After maintaining your simulation pool for only one year, you find
a significant decline in the number of moderately colored guppies. The brightest males
and drabbest males are still faring pretty well under the extreme predation pressure,
but all others are quickly weeded out of the population.
Number of guppies: 171
Number of generations: 4
Number of weeks: 57
Male color types:
Brightest: 15%
Bright: 9%
Drab: 26%
Drabbest: 50%
In four years (or about
seven guppy generations), the brightest males are beginning to bear the brunt of the
predation pressure, while the drabbest guppies in the population dominate. After six
years, the drabbest guppies make up 90 percent of the population, and it's clear that
the brightest guppies' days are numbered. This trend is similar to the one Endler
observed in the lower sections of Trinidad streams, as well as in the experimental
pools he stocked with many predators.
Number of guppies: 100
Number of generations: 7
Number of weeks: 203
Male color types:
Brightest: 0%
Bright: 0%
Drab: 4%
Drabbest: 96%
