Megan Frederickson Interview Transcript
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Timecode / Content / Shot/NotesAmy Steptoe: Can you introduce yourself and your work?
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0.2.20.0 / Megan Frederickson: I’d love to.
My name is Megan Frederickson, and I’m currently a junior fellow at the Harvard Society of Fellows. Um, last year, about this time, so in 2006, I got my Ph.D from Stanford University where I studied, um, ants for my Ph.D thesis, and I continue to study ants, mostly in the, uh, rainforests of the Amazon, in Peru. Uh, and I’m currently doing that, doing more work on, on ants in the Amazon right now.
Should I keep going?
Um, uh, for the better part of the last two or three years I’ve been studying, uh, ants that make these very unusual gardens in the r-rainforests of the Amazon that are called “devil’s gardens.” Um, devil’s gardens are very strange places, because they are clearings, um, where only one or at most two species of tree grow, and these clearings occur in the middle of very diverse Amazonian rainforests, where usually there are hundreds of tree species growing together.
And they are called devil’s gardens by local people because local people believe that they’re cultivated by an evil forest spirit, and his name is supposed to be the, the Chuyachaqui. Um, but, in actual fact, I did, um, quite a bit of work to show that these gardens are cultivated by ants.
Uh, should I just keep going, or, um, or how should I do this? / CU
Master on grow
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Amy Steptoe: Why did you decide to study ants?
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0.3.49.0 / Megan Frederickson: Um, that’s a great question.
Uh, ants are really fascinating, uh, subjects of study for many reasons. I’ve, um, long been interested in studying, uh, the evolution and ecology of cooperation, so, uh, cooperation is really, um, any behavior, uh, or act of organisms, that, uh, uh, provides a benefit to another organism, either something that the organism is related to or not, um, and there are many fascinating examples of cooperative behavior in biology, and ants are, are one of the most interesting, because they live in societies, um, they live in colonies, and, uh, ants cooperate among one another in order to accomplish the tasks necessary for the colony to grow and reproduce, to gather food, and to take care of the young, and other, um, and other such tasks.
Uh, I also study cooperative behavior between species, so, mutualisms. I’m particularly interested in mutualisms between, uh, ants and plants, which adds a whole other level of cooperative behavior to the study of ants, which are cooperative among themselves, and the study of um, ants which are often cooperative with plants or other insects, um, in many fascinating ways. / CU on ants0.2.38.0
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Amy Steptoe: How do ants communicate?
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0.4.8.0 / Megan Frederickson: Um, so ants communicate, largely, um, um, chemically, and, uh, they do so, um, by receiving chemical signals through their antennae…
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0.5.21.0 / Megan Frederickson: Ants communicate, um, largely using chemical signals, and they, um, receive chemical signals from the environment, uh, usually through their antennae, um, and, uh, and then interpret them in some manner and respond to them in, with, with some behavior.
Um, ants can see visual cues, so they can see, but, um, many chemical cues are often stronger. So, um, they are very famous for leaving, uh, for many species of ants, they use, uh, pheromones or chemical signals in which to mark trails, so that they, um, uh, “know” where to go out and forage, uh, to look for food. Um, they also use chemical signals, uh, to communicate alarm to other members of the colony. Um, presumably, uh, to, to look for mates, uh, to look for adequate nest sites, and, um, in many other ways.
Amy Steptoe: How are ants complex social creatures? / CU
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0.6.59.0 / Megan Frederickson: Ants are very complex social creatures. Um, ants live in colonies, which can vary a great deal in size. Sometimes their colonies will have just a couple hundred ants, sometimes they can have as many as several million ants.
Um, in colonies, there are really two different kinds of ants, normally. There is the queen, um, and she is responsible for laying, usually responsible for laying all of the eggs in the colony. And those eggs eventually develop into either more queens, which will go out and found colonies of their own, or into workers, which, um, are sterile so they th-themselves do not reproduce, um, but who accomplish all the important tasks for the colony, such as going out to forage for food, and taking care of eggs inside the nest, uh, cleaning the nest by getting rid of, uh, debris, um, uh, constructing the nest by, uh, building chambers or excavating areas, uh, of, of soil, um, uh, defense of the colony against a, any kind of predators that might try to eat the ants or, uh, the queen in the nest, and many other tasks.
Um, they’re complex so-, uh, social, uh, um, and, they have complex social interactions because, um, the ants have to coordinate their behaviors inside the nest in order to provide food and defend the colony and rear the reproductives in the nest.
Amy Steptoe:Can you discuss the division of labor in an ant colony? / Master
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0.8.31.0 / Megan Frederickson: Um, the division of labor in an ant colony can take on many different forms. And it varies a lot from one species of ant to another.
So all ants have a division of labor, between the queen, who, um, only lays eggs in the colony and is responsible for all of the reproduction, um, and the workers, who do all these other tasks: of going out and looking for food, and cleaning the nest and taking care of the young.
Um, in many ant colonies, um, the worker population is further subdivided into different, into accomplishing different tasks. For example, uh, in the harvester ants, um, in Arizona, uh, there are workers who go out in the morning and patrol, uh, um, and, and I suppose, communicate some kind of signal to the colony, whether it’s a good day to go out and forage for food, and where, perhaps to go out and forage for food, and then there are workers whose task is to go out and forage for food.
Um, there’s also workers who are dedicated to, uh, cleaning the nest, and workers who are dedicated to staying within the side, within the nest and rearing the brood. Um, um, um, but it depends a great deal on which ant species, how, um, how subdivided the worker population is, and into how many different tasks. Um, and whether or not those tasks change over the lifetime of individual workers. / CU on For
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Amy Steptoe: Discuss the gender balance in the ant world. / Master
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0.10.54.0 / Megan Frederickson: So, many people…let me start again. Um…
The gender balance in the ant world is quite unique, because, really, all ants that you’re likely to see on a day-to-day basis are female. Um, and they have this unique, um, uh, sys-system for determining, um, the sex of an ant. It’s called haplo-diploidi, which is a very fancy word for something that’s actually quite simple. So, uh, females in ant-, um, ant females are produced by fertilized eggs, where males are produced by unfertilized eggs that are laid by the queen. So the queen and all of the workers in the colony are females. Um, and so all of the work of the colony is accomplished by females, and, uh, but most of those females are sterile. So they will never, um, reproduce.
Uh, the queen will lay, um, fertilized eggs, which can have one of two fates. They can either become workers, which, uh, will never reproduce: they will just, um, be responsible for feeding and caring for the colony, or they can produce, uh, fertilized eggs, which are also female, which, um, are winged, that will be queens of future nests. And so those winged females will at some point leave the nest that they were born in, and, uh, search out for a male, which is an unfertili-, which was produced from an unfertilized egg laid by a queen, and also has wings, and then they’ll mate, um, and, uh, right after mating, or very shortly after mating, the male will actually die. So males in ant colonies don’t live for very long.
And then the mated, uh, reproductive female will, um, start looking for an adequate nest site, um, in order to start laying eggs, and she’ll shed her wings, and she actually eats her wings in order to provision herself, um, during the time it takes for her to lay her first eggs, um, and produce workers, and until the workers can start to gather food to feed, um, to feed the larvae and eggs in the nest. Um, and, uh, and then she will continue to lay eggs, and produce workers, and males and female reproductives, um, for the rest of her life. / Glitch on
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Amy Steptoe: Why is the queen ant important?
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0.11.49.0 / Megan Frederickson: The queen ant is very important in an ant colony because she is the only ant who, um, can reproduce. Um, so she’s the only ant in the colony who lays eggs. Uh, really other than that, she does very, very little.
Uh, after she’s founded her colony, she’s usually, uh, located in some, um, relatively protected or enclosed space, usually deep within inside, inside the colony, if it’s a colony of ants nesting inside the ground, or inside the trunk of a tree, if it’s a colony of ants that is nesting in a tree.
And, um, she doesn’t usually venture out to do anything, she just lays eggs. And those eggs develop into workers, which do all the external work of the colony: of looking for food, and defending it against attack.
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Amy Steptoe: Why do ant societies work?
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0.17.48.0 / Megan Frederickson: Why do ant societies work? That’s an excellent question. Um…
Ant societies work primarily because, uh, they have evolved ways to allocate tasks and hence have evolved ways, um, for individual ants to specialize on particular tasks within the colony.
Um, and also, uh, um, I think that one of the primary reasons that ant colonies work and ants are so ecologically successful around the world is because, um, only the worker ants actually leave the nest, and hence are exposed to all the dangers that, um, can, uh, uh, um, imperil ants outside the nests, like, um, being eaten by some other, by a bird or, or some other insect. Um, or being, uh, if, ants that spend a lot of time outside the nex-, nest are actually very prone to desiccation, so they can dry out, um, and they keep the queen inside the nest environment, which is a very sort of safe and protected environment. Um, and, uh, as a result, uh, ant colonies can actually be quite long-lived, and, uh, it’s not so important if an ant clon-, ant colony occasionally loses a few workers, um, to predation or environmental stresses. Um, the queen is still safe and sound, and can continue to lay eggs, and, uh, can continue to have her colony grow.
Um, ants are also le-, also, um, very ecologically successful because they have a lot of complex interactions with, uh, with other, um, other insects, and in particular, with plants. Um, there’s been a lot of recent work on how the interactions between ants and plants may be responsible for, um, for ants becoming, uh, so diverse and so, um, ecologically abundant.
Uh, there actually, um, uh, there’s actually a great study that was published in the 1970s, um, and, uh, and, and some of the data was re-analyzed in, in the 1980s, um, by a professor, E.O. Wilson, who I believe will be speaking with you as well. Um, and he, uh, showed that ants are actually, uh, four times the biomass of all of the terrestrial vertebrates in an Amazon rainforest put together. So that means if you went out to an area, and collected all the ants, and all of the terrestrial vertebrates, which includes all the mammals, so jaguars and monkeys and birds and, uh, reptiles and amphibians, the ants would actually weigh four times more than all the, um, these other things put together.
So, really, they’re, um, extremely successful ecologically, and extremely abundant in many environments, particularly in tropical rainforests. / CU on queen
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Amy Steptoe: Do they work better than human societies?
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0.18.54.0 / Megan Frederickson: Do ant societies work better than human societies? Well, um, that’s kind of a loaded question. Uh…
It’s really hard to know…it’s hard to compare ant societies and human societies in many ways, because, um, the, uh, th-the, um, success rates, so, you know, for an ant colony to work well, basically what it needs to do is, um, grow, survive, and reproduce.
Um, and I think that for human societies, we would usually use a different kind of standard for whether or not a human society is working well than growth, survival, and reproduction. We’re also interested in, you know, the advancement of knowledge, and peace, and all of these things, which ant colonies can’t really be said to be interested in. Um, ant colonies, they coordinate their activities very differently than, than, than human societies, so, it’s almost like comparing apples and oranges. / Sounds like
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Amy Steptoe: Why are ants so aggressive?
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0.20.14.0 / Megan Frederickson: Well, many ants are very aggressive, but not all ants. There are some ants that are actually very timid. Um, ants can be very aggressive because they have to defend themselves against attackers. And ants have a, a wide array of chemical and physical defenses that they use to fend off attackers, and, um, most people will probably have been bit or stung by an ant at some point during their lives. Um, and, uh, ants are, the worker ants are primarily defensive because they’re defending, they’re defending their nest and their queen.
Uh, I don’t know whether I should say any more about why, um, uh…
The ants, of course, want to defend their queen, uh, because she’s responsible for, for laying all the eggs that is going to, um, produce more workers in the colony.
Uh, I guess there have been, uh, some people who have hypothesized that ants can be very aggressive, because, um, because if the workers are sterile anyways, they don’t have too much to lose if they happen to lose out in a battle with another insect, or with a vertebrate, or with any kind of enemy.
Amy Steptoe: What do ants do, especially for our ecosystem?
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0.22.12.0 / Megan Frederickson: Ants do a lot of really important things for ecosystems. Um, I’m mostly familiar with the Amazon rainforest because that’s where I do all of my research. Uh, in the Amazon, for instance, ants actually aerate more soil than earthworms, so they’re responsible for, um, providing fertile soil in which a huge number of plants and other species depend.
Um, uh, ants are, um, uh, very important, um, in playing other roles in the ecosystem as well. They have complex interactions with plants. Um, in tropical rainforests, uh, such as the ones in which I work, they often defend plants against attack by other insect herbivores. So, um, for plants, they’re, uh, responsible for keeping plants from being eaten by other insects, usually by—from beetles, or, uh, caterpillars, or, um, in some places in the world, even, um, even, ants even defend plants from being eaten by, uh, by, by, by large grazing animals, like giraffes.
Um, and, uh, uh, what, what other functions do ants have in, in, ecosystems? Well, um, (pause), hmm, um…
Ants sometimes are important as seed dispersers, and, uh, they are often important mutualists with, um, other insects as well, as with, uh, for instance, with aphids, or with, uh, butterfly caterpillars, and so there are many animals and plants which depend on ants, um, for their own growth, survival, and reproduction.
Amy Steptoe: Talk about ant agriculture?
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0.24.29.0 / Megan Frederickson:Ant agriculture is a fascinating subject and something that I’ve been very interested in for a long time. So, um, many ants, uh, behave in such a way that is very similar to, um, to, to human agriculture. So they cultivate some kind of crop.
Um, and in the case of, uh, uh, my study system, where I’ve been working in Peru, the ants are actually responsible for cultivating, um, this tree that they live in. And this tree is, its scientific name is Duroia hirsuta. Unfortunately, it doesn’t have a common name, um, uh, at least not in English. So, um, the ants actually make these very large gardens, um, where only this tree grows, and they do it by killing out, killing off all other kinds of vegetation except for the tree in which they live. And these gardens can get to be very, very large. Um, they can be a thousand trees and cover an area, (pause) at least the size of a soccer field or so. So, um, in many ways ants are, are maintaining their, their, their, crop or they’re, um, they’re growing their, their, their, home, um, by cultivating this tree species.
And it’s not uncommon, um, for ants to behave this way. Uh, um, ant agriculture is known from a lot of different systems, for instance, leafcutter ants in, uh, the r-, in tropical rainforests, in places like Peru and Costa Rica, and, and, um, and most of Central and South America are actually, um, leafcutter ants are, are famous of course, for, for being, uh, one of the most important herbivores in, in South America. They, um, eat huge, huge, e-, well, they don’t eat, they collect huge and huge amounts of leaves, and bring them back to the nest. And they actually feed these leaves to a fungus that they cultivate inside their nest. And then, um, they feed the fungus to the, to the eggs and the larvae in the colony. Um, and so yet again, it’s an example of, of ant agriculture, ’cause these ants are, are, are cultivating a fungus inside their nest, um, in order to have a, a, consistent, um, and adequate food source for their offspring.