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Anarchism in French Guiana

From Wikipedia, the free encyclopedia

Anarchism in French Guiana has a short, and little recorded, history. The only continental territory in Latin America to remain a colony into the 21st century, Guiana has not seen the same political developments as most other countries in the region. Still, anarchism has existed to some degree, mainly through the presence of political prisoners deported to the colony. In the modern era, anarchism has had a minor presence in the Guianan political milieu.

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  • ✪ Biodiversity and the Evolution of the Ants: Talk by Corrie Moreau


TREVOR PRICE: Corrie did her PhD at Harvard with EO Wilson, working on ants. And then she did a postdoc at Berkeley and then took a position at the University of Chicago Field Museum, I mean, sorry, the Field Museum in Chicago, which is affiliated with the University of Chicago. And she's worked all over the world, as far as I know, but never been to India before. Most of her work has been in South America. And most of her work has been trying to work out the phylogenetic relationships of the ants. But she's moving into other stuff, which we're going to hear about today, I guess. So thank you, Corrie. CORRIE MOREAU: And I'm really excited today to share with you some of my passion of biodiversity in ants and also to talk about some of my research. And so I think that it's probably no surprise to many of you that protected areas are critical for studying aspects of biodiversity, which is part of the reason, I think, this symposia is important. I've been fortunate enough, as Trevor mentioned, to be able to do fieldwork essentially all over the world, in protected and in unprotected areas. And you can clearly see the difference in the diversity that's still present in those regions. Trevor did mention that I've actually never done fieldwork in India before. So I'm thrilled that I get to go to the field with Supriya and see some of the work that she's been doing on bird ant interactions. And so, in those aspects of travel, I've been able to broadly sample diversity in many ways. And I've partnered with all kinds of scientists surveying all kinds of groups of organisms. And in doing so, I've been able to go to remote parts of Madagascar. I've worked in critically endangered habitats within Peru and Ecuador. I visited field stations with my entire lab in Costa Rica. I've been able to work extensively across the wet tropics of Australia, thanks to a collaboration with Craig Moritz. And most recently, I actually got to go to French Guiana. And that was really exciting for me, because I work on canopy species of ants. And so it's one of the only unique systems in the world where you have this ability to get up into the canopy as an individual. So you essentially go up on this little zip line with a remote control. And you can drive yourself around, from tree to tree, to collect ants. And as all of you know, fieldwork isn't always so glamorous. And in fact, I wanted to include this image at the bottom corner of a tick that I accidentally smuggled home inside my nose. And so it's one of those aspects of fieldwork that is enjoyable and scary at the same time. So it's maybe no surprise to say that when you're traveling the world, getting to places like this, where you have this beautiful primary rain forest, is the dream of most tropical biologists. It's where you see the highest diversity, it's where you find the most new species. It's where you see the most interesting interactions between species, at least the things that I'm interested in. But unfortunately, we also know that a lot of times this is what the habitat actually looks like, right. And so, it's often abutted up against the situations where we have humans encroaching on that habitat. And not that that's necessarily always a bad thing. But it does mean that we need to maintain some of that biodiversity for the organisms that are living there. And so thinking about what are the most important factors to take into account as we're surveying that diversity. How do we ensure that we have the most connectivity between different kinds of patches is important. So why are ants important? I get asked this question all the time and also by members of my family. But ants actually are incredibly diverse. Not only diverse in species. So there are 13,000 species that have names that have been given to them by scientists. That number's at least double if not triple. So there is a ton of diversity, and that's just ants alone. That's not even thinking about the remaining insects. And there's a lot of complexity in both their behaviors, in their morphology or their form, and the interactions they have with other organisms. And just to put that in context, there are more species of ants than all the birds and mammals added together. So those groups of organisms that people often think are great metrics for understanding diversity, I would argue that many of the insect groups are the ones we should really turn to. And so I thought I'd give you a little bit of rundown on some of the cool aspects of ant biology that intrigue me and got me excited about ants. And the first of which is that ants are a female dominated society. So pretty much every ant you've ever seen is female. If they've been walking around without wings, they're female. And so workers are responsible for all of the tasks within the nest. They're the ones that are out foraging. They're the ones that are fighting the battles. They're the ones that are caring for the young and repairing the nest itself. And males and new virgin queens are only produced about once a year. And they have to go off on a mating flight. And so actually males and those new version queens don't care at all for the natal nest. So their role is literally just reproduction. Males and these new virgin queens have wings. So if you've ever seen an ant without wings, it certainly is female. Ants are also the world's first farmers. They've been harvesting food and growing their own food for over 50 million years. And so what you're seeing here is sort of the icon of that. And that's the leaf cutter ants. And these groups of ants actually go up into trees, pull down vegetation, and then grow a fungus on it. So they don't eat the leaves that they're cutting up at all. They're actually growing their own food. And they feed entirely on the fungal farm. And army ants are another one of those iconic groups of insects that have captivated people's attention for a long time because of their raiding habitats. They'll march through entire villages, they'll clean up all of the pest species as they're looking for their own food. Because they're such voracious predators, they have to be nomadic. So they're constantly moving their nests in a very ritualized cycle, so that they don't expend all of the food in a particular habitat. Now many people are familiar with them, because they have these very foreboding jaws, the soldiers do. But interestingly, they've been used as human stitches, so essentially to close wounds, in parts of Africa-- and this is a nice image from National Geographic-- where they essentially use them to close the wound, twist off the body leaving only the head, and then allow the rest of the wound to heal. And so it's a medical use of ants as well. Some of you might be familiar with this group of ants. These are called honey pot ants. And these are ants that live in arid habitats, where food is boom or bust, right. So essentially, you have situations in which there's a lot of food all at once. You need to gather it as quickly as you can. And they have a mechanism for storing that. Now if you're harvesting things like seeds, it's not a problem to store them in a granivory. But if you have liquid food sources, how do you retain that? So what you have are these individuals that hang upside down on the top of the nest, and their entire job is just to essentially act like a living food basket. And they serve as what are called repletes. And then as food is needed, they can regurgitate it across individuals. Now interestingly, these ants-- this behavior is converged twice within ants, once in Australia and once in the southwestern part of the United States and Mexico. And in both of these places, the habitat's very dry. Now one thing that indigenous people have long known is that they can eat these as snacks. I often call them nature's M&Ms or nature's candy. So you can dig up a nest of these and eat them. And they're actually quite delicious. Every year that we teach a field course, we actually dig up a colony and taste them. The one piece of advice I would have is you'll notice some of them are really light golden color. Those tastes delicious. That means they've been feeding on nectar or honeydew that they're finding in the environment, where the dark colored ones are often feeding on carrion or carcasses. So don't eat those. So why have I told you all of this? Well, really, I want to sort of beg the question of why is it ants are so important. I would argue that it's because they're found worldwide, everywhere except Antarctica. They're highly abundant, they're highly diverse. And in this case, I think that they're a great system to study aspects of ecology and evolution. And so this is the group that I've worked on for a while. But as an evolutionary biologist, I'm interested in broader questions than just ants alone. And so for me, that really is the question of biodiversity. So what are the processes that have generated the biodiversity that we see across the planet? We know that there are a lot of factors that explain what we see. And that comes in the form of both abiotic and biotic interactions. So thinking about in the abiotic realm, things like temperature and precipitation or geology or aspects of the environment in which they're living, why is it sort of shaping the diversity that we see. And then on the other hand, thinking about those biotic interactions, whether it's competition or predation or maybe symbiosis-- so why are these organisms, how they're interacting with one another, influencing both their short term interactions, their ecology, but also that longer term history in the evolutionary scale. And so for me, a lot of the work that I've been doing is looking at the role of symbiosis in these interactions. Now as an evolutionary biologist, and Trevor alluded to this, I actually think about the world in the construct of phylogenetic trees. I really love that we can use these to ask some really interesting questions. Now clearly the first is we can ask how are species related to each other. So in this case, what we're looking at is a primate family tree. And what it tells us is which species are most closely related to each other. And although I find that interesting, to me a phylogenetic tree, once you have those relationships, is just the beginning. Now we can start to ask some really interesting questions. And those include things like the evolution of traits. We might want to understand how many times a certain anatomy or morphology has evolved. Do we see convergence? Is it due to the one evolutionary event? We also might be interested in things like biogeography. How have they moved around the planet? Is there some pattern that we can discern, based on that evolutionary relationship? Next we might be interested in questions about speciation events. Why do we see lineages splitting? Why are they splitting where they are in the tree? And then what happens to those terminals? How many species do we see in those clades once that splitting event has occurred? Now since most of my research is based on using DNA and genomics, another thing that I'm often interested in is thinking about rates of change along branches. Why is it that some lineages have really fast rates of evolution, while others have really slow rates of evolution? So we can ask questions about what are the correlated aspects of that. What does that mean for the evolution of that organism or how they're interacting in their environment? And lastly, if we have some sort of external information, we can actually put a time frame on that. We can say, when did those lineages arise? What was co-occurring on the planet at the time? Does this help us understand, maybe it's biogeography or maybe it's some aspect of a novel morphology. And so having done my dissertation with EO Wilson and Naomi Pierce, of course I loved this phrase from EO Wilson, where he once said that insects or ants are the little things that run the world. And I truly believed that, until I started studying the bacteria that are stuffed inside the ants. And now I think they're the little things that are ruling the little things that rule the world. And so what does that mean? I really am interested in how species interact and in thinking about symbiosis. And ants are a great system to do this, because they interact with the diversity of organisms across the planet. So we know that they engage in symbiosis with other animals. In the case of many of these sap producing insects, we know that they're essentially having this reciprocal relationship, where one's providing food and the other's providing defense. We know that the ant plant mutualisms have evolved multiple times. So now the question becomes, why is it that some plants engage in symbioses where others don't? Why do some ants engage in these obligate symbioses and others don't? We know that they interact with fungi. I showed you the example of the fungus growing ants. But we even know things like cordyceps fungi that are parasitic on ants. And so I'm collaborating with a colleague, David Hughes, to ask questions about how often does this arise. Why is it that some lineages are much more susceptible to infection from these parasitic fungi than others? And lastly, we've been doing a lot of work to try to understand the role of gut bacteria in the host itself, what role that has on the shorter term scale, so how they can access nutrients from food, but also on the longer term scale. How has that allowed them to move into novel niches? And so really what I'm arguing-- and this is not true just for ants, this is true for almost any group of organisms-- is that no organism is acting in isolation in its environment. And although it's very easy for us to go into the field and focus on a single group and say, OK, I'm going to only look at that group-- and I think that that's critically important. But once you get a pretty good understanding of that, you need to start to think about how is the environment in which it's embedded and all the other organisms it's interacting with influencing what we're actually seeing. So what I'm going to do is walk you through two aspects of my research program. And the first is to look at the evolution and biogeography of ants and what we can learn from that, in light of understanding flowering plant evolution. Unlike bees, we don't have lineages of ants that are directly interacting with plants across the diversity of flowering plants. We don't have ants that are very good pollinators, unlike bees. So why would we expect some sort of reciprocal interaction between ants and flowering plants? Well, there is some sort of historic point of view to think about this. And the first of which is that Wilson and Holldobler in 2005 had come forward what they call their dynastic succession hypothesis. And what they had argued was looking across the history of ant evolutionism that we might expect some lineages to have a response to the rise of the flowering plant force, or the angiosperms, because they have a close association. So many species are only found in the crowns of angiosperm forests, so maybe we might expect to see some shifts in diversification or evolution there. But in other lineages that maybe are ground nesting and predatory, we might not expect to see that sort of shift. In addition, one of the things that's often been noted is that as we see these ants expand their diet, we actually see them move up into the canopy, as they shift away from being predatory. So now we have this framework for saying, OK, well as you move on to novel food sources, maybe this is providing the framework for you to move into this new ecosystem. But now flipping an ant on its head and thinking about it from this aspect of the plants, if ants aren't pollinating them, what are the potential positive impacts for them? And first, one of the things that we see is that ants are critical to understanding plant evolution, because they've been known for a long time to be really great seed dispersers. So what you're looking at in that lower picture is a picture of a plant seed that's covered by what's called an elaiosome. And this is the sort of fatty aspect of the plant that's there just to attract ants. And that's so that the ant will drag it away from its parental plant, so that the new seed is not competing for resources in that same environment. The ant will take it away, eat off that elaiosome cover, and then either dispose of it in the environment or throw it in its refuse pile, which is a great place for a new plant to grow up, right? So essentially, they're facilitating the plants to be able to have a rich environment in which to begin their growing process. So in order to do this, the first thing we needed to do was to infer the phylogenetic relationships of the ants. So although what I was able to discern from this were which species were related to which, but as I told you before, one of the most powerful aspect of phylogenetics is what we can do next. So once we had this phylogeny, we wanted to get an understanding for the time frame involved. Now the week that our paper was published, we actually got a lot of press. And I would say all of it was right, with the exception of one news source. And what they actually said was that we had analyzed the DNA of fossilized ants trapped in amber. And if you've seen Jurassic Park, you know that they take this syringe and they pull out a little DNA from this mosquito trapped in amber. And I wish that is what we did. I wish that that actually still had usable DNA in it. But it's not. So how is it we were able to leverage the fossil record? Well, it turns out the ant fossil record is incredibly rich. So once we had that ant phylogeny, one of the things we could do was go in and assess all of those fossil records. So we were able to look at the fossil record as far as examining fossils ourselves, but also assessing the literature. There are tens of thousands of ant fossils. So this gave us the ability to really have a wide distribution of fossils. And this is what we were able to do. So we were able to use 43 fossils as minimum calibration points. And I think the power here is not just the large number of fossil calibrations, but we also have them distributed across the ant phylogeny and we have them across time. So the youngest fossils that we used were about 15 million years old, and the oldest fossils were 100 million years old. So this gave us both the breadth and depth to be able to ask questions about the evolution and diversification of the ants. Now once we did this, we were able to infer ages for all the major lineages and their ants themselves. But for me what really jumped out was when I looked at this dated phylogeny or chronogram, what I noticed was a lot of the diversification was happening in the central part of the tree. So I wanted to understand why we would necessarily see this pattern. Or was there actually even any kind of analytical power there? Was it just an artifact of the eye? The first thing that we did was on the left we constructed a lineage through time plot. This is using a birth death model of diversification. So what you're looking at on the x-axis is time. And at 0, that's the present through 200 million years ago. Then that solid line, what we're looking at is the number of lineages as they increase through time or we've binned them into their histogram or frequency. And what you'll notice is there seems to be a sort of sharp shift in the number of lineages right around 100 million years. Now we want to understand what patterns explain these data. So we used some models to test this. First we asked the question as a null model. Do we see a constant rate of diversification through time? So we wanted to understand whether we see a constant diversification rate through time. So our next model was do we see a gradual change. So maybe it's not constant, but we do see a shift. And lastly, we wanted to understand, do we see two different rates of diversification before and after that specified break point? In our case, we used the 100 million years, based on that lineage through time plot. And maybe not surprising, what we see is that model C is a significantly better fit to our data, suggesting that something's happening around 100 million years ago. Now if we go back to thinking about what was globally happening on the planet and we look at the literature, one thing that botanists agree on is that seems to be right around the window where the expansion of the flowering plant forests were happening. So really what seems to be happening is that the ants are increasing their number of species or they're diversifying, in response to the expansion of these flowering plant forests across the globe. One of the things that we know from the botanical literature is that the flowering plant forests weren't just spreading evenly across all portions of the globe. So we wanted to ask the question, could the ants potentially be tracking the flowering plant forests. And so one of the things that we also know is that ant diversity is not evenly distributed across the planet. And that's true for many groups of organisms, right. We see this sort of latitudinal gradient in species richness, where the largest number of species are centered around the equator. And so in this map in the bottom, what you see is the warmer parts the map are where we have more species richness for ants. And so you see the highest diversity right around the equator. And as we move towards those poles, we're decreasing in that diversity. Now this is even true at the generic level within ants. But this begs the question are the ants just tracking the flowering plant forest as they're moving around the planet. So in order to address this question, we need to infer an even larger phylogeny. And that was so that we could include even more information about the distributions of ants across the planet. There's some hypotheses that have been put forward to explain why we see that disparity of where species are found across the planet. So Stebbins in 1974 proposed that the reason we see more species in the tropics is that essentially the tropics are acting as a cradle. It's where we have more species arising constantly. So even if there had been an even number of species across the globe at one point, because more species are being generated there, we're just going to have higher numbers currently. But the flip side of that is maybe that the tropics are acting as a museum. So even if we had an equal number of species generating now, those oldest lineages are all sort of tracked in this environmentally stable part of the world called the tropics. The reason that this is interesting is it sets up an expectation or a hypothesis that we can test, asking what's generating the disparity in species richness that we see across the planet. Is it that the tropics are acting as a cradle for ant evolution? Do we essentially have a species pump, generating more species all the time? Or is it just where we see the oldest lineages persisting, and maybe species are arising at a constant rate across the globe? Now in order to investigate this, the first thing we did was we had to cut the planet up into sort of major biogeographic regions. And so we sort of used those that are commonly recognized. Now once we had these six major biogeographic regions, we had to assign every single ant that we had in the phylogeny to one or more of those regions, based on where they're currently found. So if you look across the top, you can see that the first species is actually only found in the Indomalayan region, where the next individual is found across multiple geographic regions. Now this is historically where biogeographic inference ended. But we know that those current biogeographic regions and have not always been where they're currently found. And I've already told you that the ants are somewhere probably around 140 million years ago. So we wanted to take into account where those potential migration patterns could occur. So in order to do that, we reconstructed a migration matrix, which essentially said how likely is it that the individual species could move across these major biogeographic regions. So for example, if we had a species that's currently found in South America, what's the migration probability through time that it could move from South America to Africa? Greater than 100 million years ago, that migration probability would be one or 100%, because those continents were in fact touching. Now as those continents moved apart from one another, we wanted to take that migration probability and decrease it through time. So as things were moving apart, we were decreasing that migration probability. And as things were coming together, we were increasing that migration probability. Now ants are actually very good at getting around the planet, so we never made the migration probability 0. In fact, the lowest we ever made it was 0.1 or 10%. And so that allowed us to infer the biogeographic history for the group. And this is in fact what we found. And the first thing that you'll notice is almost all the pies that you can see are green, suggesting that the neotropics are reconstructed as those regions where ant diversity was being maintained. Now I can't show you all the tips. But I can tell you that in many of those we also see that same pattern. And coupling that with what we know about ant diversity, the neotropics currently hold more species and more endemic genera than any other region the world. Now this begs the question if the neotropics are so important to ant evolution, in the deeper time scale as well in the recent, are they just tracking the flowering plant forests in and out of these regions? And in fact, that's not what we're seeing. They don't seem to be following the angiosperm forests as they're moving. They are taking advantage of them, as soon as they're arising on these different major biogeographic regions. So the ant diversity seem to be in low lying levels in each of these regions. And as the flowering plant forest came in, they took advantage of all these novel niches and moved up into the canopy. So going back to that hypothesis that was put forward by Stebbins, it seems that for the ants, the neotropics are acting both as a museum, where we have the oldest lineages persisting. But it's also where we have the newest lineages that are constantly being generated, suggesting that it's acting both as a museum and a cradle to ant diversity. So thinking about what are the drivers of deep time evolution within the ants, it does seem that the flowering plant forest had huge impact on the diversity that we see today. And in addition, it's not just that they are spreading across the landscape. They're taking advantage of all the niches that are afforded in an angiosperm forest that we don't see in other kinds of forests. So they're living not just in the soil. They're living in the leaf litter, and they're moving up into the canopy. And that's actually a behavior that we don't see in gymnosperm or conifer forests. In addition, we know that ants are transitioning from being primarily predatory at this point to also having species that are now moving entirely in some cases to feeding on plant-derived resources, either directly or indirectly, as in the case of this ant that's actually taking advantage of honeydew excreted by these aphids. So this really sets the stage for thinking about how these interactions are driving the evolution of an incredibly ecologically and numerically dominant group of organisms. So now I'll spend a little bit of time talking about the work that we've been doing looking at the evolution of symbiosis with bacteria and ants, and how that may have helped facilitate that shift onto this herbivorous diet. So why should we use ants to study gut microbes? There's actually a lot of compelling reasons why. First I'd say that we have this really diverse group of organisms. We have a diversity of habitats, as far as what they'll eat and where they're found. So it sets up this really nice situation, where we can ask questions about things like diet and nutrition. We can say, how often does diet shape what we see in the microbiota? Do we see convergence? Do we see single evolutionary events? Next, we can ask questions about transmission. How are these microbes shared among individuals within a colony? How are they shared among species through deeper time? What role does horizontal transfer play in understanding how these bacteria are moving across these species lines? We might also understand something about are these organisms co-evolving together. So when do we see that co-diversification, when don't we? So it's interesting to think about what are the aspects of the host and of the bacteria to explain these patterns. And lastly, because ants are found across the globe, we can ask the question of what's driving it? Is in fact just where they're living driving the diversity we see? Is it all ants in the same place just have the same gut bacteria, suggesting they're just picking it up from the environment? Or do we see that geography is not necessarily what's structuring it, that there might be other aspects of the host itself? So when we first started working in this project, almost nothing was known about bacteria associated with ants. So the very first thing that we needed to do was essentially go on a biodiversity discovery survey. So this is what we did. So with my colleague Jake Russell, who I have been working with for quite some time, we essentially went in and surveyed almost 400 individual ants from almost 150 genera and just asked, what do we see. And maybe not surprisingly, we saw a lot of diversity of bacteria associated with the guts of these ants. But for us, one of the groups that was in really high prevalence really jumped out to us. And that's the group rhizobiales. For some of you, especially if you study plants, you've probably heard of this group of bacteria. Because these are the bacteria that are associated with root nodules of leguminous plants. And we know in that case they're fixing atmospheric nitrogen for their plant host. So why are we finding a group of bacteria that are related to them within the guts of ants? Are they potentially performing some similar role? And interestingly, if we look at when do we see an association with these groups of bacteria, we actually find that they're only associated with apps that are feeding very low on the trophic scale. So what we're doing here is we're using the ratio of heavy to light nitrogen to infer their trophic ecology. Every one of those dots is a single ant genus. Each is represented by one or more species and multiple individuals to infer their trophic position. And then we've mapped whether we see an association with rhizobiales or not. And you'll notice that things can be highly predatory. So on the very right hand side of this graph, things like army ants are incredibly predatory. And then we have things that span the spectrum, all the way through be entirely herbivorous. And interestingly, we only find an association with rhizobiales for things that are feeding very low on the trophic scale, suggesting that maybe they are up regulating their host nutrition, like we see in plants. Now you might have noticed there are two points that are at the zero frequency for rhizobiales, but actually are feeding very low on the trophic scale. And it turns out that these are the carpenter ants and their allies. And in this case, we actually know that these ants have specialized bacteria residing in bacteria sites that are up regulating their host's diet. So it appears that if you're going to feed very low on the trophic scale, you'll have an association either with Blochmannia, like the carpenter ants, or you have an association with rhizobiales, as we're now finding. Now what you're looking at here is a phylogeny of the bacteria, color coded by the host or environment from which it came. And what you'll notice is that we have an entirely red clade made up from all of those individuals that came from ants. And interestingly, within that rhizobiales clade, it seems to be tracking the ant's evolutionary history once it gets in. So we see all of the samples that come from species from the same genus group together, we have genera that are closely related, grouping together as well, suggesting that there's some sort of longer term association of these bacteria within the host themselves. But if we flip it on the other side and ask what do we see when we look at the distribution of these bacteria across the ant phylogeny, what we see is we have at least five independent associations of rhizobiales across the ant phylogeny. Now interestingly, when we again use that trophic scale-- that trophic ecology-- and infer an association with the likelihood of having these bacteria, we see a strong signature of feeding low on the trophic scale and moving into the canopy but having an association with these groups of bacteria. Now one of the things that we also want to understand is not just what bacteria are found across the ants, but where are they found within the digestive compartment. So we want to control for things they might be just picking up in the environment versus things that might be stable, long term residents of different aspects of their digestive system. And so what we do is we do a lot of careful dissections to look at the bacterial community taking up residence, and we sample them out. Then we sample three distinct compartments of the digestive tract. Now in ants, much like in birds, the crop is essentially a social stomach. It's a place for holding food for regurgitation to other members of the colony. So we know that no digestion actually happens in the crop. Digestion really only begins once we get to the mid gut and into the hind gut. We had some hints that there might be some really interesting and diverse groups of bacteria. This is a method we use in my lab using fluorescent microscopy where we use a stain that adheres to DNA. And we can ask the question, do we see bacteria associated with different tissues. So on the lower left side, you see the esophagus of an ant. So we've pulled out that esophagus. All those green dots are the ant's own host cells. So since this binds to DNA, it binds to each of the ant's own host cells. In addition, when we look in the crop, again what we see is like a sea of those ant cells. We see that hardened disk called the proventriculus, which essentially is a valve that decides whether or not food can be passed into the rest of the digestive tract. So since they need to hold it there for regurgitation, this is that mechanism for doing so. But once we move into the mid gut is where we start to see an association with these groups of bacteria. So this sort of thumb-like structure-- again, you can see the ant's own host cells and then a sea of bacteria that are associated with the lining of the digestive system itself. So next we wanted to use some next generation sequencing technologies to ask how diverse are the bacteria, and how do they differ between these different tissues that we're sampling. And so maybe not surprisingly, we found a lot of bacteria. Using this, you can essentially see that we've looked at different methods to assess how comparable are they. And you're starting to see a signature that different tissues have different kinds of bacteria. But maybe a better way to visualize that is using a PCOA plot. And so all of those samples towards the top are all those samples that came from the leg, the mouth, and the crop. And we're seeing no signature of them being highly similar to the tissue from which they came. But once we move into the hind gut and the mid gut, suddenly these bacterial communities become highly similar. And these are highly similar among individuals from the same nest, individuals from different nests, and even across the distribution of the species, suggesting that it's not something about those interactions that are driving that bacterial community but there's some structuring of what bacteria we find, based on the part of the digestive system that we're investigating. And so being an evolutionary biologist, I really love getting down in the weeds and studying these really intimate associations of bacteria with specific digestive compartments. But I always kind of want to take a step back and think about it in the broader evolutionary context. So we actually have a pretty clear understanding of the diversity of bacteria found with cephalotes within the gut. We know that they're stable and persistent through time, that they're not driven by the environment in which they're interacting, diet seems to be driving a lot of what we see, and that they're sort of co-diversifying with their hosts. But interestingly, when we take that and compare it to another group of herbivores, it's actually more closely related to some generalists. We see convergence in the gut bacterial community, again suggesting that it's something about diet that's shaping the bacterial communities that we're finding. And even when we look at species that they're much more closely related to, we don't necessarily see convergence based on what they are in fact eating. Now being a field biologist, the first thing I thought was, OK, we're going to sample an herbivore, we're going to sample a generalist, and then we have to sample a predator. And a priori, I already know what we're going to see. It's going to be a simple community, it's not going to be very diverse. It's going to be stable among all the individuals that we sampled. And then this is what we got. And interestingly, those three bottom samples are individuals from the same nest. Those are individuals that are interacting with one another, and I did not expect to see this. And then actually I thought about it, and I realized I hadn't designed my study very well. So although I'm calling these predators-- and they actually will take down prey and they will eat other animals-- they actually will also imbibe on any kind of a plant derived resource they can find. And if they're in high diversity or density, they will feed almost entirely on that. In addition, unlike things like army ants, that are sort of group foragers-- where individuals are going out in the environment together, they're all eating the same item and bringing it back to the nest-- these are actually solitary hunters. Each are going out in a different direction to find food and then bringing it back to the nest. So thinking about our own gut microbiome and the bacteria we have associated with our guts, all of us that woke up this morning probably had pretty dissimilar bacterial gut communities. Maybe some of you are roommates or ate lunch together. But for those the rest of us, we had pretty dissimilar bacterial communities. We've now had the same chai, the same coffee, the same snacks. If you sampled our gut bacterial communities again, they would suddenly look much more similar. They would converge. And that's because there is bacteria on the food that we're eating, that's just passing through our digestive system. It's not necessarily long term members of our bacterial community. But we're sort of just getting a snapshot. In addition, even if it's not associated with the food we're eating, we know that our bacteria community response to the consistency of our diet. So if you were to suddenly switch to eating a high sugar diet all the time, your bacterial communities will bloom in response to that. So then I thought, OK, now I need to go back and redesign that study. So what I did is I took my lab down to Costa Rica. We collected a bunch of these same colonies of species and asked the question, what happens when we sample the wild caught gut microbiota, and then what happens if we feed them on a sterile diet through time. So we sampled individuals right when we collected them in the field and then took them into the laboratory. Now the way that I'm going to present these data, in what's called a network based analysis, and each of those nodes is an individual ant. So we're not looking at one bacteria. Were asking questions about all the bacteria that we find with their guts. Now if we have an edge or a line that's not connected to anything else, that tells us that they had a unique group of bacteria in that one sample. But those edges or lines tell us something about how similar those bacterial communities are. So the more connections, the more similar they are, and the more likely they are to be close to one another. It's almost like magnets. They become attracted to one another if their overall bacterial communities are highly similar. If their overall bacterial communities are dissimilar, they're sort of repelled from one another. So what happened when we sampled those bacterial gut communities before and after feeding them on these sterile diets? And here's what you see. All of those red dots are the wild caught gut microbes. So those are those bacteria there, just sort of interacting within the environment. And what's interesting to me is that all those red dots belong to members of the same exact colony as all those yellow dots. So once we fed them on a sterile diet, that bacterial community or that noise sort of shrunk down to something that's much more likely to either be their core gut microbiota, or we've now shifted their gut bacteria, based on the diet we fed them. So this is a lesson to myself. So not only did I not learn the first time to design my experiment well in the field. Now even a second time I'm wishing I had done different diet experiments and fed them on different kinds of diets to see are we coming down to the core microbiota regardless of what we feed them, or is this in response to what we fed them? Since we've all come here to think about conservation, I think what I would like argue is that all the work that I've presented here today is really only possible because we still can go out and sample biodiversity in the wild. I don't typically work on organisms that we're keeping in a laboratory. I want to understand how evolution and ecology are shaping organisms out in the environment in which they are actually found. And so thinking about what that means for the ants, the ants are actually a likely very old group that diversified in response to the expansion of the flowering plant forests and that the tropics, and in particular the neotropics, are really responsible for the generation of maintenance of the biodiversity that we see today. In the case of ants, obligate symbiosis can influence genome evolution. And I didn't share that with you today, but we're finding some very interesting patterns when we look at symbiosis and how they influence genome evolution. And lastly, thinking about the role of bacteria across groups of organisms, at least what we're seeing with ants is it's really allowed them to shift onto novel diets and in many cases expand into novel habitats. And so thinking about species interactions and using diverse tools I think is important for us to understand the broader picture of groups of organisms in the environment. So there's a whole suite of people I'd like to thank. Clearly, I'd like to thank my collaborators that are involved in this work; members of my lab, who are just fantastic; funding sources. And really I'd like to thank the people that have made it possible for us all to come here today, and in particular, Trevor Price. And so with that, if there's time, I'll be happy to take questions. [APPLAUSE]


Located on the northern Atlantic coast of South America and inhabited by Amerindians indigenous peoples, Guiana was first encountered by Europeans in 1498 when Christopher Columbus reached it, naming the region the "Land of Pariahs". Several attempts to colonize Guiana were made by European states, all of them failing, until the late 17th century when France somewhat successfully colonized the region. While it switched hands many times during the next few centuries, it eventually returned to the French.

The history of French Guiana since colonization can be said to largely have been defined by imprisonment, escape, and rebellion. Many slaves brought from Africa in the region escaped between the mid-17th century and onwards, forming independent maroon communities together with indigenous tribes. Contemporary communities of escaped slaves in neighboring Brazil, such as Palmares (1605–1694) and its leader Zumbi, have sometimes been upheld by modern anarchists as examples of early anti-colonialism, decentralization, and democracy.[1][2]

These communities of free escaped slaves often waged war against the French colonial settlements. Additionally, slave revolts were relatively frequent. A prominent was one in 1796, when riots broke out after plantation owners refused to obey the abolition of slavery enacted by the French First Republic. After the execution of the same man that had carried out said abolition, Maximilien de Robespierre, in 1794, 193 Jacobin supporters - political radicals whose involvement in the French Revolution and one-time alliance with the revolutionary sans-culottes had an immense impact on the later development of revolutionary and libertarian thought - were deported to Guiana. They were the first of many political prisoners to come. When in 1797 Jean-Charles Pichegru and others were sent to the colony as prisoners, they found that only 54 of the deportees were still alive, the rest had either succumbed to tropical diseases or escaped.[3]

Another slave revolt came in 1804, when Napoleon reintroduced slavery in France's American colonies. After the French Revolution of 1848, in which early anarchists like Pierre-Joseph Proudhon and Joseph Déjacque participated, slavery was again abolished, leading to a massive increase in the maroon population.

From the mid-19th century, French Guiana became one of France's primary penal colonies, seeing a massive influx of both criminal and political prisoners over the next century. One early prisoner was Louis Charles Delescluze, arrested and deported in 1853, who after his release in 1859 became associated with the International Workingmen's Association, later becoming a prominent leader of the revolutionary libertarian socialist Paris Commune. The Communard, who was killed on the barricades, wrote an account of his imprisonment in Guiana; De Paris à Cayenne, Journal d'un transporté.[4]

Most political prisoners were placed on the Îles du Salut, especially the notorious Devil's Island, which was active as a prison between 1852 and 1953. It became controversial for its reputation of harshness and brutality. Violence between prisoners was common, tropical diseases were rife, and guards were often corrupt. While most prominently known for its connection to the Dreyfus affair, many French anarchists were imprisoned on the island as well, during the late 19th and early 20th century. Many of them were illegalists, engaging in propaganda of the deed and individual reclamation.

The most prominent anarchist imprisoned in French Guiana was the illegalist Clément Duval (1850–1935), who - unable to work after being wounded in the Franco-Prussian War - turned to theft. Duval, a member of the Panther of Batignolles, was first sentenced to death for burglary (and stabbing the policeman arresting him repeatedly), but later had the sentence commuted to hard labor on Devil's Island. He spent the next 14 years in prison, attempting escape over 20 times. In April 1901, he succeeded and fled to New York City, where he lived until the age of 85. His memoirs were published in 1929, titled Outrage: An Anarchist Memoir of the Penal Colony.

In 1894, an anarchist-led prison revolt broke out on Devil's Island. The troubles began in September, when a jailer killed the anarchist Francois Briens. On 21 October, the jailer was stabbed to death. In the following manhunt, Achille Charles Simon - an accomplice of the executed bomber Ravachol - was shot after being found hiding, as were the anarchists Marsevin, Lebault and Jules Leon Leauthier (the later of which had been sentenced for trying to stab the Serbian Minister in Paris to death[5]). In the following chaos, the guards killed numerous anarchist prisoners, among them Dervaux, Boesie, Garnier, Benoit Chevenet, Edouard Aubin Marpaux, Mattei, Maxime Lebeau, Mazarquil, Henri Pierre Meyrveis, Auguste Alfred Faugoux, Thiervoz, and Bernard Mamert. Others died long after, due to the rough conditions and torture, among them Mamaire and Anthelme Girier.[6]

Other anarchist prisoners in French Guiana included Marius Jacob, an illegalist burglar who spent fourteen years in Cayenne and was one of the inspirations for the author Maurice Leblanc's character Arsène Lupin, the Bonnot Gang members Jean De Boe (who after his escape in 1922 fled to Brussels, becoming a noted anarcho-syndicalist) and Eugène Dieudonné (who was pardoned, after escaping prison in December 1926), and Paul Roussenq, who spent a whole twenty years in Guiana on charges of military insubordination, later visiting the Soviet Union (becoming a firm critic of it) and being interned by Vichy France.[7]


French Guiana remains part of France, now as an overseas department and region, not a separate territory. It remains the only territory in continental Latin America that have not been decolonized by its associated European power, and has little autonomy from France itself. The region's political situation is dominated by Guianese Socialist Party, in addition to other left-wing parties like the Democratic Forces of Guiana, Walwari, and the Decolonization and Social Emancipation Movement. In 2004 the French anarcho-communist movement Alternative libertaire established a local group in French Guiana. Alternative Libertaire Guyane is engaged in primarily anti-colonialism, but also labor struggles, immigrant rights, housing issues, and so on.[8]


  1. ^ Rodrigues, Edgar (1999). Universo Acrata, Vol. 1 (in Portuguese). Florianópolis: Editora Insular. ISBN 858-594-979-1.
  2. ^ "Brazil: Interview with the Coletivo Zumbi dos Palmares". 4 October 2005. Retrieved 1 September 2014.
  3. ^ Belenus, René (1998). Les abolitions de l'esclavage aux Antilles et en Guyane françaises: 1794 et 1848: textes et recueil de documents sur l'émancipation des esclaves (in French). Pointe-à-Pitre: Centre départemental de documentation pédagogique de la Guadeloupe. ISBN 290-364-982-0.
  4. ^ Delescluze, Louis Charles (1869). De Paris à Cayenne, journal d'un transporté (in French). Paris: Le Chevalier.
  5. ^ Merriman, John (2009). The Dynamite Club: How a Bombing in Fin-de-Siecle Paris Ignited the Age of Modern Terror. Boston: Houghton Mifflin Harcourt. ISBN 061-855-598-6.
  6. ^ Duval, Clément (2012). Outrage: An Anarchist Memoir of the Penal Colony. Oakland: PM Press. ISBN 160-486-500-8.
  7. ^ Vidal, Daniel (1998). Paul Roussenq le bagnard de Saint-Gilles. Brussels: Alternative Libertaire Belgique.
  8. ^ "Alternative Libertaire in French Guyana". 4 March 2005. Retrieved 1 September 2014.
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