Good Reading : July 2010
50 goodreading ı JULY 2010 BOOKBITE accordingly, I was drawn to the ants with oddball heads and mandibles, curious body shapes and hairs. I wondered what their bodies said about their lives and habits. Continuing my search the next day, I came upon three drawers labelled Pheidologeton, a name I had never heard before. The glass tops of the drawers were dusty, and their contents were in disar ray. The dried specimens, glued to small wedges of white cardboard that in tur n were affixed with insect pins to foam trays, had obviously not been looked at for many years. I was struck at once by the ants' polymorphism -- that is, how different they were from one another in size and physical appearance. As in most ant species, the queen was distinctive, a heavy bodied individual up to an inch long. But it was the workers that gave me an adrenaline rush. While the workers of many species are unifor m in appearance, in Pheidologeton the smallest workers, or minors, were slender with smooth, rounded heads and wide eyes. The inter mediate sized workers, or medias, had larger, mostly smooth heads, and the large workers, known as majors, were robust, with relatively small eyes and cheeks covered with thin parallel ridges. The wide, boxy heads of the majors were massive in relation to their bodies, housing enor mous adductor muscles that powered for midable mandibles. I had never seen anything like this. The minor, media, and major workers didn't look like they belonged to the same species. The heads of the largest workers were 10 times wider than those of the smallest. The biggest majors, which I came to call giants, weighed as much as 500 minors. The energy and expense required to produce these giants -- and to keep them fed and housed -- must, I thought, be immense, which meant they must be of extraordinary value to their colonies. I left the collection that day certain I had found something special: few ants display anything close to the extreme polymorphism of Pheidologeton. As a student I knew that the best studied polymorphic ants were ones I'd seen on my first trip to Costa Rica -- certain Atta, or leafcutter ants, and New World ar my ants such as Eciton burchellii. These ants have some of the most complex societies known for any animal, giving them an exceptional influence over their environment. Their social complexity is due in part to the division of labour made possible by their varied workers, which, with their differing physical characteristics and behavior, can serve different roles in their societies. Called castes, these classes of labour specialists focus variously on foraging, food processing or storage, child rearing, or defense, such as when large individuals serve as soldiers. Given its minor, media, and major castes, I suspected that Pheidologeton would be a treasure trove of social complexity. From reading the books of Jane Goodall and other modern naturalists, I had developed the view that the best path to a career in biology was to find a little known group of organisms and claim it, at least temporarily, as my own. I could then, like an old fashioned explorer studying a map in preparation for a voyage, pinpoint those regions most likely to yield rich scientific rewards. Buoyed by this belief, I decided Pheidologeton would be my version of Jane Goodall's chimpanzee. I soon found that my point of view was outdated. All around me, star ry-eyed students who had come to biology because they loved nature were becoming lab her mits, indentured to high technology. Watching my fellow students, I realised that too much of moder n 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 deter mined 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 A scanning electron micrograph of the marauder ant Pheidologeton diversus depicting the normal behaviour of a minor worker riding on the head of a major. There’s a 500-fold difference in body weight between these two workers. Mark W Moffett/Minden Pictures.