About My research

I'm working on the evolution of sociality in primate societies using long-term, individually-based, data.
I'm interesting in the main determinants of primate social relationships as well as in the proximate factors regulating them. Currently, I have three main research questions focusing on empirical aspects of the kin selection theory, on host-parasite relationships and dynamics and on sleep ecology (see below).

Since 2012, I'm running a long-term field site in Southern Gabon (Lékédi Park, Bakoumba) to study the only habituated natural population of mandrills worldwide.

I adopt a multi-displinary perspective by combining different empirical approaches and by using different tools
(artificial intelligence, behavior, biologging, molecular genetics, chemistry, hormones).

Kin-differentiated relationships

Kinship is one major driving force influencing social relationships and social network dynamics in animals. As a result of widespread female philopatry and male natal dispersal, most studies of kin selection in primates have been restricted to relationships occurring between familiar maternal kin. However, there are numerous individuals related through the paternal line that are unfamiliar (or less familiar) with each other because they are raised in different matrilineal families.

Paternal kins show differentiated relationships and phenotypic ressemblance. Unfamiliar kin are also able to recognize each other through different communication channels (audition, vision) suggesting phenotype matching mechanisms.
In 2020, we show increased facial resemblance among paternal half-sisters using AI, probably to facilitate recognition of paternal kin and nepotism.

Parasitism and sociality

Sociality results from an equilibrium between the benefits and the costs associated to group living. Parasites constitute probably one important cost of sociality because of frequent body contacts between groupmates. Several host defence mechanisms have therefore evolved to limit the spread of parasites, including social and behavioural strategies. Parasites, in turn, may also modify (manipulate) host social interactions and behaviour to their own advantage to increase transmission. Data on parasitism as an evolutionary driver of host sociality in wild vertebrate populations are, however, scarce.

As illustrated on this sequence of pictures, mandrills are highly social primates. We show that contagious mandrills are groomed less frequently than "safe" social partners, especially in risky –contagious- body areas. Medical therapy has, however, a positive feed-back on grooming rates. We further propose an olfactory pathway mediating this host-parasite relationship: faecal odours of infected animals are different from those of healthy ones and mandrills selectively avoid infectious dung samples during behavioural bioassays.

Using bioassays on captive chimpanzees from CIRMF, we found that Toxoplasma-infected (TI) animals lost their innate aversion towards the urine of leopards, their only natural predator. By contrast, we observed no clear difference in the response of TI and Toxoplasma-non-infected animals towards urine collected from other definitive feline hosts that chimpanzees do not encounter in nature.

Sleep ecology

I'm currently starting a new project on the mechanistic and functional relationships between sleep and the immune system using long-term individual monitoring of mandrills in combination with field experiments and laboratory analyses. This project takes its roots in the observation that individuals that move more at night (data obtained from accelerometers) also show more frequent daytime sleepiness indicating sleep rebound. Funded by the ANR.

Others

I'm also working on different questions related to primate communication via different modes (vision, olfaction, acoustic), on the relationships between sociality and fitness, on self-medication behavior... Finally, I'm more and more inclined to develop new non-invasive tools to obtain invaluable biological data on the natural population of mandrills I'm studying (see here).

Collaborators

Several students contribute(d) greatly to these research programs as well as collaborators: Peter Kappeler (kin selection); Elise Huchard (immunity and competition); Florence Levréro (acoustic communication); Julien Renoult (visual communication); Christine Drea (chemical communication); Jordi Galbany, Alejandro Romero and Gildas Merceron (dental microwear); Didier Basset, François Simon, Virginie Rougeron and Franck Prugnolle (parasitology and virology)... and I'm sure I forgot many others...