Doctoral Defense in Biology - Marion Dellinger

Doctoral candidate:
Marion Dellinger

Title of thesis: Eco-evolutionary processes in personality and spatial cognition of Arctic charr morphs (Salvelinus alpinus)

Opponents: Dr. Christophe Pampoulie, Research Director at the Marine and Freshwater Research Institute, Iceland.
Dr. Jolle W. Jolles, Senior Researcher at the Center for Advanced Studies Blanes, Spain.

Advisor:
Dr. David Benhaïm, Professor at the Department of Aquaculture and Fish Biology, Hólar University

Supervisor:
Dr. Zophonías O. Jónsson, Professor at the Faculty of Life and Environmental Sciences, University of Iceland, Iceland.

Other members of the doctoral committee:
Dr. Camille A. Leblanc, Professor at the Department of Aquaculture and Fish Biology, Hólar University, Iceland.
Dr. Alison M. Bell, Professor at the School of Integrative Biology, University of Illinois at Urbana-Champaign, USA.
Dr. Culum Brown, Professor at the School of Natural Sciences, Macquarie University, Australia.

Chair of Ceremony:
Dr. Snæbjörn Pálsson, Professor and Head of the Faculty of Life and Environmental Sciences, University of Iceland

Abstract:
Behaviour is a fascinatingly flexible phenotype with immense diversity of manifestations. Despite this diversity, observation of animals makes it evident that individuals show consistent differences from one another in the way they behave. However, little is known about the proximate and ultimate mechanisms leading to the emergence and maintenance of consistent among-individual behavioural differences in nature. This thesis aims at exploring the eco-evolutionary processes and developmental cues shaping two particular aspects of behaviour: personality and spatial cognition. For this, I used juveniles of five Arctic charr morphs, of which two sympatric pairs, ranging along gradients of genetic, ecological, and morphological divergence from a common ancestor. Firstly, I compared these morphs’ personality profiles and their developmental plasticity in response to feeding modalities. Then, I compared their personality profiles, spatial cognitive abilities, the cognition- personality syndrome they form, their underlying neural mechanisms, and their developmental plasticity in response to structural complexity. I show that personality and spatial cognition are under strong genetic influence with low developmental plasticity, the existence of a syndrome between the two, and that genes linked to the dopaminergic pathways and to memory suppression seem particularly involved herein. The results support a model in which all these traits develop and evolve independently from each other in a “case-by-case” fashion, depending on the specific local demands of a given ecosystem. This thesis provides the very first empirical support for a co-evolution between personality and cognition, and these pioneering results encourage further research in this direction.

About the doctoral candidate:
Marion Dellinger was born and raised in France. Always fascinated by biology, she realized at 15 years old she wanted to become a researcher. To secure solid knowledge grounds in animal biology, she completed a Veterinary Medicine degree at the National Vet School of Nantes, France, with a MSc degree double major in Functional, Behavioural and Evolutionary Ecology at the University of Rennes, France. She completed both degrees in 2019. She started studying factors influencing fishes’ behaviour early on during Vet School in 2016, in the Alison Bell's lab, Illinois, USA. There, she worked on a freshwater species, the Threespined Stickleback, thanks to a grant from the Merial Veterinary Scholars Program. She continued on a marine species, the European sea bass, during her Masters’ project at the Ifremer Institute, France. Her PhD focusses on a species that dwells in both marine and freshwater systems, the Arctic charr, in which she studies the eco-evolutionary processes involved in the development of personality and spatial cognition