The Superorganism: The Beauty, Elegance, and Strangeness of Insect Societies [Englisch] [Gebundene Ausgabe]

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."

This beautiful volume shows the amazing amount that naturalists have learned about eusocial insect species since the publication of the authors' Pulitzer Prize winning volume, The Ants, in 1990. The book is accessible to the lay reader, except for some introductory chapters that require some knowledge of genetics and population biology. These chapters can simply be skipped without compromising the understanding of other chapters. Both because of its breadth and the huge number of references to the professional literature, this book will likely become a reference for many researchers in sociobiology, including those whose specialty is eusocial insects.

From a theoretical standpoint, this book champions two ideas that E. O. Wilson has vigorously supported despite considerable criticism by biologists and social theorists. The first is that all social species share many traits in common, so that there is room for a special field, which Wilson calls "sociobiology," that charts the commonalities and differences among social species. This notion, laid out in Wilson's brilliant 1975 volume by that name, was greeted with scorn and contumely by social theorists who vehemently objected to including human sociality as a mere variant of biological sociality. The ensuing debate is brilliantly documented in Ullica Segerstrale, Defenders of the Truth: The Sociobiology Debate (Oxford University Press, 2001). Of course, sociobiology has withstood the criticism of the ignorant and the intolerant, and is now a fully flourishing field.

More recently, E. O. Wilson has become an ardent supporter of group selection, which holds that Darwinian selection occurs on multiple levels, including the gene, the individual, and in species with a high level of sociality, on the level of the group itself. The central theme of this volume is that the eusocial insects are the product of biological selection on the level of the insect society (bee hive, termite mound, ant hill). Until recently biologists have considered this concept anathema, and many still choke on the idea of selection above the level of the gene, as forcefully expounded by Richard Dawkins in The Selfish Gene (Oxford: 1976). Lately he has teamed up with a long-time proponent of group selection, David Sloan Wilson, to produce a coherent defense of the notion, in the context of insect sociality. The chapter devoted to this issue in the book is a masterpiece that explains clearly the compatibility of gene-level and societal-level selection, and avoids all of the errors commonly committed by group selectionists of a previous generation.

This volume is a true tour-de-force, ably fulfilling two often incompatible goals, that of elegance, excitement and instruction for the general reader on the one hand, and a contribution on the level of basic research on the other.

This is a fascinating book, but one that could be improved. However, the positive (FOR, below) much outweighs the negative (AGAINST, below).

FOR: This book is full of interesting material, most of which is well explained. It follows how eusocial insects construct complex insect societies that display apparent group intelligence by using only a small number of chemical signals and stereotyped responses. It seeks to understand how such complex societies came to exist, based on the competing interactions of selection between indivuals within the colony, and selection between colonies or group selection. It reviews a wealth of material on how such societies operate from relatively simple colonies to the vast and elaborate super-colonies of the leaf cutter ants. Although the shortest chapter, I was fascinated by the evolution of the ants, particularly the Sphecomyrminae, an extinct early ant with properties both of an ant and a wasp. The graphics are stunning, both the line drawings and the photography. Visually it is one of the most beautiful books I have read for some time. The images of concrete casts of ant nests are a revelation.

AGAINST: The authors often over-complicate. For instance, in one section ("anonymity and specificity of chemical signals" p270) the simple idea that some signals are widely used and recognized by many ants in a colony while others are more specific, even down to the recognition of individuals, is introduced by comparison with artificial intelligence and "class variables" and "instance variables". This is a pretentious sledgehammer used to crack a nut (and the supporting reference dated 1984 is very old). The chapter on communication is far too long, and could have been broken down into more manageable chapters. Perhaps one chapter on foraging signaling outside the nest (alarms, trails, nestmate recognition etc.) and one chapter on signaling within the colony (role of the queen, caste recognition, brood recognition etc.) would have been more manageable. There are several examples when ideas or information are repeated within pages of one another, often using almost the same wording. Another round of serious editing might have tidied the book up.
The "Superorganism" title is perhaps an overstatement; there is very little about wasps, bees and termites (but in fairness the authors do say the book is mainly about ants in the introduction). I was disappointed in the lack of material on termites, since these are not hymenoptera, and therefore a thorough going comparison of the principles by which ants and termites construct their societies would perhaps have revealed core rules of insect sociality that exist independently of taxonomic rank. The book is about 500 pages- but it is not 500 pages of reading. The margins are vast, one inch left and two inches right on a 7.5 inch page, so 40% of the book is white space right off the bat. Most pages are heavily footnoted (which is obviously necessary) but it also reduces the read space quite significantly. There are in addition empty pages between chapters so I would guess the primary text probably comes in at about 250-300 pages. This may be evidence of high production values, but in this age, when we understand the deleterious environmental impact of the pulp and paper industry, we might have expected some eco-parsimony from "two of the most renowned biologists in the world" (as the cover flap puts it). I would have preferred some of the white space to have been used expanding the discussion beyond ants.