https://online2.tingclass.net/lesson/shi0529/10000/10183/690.mp3
https://image.tingclass.net/statics/js/2012
To see how strong this effect was, Dugatkin and Godin placed two male guppies in little transparent containers that could be moved around by wires. One guppy was less brightly colored than the other. Although female guppies usually choose the brighter colored of two males, when the dimmer guppy was moved closer to the predator, females chose him over the brighter alternative. This is a dangerous game for males to play, but has its advantages for females. The guppy that takes greater risks and still zooms away has demonstrated that he is the faster, more physically fit guppy. He will probably give healthy offspring. Smarts, of course, is another issue.