Experimental evolution in natural populations of guppies

Evolution is a rapid process that can be studied experimentally in natural populations, yet we know much more about evolution as the ultimate cause of change over time than we do about how it works on a day to day basis. This study will reveal how and why evolution does or does not happen by quantifying the different factors that can contribute to the way organisms can change over time. The investigators are studying evolution by transplanting guppies from a portion of a stream in Trinidad where guppies co-occur with predators and sustain high mortality rates, into four headwater streams that were previously guppy-free and predator free. Prior research demonstrated that the lower mortality risk in such environments causes the evolution of life histories (maturity, number of offspring produced, lifespan) and other attributes (male coloration, courtship behavior, neuromuscular performance) within two to ten years. The current experiments extend that work by reconstructing the pedigrees of the evolving populations and by quantify differences among individuals in reproductive success, thus partitioning change over time into nongenetic (environmental or maternal effects) and genetic effects.

The project will involve the participation of many undergraduate and graduate students, and continued outreach through a public website (cnas.ucr.edu/guppy) and in Trinidad. The project also strengthens international collaborations with scientists in Germany.