The Arthropods of Kasatochi

For more than ten years, UA Museum of the North Curator of Entomology, Derek Sikes has traveled to the remote Aleutian volcano, Kasatochi, in order to help study how plant and animal succession reboots, how species are returning to the island after the supposed slate-cleaning of the 2008 eruption. Dr. Sikes discusses this ongoing project in light of successional ecology, Darwin and the heterotrophs first hypothesis, and the daunting work ahead required to fully catalog Alaska's arthropod biodiversity.

The More You Look is a production of the UA Museum of the North, on the campus of the University of Alaska Fairbanks and the ancestral lands of the Dena people of the lower Tanana River. UAMN illuminates the natural history and cultural heritage of Alaska and the North through collections, research, education, and partnerships, and by creating a singular museum experience that honors diverse knowledge and respect for the land and its peoples.

Transcript

Derek Sikes: 0:00

The US Fish and Wildlife Service had invited me out to sample the islands, the Aleutians, and that was very exciting work, and I was going to multiple islands. Kasatochi was a really interesting one because of it had this caldera, and unlike the other islands where I usually had about three hours, as they were setting up some camp, on Kasatochi I was there for 11 hours in June of 2008. Had the island myself, sampled a variety of different habitats on the island. And in retrospect, there's a bunch of things I wish I had done differently. If I had a time machine could go back and spend those 11 hours a little more rigorously. I think I was--because I knew I had so much time I was a little too leisurely in my efforts, so I sampled a great variety of arthropods, you know, just like I was doing everywhere: spiders, you know, insects, all kinds of stuff. And then in August, I got word that the island had erupted. The volcano erupted and buried the island in ash and I--my first reaction was, oh, that sounds horrible. The last thing I want to do is go to a muddy, you know, island with no insects on it for year after year. It just it didn't seem very appealing as a project actually, because my main focus is on documenting biodiversity.

Roger Topp: 1:47

Hello, and welcome to The More You Look, your behind the scenes journey into museum collections research, exhibition, and public programming from Fairbanks, Alaska. I'm Roger Topp, Director of Exhibits, Design, and Digital Media at the UA Museum of the North and host for today's episode. I remember the seastate the first time I sailed out the Kasatochi, seven years after the eruption. I remember the human

debris: 2:15

the bottles, the net, the buoys embedded in the ash and mud of the shoreline. I remember leaving the island and taking the skiff back to the Tiglax, the Fish and Wildlife boat, and how fogged in and isolating it was and hearing the crew well before we saw our ride back to Adak, and perhaps the stop at Koniuji on the way. For more than 10 years the UA Museum of the North Curator of Entomology Derek Sikes has travelled to the remote Aleutian volcano Kasatochi, in order to help study how plant and animal succession reboots, how species returned to the island after the supposed slate-cleaning of the 2008 eruption. I was fortunate to tag along and take photographs. We visited other islands as well capitalizing on our ship of opportunity, stopping also at Little Tanaga and Atka. The adventure felt wonderfully old school, being dropped at an island in the morning and returning to ship when dinner was already leftovers on the stovetop. Here's Dr. Derek Sikes.

Derek Sikes: 3:27

I'm not by training an ecologist who works--they work more on the mechanism of nature and systemitists like myself work more on what it's composed of, the species and where they occur. And after this eruption, I figured there would be no biodiversity. And I'm like, there's a lot of places in Alaska that have a lot of biodiversity that have never been documented. And that's what I want to go do. But but I did go maybe somewhat reluctantly that first year in 2009. Post eruption a big team had been brought together: marine intertidal, volcanologists soil scientists, botanists, all these people, including a successional ecologist, an ecologist who has gone around the world focusing on successional systems. So when we talk about succession, and that's going to be a huge topic here. So let's, let's explain that. That's how ecosystems assemble, how they form going from zero species to many species. What are the major steps and the major groups of organisms that come first and second, and third, and all that? So this team went there and I was surprised to find there were insects, and in fact, there were some what we call legacies, some survivors there were there were vertebrates, there were plants. There were insects that seemed to have survived the eruption despite the island having increased in size by 40%. The ash layers were many meters deep. The pyroclastic flow--I'm unfamiliar with, you know, a lot of these terms--but 800 degrees they estimated in some places. So, you know, before we went there, we kind of thought, oh, sterilized and buried, but not Not really. And particularly when you look at the microbes, and I'm not a microbiologist, but the microbes. It was hardly sterilized. But the insects were there. They were active on the beaches, there were flies, there were beetles and I had done some preparation for this and I had found a review paper that looked at successional systems around the world in these famous volcanic studies like Krakatau Surtsey in Iceland, Mount St. Helens and a lot of glacial studies where when a glacier retreats and they go in and watch the ecosystem or their communities assemble. And this review paper by Ian Hodgkinson was basically describing this thing called heterotrophs first hypothesis, this idea that--he talked about it as being a missing stage that's overlooked in the textbooks in our paradigm of successional ecology, that traditionally, and it makes intuitive sense. You have to have plants or something that that photosynthesizes first, because where else you're going to get the energy. Then you have herbivores that feed on plants, Then you have predators that feed on the herbivores. Very textbook, what we teach everybody, what most people know if they had to guess. But it turns out that when you actually go to these places, before the plants have really established, there are decomposers. And predators, there's a whole food web that is working on what we call allochthonous inputs, are energy that's coming into the system from outside. And with with Kasatochi, the energy is coming out of the ocean. So this energy is bound up in all this dead kelp, birds, fish that are dead on the beaches coming out of the ocean. And flies and predators are going gangbusters on these things before any plants before the herbivory. So this whole stage of ecosystem development really isn't in the textbooks. And that was a massive eye opener for me. Like it's something that as systemitists we often are very thrilled when we are the first to recognize, oh, this is probably a new species, you know, no one's ever seen this species before, but to find a--be kind of privy to a mechanism of how nature works that most people are unaware of, is also pretty damn exciting. And so, so that was a real eye opener for me. And indeed, year after year of going back, this decomposer based predator rich foodweb just got richer and richer. We started to get some I forget which year now but we there's a marine midge that is a grazer on algae that grows in the intertidal. So the algae is an autotroph you know, like a plant and and so we have like this like herbivory so we started to get some signs of herbivory couple years in. And then by 2012, we got our first true land plant herbivores. So the plants were beginning to come back and we got some aphids that feed on plants. Now even before the aphids, we did have a little bit of, of pollinators. So we had some of those flies on the beaches that were you know, feeding on decomposing matter or, or predatory, going up to plants and visiting flowers and getting maybe a little nectar, a little pollen. So the flowers were beginning--the plants are beginning to get tied into the full foodweb even before the aphids, but that was--just remarkable seeing this system develop as it as it did. The island is small enough that you can almost cover the full thing in a day. But it's really challenging to do that. And so we really focused on what we kind of call hotspots. There was an area of the greatest plant concentration, which is on a slope underneath a perigrine falcon nest. And for a while for a number of years we were able to get up to the developing auklet colony. So auklets are these cute little birds, seabirds that live in colonies and they like to live in talus, protected rockfall areas where they can get away from predators and be kind of out of sight. And there was one such talus slope that is--so before the eruption, there were a quarter million auklets living on the island. And after the eruption, there were a lot fewer, 1000s. A lot fewer. And the auklets have been increasing their numbers over the years. But when they came, apparently, when they came back that first year after the eruption, because they you know, the island, as it erupted, a lot of the auklets just flew away, right. And then they came back after. They had no place to lay their eggs and they were laying their eggs on this. Ash slopes and their eggs were rolling down the slopes into the ocean. So the intertidal--the marine biologists were finding auklet eggs in the ocean. But this auklet colony was another hotspot because auklets--one of the things it's just the driving force of energy in those islands is marine input through birds, bird guano, basically. They're doing all this feeding in the ocean and bringing this stuff back in land and pooping all over the place. And that all that nitrogen creates a great resource for all kinds of decomposers and subsequent foodweb elaboration. So that auklet colony was another hotspot, tons of algae and mosses and decomposers predators, really rich site, so we will try to focus on these different sites. But I also got really interested in driftwood, because driftwood is not just a shelter. I mean, on an island like that, there's almost no place for for insects to shelter from the wind, from the rain. And when wood washes up on the beach, it's full of cracks and crevices and things can hide in those cracks and crevices and get underneath and get a little shelter. And so I started focusing on driftwood, because on a normal Island, the driftwood could have upwards of 20 different species: centipedes, and spiders and beetles, and all these different things. On Kasatochi, lucky to get one or two species, but it became a way for me to compare island to island, which was a big problem. I was like how how do I get a comparable unit? You know, there, and you could walk a transect, oh, you could walk a transect for you know, 10 minutes, you know, there are ways to do these comparisons. But I really liked this, this driftwood idea of doing this. So I could have a quantitative way to statistically compare Kasatochi's development to other islands. And that's ongoing. That work. I haven't published the driftwood work yet. Or the ten-year review. So we went back last August and, and I'd like to go back again. But the last August was after a five year break. So we had 10 years five year break. And now I kind of want to do I want to go back this year, if I can just to get more driftwood data, I kind of figured that there would be rapid development and then it start to plateau, start to slow down. And I think that's what's actually happening. Because five years this year, just kind of my field impression is we don't have a whole lot more species than we had five years ago. So I think we are slowing down or the island is slowing down its development but I'm kind of waiting. There might be thresholds that need to be reached like need to get more just enough plants to stop the erosion on the beach is one of the huge problems there's still this massive erosion because there's no plants holding that ash in place.

Field Crew: 14:25

...So it's like a daddy longlegs. Yeah, that's what Yeah, and that's another thing I was excited down here this was it. That same group, but a much smaller version, some sort of little larva. 15 species in the wild. And the trouble oh and that is a different spider yet. I swear maybe this log came like freshly washed from Sitka or something. Because this is--there's a there's a lot of stuff on this log I normally don't see the Aleutinas anyway...

Derek Sikes: 15:06

We went out nine times. And one of those times we didn't get on the island. But the comparative Island, the most comparable Island is a little island called slightly smaller than kasatochi called Koniuji. That's in the same part of the chain. And it's also a bird island. And they talk about bird islands as being places that have a lot of seabirds. And it would be great to study that island as intensely as we've been studying Kasatochi, but that hasn't happened. We only had one quick visit to that island. And it has, it has as hard as it is to get on Kasatochi if the weather's bad, it's even harder to get on Koniuji Because there's no sandy beaches, it's all rock, and a lot of it is cliff. So there's just very little access. And the idea as nice as it is doing like whole island comparisons is just, it's like just infeasible in terms of logistics, and the amount of effort it takes to document everything. So when we go back to Kasatochi, we--Fish and Wildlife have been wonderful in supporting this research, but they provide one or two days access a year because they have to keep--their their vessel is funded through research. And most of the projects they have are funded, and this Kasatochi project is for the most part unfunded there. There was some some grant money early in that process, but we don't have--it's one of the problems with science in general is getting money that lasts more than a couple of years is tricky. So, So finding a,you know, way to subsample the island and in a more feasible manner. You know, that's the obvious way to go. And it's it's been Yeah, I'm really looking forward to writing up a review of the 10 years of data that we have so far and I've got a lot of it ready to go, just haven't found the time to write it up The driftwood stuff has been really interesting because there I do have some analyses, there are unpublished now but they're, they show for example that the size of the driftwood and Kastochi is identical to the size of the driftwood on on other islands, so on reference islands, so because the size of the driftwood is the same and we already know that there's a relationship between size of driftwood and the number of species that it can hold, bigger driftwood has more species, that since the size is the same then we can look directly at the number of species and consider each piece of driftwood as an independent sample, and very different mean number of species still, but it's slowly--the difference between Kasatochi and other islands is is slowly decreasing. Yeah, ships of opportunity and like the classic Darwin, the Beagle, right? I mean that his--his visit to the Galapagos was--is iconic in the lore of of science, not that he had some eureka insights there. It really, I mean, the full detailed story is he didn't know what he stumbled across until he got back to London and had experts look at his specimens and all this stuff, but and then he started kind of putting the pieces of the puzzle together. But visiting Islands--islands, you know, they talk about is as laboratories of evolution, you know, they're just great when they get really isolated there. They have a lot of advantages for research because you have a lot fewer variables and that you have, you know, a much more manageable system with fewer species and at least in the Galapagos, I mean they can like count every bird on each island kind of thing you know, but these boats, yeah, it does is a certain amount of as you probably remember a certain amount of adventure involved in just the logistics of going to these remote locations and having a team of experts who can get you from you know, the large boat to the island and back again safely in sometimes pretty rough seas. So it's is wonderful have research vessels that that can get scientists out to remote locations. It's logical to think that plants are the beginning, as long as you have a closed system, right, as long as there's no energy coming into that system from outside, because the only way you can have energy is if you have a photosynthesizing organism that can make it from the sun. So if you've got a closed system, then yes, you've got to start with the autotrophs, the plants, the photosynthesizers, but there's really no closed systems on Earth. You would have to treat the entire planet as a system to get to something that's closed and that's, that's assuming there's no organic matter coming from outside of the planet. And I don't know how true that is. I don't know enough about about that. But this process of--the relationship between the ocean and land got me curious. And I looked into the literature on the question of how animals evolved to become terrestrial. And just like this paradigm of ecology, successional ecology, starting with plants, the--this paradigm of of going animals moving from the ocean to land, is--they often talk about, okay, we know for a fact plants dominated the landscape millions of years before animals got up there. Yes, they were definitely first, which you can only imagine what an amazing ecosystem that was with the plants having no need to defend themselves from herbivores. But there's often this this thought that because these plants were such a rich resource of energy. That is what the animals exploited when they left the ocean. It makes sense, right? However, when you really look closely, there's a couple reasons to doubt that story. Getting out of the ocean is very hard. And so getting all these adaptations. First of all, the intertidal is hugely important. If we didn't have the moon that created the tides, that expose all these animals to air and ocean on a regular basis, it would have been probably much more difficult for animals to make that transition. But think about the adaptations.If you're a decomposer. In the intertidal, if you can feed on dead stuff in the intertidal, then you can feed on dead stuff on land, without any adaptation. The only thing you really need to deal with is the air, the lack of water, the dehydration problem. So it's, it's a lot easier to imagine an animal decomposer moving on to land than it is to imagine an animal in the ocean suddenly becoming an herbivore on land plants. Right? The herbivory on land plants must have happened later, after they had already gotten on to land. And when you look at the fossil record, the first animals on land, and these are all arthropods, were springtails. And they're decomposers. Centipedes, scorpions, these are all predators. So it's decomposers and predators--were the oldest land animals that that we have in the fossil record. And so I just think decomposers, in general, have been somewhat left out, or they just don't get the attention they deserve. You know, I think, you know, I think we focus so much on herbivores and predators, and decomposers are really this linchpin that may have been critical to the colonization of land by animals. You're not going to hear that story. I bet if you interviewed 100 random, you know, evolutionary biologists and asked them about this question, they're probably going to say, oh, yeah, animals left the ocean started feeding on plants, and then predators came. Bla bla, bla. So, I think decomposers just don't get the attention they deserve. And this, Kasatochi, looking at the small scale over a 10-year time period, kind of made me think about okay, what about 400 million years ago? You know, the connection between the ocean and land and were decomposers part of that and yeah, I mean, I bet they were. The horseshoe crab on my wall there--that is an ancient body form. Fossils 300 million years old--that looked nearly the same. And they go up on the beach to lay their eggs. Because, well now there're predators but back then, lot fewer predators up there. Their eggs were safe up on the beach, nstead of laying them in the ocean. Such a weird idea of a marine creature leaving the ocean and going up onto the beach to lay eggs, but the creature can't really survive on land very long, has to go back in the ocean, you know? Yeah, that's these these steps and stages in the process. Of course, microbes are hugely important, we can't forget our microbe friends, because they start the decomposition. And they, like if those land plants are dropping leaves and dying, it's the microbes that are, you know, breaking the cells down, and then the arthropods can come and it's so much easier for them to eat these plants that are colonized by all these microbes. Yeah, and this earlier stage of decomposers provides, you know, a fertilization aspect to the soil. So, these new ecosystems are laid bare by a glacier or volcano, having all this activity of decomposers and predators makes the soil more welcoming for plants. The primary mission as the curator of insects here at the University of Alaska Museum is to document the biodiversity of arthropods in Alaska. And I draw--I say arthropods, right, so these are are animals with exoskeletons and jointed legs. And they, most people are familiar with your insects and your spiders. But we also talked about centipedes and we're talking about mites. And we're talking about crustaceans. There's a lot of freshwater crustaceans. And I focus on the non-marine arthropods, the ones that aren't in the ocean. It's kind of hard to draw the line sometimes, because there're some crustaceans that live on land but have very close relatives in the ocean. And then there're some insects that live down in the intertidal and have all their relatives on land. And so, it's a little bit of a blurry boundary there. But yeah, documenting the diversity of Alaska is something that I consider a huge priority because it's undocumented. It's, to me, you know, biodiversity documentation has this great thrill of discovery side, and it sort of the more cartoonish vision is imagine we find a planet with life on it. Think about the work and excitement of documenting that life. Presumably, the mechanisms of how nature works on another planet would be very similar to the mechanisms of how it works here. Succession. I expect, it's going to be decomposers first, then the plants, you know, this sort of thing, that these, these patterns that we see should be the same, but the species involved are going to be radically different, with all kinds of adaptations that we've never heard of, or imagined. And so, discovering new life is what drives most taxonomists. Their kind of emotional drive comes from that discovery.

Field Crew: 28:21

That was gold mine. And it's pretty amazing. For me to look at and go, I bet it's not gonna have much of anything. I didn't, because he was so far from the vegetation, I thought like, well, it has a nice gallery.

Derek Sikes: 28:35

And Alaska is a, you know, being the only real Arctic Lands of the United States, and this massive territory, 20%, 20% of the lower 48 in land area. It's just a quite the challenge to try to document what's here. If we had a sense of, of like, what to expect, then, you know, at least we'd have a roadmap. But we don't really even know that because there's no--aside from Sweden, which isn't really a great corollary, because Sweden is-- has a much warmer climate in the south than any part of Alaska. We just don't have a great corollary. And so we don't know. In our documentation, we're adding about 1,000 species to the list every decade. And that's been going on since about 1940. So we're up to about 8,000 insect species, 9,000 when you add in all the arthropods. But the curve, the growth of discovery just is going up and up and up and up and it's not hitting a plateau. I mean, you would expect if you were studying something that didn't have very many species like, like birds or mammals, you would you would hit a plateau fairly quick. Sleep, you'd be like, Oh, it's been five years since we found a new species for the state, you know, and, and it would just be a really slow increase. But for arthropods, being so hyper diverse, it's--we're constantly finding new stuff. I mean, the more you look, the more you find. It's a huge place. There's lots to discover, and not very many people doing the work. Unlike Europe, or the lower 48 states, we just don't have the person power involved to document. It's a much smaller group of people who've been working up here on this kind of stuff. So the progress has been slow relative to Europe. I mean, I've been comparing Alaska to Sweden recently, a lot. And they're about 200 years ahead of us. For sure, plus, they have way more people doing that kind of work. But their numbers are up in there. They figure they've got over 30,000 species of insects, and they are 1/3 the size of Alaska, Sweden. So Alaska with our 9,000 right now. You know, it could--we could be up 20,000 eventually, you know. I mean, to think we haven't even hit the halfway point is kind of hard to-- hard to imagine. And I don't know, I know I'm gonna retire before we get everything documented. And I'm just hoping that someone can step in and keep the work going. When I was reading Darwin's write up on his voyage of the Beagle, I came across an entry that just--lights went off in my head because he had, he might have been the first scientist to document this sort of heterotrophs first idea, the idea of ecological succession starting with organisms before plants. And so the quote from his voyage of the Beagle is "the often repeated description of the stately palm, and other noble plants, then birds and lastly, man, taking possession of the coral islets as soon as formed in the Pacific is probably not quite correct. I fear it destroys the poetry of the story that feather and dirt feeding and parasitic insects and spiders should be the first inhabitants of newly formed oceanic land." So that was 1860 when he published that, I don't think that was really noticed by the scientific community, you know, because we proceeded down this this paradigm of ecological succession starting with plants and then herbivores and then predators, etc. But Darwin being the astute observer, he was he he was keen to note that although a little reluctant to note it "destroys the poetry" but Kasatochi, yeah. Same situation.

Roger Topp: 33:35

Thank you to UA Museum at the North Curator of Entomology, Derek Sikes for his time and invitations to join the expedition crews to Kasatochi. Thankfully, the state of the ocean let us land and I only ruined one pair of pants. Volcano rock is sharp. Explore the museum's website for more information about recent and forthcoming projects and perhaps even ways to get involved. Before we go, I remind you to check out the museum's website for the latest information about exhibits, public programming, and collections activities in the field and in the lab. Look for the UA Museum of the North. The More You Look at the production of the UA Museum of the North on the campus of the University of Alaska Fairbanks and the ancestral lands of the Dene people of the lower Tanana river. UAMN illuminates the natural history and cultural heritage of Alaska and the North through collections, research, education, and partnerships, and by creating a singular museum experience that honors diverse knowledge and respect for the land and its peoples. Thank you for listening. Please subscribe, share, and rate the program. This helps other listeners discover more about not only the work of this museum, but quite possibly other museums in their neighborhoods. The more you look, the more you find.