The famous experiment by John Endler in 1980 trialed guppies in several artificial and natural environments. He concluded that guppies kept with predators like cichlids develop fewer spots than those living in safe areas.Dec 19, 2020
What adaptive explanation can you suggest for this increase in male spot number? In the absence of any predatory fish, natural selection had favoured an increase in spot number. The more heavily spotted males had more offspring because they were more attractive to females.
Endler's hypothesis was that predators are responsible for much of this variation among populations. He had noticed that guppies sharing their stream with predatory cichlids had fewer spots than guppies living with Rivulus.
U.S. scientists say they have discovered why male guppies, the most fertile member of the fish tank, are so colorful. The University of Illinois researchers, working in Trinidad, say the answer is genetic, with the vibrant colors used to attract females.Jun 1, 2006