Bert Hölldobler on the Superoganism

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Bert Hölldobler explains that a Superorganism is a group of individuals in which the members are so tightly united and organized that they collectively develop traits commonly found in ordinary organisms. "Eusocial" insects fit this criteria. Reproduction and defense, for example, are done by specific members of the society.

Key: The superorganism can only survive through communication as a whole, rather than through individual effort alone.

They are also tremendously successful from an ecological perspective because this division of labor enables a success unattainable by individual members of other species. They provide one quarter of the entire animal biomass of the Earth even though they constitute only one to two percent of animal species.

"Without social insects the planet Earth would look very, very different," he adds.

Showing two communicating ants, he explains how ants exchange regurgitated food through tactile communication. But more than anything, "ants are little chemical factories," using various chemical mixes and receptors to exchange environmental information. He displays a number of images of their physiology, which make the point. Tests demonstrate how ants will precisely follow a trail of certain chemicals, left by scout ants for example, and avoid others.

Symbiotically, Leaf-cutting ants will carry cuttings many, many to the colony so that a fungus, grown only on that leaf, can be cultured and eaten. Each ant type has a responsibility for carrying out that process - from harvest to final product.

Reproductively, the single queen will collect sperm from one or two male ants, which promptly die. But that sperm is then stored and may be used up to twenty years into the future. The queen will produce up to 120 million offspring, most of whom are sterile workers.

Interestingly, the queen and her mates represent a single phenotype. That expression, rather than individual genes, is evolutionarily operative.

Moving to colony, he illustrates their interior structures in 3-D, which are phenomenally complex, the result of communication process that is still very poorly understood. Similarly, the foraging, cutting behavior in tree canopies is not entirely understood, but believed to have something to do with vibrations sent by the ants through the vegetation, which signals the presence of desirable vegetation. Ants, by the way, cannot hear sounds transmitted through the air.

Transportation of the cut leafs is accompanied by a veritable phalanx of defenders riding the vegetation, defending the carrier from attack by parasitic flying insects.

Highly evolved social systems will fight for space, limited resources. In ant societies, this principle is carried out by defensive strategies designed to communicate and defend against threats. Similarly, staged ant "jousting" matches that take place over days to estimate relative strength of particular colonies, the movements of which he illustrates on a grid. He also demonstrates decision trees used by individual ants to make choices when confronted by unknown ants.

He concludes with some anthropological pictures from a Harvard colleague that, incredibly, show some primitive tribe that bear a remarkable semblance to the images just displayed of ants in tournament. He hastens to add that he does not claim a "direct" evolutionary link, but suggests nonetheless that the idea cannot be dismissed out of hand. We, as humans, keep count of competitors as well!

Responding to one very interesting question from the audience, he says that ants, though very rigidly defined, do make mistakes. The difference is that they are very easily overcome by group cohesion.

Wayne

Image credit: Geoff Oliver Bugbee