Density-Dependent Selection

Abstract

Density-dependent selection, which promotes contrasting patterns of trait means at different population densities, has a long history in population genetics and ecology. The unifying principle from theory is that density-dependent selection operates on phenotypic traits whose values counter the effects of whatever ecological agent is limiting population growth, be it resource competition, predators, or pathogens. However, the complexity inherent in density dependence means that the same selective process can generate multiple outcomes, depending upon the details of how population density affects vital rates and the age or size structure of a population. Failure to appreciate the potential for multiple outcomes confounded many early studies of the process. Nonetheless, careful empirical work in laboratory studies, long-term field studies, and studies of sexual selection demonstrates the wide reach of density-dependent selection. The inconsistent outcomes observed in these studies call for renewed research into how the details of density dependence channel adaptive responses. Expected final online publication date for the Annual Review of Ecology, Evolution, and Systematics, Volume 54 is November 2023. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Population genetics and phylogeographic history of the insular lizardPodarcis lilfordi(Gunther, 1874) from the Balearic Islands based on genome-wide polymorphic data

“…A fundamental goal in population ecology and evolution is to understand the processes that maintain genetic diversity, and those that drive intraspecific/interpopulation divergence across geographic space and time (Avise, 2000). In small insular populations, free of predators and with no immigrants, genetic diversity is primarily driven by genetic drift (due to environmental and demographic stochasticity, both particularly important in tiny islets) and density-dependent selection due to competition for the limited local resources (Hoffmann et al, 2021; Hunt et al, 2022; Travis et al, 2023). Founder effect and high inbreeding levels are also expected to further reduce the population genetic variance and accelerate the process of divergence from the original source population (Keller and Waller, 2002).…”

Population genetics and phylogeographic history of the insular lizard Podarcis lilfordi (Gunther, 1874) from the Balearic Islands based on genome‐wide polymorphic data

“…A fundamental goal in population ecology and evolution is to understand the processes that maintain genetic diversity, and those that drive intraspecific/interpopulation divergence across geographic space and time (Avise, 2000). In small insular populations, free of predators and with no immigrants, genetic diversity is primarily driven by genetic drift (due to environmental and demographic stochasticity, both particularly important in tiny islets) and density‐dependent selection due to competition for the limited local resources (Hoffmann et al., 2021; Hunt et al., 2022; Travis et al., 2023). Founder effect and high inbreeding levels are also expected to further reduce the population genetic variance and accelerate the process of divergence from the original source population (Keller & Waller, 2002).…”

Population genetics and phylogeographic history of the insular lizard Podarcis lilfordi (Gunther, 1874) from the Balearic Islands based on genome-wide polymorphic data

“…Genetic diversity of P. lilfordi : evolution in islands and population conservation A fundamental goal in population ecology and evolution is to understand the processes that maintain genetic diversity, and those that drive intraspecific/interpopulation divergence across geographic space and time (Avise, 2000). In small insular populations, free of predators and with no immigrants, genetic diversity is primarily driven by genetic drift (due to environmental and demographic stochasticity, both particularly important in tiny islets) and density-dependent selection due to competition for the limited local resources (Hoffmann et al, 2021;Hunt et al, 2022;Travis et al, 2023). Founder effect and high inbreeding levels are also expected to further reduce the population genetic variance and accelerate the process of divergence from the original source population (Keller and Waller, 2002).…”