Ep 122: Ahead of the (thermal) curve (with Ray Huey)
How do biologists study the influence of heat on organisms and how can this be applied to the study of climate change? What impacts mountaineer survival at high altitudes?
On this episode of Big Biology, we talk with Professor Emeritus at University of Washington and recently elected member of the National Academy of Sciences, Ray Huey. Ray is well known for his work on the thermal physiology of lizards, but has also worked broadly in physiology, ecology, and evolution. In our conversation with Ray, we first discuss his paper, an “Acynical Guide to Graduate School,” and its ongoing relevance to graduate students. We then talk about his career path into thermal biology, how he became interested in the science of mountaineering, and his philosophy for writing science.
Cover photo: Keating Shahmehri.
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Marty Martin 0:05
Because we humans are so interconnected, we move lots of packets of well, stuff, around- locally, nationally and internationally.
Art Woods 0:14
And alas, some of those packets contain living organisms. And naturally, some of those organisms become established at their destinations, all of which has led in the past century to an explosion of invasive populations throughout the world with profound effects on pre-existing local biology.
Marty Martin 0:31
Some obvious effects are ecological, such as wholesale shifts in plant, insect, and vertebrate communities. Some examples are knapweed and cheatgrass in the American West and American waterweed in Europe, these shifts can resonate throughout food webs in which they're embedded.
Art Woods 0:45
The invasions can also cause evolution of both invaders and the native species with which they interact. Evolutionary effects have gotten a lot of attention over the years from biologists as invasions represent sometimes powerful experiments.
Marty Martin 0:58
The evolution of soapberry bugs in Florida is one example described in a now famous set of studies by biologist Scott Carroll, native soapberry bugs used to feed primarily on a native plant called the balloon vine. Balloon vines have relatively large fruits, and the soapberry bugs that fed on them had correspondingly long and unwieldy beaks
Art Woods 1:16
In the 1950s, however, an ornamental plant called the golden rain tree, which is from the same family as balloon vine, invaded South Florida and became common. Over the next few decades, soapberry bugs became established on them.
Marty Martin 1:29
Golden rain trees also produced smaller fruits than balloon vines, which led populations of bugs on them to evolve much shorter beaks, among many other changes.
Art Woods 1:37
An interesting twist on invasive species is that they also sometimes disappear, especially when we try hard to eradicate them. For example, more than a thousand islands worldwide have been cleared of invasive species, and New Zealand is implementing ambitious plans to rid the country of invasive predators by the year 2050.
Marty Martin 1:56
The eradication of invasive species also provides an opportunity to observe ecological processes reorganizing themselves and observe evolution of natives in response to the sudden absence of those invasives. In other words, eradication is a kind of manipulation that can be leveraged as a semi-natural experiment.
Art Woods 2:14
In today's show, we talk with Alison Derry and Andrew Hendry about ecological and evolutionary effects on sticklebacks of removing invasive northern pike from lakes in Alaska. Allison is a professor of biology at the University of Quebec in Montreal, and Andrew is a professor of biology at McGill University, also in Montreal.
Marty Martin 2:33
This is the second episode in a series we're doing on the team's work. We talked with Andrew last year with his colleague Katie Peichel in episode 106. In that episode, we covered a lot of the basics of the evolutionary experiment that they and their large team have started, including basic stickleback biology, the morphological and physiological traits that they're studying, and the detailed genomic information they're collecting.
Art Woods 2:53
In today's episode, we present a conversation recorded live in late June 2024 in front of an audience at the Kenai River Campus of the Kenai Peninsula College located in Soldotna, Alaska, which is just a few kilometers from the stickleback restoration lakes. Indeed, I got to see sticklebacks with my own eyes!
Marty Martin 3:27
During the conversation, we talked about the potential for rapid evolution of reintroduced fish, the massive effects the fish are already having on local zooplankton, whether those effects depend on whether the source population was benthic or limnetic, and about the evolution of the zooplankton themselves.
Art Woods 3:27
Before we start, we'd like to send a big shout out to Hunterr Morrison from the Soldotna public radio station KDLL, who provided the audio recording we used.
Marty Martin 3:34
I'm Marty Martin
Art Woods 3:35
And I'm Art Woods
Marty Martin 3:36
And this is Big Biology. And one small thing before we start, we're sorry. You're going to hear that the conversation with Allison and Andrew abruptly stops after about 45 minutes. It's a long story as to why this happened, and again, please accept our apologies for the mistake. Lesson learned that two Luddite professors should not be responsible for recording. Now onto the show.
Art Woods 4:07
Hey everyone, thanks so much for coming. We are super thrilled to be here at Kenai Peninsula College, talking with Andrew Hendry and Alison Derry about their stickleback project. We are the Big Biology podcast. Marty and I are the co-hosts. My name is Art Woods. I'm at the University of Montana. This is Marty Martin at University of South Florida. We've been making this podcast for about seven years. We're up to 115, maybe almost 120 episodes now. And the podcast focuses on just a really broad variety of topics in biology, but we're especially interested in things like ecology and evolution and organismal biology, and this project is like really great to talk with these guys about, because it combines all of those things in a really interesting way.
Marty Martin 4:52
Yep, and if you're a podcast fan, or any of you podcast listeners? If you are a podcast fan, you can find us on. Apple podcast and Spotify and all the obvious places to find podcasts. But one thing that we should mention is that we are a 5013c, non profit. So we do this largely based on grants from the National Science Foundation, some donations and things like that. But we do have Patreons, and we do have donation mechanisms, so that's always welcome, and that's also very easy to find on our website. We offer a little bit of swag if you're interested in grabbing a sticker on the back table there, but you'll see on my computer that there are some really charismatic things that you can buy. There's an artist that works with us who is a sophomore in college right now, and for every episode, he makes a custom image, which Andrew talked with us a couple about a year ago, and there's a really nice stickle stickleback image for that on the website, you can find a link to that buy T shirts and tote bags and more stickers and anything that you could possibly want, including another one in the future with a new stickleback on it.
Art Woods 5:55
So our two guests today are, as I already mentioned, Andrew Henry, who is a professor of biology at McGill University in Montreal, and Allison Derry, who's an associate professor of biology at the University of Quebec in Montreal. So do you guys ever see each other in Montreal?
Alison Derry 6:11
Y
Art Woods 6:12
You do okay, yes,
Alison Derry 6:13
We do yeah they're close by.
Andrew Hendry 6:15
There's a cafe that's halfway between the two places that we meet for coffee.
Alison Derry 6:19
Yeah,
Art Woods 6:19
Perfect
Andrew Hendry 6:19
For discussions.
Art Woods 6:20
Yeah, fantastic. Well, thanks so much for joining us today on the show, and it's great to be here like in person. We talked to Andrew last year on an episode with another person on their team named Katie Peichel, on episode 106. But it's just great to be here in person, and it's really nice to have the conversational flow of actually being able to see each other face to face, and to see your lakes
Andrew Hendry 6:43
Better yet, you got to see the lakes
Marty Martin 6:45
And we got to see the fish in the lakes
Andrew Hendry 6:46
We took them out to Hope Lake today.
Art Woods 6:49
So we're planning a kind of hybrid conversation, as it were, that will cover a bunch of fascinating biology about sticklebacks and talk about this sort of grand set of experiments that you guys have initiated in some local lakes here around Soldotna, and we want to just jump right into it. Maybe one of you explain to us in the crowd, what are sticklebacks, and what's the motivation overall, for this project.
Andrew Hendry 7:17
Stickleback are a small freshwater fish, you know, you can spread your two fingers, and that's about the biggest one you could possibly get if you spread your fingers as far as you possibly could. And they're really common in freshwater lakes near the ocean. So they're present around the entire northern hemisphere, and most of them live within those lakes or streams where they eat a variety of things, and are eaten by a variety of things, but they're also found in the ocean, so they're very abundant in the ocean, and there are anadromous ones, just like salmon.
Art Woods 7:49
And so the ones that are in the lakes around here, how recently would they have been of marine origin? How did they get from the oceans into the lakes?
Andrew Hendry 8:01
The lakes around here were probably colonized several thousand years ago by stickleback, after the last glaciation, when the land is rebounding and water levels are changing, that's probably how they got into a bunch of the lakes around here. But they can also swim up low gradient streams. So if they don't have to swim up a waterfall, they'll make their way inland. And sometimes they pop up in places, just sort of gradually move their way up a watershed, colonizing on the way and becoming established in a series of lakes and streams as they move away from the ocean.
Art Woods 8:36
But they can't go through bogs, as I learned today.
Andrew Hendry 8:39
Well, if they could make it through a bog, unless the bog is if the bog has, like, flowing water somewhere in it, then they'll make it through. But in the lakes that we're studying around here, there's a big bog that basically has no moving water through it, and they are not making it through that.
Marty Martin 8:55
Okay, great. So your team has been studying stickleback for a while, but you're not the only folks in the world to study stickleback. In fact, it's an incredibly well studied organism. Can you maybe we're going to spend a lot of time on the stickleback nearby, but maybe let's start broad. Why are people studying stickleback? Why have they studied them previously? What have we learned?
Andrew Hendry 9:18
So I could do the evolutionary part, and then Alison can maybe tell us a little bit about their ecological role in lakes.
Alison Derry 9:24
Okay, certainly, yeah.
Andrew Hendry 9:26
Basically, what stickleback are really good at is evolving.
Marty Martin 9:30
Ok
Art Woods 9:30
It's their superpower.
Andrew Hendry 9:31
They might be the most evolvable organism out there, at least a vertebrate organism. So if they colonize a new environment, they really rapidly change to suit that new environment, and the things that are changing on them are really obvious. So their big armor plates on the sides, spines that they have to defend themselves against other predators, what they feed on, the size of their heads, the shape of their body. And so they're present in tens of, maybe hundreds of thousands of different places throughout the northern hemisphere, and in each of those places, they seem to really rapidly evolve to suit that site. So because of that really interesting evolutionary position, people started developing other tools to study them genetically. And so there's really good genomic tools for studying how they evolve. And they also play an important role within lakes, and that's what Alison can tell us about.
Alison Derry 10:32
Yeah, so from an ecological perspective, they are important prey for the piscivores and fish. So they're this important, really important resource base, and they're also really important at regulating the trophic levels below them. So they feed on zooplankton. They feed on insect larva, the scuds, amphipods that live on the shore and in certain ecosystems, they've been shown to cause what we call trophic cascades, where you have, it's not just a consumptive effect of eating on one level below, but then having this cascading, indirect effect on the level below it. So for example, if they clear out, you know, the grazers, the daphnia, that are there, then it can potentially promote, for example, an algae bloom. So they're really important from kind of this kind of having this intermediate lynchpin, you know, this really important kind of keystone position in the middle of the food web for both fish and birds, but then regulating the levels below them as well.
Art Woods 11:38
Awesome. So I think that's a kind of a perfect outline of where we're going to go in the podcast. So we'd like to spend the first chunk of time, maybe 20 minutes or so, on some of the evolutionary aspects of the project, and then the remainder of the time on the ecological and trophic aspects. So yeah, good outline. Yeah, Andrew, you had someone else.
Andrew Hendry 11:54
I think I'd like to add, like, amplify something that Alison was saying, and that is that stickleback are sort of in the middle of the food web. So they form this really important link between all the small stuff you can't see that's in the water column or on the bottom, and all the big stuff that people tend to care about, birds, salmon, trout, char, all that kind of stuff. So they basically form that thing, that everything that people care about feeds on, and they get the resources from everything you can't even see below that.
Art Woods 12:27
They're the nexus
Andrew Hendry 12:28
Yeah they're that.
Marty Martin 12:29
Yeah, no. So I want to try to connect these two dots. And Alison, your license plate on your car, I think, says evoeco. So you're the perfect person to ask this question. You said that they're the super evolvers, right? And then that's really cool, like I want to talk a little bit more about that. But can you put that in the context of this? Do you think it has any relationship to this position in a web? What is their biomass? I mean, is it because there's just so many of these fish, and just by their numbers, they're feeding everything and eating everything, or is it something about their specialness as evolvers that allows them to serve this ecological role. Great. Okay, that's a great proposal, for the future.
Andrew Hendry 13:06
Yeah, that's a tough question. So early in an interview.
Marty Martin 13:12
We just start with bang, why wouldn't we, right?
Andrew Hendry 13:15
So I think that stickleback are very abundant in many ways. So they're important, not because, like, if you think about a keystone species, like a sea otter or something like that, they're important way out of proportion to their abundance. So they're not abundant, but they have huge effects. Stickleback have big effects because they are very abundant. So I couldn't really say what the biomass is within lakes, but the densities are extremely high. So in a ten hectare lake that we work on near here, called Hope Lake. I'm gonna bet there's more than 100,000 stickleback in there, adult stickleback, each one maybe like five, well maximum, let's say three to six inches long.
Art Woods 13:55
I can vouch.
Andrew Hendry 13:56
So three to three to four inches long.
Art Woods 13:58
This afternoon, we walked down to one of the lakes, and within a half a second, we saw a stickleback
Marty Martin 14:04
More than one
Andrew Hendry 14:05
We saw like a hundred. So then to the second. So they have ecological advice, because they're really important and they are really evolvable. I'm not sure if there's a link between those two things. They may be very abundant, because they're very evolvable,
Marty Martin 14:21
Yeah,
Andrew Hendry 14:21
And they may be in every habitat because they're very evolved. And then, because they're in every habitat and because they're very abundant, they form this really important ecological right function.
Marty Martin 14:32
Right, okay, that makes sense. So one more thing on this evolvable, because I find it fascinating. When you say evolvable, when they go to all of these places, do they always become something different? Or is there some sort of, is it something about the stickle type? Stickle type, I was going to say, stickleback phenotype, "a stickle type." Is there something about the sort of the organism that just is conducive? Is its body plan and its physiology and its behavior? It allows it to sort of fill these different spaces, trying to sort of add some weight to the evolvable, what specifically do you mean?
Andrew Hendry 15:09
It's hard to know why they're so good at evolving, but probably a large part of it has to do with the fact that they do colonize all those different environments, and then they also interact with these massive marine populations. So there's all of this genetic exchange between these different habitats and this massive marine population that can kind of move those genes around. So I think they're just extremely genetically variable, and it feeds on itself because they colonize those different environments, they adapt to them quickly, then they back migrate into the big marine population, mixing those genes around. So it's like a feedback process, where they're evolvable because they're genetically variable, and they're genetically variable because they're highly evolvable. That would be my speculation. I don't actually know if anyone has yet unraveled why they're so evolvable.
Art Woods 16:08
Well, maybe now, what do you tell us about? A little more about the specifics of the experiment that you've got going in these nine lakes right around Soldotna. So a few years ago, you had an opportunity to start collaborating with Alaska Department of Fish and Game to do a pretty grand experiment where you put sticklebacks of known origin in these lakes, and now you're planning to watch what happens as they evolve and to the ecology of the lakes. So how did that experiment come about? And how did you guys get it off the ground?
Andrew Hendry 16:37
So I'll start, and then Alison can follow up. And I think it's particularly appropriate that you're currently interviewing Alison, and I because it really started with us, and then everybody has sort of piggybacked on top of that.
Marty Martin 16:48
Awesome
Andrew Hendry 16:48
Now the other key player here is Mike Bell, who was a biologist studying stickleback here in the Cook Inlet area for many, many years. And he knew Rob Massengill at Alaska, Department of Fish and Game quite well. And Rob did a lot of work working on invasive species that are having negative impacts on a bunch of the native fishes here, particularly northern pike. And, well, particularly northern pike. And so in order for you to remove that invasive species, make sure it doesn't spread further. You have to basically poison the lakes with rotenone, and then that means that there's no fish in the lake, and they need to be restored. And stickleback, as Alison just explained, are this key part of the food web, so they need stickleback in there. And so Mike Bell, the stickleback biologist, had heard from Rob Massengill that they were going to be nine new lakes or ten new lakes around here that were going to need stickleback introductions. And I was and Mike Bell was telling us this at a meeting in Victoria in 2017 and then we said, "Well, wait a minute. Why don't?"
Andrew Hendry 17:59
Can we do these stickleback introductions? You think ADF and G would let us do that? And so then that sort of hatched that idea. And the part that Allison can speak to is the fact that we wanted to do a particular experiment with different foraging types of stickleback.
Art Woods 18:16
Yeah. So maybe tell us about forging types and sort of what you put in the lakes.
Alison Derry 18:19
Sure, so as Andrew mentioned, the stickleback are this incredible evolutionary model and have undergone adaptive radiations in different parts of the world. And as a part of that radiation, some ecotypes have evolved and become specialized to feeding in the open water and feeding on the zooplankton. So these are the little crustaceans that live in the water. Sorry for my voice, it's so dusty.
Art Woods 18:48
There's water too
Alison Derry 18:49
It's okay, it's like working in these dusty, dusty conditions at the lakes. Anyway., so they've evolved special adaptations. They're longer, they have more gill rakers, and they become very efficient at capturing the zooplankton, these tiny grazers in the middle of the lake, and then there's other and these adaptations tend to occur in deep lakes, deep lakes where we've have this deep open water habitat. Whereas in shallow lakes where there's less of this open water habitat, and you have much more habitat that's shallow, and where you have these emergent and submerged plants, this is where they've specialized feeding on what we call macroinvertebrates, which are the insect larva, the amphipods, the scuds that are there. And so they're stouter, they don't have the gill rakers required for filtering the zooplankton. And so they have these different feeding adaptations, these different specializations. And so we were really interested in capitalizing on this really unique opportunity to work at the whole lake ecosystem scale and do manipulations in which some lakes received these plankton-specialized fish. Versus other lakes received these kind of benthic feeding, macroinvertebrate feeding fish, because we were really interested in understanding, when you restore lakes, does it matter, not only what species you put in in terms of fish, in terms of restoring a food web, but even within a species, if you choose different population sources that perhaps have different local adaptations or specializations, perhaps during the restoration process, it'll pull the lake out in a different ecological trajectory. So this was just a really amazing opportunity to explore that restoration angle, but then also work experimentally at this whole lake ecosystem scale, which is incredibly rare to be able to do. There's like, a handful of systems in the world where we're able to do that at a replicated level, where we have multiple lakes, where we can look at these different trajectories. So, yeah, that's the idea.
Marty Martin 20:53
Yeah well so maybe say a little bit more about that. I guess you call it experimental evolution, right? I mean
Alison Derry 21:00
In nature, yes.
Marty Martin 21:01
Yeah, yeah, right in nature.
Alison Derry 21:01
Yeah
Marty Martin 21:01
So there are, there are, maybe just quickly, in a nutshell, these other systems that have been done,
Alison Derry 21:07
Yeah,
Marty Martin 21:07
Largely not in nature, the power or the insight that they've offered and a novelty that your work, yeah, system's going to provide.
Alison Derry 21:14
Yeah so there have been other experiments done. They tend to be done in enclosures. So they're either on land tanks, some people can do in situ mesocosms, which are sacks that you suspend in lakes. In some cases, people have worked in dugout ponds, but they're kind of more like semi-natural settings. They're not like a real lake with all the full complexity of loons landing and the eagles and all the different trophic levels there together, that, of course, make the responses more messy, but it's more real. And so, yeah, so there are some experiments that have been done, I mean, to support some of the things that we predict, but they're based on these more semi natural-experimental setups and not real lakes.
Andrew Hendry 22:03
I think one,
Alison Derry 22:05
Yeah
Andrew Hendry 22:05
I think one, one way to like, sort of, for me, I think about is, like, a lot of these experiments are done in cattle tanks, right? And so there's folks here tonight who live on these lakes, and I, I bet that they would say that a cattle tank is not going to replicate their lake. I mean, but that's literally what people are trying to do. They're trying to make inferences about what is going to happen at lakes, streams and stuff by t doing experiments in cattle tanks. And there's a lot, okay, the last podcast we did, apparently some people got annoyed because I was like downgrading, like all of these artificial like tank experiments. And I want to make clear, for the haters out there, that you can learn a hell of a lot from those things, but you still need to take it to the next step, which is to go out in nature and see if what you saw in your cattle tanks or your stream channels or your duck ponds, does it apply in the real world? And that's where we come in.
Marty Martin 23:02
Right
Alison Derry 23:02
Yeah
Alison Derry 23:02
Yeah? So you can also go the other way and say, oh my goodness, we observed this in nature. So now we're going to reduce it and do a smaller experiment to understand, more specifically, the mechanism of what's going on in nature. So it's kind of a it's a reciprocal feedback.
Marty Martin 23:19
So, so maybe, I think we can't trivialize the, sorry to use the word, but crazy amount of work that went to the starting this project. So presumably that's some reason that a lot of people don't do experiments like this in nature, because you have to be ambitious, maybe audacious. So can you say a little bit? You just cut a nice paper that sort of stepped through the decisions that you made about why we did it this way, why we had the benthic and the not and all the genetic diversity, which we've sort of danced around but not talked about, but maybe just run us through the process of starting the experiment and some of the biggest hurdles, and your favorite stories of how it happened? Yeah.
Andrew Hendry 23:59
Yeah I mean, it was, it was really urgent, to be honest, because, okay, so the first thing is, is that opportunities like this just almost never exist, because you can't just move organisms around willy nilly, then they are themselves, invasive species, right? So it's only a really rare set of situations where you could do whole lake experiments like this. And we heard that there were going to be these ten empty lakes, and so our first step was to be like, well, will Alaska Department Fish and Game like, buy into us doing this, right? So the first thing was the nervous phone call. You know, I went in emails to ADF and G to see if they were into it. And sure enough, they said, "Well, yeah, if you guys want to do the work and are serious about it." And then that meant that within one year, we had to figure everything out. So we rushed up here that next spring, Alison was here, I was here, and we had a bunch of students. This is before like, there's no grant, research grant for this. There's no students in place to do this work. Like we hadn't hired any students on this project, so it's the PIs.
Alison Derry 25:04
We were the students.
Andrew Hendry 25:04
Yeah, we were the students, basically. And then we had some undergrad assistants and stuff. And so we just drove around the Cook Inlet area sampling stickleback to try and figure out which populations would represent these benthic and limnetic types. Now, we did have some additional work to go on there. There was a former UAA Professor, University of Alaska Anchorage professor, Frank von Hippel, who had done a lot of background work with Mike Bell that had identified some benthic and limnetic populations within the Cook Inlet region. So we went and sampled those so that we would be able to confirm that they were really these two different types. And then in that same first year, we were short on limnetic populations. We just couldn't find ones. And so we called up ADF and G Rob Massengill and said, you know, you tend to find these limnetic type stickleback in bigger, deeper, clearer lakes. Do you happen to know any? And Rob said, well, spirit, you could try Spirit Lake and Wick lake. And they were perfect. They were beautiful limnetic fish. I mean, Rob probably hadn't seen the actual fish in the lake, but you can make predictions about the stickleback will evolve in those lakes based on the shape of the lake. So then, long story
Andrew Hendry 26:23
So then we had all these fish, and then we basically had to confirm which populations were the most benthic and which were the most limnetic, because we wanted four of each. And so that just required a student of mine grant, Haynes, measuring everything for four months, just intensive measuring, because then we had to do all the statistics, all within one year, because we had to introduce the fish then and have everything arranged the following year. And then in that year, we introduced 10,000 individual sticklebacks, each one captured from eight different lakes, all brought back to our lab. Each one have a thin clip taken for DNA. Each one have a photograph and then mixed into different combinations and then put out into all of the different lakes, all within six weeks. And again, it was all professors and undergrads who were doing the work, because we had no grant and we hadn't. Everybody was like grabbing little extra money from their little various pots, and funding it themselves. So it was super fun, actually.
Speaker 1 26:29
Awesome. We talked about this last year. But one of the other things that I think we shouldn't delve into here, since we already covered in the last episode, was the fact that you're gonna that you're in the process of sequencing the genomes of all 10,000 of these fish. So you're gonna know at a very, sort of fine granular detail, the starting genomic, genetic material that's going into these lakes, which I think is super cool.
Andrew Hendry 27:50
Yeah, so it's crazy. I just was realizing that, like I was listening to something recently about the, you know, the human genome, when they sequenced the first human genome, right?And it was this massive deal. It took, you know, 10 years, and it was a poor, like, poorly constructed genome. We're going to have all 10,000 fish, every single one. We will have the complete genome at high coverage.
Art Woods 28:12
Yeah.
Andrew Hendry 28:13
So yes, it's a awesome. It's a whole new world. It is big biology, let's be honest.
Art Woods 28:18
So in terms of the traits that you're following and the kinds of evolution that you expect to see. Maybe just give us a brief three minute nutshell of what are the most important traits you think are evolving, and which direction are they going?
Andrew Hendry 28:31
I'll say some things that don't relate to feeding, and then you can talk a little bit about some of the feeding traits.
Alison Derry 28:37
Okay, okay.
Andrew Hendry 28:38
So one of the things that stickleback really evolve quickly in is their defensive traits and their armor. So basically, they have plates along the side of the fish that the number of them and the size of them is a defense against birds like loons and grebes and things like that, and also predatory fish like trout or char or lake trout, or things like that. And so we expect those things to evolve quite dramatically because and this, this insight came from talking to Bill, who lives on one of the lakes, and who we have an Airbnb from every single year. He was telling me about the loons are only on some of the lakes and not the other ones. So loons like big lakes, right? And Bill surveyed birds like this for many years, so he knows a lot about this stuff. And on Hope Lake, there's a lot of loons, or there are loons a lot, and they will drive the evolution of increased armor on the stickleback, so that should change really quickly- the spines, the plates, should be less likely to be lost. But then in the lake right beside it, just across the road, it's too small for loons, so there we would not expect the same evolution. So there's going to be this, this really mosaic of different predation pressures in the different lakes.
Art Woods 30:00
Just depending on the size of a lake and the sort of suite of predators that's in those lakes.
Andrew Hendry 30:04
That's right, yeah,
Art Woods 30:05
Awesome.
Andrew Hendry 30:06
So that's one example. Those are the predator related trades, and those should evolve in like, a very specific mosaic with just like the little road between two lakes. So this, I don't know, maybe, maybe 50, meters, 50 yards between the two lakes, maximum, and you're going to have completely different trait evolution when it comes to defensive armor. But the other thing we expect to evolve will be the feeding traits. And so Alison could speak to that.
Alison Derry 30:34
Yeah. And similarly, I mean, there's bigger lakes, smaller lakes, deeper lakes, more shallow lakes. And so not only does that change the suite of predators that are there, but it also changes what dietary resources are there. And so in lakes where there's more availability of zooplankton that they can access, for example, we expect, for example, if the limnetic fish have been placed in that situation, they might retain their limnetic traits, and perhaps they're not evolving so much to their prey. However, if they're placed in a shallow lake and they've suddenly lost what they're specialized to feed on, we actually might see perhaps quite quickly evolution or, you know, a reversion back to this stouter fish that is now able to more efficiently access the benthic resources in the lake.
Art Woods 31:24
And I want to ask a follow up about that.
Alison Derry 31:26
Yeah
Art Woods 31:27
So you're talking about transitions between benthic and limnetic types. Is there a difference in how easy it is to go in one direction? So is it sounded like you said limnetic was derived compared to an ancestral, more benthic type, is that right? No?
Andrew Hendry 31:44
I wouldn't say that exactly, but, but I think there's a nice feed in here. So Alison has done environmental work on all of the source lakes I was we used, we collected the fish for the introductions and all the restoration lakes. And so the restoration lakes are relative to the other lakes are all more benthic, right?
Alison Derry 32:02
Yeah, yeah.
Andrew Hendry 32:03
So we kind of expect everything to evolve to be benthic, but the limnetic ones are going to should evolve the most rapidly to be benthic, because all of the lakes are more benthic than the really limnetic.
Art Woods 32:17
So the selection pressures in theory may be much higher on limnetic
Alison Derry 32:22
Absolutely yeah
Andrew Hendry 32:23
That's what we expect
Alison Derry 32:24
But there could be a gradient, because there are still some lakes, like HopeLake, for example, which is a deeper, bigger lake versus another lake that's smaller and shallower
Art Woods 32:35
Ok great
Marty Martin 32:37
So you're let's maybe turn to the community ecology in a really explicit way. And you named some of the players in the food webs and the various different lakes. So one of the things that did resonate with me, we all got together a couple of hours ago and talked a little bit about this. So in a way, we've had a podcast before the podcast. One of the things that I didn't realize in our conversation earlier was that, you know, by and large, given the nature of the lakes, you're going to get a lot of this, maybe stronger selection on the limnetics, and so a polarization more towards the benthics. But in through the lens of community ecology, it's going to be the relationships among these organisms that are there, that themselves evolve, and we name the players. But what do you predict about the relationships?
Alison Derry 33:19
Yeah, so, yeah. So that's a really interesting question. It's obviously very dynamic.
Marty Martin 33:25
Yeah
Alison Derry 33:25
And so it's going to be very different from the beginning, when they're first put in, versus a couple of years out, where those relationships and the players change. So when the fish are first put in these lakes, and in fact, many of the recipient lakes were actually without fish, and they had enormous size zooplankton, very large daphnia, very large copepods, another crustacean. And so when so these plankton assemblages were naive. They were at kind of they were assemblages that were adapted to being without fish, and so they were really hammered when those stickleback were first placed in those lakes. And so we did see differences already, right away, immediately in the first year, of differences in terms of how the limnetic fish versus the benthic fish affected the zooplankton community, and so the limnetic fish, right away were way more efficient at eliminating the large zooplankton and transferring and shifting the community to smaller body species, whereas the benthic fish, they still had an impact. They were less efficient. They kind of had a more variable kind of shotgun influence on the community, but we need to remember that that was when these fish were first put in.
Alison Derry 34:48
Now they've changed the community, and the relationships change, and now what we have is a more predator resistant community of zooplankton. And so these are animals that are going to be able to coexist with these fish. The fish are now less efficient at getting them because they're smaller bodied and the stickleback are visual feeders, and so it's a changing relationship. The other thing that can occur, and there's been quite a bit of research on it, is that fish can not only can we see evolution in the stickleback, but zooplankton are also highly evolvable themselves, and so they can also start to quickly evolve adaptations to this new or returned predator in their lake, in terms of their ability to escape, in terms of how they're moving through the water column between day and night, going up in the surface, perhaps at night, to evolve the visual predators, changing their pigments so that they're less visible. These are all different ways that zooplankton can genetically change over several generations themselves in response to a new predator. And we have quite a large community of researchers that are working on this project. One researcher, his name is Matt Walsh. He's at the University of Texas at Arlington, and so he is studying the evolution of daphnia in response to the stickleback additions, and also in terms of their adaptations in the lakes, the source lakes where we collected the stickleback. So that's someone who is tackling that directly, on daphnia evolution.
Marty Martin 36:26
So just to connect to something that you'd said earlier, with the stickleback sort of sitting at this intermediate level food web, what does that mean? Or can you make any generalizations about effects from diversity for sort of large scale descriptors of communities, diversity, stability, you know, that kind of stuff. Or is it too early in the process to say?
Alison Derry 36:50
Yeah, yeah I think it's still too early. I think it's, I mean, I think that when they were first added, they shook up. They definitely shook up those ecosystems pretty hard. And, you know, so when we talk about diversity and resilience, we're talking more at like an aggregate scale. So in other words, you could, you could say, "Okay, so we've knocked out, we've perhaps we've knocked out this big, this big daphnia, but maybe there's another player that could replace them, if there's functional redundancy," and that is called resilience. In other words, it's how fast a system can come back, kind of in a in a functional way, of maintaining its functions. And so I would say it's, I think it's still a little bit too early in the goings on. I mean, we haven't, kind of measured, done those calculations, done those measures. We do now have, you know, well we're on our fifth year now. So we've got two years of the pre-stalking, so three, four years of the after. So I think we're still in the early goings on. I can't really speak so much to that, but I mean, certainly early on, they really shook up the system. They dropped the diversity of their prey community. But I think, you know, as it readjusts, right, it might come back up,
Marty Martin 36:50
Yeah
Alison Derry 36:51
So you know how, when you read a scientific paper, it always says we predicted this, and then, so the funny thing was, we decided to make predictions,
Alison Derry 37:15
Oh yeah
Andrew Hendry 37:15
writeAnd write them down,
Alison Derry 38:17
Yeah,
Andrew Hendry 38:17
Four years ago
Art Woods 38:18
See if you can hold yourself to them.
Andrew Hendry 38:20
Well, not saying we're going to hold ourselves to them, I think that, you know, so we actually did write down a bunch of predictions for what we thought might happen to these lakes. But that sent me down a rabbit hole of trying to understand what prediction meant and how good our rabbits and everything. And the general gist of it is that, you know, like being really explicit about what you predict, and then whether you find that prediction or not, it's really just informing your own ignorance. It's not really like some sort of meritorious adherence to the process of science, because really, if you don't, something doesn't match your predictions, just because the world is complicated, right?
Marty Martin 38:57
Yeah
Andrew Hendry 38:58
Like if you do one thing to a particular system. I mean, managers know this, right? You put something into a system, and all kinds of weird stuff happens. It's because there's a lot of complexity out there, which is why experiments like us are valuable, like ours is valuable because we have complicated real wakes. And so I look forward to seeing how wrong our predictions are,
Alison Derry 39:20
I'm sure they'll be wrong
Andrew Hendry 39:20
Because I'm sure they'll be wrong. How depressing would it be if we knew everything about the system before we started?
Marty Martin 39:21
Yeah, that would be a lot of time spent not doing anything interesting anyway
Andrew Hendry 39:26
It wouldn't be learning anything, right?
Art Woods 39:31
Okay, so, so as you're talking about these communities fluctuating, I'm thinking it would be really nice to have historical information on how they fluctuated in the past.
Alison Derry 39:40
Yes
Art Woods 39:40
And in fact, today you told us
Alison Derry 39:42
Yes
Art Woods 39:43
That you're working on some techniques together,
Alison Derry 39:44
Yes
Art Woods 39:45
And you're doing some really interesting coring of these lakes.
Alison Derry 39:47
Yes, yeah.
Art Woods 39:48
Tell us about the history.
Alison Derry 39:49
Yes. And so kind of, again, drawing in yet another researcher, Irene Gregory-Eaves at McGill, and myself. So now we've, we're integrating all kinds of approaches. And so one approach is paleolimnology. So paleolimnology, it's basically the science of taking sediment cores from the depositional area of a lake. And when we go there, we're able to collect sediments that have accumulated in a chronological way. And so because those sediments are layering in a chronological way, we are able to pull out these cores and section them and apply dating methods such as lead-210 to place actual dates on different sections, and then extract either fossils or environmental DNA to reconstruct the assemblages of organisms that lived in the past. And so by doing that, we will be able to have more of a temporal perspective of the ecological history of the lakes in terms of what fish were there before the pike were put in and ate everything. What were the prey communities that coexisted with those fish communities, what were the phytoplankton that were there, and then move through the invasion period to see what happened, and then come up through to the present, because our experiment is in the present. It's a very, very short time shot, and so we're really lacking that perspective. And it's important to have temporal perspective, because the history, the ecological history of a lake, is so important for understanding how organisms respond in the present, because it really sets them up in terms of what they've been exposed to, what they've been able to adapt to. It really sets the stage for contemporary responses.
Alison Derry 40:31
Do you know what year the pike came into the lakes?
Alison Derry 41:44
So that is a question-
Andrew Hendry 41:47
Could we call an audience member,
Andrew Hendry 41:48
Sure yeah, let's do it.
Andrew Hendry 41:50
Rob Massengill
Rob Massengill 41:51
Well Bill might know as well as me, because he lives on hope like but our department first became aware like in like, the mid 80s. Mid 80s, a little earlier than
Bill 42:01
That's when we arrived, a little before
Rob Massengill 42:07
It started off around 83, 84 there were two lakes identified with pike, and then really nothing, as far as surveys went on for a couple of decades.
Art Woods 42:17
Oh okay,
Andrew Hendry 42:17
Okay, so I'm repeating it. So ADF and G retired biologist Rob Massengill and Bill from Hope Lake, Hope Lake Hideaway are the experts in this. And although there's no precise dates, it's like the 1980s. You already knew that pike were there, and they'd probably been there for some time before that, but for however long you don't know for sure.
Art Woods 42:42
And then a related question, which is, how far back in time can these cores go? And do you already have evidence that there were sticklebacks before the pike were put into the lake?
Alison Derry 42:51
Well, so we were just collecting the first cores this summer. So we don't,
Art Woods 42:56
I saw one of them.
Alison Derry 42:57
Yeah, we got one core, and we looked at it very gently. And so, you know, we still don't know the sedimentation rate. So once we have an idea of the sedimentation rate, we will know exactly how far back in time, but most certainly, several hundred years, certainly. And so we are really, I mean, I guess the period of time that we're really targeting is the last hundred years. That's what we're most interested in.
Art Woods 43:20
Great
Marty Martin 43:31
Thanks for listening. If you like what you hear, let us know via X, Facebook, Instagram, or just leave a review wherever you get podcasts. And if you don't, we'd love to know that too. Write to us at info@bigbiology.org
Art Woods 43:43
A special thanks to Orca Peniston and Hunter Morrison for helping us organize this event and record the audio. Thanks also to Kenai Peninsula College for supporting the event and NSF funding via Dan Bolnick and the University of Connecticut.
Marty Martin 43:55
Thanks to Steve Lane, who manages the website, and Molly Magid for producing the episode.
Art Woods 43:59
Thanks also to Dayna de la Cruz for her amazing social media work, and Keating Shahmehri, who produces our awesome cover art.
Marty Martin 44:05
Thank you to the College of Public Health at the University of South Florida and the National Science Foundation for support.
Art Woods 44:10
Music on the episode is from Podington Bear and Tieren Costello.