Adventures Among Ants - Mark W. Moffett [4]
I soon found that my point of view was outdated. All around me, starry-eyed students who had come to biology because they loved nature were becoming lab hermits, indentured to high technology. Watching my fellow students, I realized that too much of modern biology represents a triumph of mathematical precision over insight. Sure, laboratory techniques allow for unprecedented measurements, but what good are those streams of numbers if it is unclear how they apply to nature? One thing I’d already absorbed from Ed Wilson was that much could still be done with a simple hand lens and paper and pencil. I was determined to spend my life in the field.
In the fall of 1980, I proposed to Professor Wilson that I would journey across Asia to investigate Pheidologeton—which I confidently proclaimed would be among the world’s premier social species. My enthusiasm, if not my charts and graphs describing the species’ polymorphism, won him over. I received his blessing and, within days of passing my oral exams, boarded a plane bound for India. Over nearly two and a half years I would visit a dozen countries without a break, vagabonding through Sri Lanka, Nepal, New Guinea, Hong Kong, and more.
Since then, ants have led me to all the places I dreamed of as a child. That’s far more than can be described in a book, and so I focus my narrative on a few remarkable ants. I start with the marauder ant, taking my time both because this species was my own introduction to ants and because it exemplifies behaviors that come up repeatedly, such as foraging and division of labor. Thereafter, subjects are organized, in a crude way at least, by the ant approximations of human societies throughout history—from the earliest hunter-gatherer bands and nomadic meat eaters (army ants), to pastoralists (weaver ants), slave societies (Amazon ants), and farmers (leafcutter ants)—ending up, at last, with the world-conquering Argentine ant, with its hordes of trillions now sweeping across California.2
In this book, I will consider what it means to be an individual, an organism, and part of a society. Ants and humans share features of social organization because their societies and ours need to solve similar problems. There are parallels as well between an ant colony and an organism, such as a human body. How do ant colonies—sometimes described as “superorganisms” because of this resemblance—reconcile their complexities to function as integrated wholes? Whose job is it to provide food, dispose of waste, and raise the next generation—and what can ants teach us about performing these tasks?
To find out, let’s begin our adventures among the ants.
a brief primer on ants
Anatomically, ants are like other insects in having three primary body sections: head, thorax, and abdomen—though the addition of a narrow waist gives ant abdomens extra mobility, enabling a worker to, for instance, aim a stinger or repellant spray from her rear end.1 Almost every ant has pores near the rear of the thorax through which two metapleural glands discharge phenyl acetic acid and other fungicides and bactericides, required for a healthy life in the soil.
Ant antennae are elbowed at the midpoint so they can be manipulated like arms, though unlike the individual’s jaws, often called mandibles, they can’t grip. Ants keep their antennae moving for the same reason that we scan with our eyes: to monitor the environment. Beyond their elbows, antennae are flexible and endowed with sensors for touch and smell, senses more valuable for most ants than sight. An ant’s compound eyes use many adjacent facets to produce images that are put together by the brain into a mosaic view. The eyes of most ants have little resolving power, though there are certain exceptions: inch-long Australian bulldog ants are so visual that I’ve watched them station