Level 5 Reading 8B

Reading 8B

OF ANTS AND HUMANS E.O. Wilson, one of the world's foremost authorities on biodiversity, discusses his lifelong love of the natural world, including its smallest members. How did you develop a passion for nature? When I was nine years old and living in Washington, D.C., I somehow got excited about the idea of expeditions to far-off jungles to collect the sorts of things you saw in National Geographic. So I decided I would do some expeditions to Rock Creek Park, and I got bottles and everything, and I started collecting there. I would go on my own and wander for hours. Then I went to the National Zoo, which was paradise on Earth for me. How could you avoid becoming a naturalist in that kind of environment? Is that kind of exploration a rarer experience for kids today? I worry about that. I have no data, but it appears to me that many of our young people are staying at home or being influenced by an increasingly stimulating "artifactual" world. Fake nature, sci-fi movies, videos, being drawn into lives that are pursued in front of a computer. That's a trend that would take young people away from a naturalist's experience. But there are counter-influences. More people go to zoos in the United States than attend professional sports; did you know that? There's a strong pull remaining that I think is primal. Darwin loved beetles. What was it about ants for you? Originally, I was going to work on flies because I felt that was a wide-open area to do exploration, but I couldn't get the special insect pins to collect them. It was 1946, just after the Second World War, and those pins were not available. So, I turned to ants because l could collect them in bottles of alcohol. Do some say that this isn't serious science, its just collecting? Well, when people say that sort of thing, you can respond quickly that you're not going to get anywhere until you do this science, and furthermore, you're going to make all sorts of new discoveries while you're doing it. You never know when someone is going to be looking for some kind of lead in this growing body of information from mapping life on Earth. For instance, someone might say, "What I need for my work is an ant that hunts underwater and walks around submarine fashion and then comes out and goes back to a dry nest. Does any such thing exist?" It turns out, yes! A submarine ant? Yes, in Malaysia, on the pitcher plant Nepenthes. This plant collects water in which insects fall and drown, and there are substances in the water that help digest the insects. Nepenthes gets organic material from the insects it captures. There is this ant that lives on Nepenthes, and the workers walk in, right down into the mouth of hell. They just walk right in submarine-like and pick up insects that have fallen to the bottom. Are you doing any field trips these days? I get together with younger ant specialists— they all seem younger to me, these days— and we go into the field. On a recent trip to the Dominican Republic, we went up to 2.4 kilometers above sea level. Most people don't know the Dominican Republic has mountains. We were all the way up in cold pine forests, discovering new species at every mountain site. There's no feeling that the world has been conquered now? Oh, no. That's the point—we're just beginning exploration. For animals, we probably know as few as 10 percent of the species. Even in a fairly familiar group like ants, we're discovering them right and left. I estimate that maybe half the ants in the world remain undiscovered. How well did Darwin know his ants? Darwin knew his ants very well. He spent a lot of time watching ants, and part of the reason was that ants exemplified a peculiarity that he said might have proved fatal to his theory of evolution. And that potential flaw was that worker ants are so completely different from queen ants, yet they are sterile. So how would you explain that by natural selection? If worker ants couldn't have offspring, how are their traits developed and passed on? The problem was how this kind of self-sacrifice— tending the queen while giving up reproduction— evolved? Yes, and Darwin solved the problem: What counts is the group, and that worker ants are just part of the colony, just an extension of the queen. Her heredity is what matters. If she is producing separate organisms that serve her purpose, then all together, these colonies can prevail over solitary individuals. That was the solution, and actually, that isn't too far from the way we see it today. The most recent theories [are] spelled out in a book that Bert Holldobler and I wrote called The Superorganism. Why that title? The colony is the next level of biological organization. The colony, by group selection, has developed traits that could not be possible otherwise— communication, the "caste" system, cooperative behavior. It's a unit of activity ant of evolution. One colony against another is what's being selected. This happens to be close to Darwin's idea but in modern genetic terms. How does this kind of social behavior get started? It has to do with defense against enemies. Naturalists have discovered more and more groups that have altruistic workers and soldiers— ants, termites, certain beetles, shrimp, and even a mammal, the naked mole rat. What's consistently the case is that these animals have a resource, usually a place to live with food, that's very valuable. If you're a solitary individual and you build a chamber like that, somebody could chuck you out. The idea is that these lines are going to find it advantageous to develop sterile castes for maintaining and protecting the colony. So, this is a story about community and home. I've learned my lesson about jumping from ants or sponges to humans! But it does, in my opinion, call for another look at human origins.

Anthropologists now pretty much agree that a major factor in human origins was having a habitation, a campsite, which allowed for certain specialization, where some stayed and looked after the site and the young and so on, while others ventured out to bring food back. And the pressures from predators must have been pretty intense. But we don't have sterile castes. No, we have a division of labor. That is very true, and that's a fundamental difference between us and insects and these other creatures, and that's why we have to be very careful about drawing analogies. Because human beings are so flexible and intelligent, we can divide labor without physical castes. That system has worked pretty well for ants. They dominate ecosystems. In tropical forests, from one study, ants alone make up four times the weight of all the land vertebrates put together— amphibians, reptiles, birds, mammals. The weight of all the ants in the world is roughly the weight of all the humans... They are the principal predators of small animals, the principal scavengers in much of the world, and the principal turners of the soil. It's interesting that ants and humans are both social and that both dominate their environment. Sure enough, we're the one highly social vertebrate with altruism and high levels of division of labor, though not sterility, We're the one species that has reached this level, and we dominate. We also have a tremendous effect on other species. More than any kind of ant. But I'm always at risk of having it said, "That nut wants to compare ants and humans." Well, obviously not. Beyond the fact that we both reached high levels of social behavior based on altruism and division of labor, the resemblance between humans and ants pretty much comes to an end. For example, they communicate almost entirely by taste and smell. They live in a sensory world that's totally different from humans. It's like ants are from another planet. And ants are constantly at war. Well, so are we! But they are the most warlike of animals. It makes you wonder whether war and complex societies go together. It may turn out that highly evolved societies with this level of altruism tend strongly to divide into groups that then fight against each other. We humans are constantly at war and have been since prehistory. I know a lot of people would like to believe that this is just a nasty habit we developed, just a cultural anomaly, and all we have to do is get enlightened and drop it. I hope that's true. Do the ants offer any lessons? At least not any we would care to put in practice. Ant colonies are all female; males are tolerated only part of the year. Slavery and cannibalism are commonplace. There is one lesson we have already learned, however: Ants keep themselves fanatically clean, so epidemics are rare. But now ants and many other creatures are threatened with extinction. Are you hopeful that we can save enough in time? Actually, I am. The best funded global conservation organizations are now scoring successes in persuading developing countries to set up sustainable reserves— sustainable meaning they provide an actual increase in the quality of life for people living in and around them. That doesn't take as much money as some have thought. It can be achieved in many of these countries where the greatest destruction is occurring because incomes may be just a few hundred dollars a year. There are reasons to believe that where most of the biodiversity occurs— the tropical forest, grasslands, and shallow marine areas—a lot can be saved.

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