LITTLE FRIENDS OF THE EARTH : THE ANTS <i> by Bert Holldobler and E. O. Wilson (Harvard University Press: $65; 709 pp., illustrated</i> )
Who hasn’t at some time been intrigued by ants? Even while cursing their invasion of the pantry, we admire the lone scout hurrying along with the news, or the knot of workers conveying a single crumb across the unprotected wasteland of a kitchen floor. But I was unaware until I read “The Ants” that colonies range from those with only 50 workers to colonies whose populations exceed hundreds of thousands, even a million individuals.
Of all the world’s myrmecologists--that is, students of the 8,000-odd members of the family Formicidae (ants) in the order Hymenoptera (which also includes bees and wasps)--perhaps none is as well known to the public as E. O. Wilson. With the publication of “Insect Societies” in 1971 and then “Sociobiology” in 1976, Wilson announced that evolutionary biology has theoretical implications that go beyond the anthill. There are echoes of both of these earlier books in “The Ants,” which Wilson has written with his colleague Bert Holldobler.
In “Insect Societies,” Wilson discussed the evolution of insects from presocial beetles to the eusocial hives and mounds of ants, bees, wasps and termites that have sometimes been described as “superorganisms.” Ants epitomize this kind of community in which several generations overlap, and individuals are divided into specialized castes that cooperate in producing and raising the young.
In 1971, Wilson observed that many of his theories would only be proved with the reconstruction of the full colonial system in vitro, in the laboratory, which was an impossibility 20 years ago. Since then, however, procedures to isolate and expose individual ants to synthetic sounds and smells have become routine, and what was then theory is now experimentally verified. Wilson and fellow entomologists have reared isolated ants, honey bees and termite larvae and determined their caste by an appropriate manipulation of food and hormones.
Sociobiology as a scientific method has weathered stormy debates, many provoked by Wilson’s insistence that the kind of reductionism that successfully explains insect behavior as a predictable response in relatively simple animals like ants can be applied to higher vertebrates, like ourselves. Over the last 15 years, the analysis of kinship relations and investment strategies within species has become one of the most sophisticated areas of evolutionary biology. In “The Ants,” Holldobler and Wilson describe the measured investment by adult ants in the survival of their offspring, using what they admit are value-laden words such as altruism to explain the intricate and varied ways that colonies respond to environmental change.
But why write an entire book just about ants?
Because ants are crucial participants in the ecological systems of all of our fragile forests and, even more than earthworms, are nature’s leading soil turners. We need to know as much as we can about them as we race to save the ecological balance of this planet.
On another level, as the culmination of insect evolution, ants can explain a lot about how evolution works. Different species of ants have evolved ways to enslave each other, to “domesticate” a species of aphid, which they herd and “milk” for honeydew, to organize military campaigns against their neighbors. They are able to achieve these complicated systems through complex forms of chemical communication and through the evolution of altruism, the apparent trade-off of individual sacrifice for the welfare of the colony.
“The Ants” is a beautiful volume, with hundreds of line drawings and colored plates. It is an encyclopedia of ants, containing lists and descriptions, a glossary and a complete bibliography in addition to histories and discussions of the relationships within ant communities and between ant species, as well as symbiosis with other insects and with plants.
For the novitiate, there are clear, detailed descriptions of the body parts, along with an explanation of their functions. There is also, at the conclusion (by which time the authors are secure in having made a number of converts), a guide for the novice in how to collect and set up ant colonies or farms. They mention how the late Harlow Shapley, a famous astronomer and amateur ant collector, found a rare ant while dining with Stalin in the Kremlin, placed it in vodka, and brought it back to the Museum of Comparative Zoology at Harvard, where it is still on display.
For the professional, there are judicious explanations of the rival theories of “kin selection” (in which individuals are apparently willing to make sacrifices for those very close to themselves genetically, like a sister) and “parental manipulation” (the suggestion that parents willingly exploit some of their children for the perceived larger good of the next generation) to explain why some individual ants are apparently willing to forgo their own reproductive option to provide for their mothers and sisters.
For pundits interested in the roles of the sexes in evolution, there is dramatic evidence that females guide and dominate ant populations: “The ant colony is an almost exclusively female society, with the males remaining in the nest only until the time of their invariably fatal nuptial flight.” Most colonies have a single queen (although there are some with more) that determines the assignments of the workers, all female, in regards to nourishing and protecting the next generation they are preparing for life cycles of their own.
Aging workers of Australia’s green tree ants emigrate to special “barrack nests” at the territorial boundary of the colony, the first line of defense when workers from neighboring nests invade. This stimulated Holldobler to note: “It can be said that a principal difference between human beings and ants is that whereas we send our young men to war, they send their old ladies.”
The recent discovery of eusocial life in a rare, burrow-dwelling African mammal, the naked mole-rat, puts the question of these “super-organisms” in a new light. The similarity between mole-rats and ants suggests that insects and vertebrates may have more in common than zoologists once thought.
