Immortal Ants

I have written a few times about the intelligence and sophistication of ant colonies. They offer an exemplary model of what may be described as emergent cognitive qualities, in that the ant collective exhibits far greater acumen than any single ant possesses. Thus, while an individual ant is a simple critter with very little conscious capabilities, the whole colony exhibits highly developed behavior that almost seems to demonstrate an elevated level of cognizance… in fact, a kind of intelligence.

The result is that an ant colony is centered around the life of its queen, who may live for as long as 30 years. During that reign the group acts as a superorganism—an entity that exhibits capabilities far beyond any one individual’s potential, which expires only when the queen reaches the end of her existence; when the colony finally threatens to collapse.

There is one species of ant, however, that displays a kind of immortality. Their colonies do not cease when a 30-year-old queen finally dies, but find a way for a daughter ant to assume the queen's role, allowing the community to carry on.

This exceptional ant species is named the Indian Jumping Ant... and it's indigenous to India—not the Americas. For this species of ant, the queen will, at some point, actually die; but rather than have the colony collapse with Her Royal Highness, a group of “chosen” workers—all sisters—compete to assume her throne. This process begins by their ovaries expanding, while their brains shrink. A successful queen need not be at all smart, as she is reverently cared for and fed, while her main duties are to churn out eggs.

After the queen dies, half a dozen or so of the chosen sisters find their ovaries swelling to some five times their unproductive size, as their brains shrink some 20-25%. Since a brain is an energy hog, this allows more energy to be sent to egg production. Eventually one candidate queen triumphs and becomes the new queen—creating what is essentially an ongoing immortal colony.

What is even more extraordinary is that the losing queen candidates find their ovaries shrinking, as their brains once again grow.  The individual brain may be primitive, but the collective cognition emerges as very intelligent. Wouldn't it be nice if human brains—once relieved of the requirement of procreation, could expand and become wiser?

Brain-like Ant Colony

An ant colony, according to some neuroscientists, operates roughly analogous to the human brain, where each ant behaves something analogous to a neuron. Individual ants communicate by chemical signals, which determines the overall behavior of the colony. Similarly, our neurons communicate via electrical and chemical signals, which result in our behavior.

If this analogy is appropriate, it raises the question, do ant colonies remember? Human memory is the result of many neurons acting together—creating retrievable recollections of past events and experiences. Our recall depends on how individual neurons stimulate each other. Short- and long-term memories employ different collections of neurons. Every time we summon up a memory, we rearrange some of the neural circuits and then send the memory back into “storage,” slightly altered. In this way, memories will gradually morph over time—although we tend to believe there's a constancy and an accuracy to our recollections. That certainty is really not there, however.

Furthermore, our memories are not just housed in some unique place deep in our brain. Our bodies—riddled with nerves and neurons—also remember. There's so-called “muscle memory,” by which we retain the knowledge of how to ride a bike or play a musical instrument. In response to wounds and germ attacks, antibodies and molecular receptors are created; they “remember” these events. The same mechanism happens for plants—trees “remember” physical wounds and insect attacks, so as to both heal and better respond in the future.

Back to ant colonies: If each ant is somehow comparable to individual brain neurons, and signals between ants are somehow comparable to neuronal communication, does the congregation of ants—the colony—display memory? Indeed it does. Although there is no central control agent in an ant colony, the community can remember, and that memory persists over days, months, and even years. Although an individual ant has a life span of months, the colony can live for up to 30 years, the lifetime of the queen. I have written before of the phenomenal behavior of an ant colony, as it performs activities far beyond what a single ant can do—such as tend graveyards and gardens, keep the nest clean, coordinate attacks, etc. These abilities depend to some extent on memory.

In fact, researchers have discovered that while individual ants can only briefly remember the location of food, the colony retains that knowledge for much longer periods of time. What's more, an older ant colony acts more wisely than a younger colony—showing an accumulation of knowledge over time.

The enhanced performance of large collections of individual creatures is often described as an emergent property. It is a process that has yet to be fully understood. Similarly, our memory—and in fact, our consciousness—still have much to be explained.

So if an individual ant can be considered to be something analogous to a brain's neuron, we might be grateful that an ant colony contains only thousands of ants. Were those colonies to be inhabited by a few million—or, God forbid!—a few billion insects, they would be smarter than us! Doesn't the possibility of having the Earth ruled by ant colonies seem frightening?

Ain't Like an Ant

The previous posting described some interesting ways in which our human behaviors are similar to ants: they “domesticate” other critters and milk them, they farm, and they “sing” as they work. It's enlightening to open ourselves to the fact that other forms of life on Earth bear a greater resemblance to us than we've long thought. We've historically tended to place our species on a pedestal—greatly elevated from other critters. We've viewed ourselves as much closer to the gods. In the modern era, however, we have come to understand that there is far less of a difference between ourselves and simple creatures... such as ants.

When ants form a colony something very sagacious emerges: a level of intelligence that can rival human capabilities. It is useful to find ourselves toppled from our self-imagined pedestal, and realize the similarities and unity of all life on Earth. After all, every one of us has evolved from the very same primal life form. We're just different branches and twigs on the same tree of life.

While describing a few similarities between humans and ants in the previous post, I think it's also interesting to consider some ways in which we ain't like ants. They are unique little critters who possess some remarkable qualities that we can't begin to imagine. If only we had some of their skills...

We have language, giving us a sophisticated form of communication. Ants may not be able to talk as we do (How could a mandible purse its lips?), but they “speak” to each other in a very sophisticated language: they use dozens of different types of pheromones to communicate. They combine various kinds of pheromones to give each other various kinds of messages. The most common use is to lay down a pheromone trail that guides sister ants to a stash of food, the garbage dump, burial grounds, or the way back home.

Ants' pheromone chemicals are incredibly potent—they need to be, when you think about one tiny ant laying down a path over several yards long. In fact, scientists have demonstrated that just a single milligram of pheromone (less than a thousandth of an ounce!) can lay down an ant trail that would circle the Earth 60 times!

While humans tend to come in one size, some ants (even of the same species) may be 200 times larger than others (depending on the individual duties of each of them in the colony)! Each size ant has its specific job within the colony, and they cooperate beautifully, to accomplish their sophisticated tasks. Think how a human being, 200 times larger than another human of the same species, would treat its tiny relative.

When it comes to the subject of sex, humans and ants could hardly differ more. The colony is composed entirely of females—all sisters, the daughters of one queen. When a nascent female ant mates with a male (who immediately thereafter perishes), she becomes a queen who stores the sperm in her body for 10 years and more, to fertilize millions of eggs. Not much of a sex life!

So the next time you spot an ant trotting across the floor, you might ponder the various ways it is like us (farming, domesticating other critters, and singing as they work), as well as the ways we are alien (pheromone communication, size, and sex). Ain't life's variations grand?

Am Like an Ant

Ants are fascinating creatures, which is why one of my mentors, E.O. Wilson—a distinguished professor and researcher at Harvard—has devoted many decades to the study of their behavior. Wilson was one of the first scholars to describe an ant colony as a “superorganism,” which defines the colony as exhibiting an intelligence and cognitive ability that is far beyond the capabilities of any one ant. Scientists refer to this phenomenon as an “emergent” quality. It is a capability that no human theory or model can predict—it's almost as if it magically appears when a large number of simple creatures cooperate.

We humans tend to look down upon lowly ants as primitive creatures, because any single ant is rather rudimentary, when compared to one of us. An ant doesn't have much of a brain and its behaviors are extremely limited. Yet a colony of ants can perform acts that are strikingly similar to us. Here are a few examples.

Some ant species herd and milk bugs, rather like we herd and milk cattle and sheep. Some ant species are very sophisticated farmers—they are, in fact, considered to form highly-civilized farming communities. Millions of years before we humans discovered agriculture, these ants evolved into accomplished farmers. They are commonly known as leafcutter ants. They harvest leaves of plants (or portions of leaves), which they cut and drop to the ground, where sister transporter ants carry the fragments back to the “farm.” It's not the leaves they are interested in, but the fungus that they cultivate on the leaves and then consume. Our human ancestors could have learned a trick or two about farming from these ants.

Have you ever hummed a tune, as you engage in some routine task? Well, ants do it, too. As the leafcutter ants scissor away at a leaf, they “sing” by rubbing body parts together (sort of like crickets). But these little singers are smart—their singing helps them in their surgical efforts, by assisting their mandibles (their chewing mouth parts) to cut a leaf more efficiently. But they also sing for help. If one ant gets trapped, it cries (oops, sings) out for its sisters to come to the rescue.

We may look at a tiny ant and experience it as an alien critter, but it's more like us than first meets the eye. If we take a closer look—as E.O. Wilson has done all his life—we begin to understand the similarities in our behavior. I may look down upon it, but in many ways I am like an ant.

Next time: ways we ain't like an ant.

Superorganism Ann—Part 2

Like all creatures, Ann also has some qualities that uniquely define her. She is deaf and blind—but in compensation, she possesses superior senses of smell, taste, and touch. Living underground in one location all her life, she neither needs to see nor hear. But oh, her sense of smell! For instance, she can emit some 12 different chemical signals, which she can combine in a highly skilled manner—deciding when, where, and why to release pheromones, as well as to mix them on certain occasions. She has a chemical communication system analogous to the chemical signals our guts and brains emit, as they successfully carry out their functions.

Ann could be perfectly happy if she never met another being of her kind. She is a hermit (I can relate to that). But similar beings do live nearby. She knows they’re out there and she occasionally encounters one of them. And they are usually not friendly meetings—as she and each of her rivals (I’ll call them Judy and Sally) need a minimal amount of territory to survive. Evolution has seen to it that there is plenty of competition for the available space and food. When Ann was younger she was robust and virile. Neither Judy nor Sally dared to challenge her then.

But when Ann reached 30, something fateful happened: the queen died. It was as if one of our vital organs became diseased and began to shut down. Our intelligent bodies would try to fight off the problem, but if the disease seized the upper hand or if we are simply too old to keep up the struggle, we will at some point succumb.

Ann began to falter and weaken. Judy lived right next door and began to sense her advantage. At first, Judy tentatively challenged, as Ann bravely put up a front. But in time Judy sensed her rival’s frailty and launched an all-out invasion. In a matter of a few days Ann lost the battle and perished. Judy now prospered with her expanded territory. Ann had lived a full and lengthy life. She did well. But like all creatures, death is the final destiny.

I like thinking of an ant colony as a specific individual. It puts the story of the life of this superorganism on a par with that of a bird or a rabbit. I can ponder the intelligent behavior of the colony and not get stuck with the unlikely image of how a collection of dumb creatures could possibly do all that. Instead, I imagine Ann, and her amazing accomplishments then seem more reasonable to me. (Besides, it’s fun.) The next time I come upon an anthill, I’ll picture the blind and deaf creature who lives down there—a creature whose sense of smell is just amazing. Thanks, Ed Wilson!

Superorganism Ann—Part 1

In the January 25 issue of The New Yorker is a wonderful article of “fiction” by E.O. Wilson. I’ve written here before about Wilson, a preeminent writer-biologist who is quite likely the world’s leading expert on ants. His article in The New Yorker is “fiction,” only in the sense that he is describing the life of a hypothetical ant colony—how it began, how it thrived, and how it expired. It is a delightful story that pulls the reader into the heart of a prosperous community of 10,000 ants and the workings of its complex society.

Wilson describes how the queen of his imagined community flew from her birth colony, became inseminated, and initiated her own colony. She is the vital center of the community, which Wilson calls a “superorganism.” I have written before about the phenomenon of emergent intelligence (1/28/09 and 5/7/09) and how a tight-knit group of creatures exhibits intelligence far beyond what any one of them possesses—a kind of superorganism.

As I pondered Wilson’s story—titled “Trailhead”—I found myself thinking of his superorganism of ants, not as a collection of cooperating insects that achieves its remarkable feats, but as a specific being; like a frog, or a dog, or even a human being. I imagined the colony as an intelligent individual—one that encompasses all the discrete insects, much like our bodies encompass multitudes of cells, organisms, and organs. Our bodies are a cooperative collection of countless beasties, and so is an ant colony. So let me think of the colony as being a being. I’ll call her Ann.

Ann possesses essentially all the qualities of any intelligent creature. (I’m using the word intelligent here to mean the skillful accomplishment of complex tasks of living successfully—a much broader definition than just a measure of cerebral capability.) Ann was conceived at some point, was born, has thrived for 30 years (30!), and will someday perish—just like all critters. She forages for food, possesses a superb digestive system, defecates, and skillfully disposes of her wastes—often using it to fertilize her gardens. Ann’s immune system fights off disease and she successfully repels periodic invaders. As long as her multitudinous elements cooperate with one another and luck is with her, she lives a long and healthy life. Similarly, as long as our various organs work together and fortune smiles upon us, we stay healthy.

Ann inherently knows how to respond capably to varied circumstances. When food is plentiful she grows fat and robust. When provisions are lean she hunkers down and loses weight. Some of Ann’s components periodically sacrifice themselves to maintain her health—much as some of our white blood cells attack invasive bacteria and perish in the process. It’s all for one and one for all.

More on Ann’s qualities next time.

Those Clever Ants, Part 2

I’ve been looking here at the extraordinary capabilities of ants, that stem primarily from their social nature. Ants have an elaborate communication system, which they use to attract one another, raise an alarm, recruit new members, control group activities, and groom one another; especially the queen. Any outsider who does not smell like a colony mate will get warded off or attacked. Yet some sneaky and cunning solitary critters—beetles, mites, wasps—are able to crack the colony’s communication code and live as a pampered member, getting workers to groom and feed them as they do the queen.

Most residents of a colony are female workers, who live a predominantly altruistic life. Biologists do not agree on referring to the actions of sterile workers as altruism, since it seems to contradict the “selfish gene” theory, which describes the activities of most critters as being dominated by a drive to propagate one’s own genes downstream. If so, why would a worker ant devote her life to the continuation of another’s life, another’s genes—specifically the queen? But workers do lavish extraordinary care on the queen and zealously guard and tend her eggs and offspring, forgoing any chance at having kid ants of their own. Let’s call it altruism. It still manages to do a superb job of sending the group’s genes into the future.

Ants exhibit their swarm intelligence in scores of ways—depending on their local habitat. To begin with, the size of a colony is wisely maintained—growing when conditions are favorable and stabilizing (or even shrinking) when times get lean. Some ants form symbiotic relationships with plants—weeding and pruning their environs, to promote the health of the plants they use. One clever species of ant lives unharmed on pitcher plants. As other bugs fall in, to become digested by the plant, ants get a safe home (no ant predator would dare invade) and the plant gets protection from ant-sized herbivores. Some ant species even farm—carrying preferred seeds into the colony, planting them in rich ant detritus, and later harvesting nutritious fruit.

Leafcutter ants cut pieces of vegetation (sometimes stripping human gardens in the process), carry them to the colony, and grow a fungus which they feed upon. Weaver ants create nesting enclosures by forming long chains with their bodies to curl leaves up, and then binding the edges together with larval silk. Some ants tend aphids and mealy bugs as cattle, which they milk (by tenderly stroking them) for a source of nutritious honeydew. Some species of ants coevolved with seed-producing plants—trading nectar for pollination and seed dispersal. And the list goes on.

I may have failed in absorbing most of the voluminous book Ants, but I got enough to significantly increase my appreciation, even if I still don’t revere those little black pests who insist on trying to set up their colony in my kitchen. I guess I should be grateful that army ants aren’t indigenous to these woods.

Those Clever Ants, Part 1

I recently attempted to tackle a weighty book (7 ½ pounds, 732 pages, letter page size) by Burt Hölldobler and E.O. Wilson. Titled simply Ants, it got the best of me… just a little too heavy a read. But I wanted to try, and I did get a major boost to my appreciation of this social insect of the order Hymenoptera, family Formicidae, subfamily Myrmicinae. (All those 25-cent words is one reason why the book was more than I could handle.)

Ants are the pinnacle of insect evolution, and that’s a lot to say, given that insects are the most copious of critters. Ants' extreme success and longevity can be attributed to their highly developed social lives. Social critters generally seem to thrive better than solitary animals do. Life is a struggle. There are numerous threats to endure, such as competitors, predators, and natural catastrophes. When animals band together cooperatively, their chance of survival increases. (Consider Homo sapiens!)

Thus ants are both robust and plentiful. There are some 8800 known species. They make up some 10-15% of animal biomass in most areas where they live; in the rainforest, as much as 75%. Think of that: such tiny creatures outweighing most all other animals in their vicinity—even elephants and giraffes! They turn and enrich more soil than earthworms. They’ve been around far longer than many extant creatures. They first appeared about 100 million years ago and were unfazed by the disaster that drove the dinosaurs to extinction. Most species last, on a gross average, about one million years. Ants have pushed that much further. Pretty dazzling feats for such a little critter!

I wanted to try to understand ants better, partly because most of my impressions were formed years ago, when I learned to regard them mostly as pests. I came to think that the only thing rivaling a termite or cockroach infestation is to see a line of ants parading across the kitchen counter. But I sensed that, like all the works of Mother Nature, there must be something to appreciate about them, and even revere; so I decided to take a closer look, try to drop my prejudice, and seek to understand them.

I have written here before about my fascination with watching ants (6/9/08) and a bit on their intelligent behavior due to something referred to as swarm intelligence (1/25/09). My ant appetite had become whetted and Ants was a book to try.

Crucial to ants’ success is their caste system: an effective division of labor that gets many sophisticated jobs done. But even though they have a strict hierarchy of tasks, any one ant is free to communicate (mostly chemically, via pheromones) with any other member of the colony. This democratic feature is a major aid in helping the group to be successful—in contrast (the authors of Ants point out) to the rigid hierarchies in the human military and factories, where communication goes from the top down only. In some ways ants are smarter than we are!

Next time, more on ant intelligence and skills.

Watching Ants

The homestead clearing, after years of labor, is getting so pretty that it distracts me. As I work, I sometimes have to stop and gaze at something that arrests me with its beauty. It makes me realize just how fortunate my mate and I are to be living here.
Recently I was pumping water and found my gaze falling on one of the posts that holds up the enclosure over the hand pump. I noticed a line of ants crawling up the post and another line headed down. I moved closer to watch what they were up to. What amazing little critters they are! They are so social. They each have their place in some grand scheme of the community, that I don't think any one of them vaguely comprehends. They just go about their work, busily providing for the greater good.
One line of these ants was moving up the post. I think they were carrying something up to the nest, but I could not see what they may be toting, without my glasses. (They are those tiny little black ants.) About half way up the post they disappeared into a knot hole. Another line of descending ants emerged from the hole. I guessed they might be headed off for the same provisions that the ascending ants were returning with.
Many of the ants in the downward-headed line briefly paused, touching heads with the ascending crew, before moving on. I think this is a way for the departing ants to check out their returning fellows, to see what they are carrying and to pick up a smell, so they can follow the trail to the source of provisions.
Then I noticed a third category of ants. They emerged from the hole and appeared to be dropping something to the ground, before moving back inside. That was just too fascinating for me, so I got my magnifying glass from my nearby workshop and moved in close, to see if I could discover what they were doing.
Imagine the shock of an ant, emerging from the dark hole and looking up to see this giant eye peering at it! The first ant that came out and saw me literally jumped and rushed back inside. I stood my ground, magnifying glass to my eye, immobile. A few more ants soon came out. I could see that they indeed had something in their mouth pincers: a tiny ball that they dropped into space, then wiped off their pinchers and returned inside. Was it shit they were removing? The remains of some excavating they were doing? I may learn that another day. None of the ants would tell me.