PhD title : The COCOON project

PhD supervisors: Pr. Sandrine MEYLAN (IEES/EPE) & Dr. Anthony HERREL (MECADEV/FUNEVOL)

KEYWORDS:Behavioral ecology, chameleon, color change, color signal, communication, evolution, Modeling

During sexual selection, animals rely on communication signals to choose their mates. This choice can rely on signals produced during a short period of time, called events. In some cases, events, like mate calls in some tree frogs, can be a driver a speciation by creating a pre-copulatory barrier. However, even if mate calls are intuitive to us, some animals rely mostly on their eyesight to communicate and use their incredible color change ability to communicate, as octopuses, cuttlefishes, and chameleons. Here I propose to investigate if color change, like mate calls, can drive speciation in chameleons, using the panther chameleon (Furcifer pardalis) as biological model.

We chose specifically this species of chameleon because they present a wide range of colors, they are common in the pet trade and finally because according to their original locality, they differ greatly in their body color patterns but still genetically from the same species.

This project is developed along five axes: first, we will study the chameleon's eyesight: spectral sensitivity and motion perception, using the electroretinography, to determine what they exactly see when an another individual color change. Next, we will study the importance of color change during sexual selection by recording the courtship of chameleon both in visible spectrum and in UVs, to see which color patterns are relevant to the chameleon's eye and on which the female relies her mate choice. In a third part, the fitness relevance of the color change ability will be investigated by analyzing if there is a link between color change ability and performance, fertility and/or physiology (e.g. corticosterone level or testosterone level). This links will tell us if the male is giving information about his quality and/or if cheaters exist. Thanks to the data gathered in previous parts and in the literature, I will create a demographic model followed by an evolutionary model, to see if color change could lead to evolutionary diversification. And finally, to confirm our hypotheses, we will perform a comparative study of diversification rates across chameleon genera which have a different color changing ability.



Dollion A.Y., R. Cornette, K.A. Tolley, R. Boistel, A. Euriat, E. Boller, V. Fernandez, D. Stynder and A. Herrel (2015) Morphometric analysis of chameleon fossil fragments from the Early Pliocene from South Africa: a new piece of the chamaeleonid history. Naturwissenschaften 102:2. DOI:10.1007/s00114-014-1254-3


Dollion, A. Y.,  G. J. Measey, R. Cornette, L. Carne, K. A. Tolley, J. M. daSilva, R. Boistel, A-C Fabre and A. Herrel (2016). Does diet drive the evolution of head shape and bite force in chameleons of the genus Bradypodion?. Functional Ecology