Ants are simple creatures, yet they can perform complicated tasks. They create highways leading to food, organize the distribution of larvae in the anthill, form cemeteries by clustering dead ants, build living bridges to cross gaps in their way, and assign tasks as needed without any centralized control. Thus, ants provide an excellent model for programming simple devices to achieve complex results.

Boil down ant behavior and what do you get? A new set of business tools known as ant algorithms: basic behaviors that can be programmed into a large number of independent software agents to solve human problems.

Consider the way ants forage. When an ant comes across food, it returns to the nest, leaving a scent trail. Other ants follow the trail, find the goods, and carry them back to the nest, reinforcing the path with their own scent, which attracts still more ants. Shorter routes get more traffic, so the scent becomes stronger along these, while it dies away along lesser-used ones. In this way, ants follow the shortest paths between their nest and nearby food sources. link

Armin: Genetic algorithms, swarm particle intelligence, etc can also be used for portfolio optimization problems.