Abstract The stoichiometric knife-edge refers to the reduced performance of consumers encountering food with excess phosphorus (P) relative carbon (C) or nitrogen (N). Studies that provide evidence for such in aquatic systems often apply phosphate supplementation create P-rich treatments. However, this method may suffer from artifacts, because after uptake algae store P a form different biomole...

Using rotifer-algal microcosms, we tracked rapid evolution resulting from temporally changing natural selection in ecological predator-prey dynamics. We previously demonstrated that predator-prey oscillations in rotifer-algal laboratory microcosms are qualitatively altered by the presence of genetic variation within the prey. In that study, changes in algal gene frequencies were inferred from t...

Microevolution is typically ignored as a factor directly affecting ongoing population dynamics. We show here that density-dependent natural selection has a direct and measurable effect on a planktonic predator-prey interaction. We kept populations of Brachionus calyciflorus, a monogonont rotifer that exhibits cyclical parthenogenesis, in continuous flow-through cultures (chemostats) for more th...