Skip to main content

Effect of nutrient intake on the expression of genetic variation in behavioural syndromes

Final Report Summary - DIET AND PERSONALITY (Effect of nutrient intake on the expression of genetic variation in behavioural syndromes)

The proposed study aimed to test a role of variation in diets (environmental variation) on the development and the expression of behavioural syndromes (among-individual behavioural correlations) in field crickets Gryllus bimaculatus. The researcher (Dr Changseok Han) finished his planned project in the Marie Curie Action proposal in the first year of the fellowship period (between April 2014 and April 2015), and he conducted additional quantitative genetics experiments in the second year. Currently he is analysing experimental data from two large-scale quantitative genetics experiments and preparing several manuscripts based on the results.

He published a review paper about diet-dependent multivariate gene-environment interactions in Frontiers in Zoology (Han & Dingemanse 2015). This review paper provides the framework for studying environment-specific genetic correlations which relates to his research on the effects of nutritional stress on genetic correlations between behaviours. In addition to the proposed study, the researcher conducted additional experiments using another animal species (water strider (Heteroptera: Gerridae)), so that he introduced another animal system to the Ludwig Maximilian University and the European Research Area. From the additional behavioural experiments, he had published 5 papers in behavioural journals (Han et al 2016 Behavioral Ecology; Han & Jablonski 2016 Animal Behaviour; Han et al 2015, 2016 Animal Behaviour; Han & Brooks 2015 Animal Behaviour).

His main research using field crickets has firstly shown that the genetic correlation between behavioral traits depended on nutritional treatments. Interestingly, nutrition affected the amount of genetic covariance between functionally distinct phenotypes without changing their genetic variances. Phenotypic correlations exist not just due to pleiotropic effects of genes (or linkage disequilibrium) but also due to pleiotropic environmental effects (such as nutritional condition). The covariance between phenotypes is thus shaped by the combined effects of environmental and genetic correlations. In addition, he found that environmental conditions can also affect the expression of genetic covariance as well as the one of genetic variance, leading to environment-specific genetic correlations.

His project had an unusually strong interdisciplinary focus, by integrating quantitative genetics and animal behaviour. How concepts developed in behavioural ecology translate to quantitative genetics theory has been broadly neglected, and we still lack a more nuanced understanding of genetic correlations between traits. His research is the first to provide a rigorous evaluation of the evolution of phenotypic correlations, by using tools from quantitative genetics and animal behaviour in an animal model system with known pedigreed individuals.

His research also contributes to a more realistic understanding of phenotypic evolution and a more complete understanding of how individuals respond to their environments. Phenotypic correlations do generally not indicate the sign of genetic correlations, and hence the environment has a strong modifying effect. Proper understanding of the role of environmental effect on the development of behavioural correlations allows a greater understanding on the evolution of labile phenotypes in response to changing environments. Therefore the results of his research will not only yield novel insights into evolutionary biology, by revealing the genetic architecture of phenotypic correlations and their cross-environment stability, but will also contribute more broadly to our understanding of the effects of environmental change on individual and population resilience.

His research is thus at the forefront of studies on behavioural ecology and evolutionary biology, and can address key questions related to behavioural genetics. The multidisciplinary nature of this proposal, integrating fields of evolutionary genetics and behavioural ecology will make this research of broad scientific interest. For these reasons, his research will be of considerable interest to both high impact journals, as well as the local and international media.