Mighty societies, miniature citizens
Ants lack human consciousness. They don’t make decisions, they respond to stimuli -- with a limited number of algorithms at that. Yet it’s hard to absorb E.O. Wilson and Bert Holldobler’s “The Superorganism: The Beauty, Elegance, and Strangeness of Insect Societies” without projecting human awareness onto them.
That’s because Wilson and Holldobler, who shared a Pulitzer Prize for their 1990 collaboration “The Ants,” seem less like naturalists than anthropologists reporting on a highly developed, newly discovered civilization. Not only have social insects produced architectural marvels -- subterranean fortresses with sophisticated air-conditioning systems -- but they engage in human-looking social rituals, such as making cemeteries for their dead.
As a result, reading “The Superorganism” is like learning a foreign language spoken by a large group in your hometown. You discover a world that had been hidden in plain sight -- one you noticed only when, say, its citizens overran your picnic table. Wilson and Holldobler have studied a variety of social insects (bees, wasps, termites), but the undisputed stars of this book are the ants. And the most dazzling of these are the Atta leaf-cutters, whom Wilson and Holldobler term “Earth’s ultimate superorganisms.”
As Aesop pointed out in his famous fable, ants do indeed plan for the future -- because they actually have a future. Unlike honeybee workers, which die of old age after a few weeks, worker ants in some species can live for years. During that time, they learn things, store sensory memories and record events in their lives. Based at least in part on “prior cognition,” the authors observe, ants decide what they will do next: finish a chore, look for a new chore, stand guard or rest.
They also speak a rich chemical language.
“Most species of ants learn their colony odor, a complex bouquet of hydrocarbons resident in the outer cuticular layer of the exoskeleton,” the authors write. Not only do ants recognize family members by scent, but they also mark trails with pheromones and use them to distinguish between castes within the colony. By explaining in great detail how chemical language works, the authors argue convincingly that the leaf-cutters have “the most complex communication system known in animals.”
Even before I discovered feminism, I admired the way ant colonies were organized: Everybody answers to a queen. Some queens, however, are more like duchesses: They manage a mere hundred serfs and live in a haphazard castle. The queen of an Atta colony, however, rules from a palace. To make a typical Atta nest, worker ants must excavate about 40 tons of soil. Nor are Atta colonies staffed by a skeleton crew. In the course of a standard 10-year reign, an Atta queen can produce as many as 150 million daughters -- of which the vast majority are her slaves.
Worker ants are all female, and in situations where a clear queen is not evident, they are terrifyingly competitive. “The highest ranking individual,” Wilson and Holldobler tell us, “is the most productive one. She also patrols the egg pile, frequently stopping to cannibalize eggs laid by subordinates.”
That’s not the only type of cannibalizing that goes on in ant communities. Sex can be unsavory and violent, particularly if you happen to be a male of the Diacomma species. After copulating with the queen, the male is assaulted by nest workers, which “bite off its head and thorax, while leaving the gaster attached.” For reasons Wilson and Holldobler do not explain, the workers let this gaster -- or genital -- remain with the queen for a few days before throwing it out.
Ant cuisine also leaves something to be desired: “In the ant Pheidole spadonia, native to the southwestern United States,” the authors observe, “workers cut prey into small fragments and place them into little hairy depressions near the mouth of larvae in a late stage of development. By secreting enzymes, presumably from the labial gland, onto the pieces and employing further mastication, the larvae dissolve the food into a liquid, or slurry, for distribution among other colony members.”
Ants work extraordinarily well together, especially when transporting heavy objects. Teams of Eciton burchelli, the swarm-raiding army ants of South and Central America, can move bigger items as a group than they could if the burden were cut into pieces and each ant, working alone, attempted to carry a single part. “Once a prey is subdued,” Wilson and Holldobler write, “some of the raiders cluster around and on top of it. The groups often include a large major that stands guard. A worker starts to drag the prey along, and a transport gang then quickly forms up to complete the transport back to the colony bivouac.”
“The Superorganism” is not dumbed down for lay readers. In general, the prose is accessible, robust and witty. Occasionally, to satisfy a scholarly audience, Wilson and Holldobler use technical language. Here’s an example: “A cladistic analysis of yeast-culturing attine ants (Cyphomyrmex rimosus group) revealed that this clade is not basal but actually derived within the lower attine ants.”
Yet non-biologists need not throw up their hands in frustration. The authors have compiled a thorough glossary that explains nearly every specialized term. (A “clade,” for instance, is “a species or set of species representing a distinct branch in a phylogenetic tree and hence of single common ancestry.”)
Insect architecture serves as a snapshot of insect behavior; it is often a spatial representation of the divisions of labor within a species. And just as in human architecture, what matters is location, location, location.
Remarkably, honeybees choose a nest site by, in a sense, voting. Scout bees survey the turf, then communicate the desirability of various spots to the rest of the hive by frenzied waggle dancing (a practice less common among human Realtors since the collapse of the housing market). Onlookers and competing scouts evaluate the quality of the dances (and the dancer’s conviction) to determine where the hive will set up house. “It is, in effect, a democracy,” the authors write.
Ants are more totalitarian, and their rigid caste system, limited life choices and 120 million years of evolution have made them frighteningly able to crush their enemies.
“The Superorganism” can’t help but leave us with respect for ants, and relief that they are not the size of ponies. In Robert Heinlein’s science-fiction novel “Starship Troopers,” humans fight to save the Earth from an invasion of giant insects. For Heinlein, the insect superorganism is a metaphor for totalitarian communism; the humans for capitalist individualism. And in the book, people prevail.
But that was fiction. In life, I’m not sure we’d stand a chance.