The Pulitzer Prize-winning authors of Ants present a lavishly detailed account of the extraordinary lives of social insects that draws on more than two decades of research and offers insight into how bees, termites, and other insect societies thrive in systems of altruistic cooperation, complex communication, and labor division.
A superorganism is defined as a society such as an insect colony that possesses features of organization analogous to the physiological properties of a single organism. There are three basic behavioral mechanisms discussed that allow the ants to develop into a superorganism. The first is altruism; evidenced by the fact that the vast majority of the insects in the colony do not reproduce but instead spend their lives raising someone else's offspring. This runs contrary to the basic drive to reproduce. It is the first step down the evolutionary path to the development of a superorganism.
Altruism allows for the development of division of labor which allows some of the insects in the colony to function as a separate physiological process within the superorganism. Some of the insects do nothing but gather food for the colony. They bring in the food in a raw state and then another group of insects turn the raw food into something edible for the members of the colony. The foragers needs for shelter, food and protection are met by other specialized insects within the colony. In some species the division of labor changes as the needs of the colony change. If there is too much raw food some foragers may adopt another role necessary for the colony such as processing the food. The adoption of another role may require the insect to change some of their physical characteristics to those required by their new role. Often these changes are triggered by some method of communication between the individual insect and other members of the colony.
Communication is the third requirement for the development of the superorganism. Much of the communication is chemical. I got quite lost in some of the explanations about the processes of chemical communication within the colony. The insects have incredible sensitivity to a large variety of chemical markers produced by the other insects, some of the amounts involved are measured in nanoliters. A simple example goes back to the foragers. Once a forager finds a food source they will put down a chemical trail for other foragers to follow. The chemical trail may let other insects know what type of food there is, the quantity or how far away it is. This is a simplistic example that is multiplied by the vast number of operations necessary to keep the colony going. A large amount of the communication is about reproduction. There is also a lot of physical communication. The variables involved in physical communication are only limited by the number of body parts each insect has and how many insects can be involved in the actions. Some foragers will lead other insects to a food source by maintaining physical contact as they walk down the trail.
At the top level of complexity are the leaf cutter ants. The authors state that they are the second most complex society in the world and I will not argue with them. There are many different species of leaf cutters who all live by raising the same species of edible fungus. They cut up leaves to provide a growing medium for the fungus. Some species use the silk from larvae to hold pieces of cut up leaves together and build growing beds for the fungus. This operation was shown in one of the photographs. Most amazing were the species who have a symbiotic relationship with parasites that produces antibiotics for the fungus.
Reading this book made being a scientist sound like a nice way to live. A lot of the research that was described seemed like play for grownups. In the chapter on colony architecture the scientists would fill a colony with plaster of paris or molten aluminum and them excavate the dirt to reveal the structure of the colony. Some of the photos had large groups of ants with colored dots on them so the scientists could follow their activities. I am really glad I took the time to read this book. Maybe I will get an ant farm.
Yeah, I said gumption.