In 2018, I received a two-year Marie Slodowska Curie fellowship (program Horizon 2020) to study the evolution of ultraviolet (project UVSIGNAL, n°796662) signals at the institute of Ecology and Environmental Sciences (iEES-Paris), Sorbonne University. A large part of this project has been undertaken at the CEREEP-Ecotron, an experimental research station hosting a large captive population of common lizards (Zootoca vivipara), the model organism of this project.
Animals use a bewildering diversity of signals to communicate. Displays of colour signals have always baffled naturalists and their study has greatly advanced our understanding of animal communication. Invisible to the human eye, ultraviolet (UV) signals have long been overlooked by scientists and yet, they are ubiquitous in the animal kingdom. Despite a growing body of work in the recent years, the mechanisms involved in the evolution of UV signals are still far from fully understood. The over-arching aim of this project is to provide insights on how UV signals can become evolutionarily stable. Common lizards (Zootoca vivipara) are an excellent model species to tackle these questions because males display a conspicuous patch of UV colour on their throat, which is sexually selected. To investigate the forces that shape and en force the honesty of these signals, this project will use several complementary approaches combining field studies and experimental approaches using wild and captive populations of common lizards. More specifically, we designed a series of experiments to identify the physiological costs, social costs, and predation costs that are potentially associated with UV signal expression. The results of this combination of experiments will provide invaluable insights on the evolutionary mechanisms maintaining UV signal honesty. In addition, we also planned a study aiming at investigating the relationship between male UV signal and male reproductive success to assess the true role of these signals in common lizards and the intensity of selection acting on them. To explore whether or not our findings resulting from these experiments are corroborated in the wild, a field study involving wild population will allow us to assemble a large data set and test for correlative relationships between UV signals, male quality traits, parasitism, testosterone levels, and environmental variables. Finally, we assembled another data set with the objective of investigating whether and to which extent UV signal expression is heritable from fathers to sons. The multi-disciplinary and multi-angle approach of this project will bring novel and valuable insights into the evolution of UV signals, and of animal communication more generally.