Adventures Among Ants - Mark W. Moffett [98]
But looked at another way, ants aren’t small at all. A leopard may impress with her bulk and power, but compared to the ant, she is a minor part of the forest in which she lives—measured in terms of both her ecological impact and her size. Ants have, in effect, two body sizes: the individual’s and the colony’s. To understand this basic truth, I use a mental exercise I learned as a graduate student studying the marauder ant. First, I follow an individual ant. Then I take in several ants collectively, a group of workers busy at a task. Finally, I liberate my imagination from what is directly before me, emulating German chemist August Kekulé, who discovered the beautiful structure of the benzene molecule in a dream. Allowing my reverie to expand beyond what is visible, I contemplate the functioning of the whole: all the ants, in the nest and out, with the workers integrated like the cells of a human body into a superorganism.
This is more than mental gymnastics. By living socially, ants break through the glass ceiling imposed by their exoskeleton. At nearly 40 kilograms, a large driver ant colony is the size of an eleven-year-old boy. However, this particular young man would be a kind of superhero, one who can disassemble, such that his hands can stop a crime while his head commutes to the office to write up the news report—both Superman and Clark Kent at the same moment, an analogy that is particularly apt for ant species whose workers spread out widely. Even an atom ant colony, which might fit within the head of a Camponotus gigas worker, is a superhero in miniature.
A colony is an organism divided, with no loss of integrity. Its body spreads over space in pieces that give it a multitude of eyes and brains with which to glean nutrients, energy, and information. It does this with a microscopic attention to detail that no unified body can match. It’s more flexible than an organism, too: the superorganism counterparts to tissues and organs range from transport teams to nurseries and are easily assembled or taken apart or shifted to a different function. Whereas a human vascular system has well-established roles, its colony analogue, the trail system, is flexible; it can serve as a snare for food and later be co-opted for migrations or a fight.
This fragmentation helps a collective of ants to succeed when a single big vertebrate would fail. The workers in a weaver ant colony, with a combined weight, at 14 kilograms, of a young leopard, can disperse among leaf nests on many frail branches—or, in other species with big colonies, fill up cracks, crevices, and galleries in wood—and thereby live where no hefty vertebrate could. Furthermore, most of the food available in nature is present in packets too small for a large animal to glean. A young leopard or a man would starve trying to gather the tidbits that make up the diet of a large ant colony, and neither is muscular enough to carry as much food as all those ants can move collectively. A whale trawling for zooplankton is the only vertebrate creature that scoops up as many bits of prey; indeed, a baleen whale is the marine equivalent of an ant colony.35 To accomplish this task as a group, bulky individual ants (even ones of weta cricket size) would be at a disadvantage. That’s why so many plants have evolved to support ants,