(to be published in: Artificial Life VI 1998, MIT Press)
Attractiveness vs. Efficiency
How Mate Preference Affects Locomotion
in the Evolution of Artificial Swimming Organisms
Jeffrey Ventrella
Abstract
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.
