect habitat. Additionally, and most pertinent to today’s conversation, she leads the Xerces Soil Life project that focuses on soil invertebrate ecology and soil health.

Rachel: Welcome back, Jennifer! And welcome to Bug Banter, Stephanie! We're super excited to have you both here.

Stephanie: Thank you, Rachel and Matthew. Great to be here, and hello, everyone.

Matthew: Yeah, we really appreciate you making the time today. So I know in most of our previous episodes, we talked about arthropods—i.e., invertebrates with jointed legs and a hard exoskeleton, which includes insects and spiders. Earthworms are quite different—no legs, kind of squishy, and a bit slimy. So if they're not arthropods, what are they?

Stephanie: They are not arthropods. They're another kind of invertebrate called annelids. Or really you can think of them as tube animals—how I think of them to start with—and even more specifically, animals that are made of lots of rings, or these little donut shapes that are stacked together to form a tube, with a feeding end and an excreting end. That name or word, annelid, is derived from a root word that means little ring. So yeah, lots of stacked up rings. Not—separation of rings may or may not be evident from the outside of the animal. Currently, scientists have described more than 20,000 species of annelids and so that's a big number, and represents a very diverse group of animals that live across many habitats. Some examples of annelids are marine worms that live in ocean environments, leeches in other aquatic and wet soil environments, potworms—they are associated with highly organic soils—and then our featured group today, earthworms.

Stephanie: Thinking a little more about and picturing in our heads these animals, another common trait to highlight is that annelids don't have legs. That's one way to distinguish them from caterpillars. So caterpillars are also like tube-like and squishy, but they are insects. They're the larval stages of moths, skippers, and butterflies. And if you can look closely at a caterpillar, you can find that they have stubby little prolegs. And annelids don't have any kind of legs, really, but instead they have little bumps or bristly hairs along the outside of their body. Those bumps or hairs provide friction and force to help them move around in their environment. And if you've ever held an earthworm, especially running your fingers along its body forward and backward while it moves, you can feel those bristles. It's like a funny sensation of scratchy and slimy at the same time.

Stephanie: Another feature you might associate with earthworms is a part of their body called the clitellum. This is a region that looks like a thicker band or a collar encircling the body. It's nearer to the head end. And something that earthworms and leeches have in common is they both have this clitellum structure.

Stephanie: Earlier when I listed some examples of annelids, the last two groups I mentioned were potworms and earthworms. These are a related subgroup of annelids called Oligochaetes. And this word—we're going to look into what this word means to add two parts—“oligo” meaning few and “chaetaes” referring to long hairs or bristles. So that's what I referenced before where you can kind of feel those rough parts on an earthworm's body—those are those bristle hairs. This group refers to “few bristles,” and there's another group of annelids that have more of these bristly hairs—those are the Polychaetes or the “many bristles.” But again, today we're focusing on earthworms.

Stephanie: All right, a little bit more—. Like I was saying, those rings, or the donuts, they're clearly visible on the outside as segments, and each segment has those bristly hairs. And there are muscles where they can pull the hairs in or out to aid in movement, along with this peristalsis, or like what we refer to even as a worm-like wave motion, where it's contracting and extending its body. The slimy aspect of worms is because they are protected by a mucus-secreting cuticle,. Although in many places they're limited to wetter places—marine, freshwater, wet or moist soils—and they're not adapted to the very dry soils of deserts.

Stephanie: They also make protective burrows, digging by eating their way through the soil, and leaving their droppings as a kind of telltale casting at the soil surface. And the way they eat—an earthworm's mouth is like a big sucking straw. So [they’re] kind of taking in whatever's in front of them, which is a mixture of organic material, these smaller pieces of mostly dead plants or animals, along with the mineral components of the soil. You want me to keep going? Haha.

Matthew: Haha. It seems like there's just a ton of information and knowledge that is waiting to come, which is awesome. I was going to ask: what makes an annelid? Annelid? Annelid, right? I know, before we started, we were having a conversation: “Is it ‘Oligochaete’ or ‘Oligochaete?’”

Stephanie: Haha.

Matthew: Words. Is there anything, in particular, that’s unique about annelids? But you've just been describing the donut rings, the hairs, the mucus, so you've probably already answered that question. The other one is: I mean, are there other invertebrates that annelids are related to? I mean, more broadly, are like these worms just this one group that doesn't really have aunts and uncles or cousins elsewhere?

Stephanie: Yeah, I think that question depends on who you ask. It's an active area of animal research—kind of, what are the relationships of these groups? Some will say that annelids are more closely related to mollusks. Others group them more closely with nematodes. So I don't think we have a clear, decisive answer about that yet.

Matthew: I always thought nematodes were worms, but I guess I've been wrong all this time. But that's such an extraordinary diversity of invertebrates that when you think you know something you discover that you actually know even less.

Rachel: So all of it—. I don't know a lot about earthworms. Is there a lot of diversity among earthworms?

Stephanie: Among the Oligochaete group—so that's the earthworms and potworms—there are roughly 10,000 species recognized.

Rachel: Just a few. Haha.

Stephanie: Just a few.

Rachel: And are there areas around the world that have more diversity of worms than others? And why? I know you mentioned soil moisture is a really key component to their habitat.

Jennifer: Yeah, the pattern for diversity of earthworms seems to be a little bit different than the pattern for diversity for plants and a lot of animals that live above ground, which is that a lot of diversity is more concentrated in the tropical areas, and then as you get towards the poles, it's less diverse. But with earthworms, they're more diverse in temperate regions, so in Europe, parts of Australia, New Zealand, and then parts of the U.S., too. We have about 100 native species in the U.S. and then another 50 or so that are introduced. So it can support diversity of species, our area. And you asked why, and I don't know if it's incredibly well known, but it does seem like the moderate rates of decomposition play a role, and the abundance of leaf layer, which provides nutrients. And that pattern of higher diversity at mid-latitudes below ground for worms is also in keeping with other soil life, like mites and fungi that also are more diverse at mid-latitudes. So I think the leading theory is decomposition rates and nutrients.

Rachel: Sometimes we'll ask about size, and I think this one is a particularly interesting question that might surprise people, but what is the largest worm—or the largest earthworm—and what is the smallest?

Jennifer: Yeah, turns out—. Well, I'll start with the average. Like the earthworm that we're mostly familiar with are probably somewhere around three to four to five inches in length. But in contrast, the U.S. has some of the largest earthworms on the planet. They're found in the Pacific Northwest. So the giant Oregon earthworm—the Oregon giant earthworm and the Giant Palouse earthworm both are quite large. They can reach three feet in length, which is kind of mind-blowing. But they're related to several other giant species of earthworms around the world. There are a couple in Africa and some in Australia. And some of those earthworms can reach nine feet in length, which is truly astonishing. And sometimes even longer than that, so that's really giant. But on the other end of the spectrum, there are earthworms that are as small as half an inch. So it's a really big range.

Rachel: That is a big range. It's hard to not think of like Dune and the sandworms and—. Haha. Not that big, but still, nine feet is rather long for an earthworm. But I just think it's so cool.

Jennifer: Well, you know, and Matthew, this was—. I don't remember exactly when this happened, I think it was sometime in the last 15 years though, the Giant Palouse earthworm was thought to be extinct. And then they found a couple individuals. But there are profiles on our website about these giant earthworms, too, [if] people want to seek out more information.

Matthew: Yeah, no, I remember when that rediscovery basically of Palouse worm—it was pretty big noise. Because the Palouse used to cover—it used to just be prairie, and then it became wheat fields and there's these kind of eyebrows of prairie remaining on the top of the little hills around there, so their habitat just got fragmented. And every now and then here in the Willamette Valley, people think they've found the giant earthworm. But it's a very difficult animal to survey for because it can move faster than you can dig. So it's not like you can just put a little trap out or—.

Stephanie: Are you speaking from experience, Matthew? It sounds like—.

Matthew: No, not direct experience, but I have talked with people who’ve chased after them. But apparently they have a—. Sometimes they're discovered by the smell, because they smell of lilac.

Jennifer: Oh, interesting.

Matthew: And so someone might be digging it—. It's like someone who's digging a pit, whether that's planting a tree or something else, and then they're like, “There’s this really big earthworm!” they saw, and they just see the back end of it, and they say, “There was this kind of flowery smell.” And so we do get these really erratic, isolated—. So [it] probably still survives, but you know so much of the Willamette Valley, 99% or more has been converted, so there's not much land remaining for it.

Jennifer: The way I was understanding it from our profiles, too, is that they are deep soil dwellers, too, or deeper than a lot of other earthworm species. So yeah, it's not easy to reach them.

Matthew: No, I think it might be best with a backhoe, but, you know. Haha.

Jennifer: Haha. Yeah you don't want to use that on native soil.

Matthew: Yeah, that doesn't sound very good for the worm, does it? Haha.

Matthew: All right so moving on—more sensible. Earthworms, they must play an ecological role, right? Everything plays an ecological role. I mean, we have that old adage, you know, “The early bird gets the worm.” People probably have seen robins, at least on TV, kind of yanking at worms, and so there's an obvious link in the food webs there. And I'm sure they have other benefits, whether that's to soil health, or plants, or I don't really know. I mean, so what kind of role do earthworms play in our environment?

Jennifer: Yeah they do play multiple roles. They're food for other wildlife, like birds, and also mammals will hunt them down and eat them, but also smaller animals, like insects and other arthropods. Or insects like the larva of fireflies, for example, will hunt earthworms and they'll search earthworm burrows. And that, to me, is pretty amazing thinking about the size of the larva of fireflies. They're considerably smaller than earthworms, but they must be pretty mighty, mighty hunters.

Jennifer: So they're definitely food for wildlife, but definitely, I think their contributions to soil health are the thing that they're most well known for. And as they're living in the soil, they're tunneling, and they're mixing the soil components together, and they're eating the organic debris, and they're processing it out the other end. And they influence nutrients, and water infiltration, and carbon storage, soil structure. They help aerate the soil and they also help—in doing so, help water move through, down. And that also helps plant roots move down, too. They can even influence seed dispersal, and even fungal and bacterial dispersal in the soil as they're moving through. So all these different things are really hugely influential on the soil and that's in part why they get their name “the ecosystem engineers,” because they really are doing quite a lot of activities that help support soil life. And there's quite a lot more information about soil life and earthworms, also, in our Soil Life guide, if you want to find that online. Not to act like a commercial but—.

Matthew: No, no, no, shameless plug. It's all good.

Jennifer: Haha.

Matthew: I mean, you mentioned, “ecosystem engineer.” For people who aren't quite sure what an ecosystem engineer is, could you describe that a little bit?

Jennifer: Sure. I think it's just a term that can be used to describe any organism or group of organisms that's really just having outsized impacts on the world. And in the case of earthworms—because soil is so foundational to life—that their impacts can be really foundational, as well.

Matthew: I have earthworms in my backyard. I find that when I'm digging. I'm in the Willamette Valley, but I haven't found the giant one yet. I find some pretty big ones, but not the giant ones. They must be good for my yard. I mean, are all earthworms good?

Jennifer: It's a really good question, and most likely most of the earthworms in your yard are contributing to soil health and to food chains. And in farmed soils, they're, too, likely benefiting the soil structure. But the context does really matter, both the landscape context and also the species. So some earthworm species do more harm than good in some settings. In particular, some non-native species that are present in native landscapes, like forests, for example.

Matthew: So, non-native. Is that also harmful in a kind of invasive way? I mean, how many are we talking about here? I mean, again, I don't know—it's very difficult to kind of identify earthworms when you see them, so I don't know whether the earthworms in my yard are problematic or not.

Jennifer: Yeah, and it's a great question. There are definitely some introduced species that cause ecological harm. Jumping worms is a group of related species that have been introduced from Asia and they are problematic. And they have quite a wide distribution in the U.S. right now, from the Northeast down to the South, and into parts of the Central Plains—where I live—and then also in Oregon, parts of California, other states in the West, too. So they've spread quite a lot in the short time—shortish time they've been in the United States. But this is a group of worms that can reproduce really quickly. They mature really quickly, so they can have several generations a growing season. They can sometimes reproduce without mating, which can speed up reproduction. They spread quickly, and they can survive colder temperatures. So that means they can just survive a lot of conditions in the United States.

Jennifer: And they cause significant ecological damage. They alter soils in ways that make it really difficult for plants and animals to survive in those soils. So they do this by disrupting the way that the leaf layer on forest floors, for example, decomposes. And that means that the soil has reduced nutrients, higher rates of erosion. And this means that plants don't have the same amount of nutrients accessible to them. They just really alter the soil quality, and fast. And by also reducing that leaf layer, too, they take away habitat for animals that rely on that leaf layer. And that can include all sorts of beneficial invertebrates, like millipedes or things that overwinter in that leaf layer, or even larger animals, too. So they influence the ecosystem in multiple ways. And, yeah, they've spread quite rapidly. So that's just an example of a group that can be problematic and cause ecological harm.

Matthew: Yeah, because I know we talk about “Leave the Leaves,” and encourage people to keep their leaves, but presumably the more leaves we keep the better chance that our native worms have to do their stuff in the soils. I was trying to remember what—I think it was—. So, two tons of leaf litter per year falls in a deciduous forest in an acre. Something—. It’s a fairly substantial amount of organic material that gets recycled, but some of these earthworms eat that before it helps.

Jennifer: Yeah, leaves are a good resource.

Matthew: Yeah.

Jennifer: Yeah, the way they just consume that, and rather than mixing nutrients, it just doesn't get integrated back into the soil, and it gets lost quickly.

Matthew: But, I mean, you also mentioned that the jumping worm moves, it moves far away. How do earthworm[s] move around? Like I have this little image of like they put their backpack on, off they go. And it's like—. They just don't seem very mobile.

Jennifer: Haha. Right. On their own—I mean, they can move on their own and expand their ranges on their own through moving in soil. But the way they move the most quickly is with us, as people. And in fact, that's how we have so many introduced species in—. When the U.S. was colonized by Europeans, they brought in potted plants. And so invasion of these introduced species really happened along like our major waterway corridors. As people colonized that—as European people colonized those spaces, they brought in these new earthworm species in these plants—unknowingly, of course—and those spread. So things like nightcrawlers, and red wigglers, and so forth.

Jennifer: But in the case of jumping worms, the way that they are moved—and quickly, in particular—is that they have—. They overwinter in their cocoon, or egg case, and that egg case is really resistant to cold temperatures, hot temperatures—not super-hot temperatures, but pretty warm temperatures—and just really is resilient. So it's in the soil and it's small enough that you cannot, you know, you can't see it, so you unknowingly transport it in compost, or potted plants, or on tires, in some cases. So those are sort of the unknown ways to transport jumping worms. People carrying them—you know, unintentionally—but on landscape equipment, and shoes, and tires. And because they can spread in this way—unknowingly—yeah, it's just—it kind of blossomed out of control before I think we knew about it.

Matthew: Because a lot of these things were happening before people noticed.

Jennifer: Yeah, and realizing the impacts that jumping worms were having. And so now there aren't really known control methods for jumping worms that wouldn't also cause, you know, massive harm to a lot of other important things. And so preventative measures to prevent the spread are really critical. So if you can ID them, and notify your extension office, that can be a first step. And, you know, Steph was telling about all these really important features of earthworms. One—or two clues that can help you identify them are: their name “jumping worms” refers to how they act when you handle them. They sort of have [these] crazy, thrashing movements. So, if you've ever seen a snake when it’s picked up, how they sort of thrash around because they do not want to be in your hands—that's totally similar to how these worms act when you pick them up.

Jennifer: They also have—like Steph described—that smooth clitellum, that smooth band that's raised near the earthworm's head. It's white or quite cream colored in jumping worms, so that's quite different than a lot of other earthworm species. So if you see these, notify extension. But also then that tells you what you need to do in your own space to help reduce spread. So that means you don't really want to exchange plants with other people, because probably you have those cocoons. So you could share bare root plants, or you could share seeds, but you wouldn't want to give people containers of plants from your space. And also, you probably shouldn't receive them from somebody else, if those jumping worms are in your region, without knowing more about how they took care of those plants or if they have them at their site.

Jennifer: Also, when you bring in compost, making sure it's from a—if you're in a region in which jumping worms occur, and even if you aren't, it's a good practice anyway if you don't compost on site yourself—it's a good idea, if you're bringing in compost, to get it from a facility that has commercial treatment because it can—that commercial treatment heats it up at such high temperatures that it does degrade the cocoon. So that's really helpful. And then if you are also in an area with jumping worms—like let's say you're visiting a forest in Minnesota, or even in parts of Omaha, where I live—it's good to clean your tires before you leave the site to prevent the spread of those cocoons. So those are some of the things that we can do to reduce their spread.

Matthew: You mentioned cleaning tires, but also your shoes, as well.

Jennifer: Yes. Yes, thank you for that.

Stephanie: Like Jennifer was saying, in many ways, these non-native worms, the worms out of the bin or out of the container—. I'm from Indiana, and as a kid, you know, [I] grew up digging nightcrawlers to use as fishing bait. You can also buy different kinds of earthworms to use as fishing bait. And that's another way that these non-native worms were originally introduced in places. As I learned more about entomology and ecology, I was really surprised to learn that earthworms aren't native to the glaciated parts of the Midwest, because they are really abundant in the soils everywhere. And again, that's just an indication of how they've spread through human introduction over decades and centuries.

Matthew: Yeah, that's true. Yeah, because glaciation covered a lot of the country, didn't it?

Jennifer: I'm really glad you mentioned that, Steph.

Rachel: So Stephanie, in the introduction, I mentioned that you lead our Soil Life project. And part of that does address soil health, which we've mentioned many times. Can you explain what soil health is for folks who might be new to that? And is there a definition of healthy soil? What does that mean?

Stephanie: Well, soil health, yeah, is this concept that has emerged in recent decades. It adds in ecological and biological aspects of soil. A prevalent technical definition defines soil health as this continued capacity of soil to function as a vital living ecosystem that sustains plants, animals, and humans. I just like to think of it as healthy soil is alive. It's alive with plants, with animals, with produce, with bacteria, with fungi. Healthy soil does all the things that that soil can do—it absorbs water, it's free of contamination. In earlier eras of soil science, especially with respect to agriculture and crop production, soil science or quality focused on these physical or chemical aspects of soil, like texture, or pH, or available nitrogen. But this concept of soil health takes in a bigger function of soil for us on this planet. It’s habitat where a lot of these plants, animals, and other microorganisms live. It's where carbon sequestration happens. It's a big part of the global water cycle, as well as nutrient cycling. And then it's where land plants grow, providing our oxygen, and also all the crops and livestock that we eat.

Stephanie: What is challenging about it is, it's all these different indicators that you can look at, so it's hard to quantify. It's more of a continuum. Or some people, you know, even say that like, “You know it when you see it, or you feel it, or you smell it,” what healthy soil is.

Stephanie: You know, another aspect I want to mention about healthy soil is that it's when soil is intact and in place. So in our soil health curricula and training, I like to use an image that—again, to observe or see soil, we have to disturb it. We're not in the soil ourselves—but the soil profile, you can see the horizons in it. That's soil—it's intact and in place. A pile of soil that's been dug up and dumped out—I call that soil material. It's already degraded in many ways. And then if you think of—you've swept your floor in your kitchen and there's all kinds of debris and detritus in your dustpan—that's dirt, right? Soil is not dirt. Soil is this really special combination of minerals, life, and—living life and organic matter of dead life.

Jennifer: I love that answer so much. I think it just really helps to describe soil and make it come alive for people

Rachel: Yeah, definitely. I was just thinking about myself, who's fairly disconnected from the farming community, from growers. I just started gardening when we bought our first house a couple years ago. And even though I spent a lot of time outside, I didn't think about soil very much. And it's just so short-sighted. I am so grateful that now I have this different perspective of just all the life that's living underneath our feet, and the appreciation we should have more of. And I love your definition that like what you clean up in your house is dirt. It's very different from what is outside in the ground. So I love just this exposure to this like beautiful ecosystem that often I don't think a lot of people think about unless they have to. And so with that, what can we do to promote healthy soils in our community, in our backyards?

Stephanie: I think I'll start with these classic four soil health principles. Four is a pretty manageable number here. The first is to keep the soil covered, so you're protecting the soil. And that means either with existing vegetation, planting vegetation, or some kind of organic mulch. The second principle is continuous living roots. So, plants want to grow where they can. Soil wants to grow plants. And many times where soil is degraded or disturbed, it's where the plants have been removed. So whether that's in your garden, or agriculture, or other soil that you care for, finding a way to let plants be growing there year-round is important.

Stephanie: And then the third one is adding, or increasing, or supporting biodiversity. This is in the form of both plants and animals. When we think of agricultural context, incorporating livestock and the way that they're cycling nutrients and interacting with soil is part of soil health. And then the fourth one is to minimize disturbance. So that's both the physical and the chemical, right? Tillage, digging, that physical movement of soil [is] something you want to try to minimize. And then also under this minimize disturbance, is the concept of chemical disturbance or pesticides, pollutants, or other contaminants. Protect the soil by keeping it covered and minimizing disturbance. Feed the life in soil by adding diversity of plants and animals, and keeping those roots living—they're the ones that are moving carbon in that system.

Matthew: When you mentioned continuous routes, my first thought was, “Oh, what about agriculture?” So I'm glad you mentioned that specifically. I can only assume you've had these conversations before with people, so that's great. But I was pleased that you mentioned chemical, because that was going to be my next question. It was: you know, at Xerces we talk a lot about pesticides—insecticides, in particular—and a lot of those conversations revolve around bees, butterflies, you know, animals that we see around us. Pesticides, insecticides, I don't know—is there like an oligochaete-icide? I don't know. I mean, they must impact earthworms as well, surely?

Stephanie: Yeah, like I was describing earlier, earthworms are kind of dependent, or they're really intimately affected by their environment. They have this mucus, soft skin and so they're exposed to any kind of chemical that's in their environment from something just to extreme pH, or over fertilization—that can affect earthworms. And more and more is being researched every year about things like heavy metals, pesticides, those other kinds of contaminants and what their effects are on earthworms. And I will make my plug here that in a couple weeks, on March 26th, we're hosting an online short course about soil life, especially for urban farms and smaller farms and gardeners. And we have a special topic that we'll be diving into with [a] guest speaker, focused on contamination in soils—how you can recognize it, how you can help address it, how it might be impacting the animals in that soil, as well as the plants and/or food that you're growing in that soil. You can learn more on the Xerces Events page.

Matthew: More shameless promotion—I love that.

Stephanie: Yeah, and it will be recorded on YouTube if you miss the date.

Matthew: I'm glad that you mentioned fertilizers, as well, because just recently I did find a paper that talked about over fertilization of soil building up and resulting in, you know, excess fertility that's actually degrading soils.

Stephanie: Yeah, soil health is kind of helping things get back into their natural balance of cycles.

Jennifer: Like you mentioned, of course, they have that soft skin, so direct contact with the chemical can be—they can absorb it. But if you've got contaminated soil, so if it has a fungicide or insecticide, that's another primary method of contact for earthworms. So as they're ingesting the soil they encounter those chemicals and that can impact their survival, their reproduction, how they feed, how they grow, and then that in turn can impact how many earthworms are in the area, and also their functional role in soil health. So there can—even if the chemicals don't kill them outright—can definitely have other impacts. The same—. It's very similar for heavy metals—also similar impacts.

Matthew: Are there ways to clean the soil? Or is it once you've got contaminated soil that you can't, you know, you're just kind of stuck with it?

Stephanie: Yeah, that, too—. I think it's a bit like Jennifer was describing with once the invasive earthworms are there in the soil, it can be so diffuse and difficult to isolate, and then to move. But it's another area of emerging research with bioremediation—certain plants which can remove those pollutants from the soil. But then those compounds are in the plant tissue and it still has to be dealt with, you know, by being taken off site and disposed of, or handled in some other way.

Matthew: So, really, we just need to keep our soils healthy, right?

Stephanie: Prevention is the best medicine.

Matthew: Indeed.

Stephanie: Haha.

Rachel: Well, thank you both so much for answering our numerous questions about earthworms and healthy soils. I think there's just a lot of great resources that you all mentioned—I'll be sure to put those in the show notes on our website. So we're going to end with our last couple of questions that we love asking people. And this one is for both of you that we've added this year: If you could see any bug—bug being a very loose term for invertebrate—in the wild—wild being a very loose term for anywhere outside—what would that be and why? Jennifer, I'll start with you.

Jennifer: Yeah, okay. Well, I picked one that was super unlikely to actually encounter. But if I'm just going to imagine, I might as well dream big. And I was going to pick the Lord Howe insect stick—Lord Howe Island stick insect. So it's quite a large stick insect. They're flightless, and they were thought to be extinct. But in 15, 20, 20 years ago, they found a population off the coast of Lord Howe Island, on this volcanic island way up on a cliff. And the stick insect only feeds on one species of shrubs. So there was this population of 20 to 30 individuals way up on this cliff of a volcanic island that is like miles away from the host island. So sort of an amazing, unbelievable scientific find. And of course, there's no way that I would ever get to that volcanic outcrop, but—because I think they keep it pretty tight—but like I said, I'll just dream big. I think it would be super neat to see that really critically endangered species. And also climb a volcanic outcrop.

Stephanie: Probably my answer, I think, is the opposite of that. Haha. To me—I am happy with an insect anywhere I can see—a bug—anywhere I see it, right? That, to me, is one of the wonderful things about bugs—is if you're aware and open to them, you can find them everywhere. So, you know, I was just out with a friend, and they notice a tiny, tiny wasp on their hand. It's starting to be warm here where I live, and I have noticed that moths are starting to come to the light at night. So I don't have any one bug, I just take them when I get them.

Matthew: It is that exciting time of year where things are beginning to reappear. As soon as I saw my first bumble bee this spring—it flew past my window here—and it's like, I instantly went to the team chat and said, like, “I saw my first bumble bee!”

Matthew: So we come to our last question. I'm going to start with you on this one, Steph. What inspired you to study plants, become a crop scientist, and then, you know, eventually end up working with a bunch of bug nerds?

Stephanie: I think my path to where I am at this moment somehow started as a kid who always liked plants, if I think back. And I'm—[I] had a childhood with adults, and other friends, and parents, and family around me who supported that. And I gardened with my parents. They let me pick out flowering annuals to put in the garden and care for, also. And where I grew up in the Midwest was mostly agriculture around me, and that was the view I had of a path to work with plants was through agriculture. So that is how I became a crop scientist, or agronomist. And through that, I learned more about crop biodiversity and all the crop wild relatives. I was always interested in nature and conservation and then it was, you know, by my late 20s, I just had the great fortune to live in a place where a large prairie restoration project was happening, and get to join the team there. And bring together wild plants and habitat restoration for wildlife with kind of trying to farm those plants or jumpstart them on repairing and healing that area. And then at Xerces, I think that continues to weave together the way that plants, and insects, and other wildlife are connected, so yeah.

Matthew: Everything is connected in the end, isn't it?

Matthew: So Jennifer, it's a slightly different one for you because you've already been on Bug Banter, so we've asked you that question. So the variation is: what is your favorite or most memorable experience with an invertebrate? And that’s so far—we'll keep the Lord Howe Island stick insect in our minds and be rooting for you on that one. But, so far, what's your most memorable?

Jennifer: Haha. When Steph was mentioning, you know, the fact that you can see these amazing critters anywhere, it relates to my story, which is: a couple years ago, I was walking to Back-to-School Night [at] my son's elementary school, and there was a group of kids around this tree and they were clearly looking at something on the tree, and I just thought, “I gotta know what this is,” because they were really engaged and interested. And so I went over and just took a look. And it was a Rhipicerid beetle, which is a, it's a cicada parasite—the larva of the cicada parasite. So they spend most of their life underground with cicada larva—feeding on the cicada larvae, who feed on plant roots. And so they're really uncommon to see above ground. Like I've seen a grand total of three in my life—including that one. And they are really large, and they have unusual antennae. They're really, they're just really striking beetles. And these young kids were so excited about it. And it was wonderful just to see them appreciate insects. And when I said, “Oh my goodness, that's a Rhipicerid,” one of the boys said, “Really? I've been wanting to see one of those!” He knew exactly what it was. And it was just a really wonderful moment to see people appreciate insects and really get excited, so. And it was just in an unexpected time and place, and like Steph said, the magic can happen anywhere.

Matthew: Yeah, it definitely can.

Stephanie: So yeah, I'll wear my plant person hat here, Jennifer. Could you spell that? What is that beetle?

Jennifer: It’s an R -H-I-P-[I]-C-E-R-I-D. Rhipicerid. Yep.

Stephanie: All right, I want to see one now, too.

Jennifer: My first one was one I collected, and it had a nematode inside. So when I collected it, the nematode came out, and it was very gruesome. You can feel free to edit this right out, but that’s like tied into my memory of Rhipicerids. Haha. Because I thought—I was like, “Oh my goodness, this is a really unusual species, or group of beetles. I haven't collected this before. I really need to get out my key here.” And then, yes. Yeah.

Matthew: I was thinking this episode was going to end on like our first Bug Banter Spelling Bee, but then it went totally back into nerd territory, which was awesome.

Rachel: I'm so impressed with that.

Matthew: These are the moments we live for in the podcasting world, isn't it? Haha.

Stephanie: Yeah, it was like the tree roots, the cicada larvae, then this Rhipicerid beetle. And I thought that was it. But then, no, there's a nematode in the picture, too.

Jennifer: Haha. It's never, yeah, it's never—. It's always more complex than you think it might be.

Matthew: Yeah, and as you say, there's always that chance of discovering something right, you know, right there.

Rachel: Well, thank you both so much. This has been really enjoyable. I am sure our audience enjoyed this conversation about an invertebrate that you don't hear often about. And it definitely makes me want to go dig for an earthworm, but now I'm like, “I don't want to disturb the soil,” so I'll go plant some native plants instead. But yeah, thank you both so much for your time.

Jennifer: Thank you both. It's such a pleasure.

Stephanie: Thank you, Rachel. Thank you, Matthew. And thank you, Jennifer. And thank you, worms.

Rachel: Thank you, worms.

Matthew: Go, worms!

Jennifer: Haha.

Rachel: Bug Banter is brought to you by the Xerces Society, a donor-based nonprofit that is working to protect insects and other invertebrates—the life that sustains us.

Rachel: If you’re already a donor, thank you so much. If you want to support our work go to xerces.org/donate. For information about this podcast and for show notes go to xerces.org/bugbanter.