It is about time: effects of thermal fluctuations resulting from climate change on trophic interactions with a focus on host–parasitoid interactions

Climate change alters many environmental parameters with strong consequences for ecological interactions, from species interactions to community dynamics. Temperature is crucial in determining ecosystem dynamics, especially for those involving ectothermic species such as plants or insects. Phenotypic plasticity, the capacity of one genotype to produce different phenotypes in response to environmental conditions, is a common mechanism by which individuals adapt to changing environments and is observed in multiple traits. The capacity of genotypes to adapt to novel temperature conditions plays a crucial role in structuring ecosystem dynamics and species persistence in adverse conditions. It is well recognised that temperature in natural ecosystems fluctuates over multiple time scales (e.g., hour, day, season, year). These fluctuations can follow predictable patterns or be unpredictable, with different consequences for phenotypic plasticity and ecosystem dynamics. Among trophic interactions, host–parasitoid interactions represent a special case because of the intimate symbiosis of the parasitoid larvae with their host. Understanding how and to what extent phenotypic plasticity structures species’ ecological niches is of utmost importance in the context of rapid climate change. With a particular focus on host–parasitoid interactions, this review discusses the literature on the role of phenotypic plasticity in fluctuating environments, highlighting the role of temporal dynamics. While we discuss literature on phenotypic plasticity at large, this review emphasises the fundamental effects of extreme temperatures in driving biochemical rates underlying phenotypic plasticity.