Naturalist Dehua Wilson: The Story of the Ant Society

Ants are everywhere; black and light red dots travel around on the ground and in caves; this kind of earth dweller with a weight of only milligrams and a strange civilization avoids our eyes and eyes. For more than 50 million years, ants have been the overwhelming majority of insects on the ground outside the polar regions and the tops of frozen mountains. According to my estimation, there are between 1 000 trillion and 100 billion ants living on the earth at any time. Adding up their total weight, it is almost equal to the total weight of all human beings.

Ant

However, in this equation, a very important difference is hidden: the number of ants living is just right, but there are too many humans. If human beings suddenly disappear from the earth, the surface environment will return to the state of fertility and equilibrium before the population explosion. Only about a dozen creatures depend entirely on the human body to live, such as lice and mites that live in the sebaceous glands of our foreheads. However, once the ants disappear, there will be tens of thousands of species of animals and plants on the earth also disappear, and almost all terrestrial ecosystems will be degraded and decayed as a result.

Pharaoh Ant Incident

In addition, ants have also been deeply involved in our world, which can be seen in an accident that occurred in the Biological Laboratory Building of Harvard University in the late 1960s. If I were allowed to use words casually, I would call this incident “Ant’s Revenge”.

The big trouble started like this. Putashny’s laboratory is a very active laboratory that specializes in gene expression. The assistant inside is about to start a routine job one day: dripping sugar into a bacterial petri dish. However, she could not suck up the liquid that day. Looking closely, she noticed some small yellow ants stuffed in the narrow glass straw. Then everyone noticed that there were more subtle symptoms of this strange invasion in this building.

Leftover food from lunch or afternoon tea is always quickly filled with these small yellow ants. Part of the breeding colony, including the queen and the worker ants surrounding the young ants, also appears under glassware, in letter files, or in notebooks like magic. However, the most shocking thing is that the researchers also discovered that the ants got radioactive materials from the petri dishes, leaving faint traces of radioactive materials on the floor and walls of the laboratory. After a careful inspection, everyone found that a large group of super ant colonies of the same species were spreading to all sides of the building through the space between the walls.

I have reason to believe that this ant invasion is related to me. It started in my own room. This ant is called Monomorium pharaonis, commonly known as “Pharaoh ant”. It is a notorious pest originating from the East Indies, and it is a nuisance to buildings all over the world. Once the super colony enters the hospital, the worker ants will eat human tissues removed by surgery and wound tissues of patients with limited mobility, and sometimes spread germs in the process. Some settlements will move on their own, by boarding luggage, books, clothing, or anything that has a space of one or two centimeters. After arriving at the destination of Suiyuan, they moved out and began to multiply. Such a destination could be a flower shop in St. Louis, an apartment in Oslo, Norway, or a construction space in Caracas, Venezuela.

Afterwards, we traced the ins and outs of the pharaoh ant’s nest building at Harvard, thinking that it should have come by plane from the airport of Belém, a port city in Brazil. First, a part of the super colony sneaks into Robert Jeanne’s two wooden boxes. At that time, Genie was a PhD student under my supervision, and he is now a professor of entomology at the University of Wisconsin. In 1969, Genie had just finished a long field survey of the Amazon rainforest and returned to the United States. When he returned to the biology laboratory of Harvard University and opened the suitcase, he found that this group of hitchhiking ants had made nests on the walls of the wooden box, and they were spreading everywhere.

If you want to eliminate a large group of pharaoh ants through formal channels, the cost may be very expensive, and you have to make a lot of efforts. At this time, the entomology graduate student Gary Alpert, who was particularly interested in pest control, devised a very clever alternative. He ran to ask Williams, Professor of Insect Physiology at Harvard University. Williams provided a chemical that could simulate the action of insect juvenile hormones, making the queen infertile and preventing the larvae from developing completely and becoming adults.

Alpat mixed this compound with peanut butter to make bait, hoping that the foraging ants would bring it back to the nest so that it could spread the destructive power of the bait. At the time, this method was still in the early stages of the experiment, but it was quite effective. After a few months, the ant population began to decline steadily. Two years later, they disappeared without a trace.

However, the heroic deeds of the pharaoh ant did not end there, it ended in the title page of the science fiction novel. In 1983, William Patrick, who was still an editor at Harvard University Press, wrote a novel “Spirals”. The plot of the story was inspired by this ant invasion. In the book, an ant he imagined is suspected of bringing genetically engineered DNA from the laboratory. This DNA can cause progeria and accelerate the death of patients with aging. The daughter of the key figure in genetic engineering technology in the book also died of this disease. She became an old woman before her childhood was over. At the end of the novel, the ant finally cleared his guilt. It turned out that the researcher made a mistake: he cloned a daughter from his dead wife by extracting cells from his dead wife, so the daughter’s development process was deformed and distorted.

Even if they are not the protagonist of the novel, the ant is still worthy of attention. I put them at the center of my career, with almost paranoid attention to them, and I do think this is a wise move. However, I have to admit that what attracted me the most at the time was not their environmental and ecological importance, nor their social evolutionary stories. This attraction comes from the new discoveries they generously provided to me. Among the research topics I put forward, the most important one is the communication method of ants. This topic has led me to carry out fruitful long-term research in animal behavior and organic chemistry.

Lorenz shocked

My interest in chemical communication began in the autumn of 1953, when Niko Tinbergen and Lorenz visited Harvard University to explain the emerging science of animal behavior. Twenty years later, they won the Nobel Prize in Physiology and Medicine, as well as Austrian zoologist Karl von Frisch (the hypothesis of the dance language of bees).

Timbergen was the first to arrive at Harvard University. He was an Englishman of Dutch descent who used precise and careful words. He gave a speech on animal behavior, and his important findings shocked me deeply. However, since my interests are mainly in taxonomy and biogeography, they are at a distance from behavioral studies. Therefore, I don’t remember many notes and didn’t pay much attention to the lectures.

Then Lorenz drove over. He talked about his research since the 1930s and continued to talk about his work at the Max Planck Institute at that time. He is a man born on the podium, full of enthusiasm, anger, and constant petitions. The words he emphasized to us soon became well-known in the behavioral science community, such as “imprinting” (also known as inscription), “ritualization”, “aggressive impulse”, “overflow” and other words; also There are famous animals, such as wild goose, jackdaw, stickleback, etc. He foretold new ways to study behavior. He pointed out: “Instinct” has returned to its original position; the role of “learning” has been overemphasized by Skinner (B.F. Skinner) and other behaviorists; we must continue to advance in new directions.

Lorenz grabbed my full attention. At that time, I was young and easily moved, and I immediately responded to his call. Lorenz is declaring war on the solid comparative psychology camp. He told us that most animal behaviors are predestined and consist of fixed behavior patterns. The so-called fixed behavior pattern refers to a series of actions predetermined by heredity, which will unfold one by one in response to specific signals in the natural environment during the life of the animal. If they are triggered at the right time and place, they will be able to guide animals through a series of correct steps to find food, avoid natural enemies, and reproduce the next generation smoothly. Animals don’t really need to rely on experience to survive, they just need to “obey” instincts.

“Submit instinct” seems to be an boring cliché. “Operant conditioning” sounds much more fashionable. However, Lorenz especially adopted the logic of evolutionary biology to emphasize his research case, which deeply won my support. He said that every animal has its own set of fixed behavior patterns. For example, a certain kind of bird will stretch its feathers in a specific way to attract mates among the same species. This action is fixed at a certain time of the year; in addition, some birds will build appropriate nests in appropriate locations. . Fixed behavior patterns are events in “biology” rather than “psychology”. They have a genetic basis and can be divided into categories and then studied one by one in the same way as studying anatomical parts or biochemical reactions, and they can also be studied on a species-by-species basis.

Each fixed behavior pattern is determined by a specific gene on a specific chromosome. When one species evolves into another, they will also change. Their functions are no less than anatomy and physiology, and can be used as the basis for animal classification and reconstruction of the evolutionary tree, because they can also clarify the true relationship between species.

This great animal behaviorist made me understand that animal instincts belong to the category of new comprehensive theoretical research in evolutionary biology. And this means that we can also put animal behavior into this field and conduct related research.

Lorenz’s speech, coupled with my own hard study for the next few months, led me in a new direction. This phenomenon revealed to me by animal behaviorists is exactly what I have been trying to do when I studied the stinging ant family in the early years. It’s just that I lacked both theory and vocabulary at the time. At this time, my thoughts began to rush.

Lorenz has returned animal behavior to the field of natural history, and this is my field. The people who are best suited to study animal behavior are naturalists, not psychologists who play with oversimplified mazes and white rats.

I learned that what is really important is a fixed behavior pattern. To understand it, you must treat this behavior as an evolutionary adaptation of an individual animal to a specific natural environment. If you observe a chimpanzee in a cage, even if you have tested all its possible learning abilities, what you can see is always only a small part of its preset behavior program, and even that small part is difficult. Figure out the full meaning of it.

Wrong object

What makes animal ethology even more fascinating is the principle: Although fixed behavior patterns themselves are complex, the signals responsible for triggering them are simple. Take European robins as an example. They were the subject of early animal behavior analysis. The researcher was British ornithologist Luck. Male robins are affected by spring hormones and use singing and display actions to drive other male birds out of their sphere of influence. If these warnings fail, it will flap its wings or prod the intruder with its beak. However, the male bird’s aggressive behavior is not really what we have seen, it is inspired by the overall image of a male robin. Its anger was mainly directed at the “red chest” between the branches. Therefore, a baby robin that is not sexually mature and has an olive-green breast cannot provoke their response, but you only need to tie a pinch of red feathers to the coil to provoke their full response.

Lorenz also selected several other cases of triggering stimuli or what animal behaviorists call “releasers”. Before 1953, most of the research cases focused on birds and fish, and he himself specialized in these two types of animals. However, the selection of these animals as research subjects implies a big prejudice: their communication medium is mainly sight and hearing. I immediately thought that the fixed behavior patterns of ants and other social insects should be inspired by chemical substances, which are substances that such animals can smell or taste. Early entomologists have thought about this direction. After all, these animals cannot see things clearly in their dark nests, and there is no evidence that they can hear sounds transmitted in the air. Some early scholars also believed that ants would use their tentacles and front feet to touch each other, using a way similar to the blind Morse code to communicate.

In 1953, we still knew nothing about the body structure of ants receiving smell and taste chemicals. With one exception, British biologist J. D. Carthy discovered in 1951 that ants The hindgut secretes some kind of trail substance, which is excreted through the anus. However, no one can determine what the gland secreting the molecule is, where it is, or identify the chemical structure of the trace pheromone.

This concept of fixed behavior patterns and releases made me think of a way to enter the unknown world of ant communication. This method should consist of several consecutive steps: decipher the social behavior of ants into a fixed behavior pattern; then, use trial and error to determine which secretions contain this release; finally, by The secretion distinguishes and identifies the chemical substances that actually work.

Looking for the mysterious ant signal

As far as I know, I am the only one who has thought of this research method. Therefore, I don’t think I need to rush to start. In any case, I always feel that I should finish my doctoral dissertation first, and my doctoral dissertation experiment is about the anatomy and classification of ants of the genus Trichosanthis, which is very tiring.

In the fall of 1954, after the completion of my PhD thesis, I left the United States for the South Pacific to conduct my research on ant ecology and island biogeography. Four years later, I finally have a well-equipped laboratory at Harvard University where I can begin to study the chemical releases of ant communication. Even at that time, other people obviously didn’t think of this idea; my chances are pretty good. Adolf Butenandt, Peter Karlson, Martin Lüscher and others introduced the term “pheromone” into the ethology vocabulary only a year later. Replace the original term “ectohormone” (ectohormone). They defined the term “hormones” as “chemical pheromones in animals”, and pheromones as “chemical pheromones between individual animals”.

I started my research with exotic fire ants. This is my favorite kind of ants since I went to university, and they are also one of the social insects that are easiest to keep in the laboratory. I newly designed an artificial ant nest, made small rooms and compartments with Plexiglas, and then stood them on a large glass platform. This design allows me to continuously observe the entire ant nest, and I can also arrange time freely, conduct experiments at any time and record all the ants’ responses. This super simple nest did not make the worker ants helpless. After a short period of time, they adjust to the lights of the new environment and perform daily tasks in a seemingly normal way. They quickly reproduced and prospered like a goldfish bowl full of small fish.

The most obvious form of communication for fire ants is to leave a smell on the path to food. When soldier ants leave the ant nest alone to go out for food, the path they take is irregular. When they encounter food that is too large or difficult to transport at one time, such as dead insects or aphids honey most commonly, they will walk back to the nest in a relatively straight path and leave an odor on the way back. . As a result, part of the nest of ants will follow this invisible path to the food location. When I observed the foraging ants from the side, I noticed that on the way home, the soldier ants always let the end of the abdomen (that is, the end of the ant’s body) touch the ground, and stabbed the tail at a short distance. Highlight and drag. Obviously, their chemical release is released by a needle, in a manner similar to the release of ink from the tip of a pen.

Now I have to determine the source of this compound. According to my guess, it should be somewhere in the abdomen of the worker ants. In the next step, I need to find the organ that makes this chemical substance, and use it to draw an artificial path made by me; that is, I need to steal the ant’s signal, and then use the signal to target them. say.

The abdomen of worker ants is about the size of a grain of salt, and it is packed with organs that are difficult to see with the naked eye. What makes this task even more difficult is that no one has ever studied the anatomy of fire ants before, so I can only refer to it. Anatomy of other ants, plus a little imagination.

I placed the snipped abdomen of the fire ant under a stereo microscope, and then used microneedles and fine forceps used by the clock master to open the abdomen and take out the internal organs one by one. Although these organs are very small, their size is just right for me to dissect them without using auxiliary equipment; if these organs are smaller, I have to use a micromanipulator, which is expensive. It’s difficult to operate, and I always hope that I don’t have to use it. If you buy an instrument of this kind, and the experiment fails, you will really lose money.

Although my hand is quite stable, I found that the muscles that are almost invisible to the naked eye vibrate naturally. When they get under the microscope, they are magnified into strong jitters. When I brought the tips of the microneedles and forceps close to the abdomen of the ant, the muscles of my hand spasm uncontrollably, which would be enlarged by 20 to 30 times. But I still found a solution: it’s very simple, just make muscle spasm a part of the dissection technique. Turn the microneedles and pliers into small drills, and use the muscle spasm to tear open the ant belly and squeeze out the organs in the body cavity.

Yes, that’s it

After this part of the work is roughly completed, I then rinse each organ with Ringer’s solution; the Ringer’s solution used here is artificial insect plasma prepared by comparing various salt concentrations in insects. Next, I used the simplest and most direct method I could think of to make an artificial trail. First, I put a few drops of sugar water on the glass plate where the ants are foraging near the exit of the ant nest to gather the worker ants. Then, when the cut is ready, mash each organ one by one with a sharpened birch applicator. Then, I pressed the tip of the stick on the glass plate and used the squashed semi-liquid material to draw a straight line. The straight line started from the surrounding worker ants colony and extended in the opposite direction of the colony.

I first tried the hindgut, the venom gland, and the fat body stuffed with most of the abdomen. Nothing happened. Finally, I tested Dufour’s gland. This is a tiny structure in the shape of a finger. The scientific community knows almost nothing about its related data. It only knows that it is a catheter leading to the base of the ant stinger, and this tube is a pathway for carrying venom to the outside of the body. . Will Du’s glands contain pheromones that leave traces? Yes, it does.

The reaction of the ant colony was very strong. I was expecting to see a few worker ants leaving the sugar water solution leisurely, trying to see what good things were at the end of the new trail, but what I got was dozens of excited ants. I saw them scrambling to embark on the path I prepared for them. While they are running, they sway the tentacles on their heads to detect molecules that evaporate and diffuse in the air. When they reached the end of the trail, they were in a mess, busy searching for prizes that didn’t exist.

That night, I couldn’t sleep at all. This inspiration was delayed for 5 years, and in the end it was reaped within a few hours-I found the first gland related to ant communication! Not only that, but I also discovered a new phenomenon in chemical communication. The pheromone present in this gland is not only a signpost when the worker ants forage, but also the foraging signal itself-during the foraging process, the pheromone is both a command and a guide. Chemical substances are everything. And the steps of bioassay immediately became much easier. I quickly realized happily that I no longer have to bother to arrange a lot of designs that are mixed with many other stimulus experiments for the results I want. As long as you do an effective and easy-to-measure behavioral experiment, biologists and chemists can work together to directly study the molecular structure of pheromones. If other pheromones (such as pheromones that trigger vigilance and gathering behavior) act in the same way as trace pheromones, we will be able to solve most of the chemical words used by ants in a short time.

In the next few days, I repeatedly proved the effectiveness of the trace pheromone. There is nothing more enjoyable in scientific research than to repeat an experiment and the experiment will succeed every time. When I drew the path to the entrance of the ant nest, the ants immediately poured out of the nest, even though I did not provide them with food first. In addition, when I spilled a drop of Duchenne’s gland concentrate made by many ants on the nest, the proportion of worker ants gushing out was quite high, and they were obviously looking for food, so they scattered in all directions.

Fight with fire ants

Next, I asked John Law, a chemist friend at Harvard University, to help identify the molecular structure of the trace pheromone. At the same time, another talented university student, Christopher Walsh, also joined our research group. Walsh later became a top molecular biologist and became the director of the Dana Farber Cancer Institute.

We are a powerful combination, but we have encountered an unexpected technical problem: We found that, at any time, the key substances in the Duchenne glands in each ant’s body are less than one billionth of a gram. However, this problem is not unsolvable. From the end of the 1950s to the early 1960s, when several types of gas chromatography and mass spectrometry (mass spectrometry) were first revealed, the use of these techniques could identify parts per million of a gram. Trace organic matter. In other words, we need a total of tens of thousands to hundreds of thousands of ants, and then collect their trace pheromones to make up the lowest dose required for the analysis experiment.

Where are we going to find so many ants? Based on my field research experience, I know that there is a tricky method. Whenever the stream soars and overflows to the fire ant nest, the worker ants will form a tight ball and float on the water. They use their bodies to form a living raft to safely wrap the queen and larvae. The ant colony follows the flow like this until it touches the surface. Once landed, the worker ants will rebuild a new nest. I explained this phenomenon to John Law and Walsh, and then went to Jacksonville, Florida, which is one of the southern cities closest to Boston and rich in fire ants.

We rented a car and drove to the farmland west of the city. There, we found that there were 60 cm high fire ant nests scattered all over the grass along the way. There are about 50 ant nests per acre (about 6 acres) of land, and about 100,000 or more ants live in each ant nest. We parked the car on the edge of the interstate, then shoveled the ant nests and put them into the slow-moving ditch. The soil gradually settled to the bottom of the ditch, and most of the ants in each ant nest surfaced. We scooped up the ant masses in the commotion with a kitchen filter spoon and poured them into a bottle of solvent.

John Law and Walsh quickly understood why this ant is called “fire ant”: the feeling of being stabbed by a worker ant is like a match burning near the skin. Moreover, every ant in the ant nest wants to stab you more than ten times in a row as long as it catches the opportunity. Our hands, arms and ankles were all bitten into a mess, leaving red and itchy scars. One or two days later, many small white pustules have grown from many wounds. I am thinking privately that my two outstanding colleagues may have made up their minds because of this, and they will stay in the laboratory for biological research in the future. After paying these prices, we finally returned to Boston with enough materials to analyze the trace pheromones.

However, even if enough raw materials are collected, the structure of the molecule is still elusive. John Law and Walsh further analyzed the effective part of the spectrum vector table. At this time, the most likely pheromone substance at the peak of the data was the pheromone substance, but the content was too low for further analysis. Is this substance extremely unstable during the separation process? It is very possible, but we have used up all the extracts now. Finally, the two chemists speculated that the substance may be a farnesene, which is the most common terpenoid compound composed of 15 carbon atoms in natural plant products. Their amount is not enough to determine the exact structural formula, and each double bond in the structural formula should have a certain position.

Twenty years later, this feat was finally accomplished by the chemist Robert Vander Meer and a research team in the US Department of Agriculture laboratory in Gainesville, Florida. They found that the trace pheromone of fire ants is actually a mixture of many farnesenes, one of which is “Z, E-α-farnesene”, and there are at least two or more similar compounds that can enhance the effect. One gallon (approximately 4.5 liters) of this mixture is enough to attract 10 million nests of ants, at least in theory.

One smell, one action

Since I found out the source of the glands of ant trace pheromone, in the next few years I have focused on interpreting the communication language of ants as much as possible. I noticed that the signal from a single soldier is not enough to express the amount of food or the lineup of the enemy. When I took a closer look at the path of fire ants, I stumbled upon a second type of pheromones related to social behaviors, which was specialized in mass dissemination.

Such information can only be transmitted from one group of worker ants to another group of worker ants. When many worker ants, say 10, overlap and draw paths in a very short time, it can convey the signal that “there is a target larger than the target shown by a single worker ant’s path.” If 100 ants move together, the smell will be even higher. When the food location is too crowded, or the enemy has been defeated, there are fewer ants in the colony that will leave a mark. Therefore, when the excess pheromone evaporates, the signal is also weakened, and the number of ants in the nest that comes to help also decreases.

The signal that drives a large group of ants to the target is surprisingly accurate. Later, someone pointed out that there are parallel reactions between a large group of brain cells in animals. Insect social settlements (the so-called “superorganisms”) have similar phenomena with the brain, the organ responsible for thinking. I believe that the first person to propose such a simulation was Douglas Hofstadter, who wrote a book “Gödel, Escher, and Bach-An Eternal Golden Belt” (Gödel, Escher, Bach: An Eternal Golden Braid), is a long discussion with both creativity and rigor, mainly discussing the characteristics of organization and creation.

The following question is often raised: Does the similarity of the brain and the super individual mean that the ant colony can “think” in a certain way? I don’t think so. As far as the composition of the brain is concerned, the number of ants in the nest is too small, and the organization is too loose. I continue to explore pheromones that are attractive or warning to ants. The simplest of these substances I have found is almost certainly the most basic of all known pheromones, which is carbon dioxide. Fire ants can use carbon dioxide to hunt underground prey, and they can also find out each other’s position in the soil. As for the most peculiar kind of pheromones, if I were to use non-professional general terms, it would be “death signal”—that is, the ant corpse is a signal used to “announce” its new state to its buddies in the nest. When an ant dies, if it is not squashed or torn, then it just collapses and lies quietly. Although its posture and lack of vitality are very abnormal, the nest friends still come and go from him indifferently. It takes two or three days for the recognition action to begin to appear, and it can only be completed through the smell of the decomposition of the body. As long as it smells this kind of smell, a certain ant in the same nest will lift the body, transport it out of the nest, and throw it into the nearby “trash dump”.

I’m allowed to come back after washing up

I have an idea, if I choose the right chemicals, I should be able to create an “artificial ant carcass”. It should be feasible to transfer the smell of one object to another. I soaked a few pieces of paper with the extract of air-dried ant carcasses. As a result, the ants also transported these pieces of paper to the garbage dump.

Recalling the basic concept of chemical releases, what I want to ask is: can any kind of corpse decomposing material stimulate the ant’s instinct for corpse removal? Or do they only react to one or two of these substances? I found that the answer might be soon, because biochemists have already identified a long list of compounds that appear in insect carrion. Don’t ask me why anyone does this kind of research. The scientific literature is full of this kind of information, and no matter how weird it is, it usually comes in handy when you don’t expect it.

My own research is also very weird, and it also belongs to this type of case. With the assistance of two newly hired assistants, I collected a lot of rotten materials and distributed them to the ants one by one using small pieces of paper. These substances include skatole, which is one of the fecal components, trimethylamine, which is one of the basic elements of carrion fish, and several other fatty acids that make up the smell of human carrion and are more pungent. For weeks in a row, my laboratory was filled with a weird smell that mixed the team’s locker room, gutter, and garbage dump. However, the response of ants to these substances is very different from what the human nose and mind can “smelt”. Their sensitivity to such substances is rather narrow. They only clean up scraps of paper that have been treated with oleic acid or ester.

These experiments proved that the ants did not clean up their nests based on human sense of beauty or cleanliness. They are only pre-set and will react to some very narrow but reliable rancidity. Eliminating the odor source is tantamount to unconsciously maintaining the sanitation of the ant nest.

In order to test this conclusion about the simplicity of ant behavior, the last thing I want to ask is: What happens if a dead body comes alive? To find out, I applied oleic acid to some live worker ants. As a result, their partners in the nest immediately picked them out, even if they struggled desperately, they would never escape the fate of being thrown into the garbage. Then these “living dead ants” began to clean themselves for several minutes; they lifted their feet to rub their bodies, and cleaned their tentacles and feet with their mouthparts before they dared to return to the nest. Some ants were expelled again, and a few or even three times were expelled, until they completely cleaned themselves, enough to prove that they were alive.

Author: Edward O. Wilson (Edward O. Wilson)

About the author: Edward Wilson is an American entomologist, naturalist and biologist. He is especially famous for his research on ecology, evolutionary biology and social biology. His subject is ants, especially ants communicating through pheromone; he retired from Harvard University in 1996.