We look at animals in natural domains and marvel at how well they get by, how they integrate themselves into the world, exploit their niches, and leave progeny. Anyone who examines social insects, like ants and bees, has to be particularly impressed. In fact, insect societies have been a particular inspiration to those who would like to see human societies operate just as smoothly, with every member dutifully fulfilling a role to the benefit of the larger group. Liberal and conservative politicians have turned to ants and bees for inspiration and for metaphors, but that's just because they don't know how basically weird such societies are. Let them read _The Superorganism: The Beauty, Elegance, and Strangeness of Insect Societies_ (Norton) by Bert Hölldobler and E. O. Wilson. The authors are among the world's experts on ants, and in 1991 their book _The Ants_ won a Pulitzer Prize, so it is not surprising that ants get most of the pages here. Bees and termites are also covered, but naked mole rats, the closest mammalian example of this sort of colony life, are barely mentioned. This is a big book, beautifully produced with color pictures of insects in their home environments and drawings to show how they move, signal, and reply. It is also dense with serious scientific descriptions. It is not dumbed down for the lay reader, and could do for a textbook in an entomology course. Nonetheless, the descriptions are clear and the scholarship is deep, and any reader with an interest in science or nature will come away with an admiration for these strange societies and for the intensive research that is solving many of their mysteries.
The term "superorganism" for social insects was first used in a book in 1928, and the idea has waxed and waned over the decades, sometimes producing acrimony. It denotes a group of individual members that form a colony that has many attributes of a single organism. The authors' explanations of how the members of the colony function seems to be fully analogous with how an organism functions. Colony members, for instance, can be regarded as an organism's cells, and different castes can be organized as organs are in a single animal. These members can act, for instance, like a circulatory system, taking care of distribution of food, dispersal of waste, and transmission of chemical cues. The nest can be seen as the superorganism's skin or skeleton. The astonishing complexity of a colony does result from simple decision-making processes hard-wired into the colony members. As computers have shown, tiny repetitive algorithms can eventually yield astonishing complexity, and the tiny brains of ants and bees can store plenty of such programs. The result is that the colony can make decisions: Where shall we bivouac? Where does the next wall go? Where shall we roam for food? The decision-making and teamwork bring success. Social insects are hugely abundant; they are only 2% of the 900,000 insect species, but in total weigh more than all the others. A measurement in the Amazon rainforest showed social insects to be 80% of animal biomass, more than the sum of the mammals, birds, reptiles, and amphibians.
This comprehensive book has one surprising fact after another about insect societies. It describes the now-famous waggle dance used by bees to inform the hive where a nectar source is, but research has revealed "other performances on the honeybee dance card". The returning bees do a shaking dance to get more bees onto an empty dance floor to get the news, or they do a tremble dance if they can't unload the incoming nectar, a dance that recruits more bees to be food handlers. Some ants engage in child labor. The queen of the Dracula ants pierces her own larvae to feed on their blood. Tropical weaver ants use the sticky threads produced by larvae, swinging the larvae back and forth like shuttles to bind leaves together to make a nest. There are over forty distinct glands in ant species that send hormones, mostly pheromones, out to communicate with others, but ants also "stridulate" (make a chirping sound like a cricket, although it is too small and high for us to hear) to get messages across. An ant grabs hold of another and shakes in a particular way to get the other to follow to a food trail, or shakes another way to get the other to go to a new nest site. Some ants have a "social stomach", a gastric crop within all the workers that holds nutrition to be shared with any other ant that does not have enough. Ants measure the way to a food source by counting their steps; researchers glued stilts onto foragers' legs as they went into the wilds, but took the stilts off before they could return. The ants returned the right number of steps, but found themselves short of home. These sorts of facts in such abundance here can only increase our wonder at the determination of the researchers prying out insect secrets. The authors end with a cheery recognition of how far this research has come, and how much more will be coming: "None of us now present can imagine the great advances certain to come. But of course, that is one reason we have future generations."