A study on the effects of stoichiometric constraints on rotifer populations

A study on the effects of stoichiometric constraints on rotifer populations

Host-plant suitability and quality for herbivore (and possibly natural enemy) development is determined by the presence of sufficient levels of nutrients and concentrations of adverse metabolites such as specific secondary plant compounds and digestibility reducers. In nature, these characteristics are dynamic and can change within individual plants over the course of a growing season. Many species of multivoltine insects (insects have more than one generation per year) are known to attack short-lived annual plants i.e. plants that are present for only 1or 2 months in the field. These short-lived plants may germinate and grow at different times and/or locations during the growing season. In this situation, each herbivore generation is faced with the challenge of leaving the natal patch to find and lay eggs on a different plant species that may be growing some distance from where they themselves developed. At the same time, the quality of the different food plant species on which they feed and grow over the spring and summer seasons may also be highly variable.

Host-plant suitability and quality for herbivore (and possibly natural enemy) development is determined by the presence of sufficient levels of nutrients and concentrations of adverse metabolites such as specific secondary plant compounds and digestibility reducers. In nature, these characteristics are dynamic and can change within individual plants over the course of a growing season. Many species of multivoltine insects (insects have more than one generation per year) are known to attack short-lived annual plants i.e. plants that are present for only 1or 2 months in the field. These short-lived plants may germinate and grow at different times and/or locations during the growing season. In this situation, each herbivore generation is faced with the challenge of leaving the natal patch to find and lay eggs on a different plant species that may be growing some distance from where they themselves developed. At the same time, the quality of the different food plant species on which they feed and grow over the spring and summer seasons may also be highly variable.

Rapid evolutionary adaptation is increasingly considered as an important mechanism allowing animals to adapt to a rapidly changing world. Our research has shown that rotifers, a type of very common freshwater zooplankton, are able to adapt to poor food quality or enhanced salt concentrations in not more than a few months. At this moment, we investigate how rotifers cope with combinations of stressors. More specifically, we run evolution experiments in the laboratory exposing populations to the metal Cu and high temperatures, with the aim to study how adaptation to one stressor impedes or enhances the response to the other stressor.

Rapid evolutionary adaptation is increasingly considered as an important mechanism allowing animals to adapt to a rapidly changing world. Our research has shown that rotifers, a type of very common freshwater zooplankton, are able to adapt to poor food quality or enhanced salt concentrations in not more than a few months. At this moment, we investigate how rotifers cope with combinations of stressors. More specifically, we run evolution experiments in the laboratory exposing populations to the metal Cu and high temperatures, with the aim to study how adaptation to one stressor impedes or enhances the response to the other stressor.

Secundaire plantenstoffen kunnen een rol spelen bij afweer tegen zowel herbivoren als fytopathogene schimmels. In natuurlijke populaties wordt vaak een grote mate van genetische variatie in (constitutieve) gehaltes aan secundaire plantenstoffen gevonden. Een algemeen aanvaarde verklaring hiervoor is dat er kosten verbonden zijn aan deze vorm van afweer: waardgenotypen met hoge gehaltes hebben een selectief voordeel bij hoge selectiedruk door herbivoren, maar genotypen met lage gehaltes, d.w.z. lage kosten, bij een lage selectiedruk.

Een groot deel van de potentiële reproductie van planten in natuurlijke populaties gaat verloren door toedoen van pathogenen en herbivoren. Twee anjerachtigen, Silene alba en S. dioica worden in ons land bijvoorbeeld geïnfecteerd door de brandschimmel Ustilago violacea, die de vruchtbeginsels van geïnfecteerde bloemen aborteert, en de helmhokjes gebruikt om haar eigen sporen in te produceren.

Woodland expansion in arid environments occurs episodically during wet years. Recent research indicates that tree seedling growth rate and survival is crucial to explain the differences across ecosystems and that soil microorganisms likely play a crucial role.

Woodland expansion in arid environments occurs episodically during wet years. Recent research indicates that tree seedling growth rate and survival is crucial to explain the differences across ecosystems and that soil microorganisms likely play a crucial role.