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...

The freshwater chlorophyte Scenedesmus obliquus (Turpin) Kützing produces colonies as an inducible defence against herbivores. We investigated the dynamics of Scenedesmus colony formation and disintegration in response to the density of the herbivorous rotifer Brachionus calyciflorus in large-scale mesocosms. Additional bioassays were performed to investigate Scenedesmus colony disintegration u...

Brachionus calyciflorus typically develops long, defensive spines only in response to a kairomone from the predatory rotifer, Asplanchna. However, in the absence of any environmental induction, females of some clones produce daughters with increasingly long spines as they age; late-born individuals can have posterolateral spines as long as those induced by Asplanchna: up to 50% or more of body ...

BACKGROUND Asexuality has major theoretical advantages over sexual reproduction, yet newly formed asexual lineages rarely endure. The success, or failure, of such lineages is affected by their mechanism of origin, because it determines their initial genetic makeup and variability. Most previously described mechanisms imply that asexual lineages are randomly frozen subsamples of a sexual populat...