Note: This software that creates the Nature's Archive transcripts appears to have a bug making it unable to split Dr. Olson-Manning and Sydney Kreutzmann's audio. Apologies for the lack of transcript fidelity.

[00:00:00] Michael: Carrie and Sydney, thank you for joining me today.

[00:00:03] Carrie and Sydney: Yeah. Thank you. Yeah. Thanks. Great to be here. 

[00:00:06] Michael: So I've always had a fascination with milkweed. When I was growing up, there was actually this little vacant lot behind a friend's house, and he knew all about the milkweed and what it did. And I had no idea I was ignorant to the whole thing. And I remember one day, I don't know, he's nine or 10.

[00:00:23] We went into this vacant lot and he broke the milkweed in half just to show me the, the latex that oozes out of it. And that stuck with me, even though I didn't really stick with nature for a long time, but I still have that memory. And it's a fascinating topic. And that's exactly why I reached out to have you on the show today.

[00:00:43] So I'm really looking forward to it.

[00:00:46] Carrie and Sydney: Yeah, we are too. And actually that's so funny because milkweed also played a large role in my childhood as well. I remember, like I grew up on a farm and I remember running around and finding milk and trying to see how many, caterpillars I could find. So yeah, it.

[00:00:59] was formative for me as well.

[00:01:01] I think maybe for a lot of kids. 

[00:01:02] Michael: So before we get really deep into the main topic, I'd like to establish a little bit about your lab and your interests and how we ended up here today. Carrie, can you tell me a little bit about your areas of research at the unit?

[00:01:18] Carrie and Sydney: Yeah. My lab is primarily interested in understanding how plants are so good at defending themselves. So plants, unlike animals can't move. So they need to be ready for anything that comes up. They have to be ready if they're right. An insect that wants to eat them, or if the sun is too bright or if they don't have enough water.

[00:01:38] And the way that they do that is through this amazing diversity of chemicals that they produce. So these like small molecules that they produce in their cells that allow them to just deal with the stresses of the world. And so plants are just really good chemists. And one of the things that I'm really interested in studying in my lab is understanding how plants are able to defend themselves against all of the stresses of the work. 

[00:02:08] Michael: So that is just such a huge. Topic. There are so many thousands and thousands of plant species that you could dig into. Obviously milkweed is one that you look closely at. Do you have other species or families or a taxa that you tend to investigate more deeply and why?

[00:02:26] Carrie and Sydney: So in my graduate research, I studied the relatives of broccoli and broccoli is a really interesting, like the relatives of broccoli are really interesting. Like they have that characteristic flavor. And to us, it just has that flavor that we like about, broccoli or cauliflower or whatever, but two insects that's toxic.

[00:02:43] And so my graduate work was focused on a wild relative broccoli that grows in the Western us. And it makes these diversity of chemicals that allow it to protect itself against rubbish. And also drought. So it uses the same chemicals to deal with, the biotic pressures of insect herbivores and the Adriatic pressures of, lack of water. 

[00:03:07] Michael: So are these what like in the nutrition world are called flavonoids?

[00:03:13] Carrie and Sydney: No, these are actually glucosinolates, so it's a different type of compounds. So the glucosinolates are really important in the relatives of broccoli And humans are interested in them because some of them have sort of anticancer properties.

[00:03:30] Michael: And right now your labs specifically, what different plants are you investing in?

[00:03:36] Carrie and Sydney: So currently in?

[00:03:36] the lab, we are, we're still looking at some of the relatives of broccoli. But our main focus right now is on milk. And So we are interested in how does milk. Defend itself a lot is known about it. And so we don't have to like, figure out what are those compounds. We can study the Cardinal lights and other, the flavonoids are a good example.

[00:03:58] We are also studying compounds like Fino pro Benoit's dobutamine. All of these compounds are things that plants use specifically milkweed to, to deal with the stresses.

[00:04:12] Michael: So there's dopamine is in the same dopamine. That is a chemical that our brains rely on for feeling 

[00:04:20] Carrie and Sydney: Yeah.

[00:04:21] Michael: The same, dopamine.

[00:04:22] Carrie and Sydney: Yeah. It's exactly the same molecule. It's actually a very ancient molecule. It is used by all life on earth for a variety of things. Humans use it as part of that reward pathway, and learning. But plants use it to overcome stress so plants can produce large amounts of dopamine.

[00:04:45] and it allows them to continue To grow even in stressful environments.

[00:04:50] Michael: To me that's mind blowing because it sounds very similar. You mentioned dopamine is part of the reward pathway in people, and it sounds like it fulfills a very similar function in the milkweed.

[00:05:00] Carrie and Sydney: It really does. Yeah, no, I even a lot of plant biologists are interested to find out that dope Levine is present. Yeah, it's actually really important in the two species that we study. It's a big difference. 

[00:05:11] Michael: Okay. We'll find out more about that. Then here in a few moments and Sydney, how did you get involved with Dr. Olson? Manning's lab?

[00:05:22] Carrie and Sydney: Yeah. So I was a student here, August Anna. I graduated back in 2018. And when Dr. Elsa Manning came in 2016, I think she came to one of my classes and just asked for some part-time help to help with some of her research projects. And so I helped her out on a different one related to a different species of butterfly That wasn't related to milkweed, but it made me interested in research.

[00:05:45] And so I stuck around with her lab working on different projects. And then I graduated in 2018. And about a year ago, she approached me asking if I wanted to do research technician as well.

[00:05:57] Michael: That sounds like a lot of fun. So as a research technician, how much time do you spend out in the field versus in the lab doing research and what other duties might be involved?

[00:06:08] Carrie and Sydney: It depends on the time of the year. So during the summer, obviously we do a lot more field work especially this year because we planted a large garden here in town. So there was a lot of outdoor field work this summer, but then during the winter and other times I'm doing a lot more work in the lab processing different samples or different things like last winter I was processing different tissue for genetic testing and metabolite tests. And then I also do a lot of outreach work trying to connect to people across the country, which is how I connected with you. Just asking for seed pods from all across the country and things like that. 

[00:06:42] Michael: Yeah, I hope we can talk a little bit more about I naturalist later, but that's how we connected was I had submitted an observation. And I think it was a showy milkweed. If I remember correctly from a Prairie in central, Nebraska on and you'd reached out asking if I could collect seeds from it later in the year.

[00:06:59] And unfortunately I don't live there. I was just passing through. But but yeah, it's a part of your research that we'll talk about here in a moment. Okay, Carrie how did you get interested in nature in the first place? What led you on this. Yeah.

[00:07:14] Carrie and Sydney: I grew up on a farm in Northwestern, Minnesota, and in addition to having farm land we also have. Over a hundred acres of Woodlands. And that's just where I grew up. That's where I spent, my childhood summers was up there with my siblings, just, hanging out in nature, we had forts and it was just a really fun, magical place to grow up.

[00:07:36] But yeah, I had been interested in biology for a really long time. I think the first time that I had the idea that I would want to pursue science was after my, the first day, the very first day of seventh grade life science. I , remember where it was sitting and I can like, remember the teacher, I got this very clear picture in my mind, but I don't even remember what was said, what we talked about, but I left that class and I was like, I'm going to be a bile.

[00:08:06] And so I'm not even sure what that was, that inspired me, but yeah, that first day of life science. And so then I was very science focused after that, but after my sophomore year of high school, the first draft of the human genome project was finished. And I was like, this is exciting. If we can do this for humans, we can do this. for anything that's alive, we can get their whole genome.

[00:08:26] We can understand what makes them, how they are. And that was just really exciting to me. Yeah.

[00:08:33] I've been obsessed with ecology evolution and genetics ever since. 

[00:08:36] Michael: Sounds like a great path and yeah, it'd be great to somehow go back in time and capture what that was in seventh grade that set you in this direction, because I it'd be nice to be able to replicate that for more students.

[00:08:48] Carrie and Sydney: I'm pretty sure. I was the only one who walked out like that. So I'm pretty sure that it wasn't like all of it. And now we have a generation of biologists from that one day, but you're right. You're right. How do you capture the imagination of students.

[00:09:03] and let them know that a career in science is possible for them is something that we think about a lot. 

[00:09:07] Michael: And Sydney. How about you? When did you realize that you wanted to get so deep into this?

[00:09:11] Carrie and Sydney: So I didn't have a specific memory like Perry does. But I remember growing up science was always my favorite class. Whenever anyone asked me, I was always like, I love science. I get so excited about science, especially the life sciences. And both of my parents are in the medical field. And so I always attributed my love for science to go into medicine. And so I was always determined to go to medical school and growing up. We never really learned about scientists as a profession. And so it was always in my mind that if you wanted to go into science, it was either medical school or teaching science.

[00:09:48] And since both my parents were in the medical field, that was my direction for the longest time, even until sophomore year of college. But then I decided that I didn't want to go to medical school. And luckily that lined up perfectly with when Carrie joined August Santa and came to one of my classes, asking to be a research technician. And then that's how I got interested in research and fell in love with it. 

[00:10:11] Michael: Sounds like a great alignment of fortunes to make that happen. 

[00:10:17] Carrie and Sydney: Yeah.

[00:10:17] For me too, for sure. I got really lucked out. 

[00:10:21] Michael: That's those are the best ones. let's dig in then to the main topic here, we started to talk a little bit about what the lab does as a whole. And our focus today is the milkweed research. And as I understand it, your really focusing on two species in particular. Can you tell me about that and what you're looking for?

[00:10:42] Carrie and Sydney: Yeah. Yeah. When I came to Augustana I knew I wanted to branch out my research a little bit and to identify something that grew locally, some native species that I could study and that I could get students involved with research. And so I wanted to pick something a little bit charismatic, and I was just looking through some of the native species in South Dakota came on, milkweed are just famous for the reputation of being really great chemists.

[00:11:11] He'll be as all these famous chemical compounds that. And so it was attracted to them. But then I noticed there are two species that both grow in South Dakota and across the us and they hybridize, and that is really exciting to a geneticist. So you're a geneticists and you can get two species to mate together and produce offspring.

[00:11:32] Then you can study how, what makes those species the way they are. And yeah, I was immediately attracted to the system. And then we also noticed, actually, I didn't notice this. It was my collaborator, Dr. Steven Matzner, but he noticed that exactly where these species meet is right on the divide between the humid east, like the humid Eastern north America and the arid west. And so it was like this very interesting, very provocative, exciting. System right from the bat. Cause we think that maybe these two species are differently resistant to trout and the Eastern us and the Western us look, if you look at Google earth, basically right where these two species need is right. Where it starts to get, from greener in the east to browner and dryer in the last, and that's exactly where they meet. And so immediately all of these hypotheses about how these species differ, what might be the consequences of them, forming hybrids, all of these sort of popped right out.

[00:12:40] And Yeah.

[00:12:41] It's been an exciting system to be in and it's just gotten more exciting, I think, as we've learned. 

[00:12:46] Michael: Yeah, I grew up in Nebraska and Nebraska is just south of South Dakota. And one of the things that I took for granted when I lived there was that transition from humid, moist to arid west, as you proceed westward. And now when I travel across the state, I try to take more.

[00:13:05] Note of the transition that happens. And it really opened my eyes to the biodiversity that exists because of that. And it's a, it's just a great area to look at those interactions. I think that kind of push pull of climate.

[00:13:20] Carrie and Sydney: Yeah, it's pretty cool. Because in South Dakota we have the Missouri river going down the middle of our state. And so if you just drive straight across the state from east to west, you can notice an obvious difference just in the landscape, even, which is pretty cool. Yeah, you got time Missouri, and it's just like a different world, almost different species, just it's so cool. 

[00:13:41] Michael: You have the added bonus, there's the dramatic shift to the Badlands, but then also the black Hills. So even more biodiversity in South Dakota.

[00:13:53] Carrie and Sydney: Yeah, The black Hills are like their own thing. And so that's a really cool that's a side note.

[00:13:56] Michael: Yeah, gotta be careful. It's easy to go down those 

[00:13:59] Carrie and Sydney: I know it is. Yeah, 

[00:14:01] Michael: So the showy and the common milkweed that hybridize is that unique to have hybridization in milkweeds.

[00:14:08] Carrie and Sydney: not at all. No. There's many species that hybridized and milkweed. The thing that we noticed that was unique in this system is their ranges like where these species are found is the Western us for the showy and the Eastern us or the comment. And then they come to the middle and then they. You can find some hybrids, but they basically stop a lot of times when you see hybridization in milkweeds.

[00:14:30] One of the species is completely subsumed in the range of the other.

[00:14:35] And so it is a little bit of a unique distribution of the species and how they hybridize. So yeah, there is not uncommon, but this, these have a different a different way of doing it, we think. 

[00:14:51] Michael: Thus your research. And when I think of hybrids, a lot of times the offspring of a hybrid ends up not being viable. Are these. Do they produce viable offerings?

[00:15:04] Carrie and Sydney: Oh yes. So yeah. It is very common to have, what you're talking about, where you have, buyability or growth issues and hybrids, but the flip side of that is you can have hybrid. And that's, I think that's what we're seeing in our species. It's some, it seems like the hybrids, grow bigger, they grow more stems.

[00:15:24] They are, they produce seeds, those seeds are viable. So I'm not going to say that every single hybrid is, is better than either species, but it seems like the hybrids are pretty robust and they seem to be fertile. So it is a big mystery for Y you know exactly what is going on in the system are these two in the process of becoming a single species. So really good question. Yeah. That's there's we have a lot more questions than answers in the system. 

[00:15:54] Michael: So you've planted a seed in my head with this. Like I have a range map that I'm visualizing and, and I see the two species and then an overlap zone. And is it really an overlap or is that intermediary? Just the hybrids.

[00:16:11] Carrie and Sydney: It's an overlap because in the hybrid zone we find both speechies and hybrids offense. So yeah, it's more of an overlap, not as hybrid species, specific stuff, genetic analyses that we've gotten back recently that we're just working on shows that yeah, there's lots of hybrids there, but they're also just like the parental species in that hybrid zone.

[00:16:33] So it is just a regional area. 

[00:16:35] Michael: And do you see the hybrids? Are they able to, you'll probably get into the, to reproduction more later, but milkweeds are notorious for having these little fluffy seeds that can be. very long distance. Do you find the hybrids popping up further and further away from this transition zone?

[00:16:52] Or is that one of the mysteries that that they aren't really showing up outside of this area.

[00:16:56] Carrie and Sydney: The transition zone seems to Peter off pretty quickly when you get into one of the species ranges or the other, but you do find little chunks of the genome from one species very far away from the hybrid zone. So it looks like they're able to, those hybrids are able to back across to those parental species.

[00:17:18] And perhaps this is a, this is an open question, but perhaps some of those, pieces of DNA, those genes that come from one species could be adaptive in the other species. We have found chunks of the genome from the Western species as far east, as like Pennsylvania. And we found little chunks of Eastern species in the Western species genome as far west, as Nevada.

[00:17:43] So it seems like they could be exchanging genes. Now we're not going to say that. Oh yeah. That's all beneficial, but it is provocative to see you know exactly what is being exchanged between these two species. 

[00:17:57] Michael: Provocative is a great way to, to describe 

[00:18:01] Carrie and Sydney: You didn't tell her really. I really get excited about 

[00:18:04] Michael: Yeah, no I'm serious too, because as listening to you, describe that a whole bunch of hypotheses pop into my head as to how that may have occurred and what may be happening there. Yeah. Loads of research for you all. 

[00:18:15] Carrie and Sydney: yes. 

[00:18:16] Michael: This is probably a bad question, but how are these hybrids first discovered?

[00:18:20] Are they just obviously showing traits of the two different species or did it actually take some genetic research?

[00:18:27] Carrie and Sydney: They were first discovered actually in Western Minnesota. As an aside, I feel very excited because it's 25 miles from where I grew up was when they were first discovered. But when you see the hybrids, so the hybrids were first discovered in Western Minnesota, and these two species actually, when they're not flowering, they look really similar.

[00:18:45] They are both broadleaf milkweeds. It might actually be really hard to tell the difference, but when they're flowering, their flowers are completely different. And when you see the hybrids, their flowers are intermediate between the two parental species. And so the common milkweed. these clusters of flowers and there's tons and tons of flowers and the flowers are all kind of small.

[00:19:08] And though the showy lead has these big, very showy flowers. We say ostentatious, these ostentatious, it's just very showy flowers. But there's fewer of them. And the hybrids are just in between those. 

[00:19:21] Michael: So seeing at flowering time is really the key. If you aren't going to do a genetic analysis, which I think most of us.

[00:19:27] Carrie and Sydney: Absolutely. And so they were identified first in Western Minnesota based on their floral morphology. And that was in 1945. And that was done by people who were really interested in maybe, using milkweed as an agricultural crop, maybe for the fluff to stuff, pillows, or maybe using the step for, I don't even know.

[00:19:46] I don't think they even had any ideas of what they were going to use it for, but they were just trying to see how easy it was to propagate it and to get it to reproduce. Because it is everywhere. And so they were just excited. Like maybe we can make this useful for us.

[00:20:01] but it turned out not too useful.

[00:20:03] It grows so well. Like it's, once you have an eye for it, you just notice it everywhere. It's in the ditches. It's every is in natural areas. It's just, it's a very prolific plant. 

[00:20:14] Michael: And then I guess that ties into the fact that for a long time, it so it wasn't really useful economically to your point. And and it has weed in the name. It was disparaged, for a long time, but in recent years it's had a popular resurgence.

[00:20:29] Carrie and Sydney: The weed and his name is definitely a misnomer. There are definitely weedy species and it does grow in disturbed areas, but it is a native, it belongs here in north America. It can be a nuisance to farmers. And so whenever we're out in the field, And we see some farmers, they tell us about how they like to spray it. So yeah, I think, but you're right. It has experiences like popular research. Every little kid knows about milkweed and monarchs and I think that's wonderful. 

[00:20:57] Michael: Do farmers consider it a nuisance just because it's competing for space and resources like soil nutrients and things like that, or is it a grazing nuisance for those that have lifestyle?

[00:21:07] Carrie and Sydney: It's not necessarily a grazing nuisance because cattle will avoid it. But if you bail it up and then the cattle eat that later, and if there's enough of it, then it can cause some problems. So milkweed have these compounds called Cardina lights and that card like in cardiogram or cardiovascular is, has to do with the heart.

[00:21:31] And so these compounds will. Bind to the pumps in the heart and cause cardiac arrest eventually. So cattle have died from milkweed. It isn't something you see a lot. They really have to consume quite a bit, but probably easier just to spray for it if you're a farmer. So yeah, we definitely understand like that aspect as well in the milkweed send out long shoots under ground.

[00:21:56] It can go six feet away. And so it's very hard to get rid of once it started and that can definitely cause problems in their crop fields. For sure. 

[00:22:04] Michael: So it gets a toehold and then it's hard to get rid of,

[00:22:08] Carrie and Sydney: It's hard to get rid of. Yeah, it does a lot of,

[00:22:10] under the ground propagation. 

[00:22:12] Michael: Maybe this is a good segue into the topic of the toxicity of the milkweed a little bit deeper. And I think one thing that friend of mine I mentioned at the beginning said was that Milky latex, that, for which milkweed gets its name that, that was toxic. And like you, you should.

[00:22:31] Touch that or drink that. I think it was a little overblown. Like you shouldn't drink it. 

[00:22:34] Carrie and Sydney: Don't drink it. 

[00:22:35] Michael: but I think it's a little overblown in terms of touching it. It can get on your skin, you wipe it off it's I think that's okay. You can correct me if I'm wrong. But can you tell me a little bit more about why it's so profuse, if if the plant is damaged, it just oozes out.

[00:22:49] Is that where the toxicity then comes from and does it have the same sort of behavior on insects as well as cattles and that sort of herbivorous.

[00:23:00] Carrie and Sydney: Yeah, we all have those same pumps in our heart that these car, dental lights bind to. And So it, and in our circulatory systems, even in insects, they have these same types of pumps. And so yeah, it affects all animals in the same way. Which is great for it. But yeah, that lead ticks, this is interesting.

[00:23:19] Yeah. The latex acts as an anti herbivory defense. And so just an example of one, a Monarch caterpillar. It takes a bite of belief. It, if the latex is too thick or too late taxi and kinda blobs up in its mouth and actually 25% of Caterpillar's are killed by that latex, just because it prevents them from eating anything that kills them on the spot and yeah.

[00:23:44] Like they essentially bite in and they get this like gush of latex that just gums up their mouth. And it also is full of toxic compounds. And then, yeah, like 25% of them perish after that first bite. 

[00:23:58] Michael: So these stories about this wonderful. Relationship that exists between the monarchs and the milkweed. It's a little more nuanced than maybe it's told in the storybooks.

[00:24:09] Carrie and Sydney: The monarchs need the milkweed. They have to have the milkweed is their host plant. With, unless they have access to milkweed and milkweed would be better off without the monarchs. It is, it's just, that's everything right? That's everything we see. But yeah, it's not like this beautiful symbiotic relationship.

[00:24:29] No. 

[00:24:29] Michael: In the monarchs, aren't the only one that they have this obligate relationship with the milkweed. I know there's some other insects as well. Can you tell me a little bit more about this broader ecosystem that the milkweeds.

[00:24:39] Carrie and Sydney: Milkweed are very restricted in the number of herbivores that can feed on them without dying. There are only 11 species of herbivores that can feed on milkweed that are specialists just for milk milkweed. So of these 11 species, there are, I think three species of beetles. There are several species of butterfly. And if you go look at a milkweed plant and you see something that's like brightly colored on it, that's probably a milkweed specialist.

[00:25:12] So the monarchs are orange. These aphids that live and specialize on milkweed are yellow. The milkweed bug and the milkweed beetle are both brightly, reddish, orange colors. And the reason for that is that. They eat the milkweed, but they have mutations in those pumps that allow them to tolerate those Cardinal lines.

[00:25:34] And instead of, being killed by them, they're actually able to sequester them to hold them in their tissues and their body so that if they're attacked by predators, they taste bitter and then they're toxic. And so they use those bright colors as a warning Hey, I don't taste good.

[00:25:53] You, you better.

[00:25:55] Michael: This reminds me of a few different experiences I've had in on a side note, I did interview a pair Tora Rocha and Terry Smith. They call themselves a pollinator posse and they're huge Western Monarch advocates. So they're very interested in the topic of milkweed. So I'll make sure to link to those recordings here in the show notes.

[00:26:16] I have some milkweed in my backyard and I'm out west I'm in California. So some different species. And what I see most often on my suburban milkweed are the milkweed bugs. And I think there's two different species that I typically see. And then the aphids that you mentioned, which I think we need to petition to change the common name, because they're usually referred to as oleander aphids, but I see them so much more on milkweed than on oleanders.

[00:26:43] So I, I think we need to give them the credit, give the milkweeds the credit of supporting another insect.

[00:26:50] Carrie and Sydney: Yeah, you should go petition the people. 

[00:26:53] Michael: I bet he, even people. A lot of people when they hear aphids, if they aren't entymology knowledgist or naturalists cringe, it's like, oh no, aphids there. They're going to go kill my plants. I love to see the aphids on my milkweed because within a few days, maybe a week, suddenly the lady bugs show up and the lacewing show up and the flower flies, the surfeit flies start to increase in numbers because their larva eat the aphids.

[00:27:19] So even though they have these toxic chemicals, it does seem like there's a downstream effect that there are other insects then that can still predate on these insects that are the primary consumers of milk.

[00:27:30] Carrie and Sydney: Yeah. Just like there are these 11 species of insects that specialize on milkweed and there are predators. Of those insects that have specialized on eating those. Yeah, it's, I guess what it look like I'm trying to make here nothing's ever safe in biology, right? Just because you're brightly colored and toxic doesn't mean there's not going to be someone who's going to figure out a way to. 

[00:27:51] Michael: Well, In the vast majority of species we find out in the wild have these, sorts of relationships, there are a lot of generalists out there that can get away with losing their dependencies upstream in the food web. But like every little corner that we peer into, we always find these downstream effects.

[00:28:09] That's one lesson I like to impart to people. On these sorts of topics. And the last thing that I discovered on my own personal milkweed it was a leaf mining insect that it actually was not mining the leaf. It was in the stem and I got some really good photos of this. I'll make sure I put them in the show notes as well.

[00:28:29] But it sounds like I'm tooting my own horn, but I had a previous guest, Charlie Eisman, who's the foremost leaf mining insect expert, and, fascinating story for him because he was a generalist naturalist and then found leaf miners. And now he's published a 1400 page field guide with keys to all the leaf miners of north America.

[00:28:55] But in any event, I showed him this photo and it seems like it's unclear what species it is. I like the, he knows the genus, but it may be a new species. So just in your own backyard, you can find some of these things and I'll link to that observation. And I now in the show notes too maybe there's somebody out there that has the same thing and can actually catch it early enough to rear it and determine the species.

[00:29:18] Carrie and Sydney: Wow. That's really cool. Yeah, I am. Yeah, we were unaware of that. And wouldn't that be fun if you discovered a new species.

[00:29:27] of weak miner? 

[00:29:29] Michael: There's a whole bunch of new species out there Charlie himself has discovered dozens and and in the west, especially, I think there's a lot of fertile ground for a discovery. 

[00:29:39] Carrie and Sydney: Definitely. 

[00:29:41] Michael: Okay. I want to circle back a little bit. We've been focusing on these two species, the common milkweed, the showy milkweed.

[00:29:48] I want to establish a little broader context though. How many milkweed species are there? What's their range. Can you set some bounds on what we see in milkweeds across the world?

[00:29:59] Carrie and Sydney: So there are around a hundred species of milkweed that live in north America. They're spread all across north America and there's also some species that are found in south America and Africa. But then main radiation. Most of the species are in North Korea. 

[00:30:13] Michael: So the majority are in north America. Does that give any hint as to where they originated? Do we think that if you were to trace the lineage back, as far as it could go, that's the source of milkweed 

[00:30:22] Carrie and Sydney: I pause here because it's just more complicated than that, so we can trace milkweed back, we'll just see where the closest relatives are from and their closest relatives are found in Africa. All across Africa, especially in South Africa. So it's, that's a really hard question. And for, even if we're looking at like fossilized milkweed or evidence of milkweed pollen, we're able to date that back, who's to say

[00:30:47] if that pollen that we're looking at would be something that we would call a milkweed.

[00:30:51] Yeah. But what I would say is that just because something has the most diversity somewhere doesn't necessarily mean that's where like first arose and so will probably happen is the relatives of milkweed, arrived in north America and it, there were just niches available and they were able to spread across and, undergo many speciation of it.

[00:31:14] In a relatively short time, only a couple, five to 10 million years. And so north America is where the majority of the milkweed diversity exists. 

[00:31:25] Michael: One of the things that really stood out and what you just said about the complexity of even being able to approach that question is the re you to quote the relatively short period of time of five to 10 million years. And it's a good reminder that when we talk about these things, the timescales are immense.

[00:31:42] It's sort of hard to wrap our heads around and so much could happen. So to your point, yeah. Maybe some predecessor of milkweed popped up somewhere else in the world, but there's been five to 10 million years of it evolving and splitting and whatever else is happening during that period. 

[00:31:58] And of course, fossil records are just a minor picture of that history. So the a hundred species ish that exists in north America. I know that they've been able to establish themselves and lots of interesting, biomes in many of the biomes. What sorts of areas do you find the greatest diversity and what are some of the weird outliers that, that you might be aware?

[00:32:23] Carrie and Sydney: Some of the weird outliers, there's species that grow just in desert areas, there's species that are adapted to, just right around swamps. So I think if you can think of a bio I there are species who. Really can only exist in, in the shaded canopy of a forest. And then there are species that need to be in the full Prairie, full sunlight.

[00:32:49] So yeah they have adapted themselves to all sorts of terrestrial biomes that just across north America, there are tropical milkweeds. There are milkweeds that can only grow, further north. It is. It's a very wide diversity.

[00:33:06] Michael: I was, before hopping on here today, I pulled up my own personal I Nat observations, and I was disappointed that I've only recorded five species of milkweed. So, I have 95 more to go. 

[00:33:20] Carrie and Sydney: That's exciting. I actually feel like that's an opportunity, you know, like collect them all. 

[00:33:24] Michael: Yeah, exactly.

[00:33:25] Carrie and Sydney: Yeah. They, they go, they, yeah, they do go up into Canada. They go down to Mexico. You've got, you got some travels to do with my friends. 

[00:33:32] Michael: So how, yeah you mentioned some of the interfacing that milkweed has with society and, the history of trying to cultivate it, seeing if there was a use. And then now the impacts that maybe exist in grazing and with farmers, what's the current condition of milkweed diversity in their populations in general and the United States.

[00:33:53] Carrie and Sydney: So milkweed is, although it is very prolific. There are some species that are threatened. There's specifically one species, the needs milkweed that is very threatened because of herbicides, habitat, destruction, climate change, all of these things are adding together to make it, difficult for the milkweed to survive.

[00:34:14] A lot of plans. We've replaced, natural Prairie, the natural habitats of these species with farmland and cities. And so we've lost a lot of natural milkweed habitat. Their numbers are a lot lower than they used to be. And I, and it's w when you think about milk, we mean, we don't notice that or think about it, but we've seen a very precipitous decline in the Monarch butterfly. Overwintering to overwinter in Mexico, and, the populations there have taken steep losses in the last decades, and that has coincided mostly with climate change and herbicide use. And yeah, destroying their habitats. if you go out, you can find milkweed and. , when you find them, they're doing really well, but they have fewer opportunities to thrive.

[00:35:04] There's fewer habitats for them to exist in. 

[00:35:07] Michael: Where is the Mead's milkweed typically found.

[00:35:10] Carrie and Sydney: It's in the great lakes region. I want to say Michigan, like Ohio, that region. 

[00:35:19] Michael: And when you talk about the multiple pressures that sorta combin notarial effect on the monarchs and we think about milkweeds. So there's less opportunities for the milkweed to thrive. Given the habitat loss that you refer to and this may be another really hard one to answer, but connectivity.

[00:35:38] Yeah, so monarchs migrate do they need a consistent constant stream of milkweed or can they have stopover points that are spaced? Is there any research that indicates their tolerance to like how dense that connectivity needs to be for them to be successful?

[00:35:55] Carrie and Sydney: Yes. I don't know exactly about how dense it would need to be, but there, do need to be pretty frequent weigh points for those monarchs. Each generation is only about a month and . go all the way from Mexico to Canada, right? So that's a long ways for several generations of monarchs to travel.

[00:36:17] So we'll only ones that are very good at long distance flight are the ones that are born right before the fall. They have all these different morphological. They're bigger, they have stronger wanes. Those are the best at migrating, your average, middle of summer Monarch can't really fly that far.

[00:36:35] And so Yeah.

[00:36:35] there, there needs to be, milkweed presence really through these corridors that they prefer to take. If you look at the research that people have done, and there's been so much of this over the past 50 years, , there are certain ways that the monarchs like to take these sort of these like highway, these avenues, you'll find them everywhere. So if there aren't milkweed available along those routes , they won't make it. 

[00:36:59] Michael: The other thing that popped into my head too, is we were talking about the Eastern population and monarchs is also a Western population of monarchs that has a similar but different sets of problems. And there's an interesting tie in that's heavily research. I'm not going to pretend to be an expert in this.

[00:37:17] But I've seen that. One of the concerns we have here in the west is the overwintering sites are along the California coast. And a lot of people are planting milkweed, trying to be. Citizens and the selection, the gardener selection is the tropical milkweed. And in fact, I made the same mistake. I went to a garden center and it was in the native plant section.

[00:37:42] And, I didn't know any better. And I couldn't tell, in fact at the time what it was, I could just tell it was a milkweed and then it bloomed. But anyway, long story short is the tropical milkweed bloom pretty much all year here in the temperate, mild, Mediterranean climate of California.

[00:37:57] And it's thought that can confuse the monarchs. So we such one hypothesis I've seen so that they don't properly overwinter, in the same way. And there's a lot more to that. That's just like the tip of the iceberg, but I don't know if you have any insight into the plight of the Western monarchs that you can add to that story.

[00:38:16] Carrie and Sydney: I am familiar with some of the research that's come out of that with the tropical milkweed and climate change and planting it for an aware of not native, like there can actually be issues. Yes. That's a really tricky one. You can actually find in garden stores here. It's it's a big problem everywhere. 

[00:38:35] Michael: Yeah. And just to hit a couple other tidbits, I know, and I'll, again, I'll point back to the pollinator posy episodes because they got pretty deep into it. But since it's growing and blooming all year, it becomes a vector for disease as well, which is another problem. And and these days it seems like the approach is if you have it and you want to keep it, you want to cut it back a couple of times a year at the right time.

[00:39:00] To help with the disease propagation problem. And also don't plant it within, I'll have to double check. It was something like 15 miles of the coast, so that you don't give those overwintering monarchs, some sort of temptation to start their cycle too early or at the wrong time of the year. But better still is just to plant native.

[00:39:19] And in fact, I wanted to ask you to what suggestions do you have for gardeners or landscapers when it comes to milkweed? Like we, we started to hit on the nuance of picking the right milkweed. There's probably more to it than.

[00:39:31] Carrie and Sydney: So it's definitely important to choose native milkweed to your area. And we have a good PDF that we'll send a link to you, and maybe you can link in your notes that has a list of species for the different areas all across the U S so it makes it easier to figure out which ones are native to your area. Yeah, we don't necessarily expect, I mean, they are native to north America, so technically native works. Even though it's native to Florida and I, and then Minnesota, right? So picking milkweeds that are appropriate for your area is important. 

[00:40:08] Michael: Yeah. And if it's hyper native, like hyper-local native, I guess I'm making up terms. It should be easier for you to grow to then because it's going to be adapted to your soils and your climate, and, those sorts of.

[00:40:19] Carrie and Sydney: Absolutely. We have had a debate. So I told you how I collaborate with Dr. Mattson or Dr. Steven master, and he's ecologist and a physiologist. And so our work really lines up really well together. But we have this disagreement about whether or not we should use weed cloth. So when we plant our gardens outside, should we just plant those plants directly in the soil among the natural vegetation?

[00:40:43] Or should we do something to give our milkweed an advantage? And so we've gone back and forth with this over the last few years, but I think The last straw for me was I was out there taking up some weed clock that we needed to remove. And I was in our garden in Sioux falls and I pulled them up and there was a snake and I feel like I'm a biologist.

[00:41:03] Like I can be pretty cool with snakes I don't love them, but I'm not like just like afraid of snakes, but we live in a South Dakota and we're an Eastern South Dakota. So there aren't a lot of venomous snakes. So I really shouldn't be afraid of snakes here, but I pulled it up and I just stamping around trying to get it to go away.

[00:41:25] And it kept coming towards me. And so I was over it like, I was like, no, so I ran away. And then that same week we went to Western, South Dakota and we were doing the same thing in our garden in Western South Dakota. And there was like one piece of weed clock left and I pulled it up and there was a snake under it.

[00:41:44] And I was like, I'm done. Cause we, cloth is cursed. I yeah, I really fall on the side that we shouldn't use weed cloth because it's better for the plans. It's a more realistic environment and also it doesn't Harbor space.

[00:41:59] Michael: The snakes need a home too, though.

[00:42:01] Carrie and Sydney: I get it. I know.

[00:42:04] Michael: I hear you. It's this it's also just being startled. Yeah. Way, like nobody likes surprises in that way. Anyway.

[00:42:12] Carrie and Sydney: I'm not afraid to say that I'm a little freaked out by snakes, but I don't need, I don't need it. I don't need it in my life. I don't need it. 

[00:42:18] Michael: So thank you both for being so generous with your time. I really enjoyed the conversation and I have a few questions that I like to ask at the end to get a different perspective on the world of nature and ecology and connecting people to it. So first of all, do you have any favorite resources?

[00:42:37] Like it could be books, videos, documentaries, whatever that you'd recommend for people that are interested in learning more.

[00:42:44] Carrie and Sydney: There's a really great book called monarchs and milkweed, and it was published by, it was written by, one of the preeminent milkweed, Monarch researchers. He actually studies the monarchs on Rog eyebrow. And I'm not sure if that is how you pronounce his name 

[00:43:00] Anyway, monarchs and milkweed is a fantastic book.

[00:43:03] So if you're just looking into, basically learn everything. About milkweeds and monarchs. He does a really great job on just breaking it down into language that anyone can understand, but he also includes some really excellent science and how to break down that science for anyone to understand.

[00:43:21] I've been impressed with that book. There's also a website Monarch joint venture.org, and that has that milkweed information sheet. If you're looking to figure out exactly which species , those hyper-local species that you've planted in your own yard. 

[00:43:36] Michael: Great. And I see that monarchs and milkweed book is through Princeton university press and for naturalists out there, I've found virtually everything that Princeton university press has produced. Of good quality. So it's a good default place to look. 

[00:43:51] And if you could exactly snap your fingers and in part one ecological concept to the general public, so they could help see the world as you've learned to see it, what would that be?

[00:44:01] Carrie and Sydney: I would magically let everyone know that we live in a complex ecosystem, but we are part of it and that we need to do a better job of playing our part. So I don't love snakes, but I don't want them all to disappear because I know that they play an important part.

[00:44:18] And I wish that people understood, that we are, we not only get to enjoy the beauty of nature, but we also have responsibility to take care of it. 

[00:44:28] And I feel like if there's one ecological concept that I could impart on people, it would be that we are all part of a very complex biosphere and we can appreciate the beauty of nature, but we also need to take care of it. And so if someone, ever, I wish that everyone who had just a turf lawn that they have to mow, I wish they would just take a strip of that, take out the lawn, put in some native plants and just, not only will that help monarchs, but that will help all types of native insects and rabbits.

[00:45:03] And maybe you don't want to help the rabbits, but birds, everything in your area will benefit from that. And then just spend some time. Watching and seeing what you can see. I'm always surprised, I have a little corner in the back of my yard that we put this, our native plants in and I just go out there and walk in the morning and I see five, six different species of bees, in addition to all the butterflies and the other beautiful creatures that are back there.

[00:45:31] So yeah, it would be that , to not only realize that we can enjoy nature, but that we also have a responsibility to protect.

[00:45:38] Michael: That is a hundred percent in line with what. Always talking about here on the show. And the way I think about it is, for however many decades, centuries, I guess maybe since the beginning of society, we've been working to suppress nature because it was a threat and we're no longer living in those times, it's no longer a threat.

[00:45:59] And instead we, we sit at home and we watch nature shows and think, wow, wouldn't it be nice to see these interactions? When in reality, we could bring them back to our own backyards pretty easily. And that was a big discovery that I had during the pandemic. Just, developing a practice of looking at my native plants and seeing what was going on.

[00:46:17] And it's just been so eyeopening. So yeah, a hundred percent on board with that oh, by the way, I wanted to add one more thing. So when we're thinking about, adding some native plants to an existing lawn, I always like to tell people. That it's an empowering move because not only are you bringing back nature, but if you pick those hyper-local plants, you can be lazy with them.

[00:46:43] And in fact, being lazy is another principle that I think is part of having a good backyard habitat. If you leave, if you leaves on the ground, if you leave some dead twigs for those carpenter bees to overwinter in all these different things and don't worry about it until spring time later spring and clean up at that point, then you're also helping to improve that habitat.

[00:47:06] So be lazy is what I would also add on to to that.

[00:47:11] Carrie and Sydney: I'm on board. I love this. It's so true. We had a pretty dry summer here and a huge part of my lawn died, but I didn't touch it. So I didn't water my lawn. I didn't water that little Prairie and the Prairie flourished. It was just beautiful and the lawn died. And so it was like if I was trying to be lazier, I would have a Prairie. 

[00:47:29] Michael: Yeah. And in your outreach efforts, what have you found to be more, most effective in engaging with people? He's I'm sure you encounter people, whether you're in the field or in the classroom, or just friends and family that are like all over the ladder of knowledge when it comes to ecology.

[00:47:45] So there's probably different techniques, but regardless of where people are at, what have you found to be helpful?

[00:47:49] Carrie and Sydney: One very helpful thing was I naturalist a website that kind of connects citizen scientists all over the globe even. I've been using it to connect to people all over the us in order to collect seed pods. We went to grow these gardens with a wide variety of seeds, just to try and better understand these species.

[00:48:07] And instead of taking this big long road trip all across the U S it's so much simpler to get in contact with these people and have them mail as a seedpod and then we can associates in our own garden. And that's how we got connected with you because I saw the maiden iNaturalist post. And so I just connected with you that way.

[00:48:24] Last year, my efforts and I naturalists we're focused on we're focused on getting a wide range of seed. And so I got seeds from Washington Montana. We've gotten seeds from New York and then this year I was focused on collecting seeds from the hybrid zone. Ranging from North Dakota down, even down to Texas, just to get a wide range just in that hybrid zone it's we can have a big collection of potentially hybrid species seats to use in our studies without trying another thing that has helped us in our outreach efforts is buying these t-shirts that we have for our lab.

[00:48:58] We just all want to be silly matching. We got milkweed t-shirts that have a milkweed plant and a butterfly on them. And one silly story is that our collaborator, Dr. Steven master was wearing his, we got milkweed t-shirt in an airport when he was traveling to Hawaii and he got stopped by multiple people saying that they were planting milkweed and we're seeing on our clarifies and just got super excited about it.

[00:49:21] And so that's helped us in our outreach efforts do and just connecting with the outside. Other citizens. Milkweed is just so people love it. Monarchs, I think the monarchs do a lot of our outreach for us, honestly. Easy because they're so pretty and people see in all of it and they're danger and people want to help. 

[00:49:40] Michael: Yeah, we need more of those charismatic species to help with the outreach efforts.

[00:49:48] Carrie and Sydney: All right. They're a wonderful ambassador. Monarchs are just wonderful at being ambassadors for the natural world. 

[00:49:53] Michael: And do you have any upcoming projects that you'd like to highlight?

[00:49:58] Carrie and Sydney: We're collaborating with K-12 schools to use milkweed and monarchs as a way of teaching, the reading and math and science standards that students have to get anyway, but doing it in a way with the milkweeds and the monarchs to, reach students so that they can connect to. Nature and something that they might see maybe on their walk home, or when they're out with their family.

[00:50:21] Really it's, it's a fun system. Kids love it. And our dream, like our overall dream would be to have these gardens with our two species across the U S that students could start studying maybe when they're in third and fourth grade. And then, maybe just then they're learning about how pollination works or, how different plants are better suited to different environments.

[00:50:44] But then by the time that they're a chemistry students, they could look at maybe quantifying how much dopamine that plant is making or how does it respond to different stressors. And using these milkweed gardens as a tool to connect students to nature, and also to reinforce the concepts that they have to learn. Yeah, 

[00:51:02] Michael: Yeah, it sounds great. And it wouldn't be too hard, to have a little plot. And I think that also fits in, with a bigger picture of connecting students with nature I know there's a lot of teachers and different people influencing curriculum looking to do that.

[00:51:16] So yeah that's amazing.

[00:51:16] Carrie and Sydney: If you have any listeners who are interested in planting a milkweed garden, we can send you seeds. We can send you advice. We can, zoom with your classroom. We'd love to find ways to connect to people. You can contact us through, I'm sure it'll be in the show notes. And we also have a lot of information on milkweed, flower.org. 

[00:51:36] Michael: And would that be limited to people just in the native range for showy and common milkweed?

[00:51:41] Carrie and Sydney: That's most of the units. I guess if you're in like Southern Texas, then maybe we'd have to find some different species for you to plant. It would be great to work with people to try to figure that out. Which species work best for their garden. 

[00:51:55] Michael: So yeah, if so, I guess the bottom line there is, if you're interested, don't assume anything, just reach out and you'll help them figure it. 

[00:52:03] Carrie and Sydney: Absolutely. 

[00:52:04] Michael: And you mentioned milkweed flour.org. Where else can people find you and keep up with your work?

[00:52:09] Carrie and Sydney: We also have an Instagram page at me got milkweed. So that's an easy way to contact us as well. 

[00:52:16] Michael: Yep. And I will certainly link to that. Additionally, what about on naturalists? Should people be following you there?

[00:52:23] Carrie and Sydney: Yes, we do have a project going on. I natural so you can join and then you can make observations underneath that project and it helps us with data collection. And if you have any questions, you can message us through there?

[00:52:35] Michael: What's the name of the project?

[00:52:37] Carrie and Sydney: Yeah, iNaturalist project is called the lead flower photo project. 

[00:52:41] Michael: Is that open to any species of milk?

[00:52:43] Carrie and Sydney: In that project, we are specifically focused on the showy and the common and they're hybrids, , anyone who contributes any observations to iNaturalist is probably going to end up helping the scientists down the road. Even if it's not something that we're interested in this moment we are generally interested in milkweed or implants in general.

[00:53:03] So it's really just a worthy thing to do with your time. If it's something that you enjoy. But if a K-12 teacher was interested in maybe putting their toes in the water connecting through the naturalist and having the students go out and just take pictures with their phone and upload them to a naturalist is something that we've had.

[00:53:18] Some people do. And I can just be like an easy, maybe it's not like a full-blown garden, but it's an easy way to get the students connected. And generally in most places in the U S you could take a short walking field trip and find an abandoned lots. And chances are, you might find some locally there. 

[00:53:34] Michael: There's definitely a subset. Maybe it's bigger than a subset of the population that I think is like me. And we'll find I naturalists to be a little bit addictive too. Just be aware of that. It's fun. It's fun though. Addictive in a good way. 

[00:53:47] Okay. Then I think with that, we've covered a lot of ground.

[00:53:52] There was a whole lot more we could have gotten into, we didn't really even talk about reproduction in milkweed. Maybe we can do a part two sometime.

[00:54:00] Carrie and Sydney: yeah, that would be very fun. 

[00:54:03] Michael: All right. Well, Thank you again so much for spending all this time today. I definitely had a great time and I hope you did as well. 

[00:54:10] Carrie and Sydney: Thank you for having us. This was really fun.