Mothers choice: maternal effects on the offspring population dynamics differed between exposure to microcystin-free algae Microcystis aeruginosa and chemical MC-LR environments in the rotifer Brachionus calyciflorus

Maternal effects can affect the offspring population dynamics by influence on the offspring’s phenotypes related to fitness, which is of great significance in regulation of population dynamics. The inhibitory effect of bloom algae Microcystis aeruginosa on the rotifer Brachionus calyciflorus has been extensively studied. However, weather algae M. aeruginosa or its toxin MC-LR will affect rotifer’s population dynamic via maternal effect is not clear yet. In this study, we investigated if fitness related phenotypes would change in offspring from mothers experienced microcystin-free M. aeruginosa or MC-LR stress environments by population dynamic, life history traits, and morphology respectively. We find that the survival and reproduction of offspring decreased under maternal microcystin-free M. aeruginosa stress, but increased under maternal MC-LR stress. Our results indicate that the maternal effects act on the offspring in different forms when faced with different environments. Our research further demonstrates that, unlike the common belief that algal toxins are the main factor inhibiting rotifer population growth, non-toxic Microcystis aeruginosa in fact shows a more potent suppressive effect.