An official website of the United States government
Evolution: Plasticity versus Selection, or Plasticity and Selection?
More Like this
-
Caruso, Christina; Morlon, Hélène (Ed.)Abstract Plasticity to reduce activity is a common way prey evade predators. However, by reducing activity prey often experience lower individual growth rates because they encounter their own prey less often. To overcome this cost, natural selection should not simply favor individuals generating stronger plasticity to reduce activity rates but also selection to resume activity once the threat of predation subsides. If such plasticity is adaptive, it should vary under environmental conditions that generate stronger selection for greater plasticity, such as predator density. Using a mesocosm experiment and observational study with a damselfly-prey/fish-predator system, we show that fish predation exerts selection for greater plasticity in activity rates of damselflies. Such selection allows damselfly activity levels to initially decrease and then rebound when the threat of predation dissipates, potentially helping to ameliorate a hypothesized growth penalty from activity reductions. We also find that the extent of plasticity in activity to the threat of fish predation increases, albeit slightly (r2 = 0.04%–0.063%), as fish densities increase across natural lakes, consistent with the idea that the magnitude of plasticity is shaped by environmental conditions underlying selection. Collectively, these results demonstrate how selection acts to drive adaptive plasticity in a common predator avoidance strategy.more » « less
-
Relatively little is known about whether and how nongenetic inheritance interacts with selection to impact the evolution of phenotypic plasticity. Here, we empirically evaluated how stabilizing selection and a common form of nongenetic inheritance—maternal environmental effects—jointly influence the evolution of phenotypic plasticity in natural populations of spadefoot toads. We compared populations that previous fieldwork has shown to have evolved conspicuous plasticity in resource‐use phenotypes (“resource polyphenism”) with those that, owing to stabilizing selection favouring a narrower range of such phenotypes, appear to have lost this plasticity. We show that: (a) this apparent loss of plasticity in nature reflects a condition‐dependent maternal effect and not a genetic loss of plasticity, that is “genetic assimilation,” and (b) this plasticity is not costly. By shielding noncostly plasticity from selection, nongenetic inheritance generally, and maternal effects specifically, can preclude genetic assimilation from occurring and consequently impede adaptive (genetic) evolution.more » « less
- Free Publicly Accessible Full Text
-
Accepted Manuscript
- Journal Article:
- https://doi.org/10.1016/j.cub.2018.07.050
