Down on the Ant Farm : NONFICTION : THE EARTH DWELLERS: Adventures in the Land of Ants,<i> By Erich Hoyt (Simon & Schuster: $24; 319 pp.)</i>

I have to admit that I nursed a measure of skepticism when I cracked open “The Earth Dwellers.” After all, I consider myself fairly knowledgeable about ants, the subject of Erich Hoyt’s latest book. And I know La Selva Biological Station, the principal location of his book, very well, having many times visited this gem of a tropical rain forest in Costa Rica. Would Hoyt be able to facilitate a closer connection for me with these fascinating creatures and their richly diverse habitat? I doubted it.

Hoyt, an ecologically oriented science writer who lives in Scotland, explains that his interest in ants was sparked a decade ago by two events. The first was witnessing columns of leafcutter ants in the Chaco region of Paraguay: “Ants! Ants coming and going, ants everywhere,” he recalls. By retracing the path of the flowing column, Hoyt was able to find the colony, its underground location betrayed by mounds, turrets and ventilation holes over a wide area of high ground. “It was as if we had chanced upon an ancient civilization, some forgotten band of Mayans, untouched by time and still carrying on.” The comparison of an ant colony with human society is no accident.

The second event was the opportunity to audit the lectures of Harvard’s E. O. Wilson, arguably the world’s greatest authority on ants and certainly one of its most spellbinding speakers. At the time, Hoyt was a journalism fellow at MIT. Already primed by his Chaco epiphany, Hoyt was now hooked by the world of myrmecology, the study of ants. Early in 1987 he joined Wilson and fellow ant enthusiast William Brown of Cornell University for several weeks as they poked and prodded tree stumps and underbrush in La Selva, often finding familiar species, always looking for new ones. Always immersed in the ants’ world.

Hoyt explains that he has two aims with “The Earth Dwellers,” which is the product of that joint immersion. The first is an attempt to convey what it is like to be an ant. It is not merely a matter of scale, he explains, but one of different dimensions of perception, a world where smell and taste are paramount, while sight, hearing and touch are minor channels of communication. The second is to give us a glimpse of the myrmecologists themselves, a “strange and obsessive breed of scientist.” The first goal might be thought of as overly ambitious, given the experiential chasm between humans and ants, and the second redundant, particularly since Wilson published his own memoir, “Naturalist,” last year.

In the early sections of the book, Hoyt proffers many facts that make ants the remarkable creatures they unquestionably are. There are almost 10,000 known species of ant, often descriptively named: leafcutters, fire ants, bullet ants, army ants, honey ants, harvester ants and so on. Individual leafcutters often heft foliage fragments six times their body mass. A colony of leafcutters gathers as much foliage as a single cow, every day. There are seven castes of leafcutters, making for a social and economic structure that is as complex as it is efficient. And sociality is central to the lives of many ant species, making them perhaps the most successful creatures on Earth, humans notwithstanding. Collectively, ants form at least 10% of the world’s animal biomass.

A colony of leafcutter ants may contain 3 million individuals, centering on the queen. But, as Hoyt points out, the colony is more than 3 million individuals; in a very real sense it is a single organism, or superorganism, containing 30 times more neurons than a human brain and communicating collective needs and plans with a cocktail of simple chemicals. This is particularly so with the leafcutters, who, as Hoyt explains, are not simply herbivores but farmers. They feed the leaves they cut to a fungus that is cultivated in underground chambers. It’s the fungus that sustains the ants and, because of the long-established relationship between the two organisms, the ants sustain the fungus, the latter having lost the ability to exist without such cultivation.

Much of “The Earth Dwellers” is devoted to the day-by-day existence of a leafcutter colony. Traveling through several generations, we see individual ants scouting for new sources of vegetation, encountering friends and foes alike on their forays, and interacting with the rest of the superorganism. Other ant species figure too, but in less detail. We read of slave-making ants; ants that engage in tournaments to avoid outright war; ants whose existence seems predicated on warfare; big ants that prevail through muscle; little ones that use guile, such as hurling “rocks” into the nests of more aggressive species; and still others that explode as a means of defense.

Initially, the narrative is a little forced, making the weaving of stories about ants and myrmecologists rather uneven. At this point I suspected that my skepticism had been justified. But very soon I was caught up in the dramas Hoyt relates; I was rooting for the leafcutter scout when a pair of bullet ants approached her with less than friendly intentions. And, despite Hoyt’s comments about scale, I felt myself physically in the ants’ world. One of the most arresting features there is smell. Without being directly descriptive, Hoyt manages to bring this foreign dimension of perception very much to life. His book is redolent of La Selva in a way that escaped me when I was visiting the place. I was charmed and humbled by Hoyt’s power of evocation.

The book culminates with the description of all-out war between colonies of aztec ants in a cecropia tree near the laboratory at La Selva. “The mother of all ant battles,” Hoyt calls it. The drama is palpable and the fugue of war (literally, for ants) perceptible. While Hoyt’s skill in taking the reader into the ants’ world is admirable, as in this final confrontation, he is less successful in creating a portrait of the scientists who study this world. As they say in Hollywood, whenever a human competes with an animal for an audience’s attention, the animal always wins. And when the animals in question are as truly fascinating as ants are, human stories pale by comparison. “The Earth Dwellers” is an unexpected and enchanting view of another creature’s world.