Phenotypic plasticity describes the ability of individual genotypes to develop alternative phenotypes in different environmental settings. Such plasticity is therefore a central concept for our understanding of adaptive evolution as it offers organisms a flexible way to optimally adjust to current conditions. This is especially important for organisms living in a variable and to some extent unpredictable environment and that are constrained in their ability to move to more favourable sites.
Phenotypic plasticity concerns essentially all types of biological traits, including physiological, morphological, life-history and behavioural traits. Illustrative and well-studied examples include environment dependent sex determination in many reptiles, predator-induced morphological defence in many animals (such as tadpoles and Daphnia), and nutrition-dependent phenotypic plasticity of horn development in beetles. Analysing individuals’ norm of reaction to environmental cues can thus offer an exciting and powerful tool to study ecological adaptations.
However, organisms also differ widely in the degree of plasticity. Some species are more plastic than others, and even within species, there is often genetic variability in plasticity, commonly observed as genotype × environment interactions. Hence, plasticity itself is an evolvable trait, which offers the opportunity to explore under which circumstances it is beneficial to be more or less plastic.
We study the evolution of phenotypic plasticity for a variety of traits in different species, but with a strong focus on traits associated with life-history and sexual selection. Current projects include:
Although plasticity is an effective way to adjust to variable environment, many animal behaviours are surprisingly consistent – both over different environments and over time. This constrains how plastic an individual’s behaviour can be. In this respect, we study how and when consistent behaviour – and, consequently, reduced plasticity of behaviour – develops throughout the ontogeny of a model species, the lesser wax moth. We also use theoretical approaches to address adaptive phenotypic plasticity.
Phenotypic plasticity in flatworms:
The role of phenotypic plasticity in climate change:
Franzke, A. & Reinhold, K. (2013). Transgenerational effects of diet environment on life-history and acoustic signals of a grasshopper. Behavioral Ecology 24: 734-739.
Ramm, S.A., Vizoso, D.B., & Schärer, L. (2012). Occurrence, costs and heritability of delayed selfing in a free-living flatworm. Journal of Evolutionary Biology 25: 2559–2568.
Lemaitre, J.-F., Ramm, S.A., Hurst, J.L., & Stockley, P. (2011). Social cues of sperm competition influence accessory reproductive gland size in a promiscuous mammal. Proceedings of the Royal Society B Biological Sciences 278: 1171–1176.