Generalist and Specialist Behavior Due to Individual Energy Extracting Abilities

The emergence of generalist and specialist behavior in populations of neural networks is studied. Energy extracting ability is included as a property of an organism. In artificial life simulations with organisms living in an environment, the fitness score can be interpreted as the combination of an organisms behavior and the ability of the organism to extract energy from potential food sources distributed in the environment. The energy extracting ability is viewed as an evolvable trait of organisms a particular organism’s mechanisms for extracting energy from the environment and, therefore, it is not fixed and decided by the researcher. Simulations with fixed and evolvable energy extracting abilities show that the energy extracting mechanism, the sensory apparatus, and the behavior of organisms may co-evolve and be co-adapted. The results suggest that populations of organisms evolve to be generalists or specialists due to individual energy extracting abilities. 1. Generalist vs. Specialist Behavior. To survive and reproduce organisms must extract energy from substances present in the environment. However, not all organisms extract the same energy from the same substances. Different organisms may specialize in the type of food they eat. For example, on Barro Colorado Island, Republic of Panama, howler monkeys (Alouatta palliata) eat mainly leaves whereas spider monkeys (Ateles geoffroyi) eat mainly fruits (Milton, 1981; 1993) although both leaves and fruits are present in the environment. Furthermore, the internal food-processing mechanism of an organism (gut, colon, metabolism, etc.) tends to become adapted to the particular diet in such a way that the quantity of energy the organism is able to extract from each food type is determined evolutionarily. Because of their internal food-processing mechanisms for extracting energy from low fiber, energy rich fruits, spider