Artificial Life VI

Attractiveness vs. Efficiency: How Mate Preference Affects Locomotion in the Evolution of Artificial Swimming Organisms

Jeffrey Ventrella


This paper describes a unique simulation in which a population of physically-based organisms evolves morphology and motor control for fluid locomotion, through competition for mates and food. Preference for mates exhibiting specified phenotypic features has an affect on the evolution of locomotion which is sometimes inhibitory, sometimes advantageous, and at times amusing. Reproduction of genotypes is autonomous and local in this spatial model, occurring among organisms which are able to approach critical proximity to a desired mate. An organism's energy level dictates whether it will seek mates or pursue food. Thus, an organism whose motions expend excessive amounts of energy will eat more, and reproduce less. The simulation was set up to determine whether mate preferences for arbitrary features can inhibit optimization of locomotion. While the general evolutionary trend is towards energy-efficient locomotion, the inclusion of mate preference causes a bias towards arbitrary anatomy and motion within the population. It was found that certain preferences indeed counter the trend for efficient swimming. A delicate balance between two forces (representing natural selection and sexual selection) is demonstrated.

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