5 Mate Preference
Three genes affect phenotypic features which come into play in times of mate choice:
• head color
• color shift from head to consecutive segments in all limbs
• favorite color in a potential mate
The first two genes control the coloration of the swimmer.
Colors include the six primary and secondary colors of a painter's
color wheel: red, orange, yellow, green, blue, and violet (violet
being followed by red, in cyclical fashion). They are stored as
consecutive integers in the model. An algorithm was designed which
is not meant to model any particular biological scheme for animal
coloration, but simply to generate phenotypic variety from a small
number of genes. Coloration is determined by the following
algorithm (expressed in C language).
for (L=1; L<=num_limbs; L++)
c = head_color;
for (S=1; S<=num_segments; S++)
c = c + color_shift;
segment(L)(S)color = red + ((int)(c*(float)(violet-red)) % (violet-red));
where c is a positive real number, and head_color and color_shift are
positive real numbers, determined by gene values. These two genes
control the making a large variety of color patterns in swimmers,
including solid colors.
The "favorite color" gene comes into affect when a swimmer
is looking for an ideal mate. When sizing up the potential mates within
its view, it chooses one who exhibits the largest amount of its favorite
color, and, to a lesser extent, the two adjacent colors on the color wheel.
For instance, a red-loving swimmer will tend to choose mates having lots
of red, violet, and orange. Red would have twice the "strength" as violet
or orange, in enticing this swimmer's lust. Swimmers exhibiting none of
these colors would not be chosen by the red-loving swimmer.
Amount, not percentage of favorite color in a mate is perceived.
Thus, more limbs can potentially have a larger effect - the expectation is
that sexual selection can have an effect on the evolution of body size.
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