Ecoevolutionary feedbacks of phenotypic plasticity and mono- vs polyclonal communities in bi- and tritrophic systems

本项目将集中于个体性状变异(表型可塑性)和遗传性状变异(多克隆系统)对以藻类为食物、草食性纤毛虫为主要捕食者及其纤毛虫捕食者的双营养和三营养系统中种群、群落和性状动态的影响。在我们的系统中，表型可塑性作用于两个营养水平。纤毛虫(毛游毛虫和八肋游仆虫)可以形成针对捕食者的表型塑料防御，这包括在防御和竞争实力之间的权衡。此外，在单克隆和多克隆实验中，我们将使用不同的Eplotes菌株，这些菌株在可塑性、生长速度和竞争强度方面的反应标准不同。因此，我们通过可塑性和克隆成分的变化来研究性状变异。此外，我们将使用能够形成诱导性犯罪的捕食者(Lembadion Bullinum)，这在一定程度上允许克服猎物防御，或者使用对猎物防御没有反应的捕食者(Sphagnetorum)。通过我们的系统，我们将解决以下假设：1.在消费者水平上，不同克隆的克隆特异性反应规范(表型可塑性)所表达的性状差异促进了三营养系统中营养水平的稳定性和持久性。2.具有克隆特异性反应规范的多克隆消费者系统比单克隆系统提高了种群稳定性。在一个三营养系统中，消费者营养水平上的特性变化可能比两个营养水平(消费者和顶级捕食者)上的特性变化更能稳定营养动态，这取决于调节的相对速度。我们的项目将结合经验实验和数学建模方法。它与SPP中的其他项目密切相关，但独特之处在于，我们研究了一个三营养系统，在该系统中，捕食者形成可诱导的犯罪，以回应其猎物的可诱导防御。我们的项目将促进对一般生态过程的理解，特别是对捕食者-猎物和食物网动态的理解。

Our project will focus on the effects of individual trait variation (phenotypic plasticity) and genetic trait variation (polyclonal systems) on population, community and trait dynamics in bi- and tri-trophic systems with algae as food, herbivorous ciliates as primary consumer and their ciliate predators. In our system phenotypic plasticity acts on two trophic levels. The ciliates (Euplotes aediculatus and E. octocarinatus) can form phenotypically plastic defences against their predators, which includes a trade-off between defence and competitive strength. Furthermore, we will use different Euplotes strains that differ in their reaction norms of plasticity, growth rates and competitive strength in mono- and polyclonal experiments. Consequently, we study trait variation via plasticity and via shifts in the clonal composition. Additionally, we will use predators that can form inducible offences (Lembadion bullinum), which partly allow to overcome the prey defences, or predators, which do not respond to the prey defences (Stenostomum sphagnetorum). With our system we will address the following hypotheses:1. Trait variation expressed in clone-specific reaction norms (phenotypic plasticity) in different clones on the consumer level promotes the stability and persistence of trophic levels within a tri-trophic system. 2. Polyclonal consumer systems with clone-specific reaction norms of traits increase population stability compared to monoclonal systems.3. Trait variation on the consumer trophic level may stabilize trophic dynamics more than trait variation on two trophic levels (consumer and top predator) within a tri-trophic system depending on the relative speeds of adjustment.Our project will combine empirical experiments and mathematical modelling approaches. It is closely linked to other projects in the SPP but is unique in that we study a tri-trophic system where the predator forms inducible offenses in response to its prey’s inducible defences. Our project will foster the understanding of ecological processes in general and of predator-prey and food web dynamics in particular.