Figs, Wasps, Gophers, and Lice: A Computational Exploration of Coevolution

The prescient thought experiment that Darwin describes in the Origin of Species is, in fact, borne out in bees and flowers (as documented in the book The Sex Life of Flowers [10]). One particularly interesting example is the symbiotic relationship between figs, their tiny flowers, and the miniature wasps that pollinate them. The story goes something like this: The flowers or “florets” of a fig are in its interior and are protected by the fig’s thick membrane. Pollinating a fig is a real challenge! However, each fig species has a species of wasp (usually just one species, but sometimes more) that pollinates it. When a female wasp of the right species finds a fig that she likes, she tunnels into the interior, generally losing her wings in the process. Once inside, she lays her eggs on some of the tiny interior flowers, and, in the process, pollinates the fig. As the host fig develops, the wasp eggs hatch and the larvae feed on the fig tissue. After several weeks, the wasps reach maturity. The wingless males have a short life with only two objectives: They mate with the females and then burrow holes to help the females escape from the fig. The males then die inside the fig and the females fly off in search for their own fig homes to repeat the reproductive cycle. This bizarre story is true [1, 14] and not merely a figment of our imagination! Biologists refer to the genetic change of one species in response to the change in another as coevolution. In the case of figs and wasps, the coevolution is known as mutualism since