Playing god with guppies: testing the effects of gene flow on adaptation, fitness, and population dynamics using a model experimental system

The consequence of gene flow for local adaptation and fitness is a fundamental, yet unresolved, problem in evolutionary ecology and conservation biology. On the one hand, gene flow may introduce maladaptive alleles into a population, thereby reducing fitness. On the other hand, gene flow can add genetic variation to small, inbred populations, increasing fitness through genetic rescue. This is also an important question in conservation, since augmentation of small and declining populations is an important, yet rarely tested, management tool. Here, I will present the results of collaborative field and mesocosm (lab) experiments in which we used Trinidadian guppies to test the multigenerational effects of gene flow on phenotypes, fitness, and demography. In our field experiments, we found that gene flow from adaptively divergent immigrants did not disrupt locally adapted phenotypes. Rather, gene flow increased individual fitness and population sizes of small, inbred populations. In our mesocosm experiment, treatments that received divergent immigrants maintained greater genetic diversity, abundance, and hybrid fitness than controls that received immigrants from the source used to seed the mesocosms. Our results support a growing body of research suggesting that immigrants can increase population fitness even when they are divergent.

Speaker: Dr. Chris Funk

Speaker Institution: CSU

Speaker Website:

Event Date: 10-18-2017

Event Start Time: 4:00 PM

Event End Time: 5:00 PM

Event Location: Biology Auditorium 136

Mixer Time: 3:30 PM

Mixer Location: Biology SW Lobby