Welcome to the Alpine Marmot Project
tel. : +33(0)4 72 44 85 83
fax : +33(0)4 72 43 13 88
UMR CNRS 5558 – LBBE
Biométrie et Biologie Évolutive
UCB Lyon 1 – Bât. Grégor Mendel
43 bd du 11 novembre 1918
69622 VILLEURBANNE cedex
My research focuses on the interface between behavioural ecology, evolutionary biology, genetics and population dynamics. For this, I combine behavioural observations, molecular tools and long-term data with the main biological model, the Alpine marmot, Marmota marmota.
Evolution of mating systems
Why do some individuals live in couples, while others choose multiple genetic and social partners (partner change, extra-pair paternity)? Based on what criteria do individuals choose their social partner(s) and genetic partner(s)? How are these criteria evaluated? What are the costs and benefits of these choices at the individual level? What are the consequences for population genetic structure or population dynamics?
In this context, my main research project currently focuses on partner choice for different genetic characteristics and the impact of choice on genetics and population dynamics. I am particularly interested in the consequences of mate choice for the evolution of genetic characteristics under selection, in particular on the evolution of major histocompatibility complex (MHC). This project builds on exceptional data, collected since 1990, on the population of Grande Sassière marmots; but also on data collected on different populations in the Alps and Pyrenees and during different time scales (contemporary, historical but also geological). It will quantify the role of mate choice in maintaining and promoting genetic diversity.
Evolution of sociality
Why do some individuals live alone while others live in complex social groups? Why do some become dominant while others remain subordinate? What are the costs and benefits of being dominant? What are the costs and benefits of being subordinate? What are the consequences of the size or composition of social groups? What are the consequences for the population genetic structure or population dynamics?
In this context, I am currently interested in the consequences of the size and composition of social groups (1) on survival and reproductive success, and (2) on patterns of senescence in individuals who make up these groups. This project is based on both interspecific analysis of the mammals and on data from the population of Grande Sassière marmots. The Alpine marmot presents, in effect, a characteristic both fascinating and confusing: cooperative breeding. The Alpine marmot is thus characterized by the existence of social groups in which only the dominant pair reproduces, assisted by subordinates. These subordinates, although sexually mature are reproductively suppressed. They delay dispersion and instead help dominant individuals to raise their offspring. Such a social structure is expected to have important consequences for the life history traits, genetics and dynamics of the population.
Post-copulatory sexual selection
Why do some males develop extravagant secondary sexual characteristics (colours, weapons …)? Why do males develop some extravagant reproductive structures (disproportionate testicles, giant sperm …)? Do trade-offs exist between these traits? Do these traits coevolve with those of females? What are the roles of male competition and female choice in the evolution of these traits?
Sexual selection acts on secondary sexual characteristics such as the characteristics of the gametes and reproductive systems of males and females. I am currently interested in the potential trade-offs between these different traits and factors that can influence these trade-offs such as the mating system or mating tactics. For this, I am particularly interested in rodents and ungulates on which both interspecific and intraspecific studies are conducted (in collaboration with ONCFS for the work on ungulates).
How does climate change affect the survival and reproduction of individuals? What are the consequences for population dynamics? Which physiological and behavioural mechanisms at the individual level can explain the observed changes at the population level? What are the evolutionary processes involved in the response of species to climate change?
Recent climate changes on Earth have consequences for the distribution, size and performance of many animal populations. Understanding the repercussions of climate change is essential if we want to predict outcomes for these animal populations. While many studies in birds have shown changes in species’ phenology, such as earlier breeding seasons, the examples of mammals are quite rare. In the context of this project, I am interested in determining how and what climatic factors affect different life history traits in the Alpine marmot.
Berger V., Lemaître JF., Dupont P., Allainé D., Gaillard JM. and Cohas A. (2016) Age-specific survival in the socially monogamous alpine marmot (Marmota marmota): evidence of senescence. Journal of Mammalogy, XX: 1-9. pdf
Bichet C., Sauzet S., Averty L., Dupont P., Ferrandiz-Rovira M., Ferrari C., Figueroa I., Tafani M., Rézouki C., López BC., and Cohas, A. (2016) Multiple geographic origins and high genetic differentiation of the Alpine marmots reintroduced in the Pyrenees. Conservation Genetics, 17: 1157–1169. pdf
Berger V., Lemaître JF., Allainé D., Gaillard JM. and Cohas A. (2015) Early and adult social environments have independent effects on individual fitness in a social vertebrate. Proceedings of Royal Society B, 282:20151167 pdf
Berger V., Lemaître JF., Gaillard JM. and Cohas A. (2015) How do animals optimize the size-number trade-off when aging? Insights from reproductive senescence patterns in marmots. Ecology, 96:46-53 pdf
Ferrandiz-Rovira M., Lemaître J-F., Lardy S., López B.C., Cohas A. (2014) Do pre- and post-copulatory sexually selected traits covary in large herbivores? BMC Evolutionary Biology, 14: 1-9. pdf
Lardy S., Allainé D. and Cohas A. (2013) Intrasexual competition and female dominance tenure in a singular breeding mammal, the Alpine marmot. Animal Behaviour, 86:1155–1163. pdf
Tafani M., Cohas A., Bonenfant C., Gaillard J.-M., Allainé D. (2013) Decreasing litter size of marmots over time: a life-history response to climate change? Ecology, 94:580–586. pdf
Tafani M., Cohas A., Bonenfant C., Gaillard J.-M., Lardy S., Allainé D. (2013) Sex-specific senescence in body mass of a monogamous and monomorphic mammal: the case of Alpine marmots. Oecologia, 172:427–436. pdf
Kuduk K., Johanet A., Allainé D., Cohas A., Radwan J. (2012) Contrasting patterns of selection acting on MHC class I and class II DRB genes inthe Alpine marmot (Marmota marmota). Journal of Evolutionary Biology, 25: 1686-1693. pdf. supporting information
Lardy S., Cohas A., Desouhant E., Tafani M., Allainé D. (2012) Paternity and dominance loss in male breeders : the cost of helpers in a cooperatively breeding mammal. PLoS One 7: e29508. doi:10.1371/journal.pone.0029508. pdf
Lardy S., Cohas A., Figueroa I., Allainé D. (2011) Mate change in a socially monogamous mammal: evidences support the “forced divorce” hypothesis. Behavioural Ecology, 22: 120-125. pdf
Cohas A., Allainé D. (2009) Social structure influences extra-pair paternity in socially monogamous mammals. Biology Letters, 5: 313-316. pdf
Cohas A., Bonenfant C., Kempenaers B., Allainé D. (2009) Age-specific effect of heterozygosity on survival in alpine marmots, Marmota marmota. Molecular Ecology 18: 1491-1503. pdf
Cohas A., Yoccoz N.G., Bonenfant C., Goossens B., Genton C., Galan M., Kempenaers B., Allainé D. (2008) The genetic similarity between pair members influences the frequency of extrapair paternity in alpine marmots. Animal Behaviour, 76: 87-95. pdf
Cohas A., Yoccoz N.G., Allainé D. (2007) Extra-pair paternity in alpine marmot (Marmota marmota): Genetic quality and genetic diversity effects. Behavioral Ecology and Sociobiology, 61: 1081-1092. pdf
Cohas A., Bonenfant C., Allainé D., Gaillard J-M. (2007) Are extra-pair young better than within-pair young? A comparison of survival and dominance in alpine marmot. Journal of Animal Ecology, 76: 771-781. pdf
Cohas A., Yoccoz N.G., Da Silva A., Goossens B., Allainé D. (2006) Extra-pair paternity in the monogamous alpine marmot (Marmota marmota): The roles of social setting and female mate choice. Behavioral Ecology and Sociobiology 55: 597-605. pdf
Da Silva A., Luikart G., Yoccoz N.G., Cohas A., Allainé D. (2006) Heterozygosity-Fitness-Correlation revealed by microsatellite analyses in European alpine marmots (Marmota marmota). Conservation Genetics, 7: 371-382. pdf
Joly P., Morand , Cohas A.(2003) Habitat fragmentation and amphibian conservation: Building a tool for assessing landscape matrix connectivity. Comptes Rendus Biologie, 326: 132-139. pdf
Lardy S, Cohas A, Allainé D. (2011) The cost of helpers in cooperative breeders: mechanism and consequences of male-male competition in a cooperatively breeding mammal. ESEB, 13th congress, Tübingen, Germany. pdf
Lardy S, Cohas A, Allainé D. (2009) Divorce in a monogamous mammal, evidences supporting the “forced divorce” hypothesis. ESEB, 12th congress, Turin. pdf
Cohas A. (2006) Causes évolutives des paternités hors-couple chez les espèces socialement monogames: L’exemple de la marmotte alpine (Marmota marmota). [Evolutionary causes of extra-pair paternity in socially monogamous species: the example of the Alpine marmot (Marmota marmota)]. Thèse de doctorat. Université Claude Bernard Lyon 1, Lyon. pdf
Dupuis F. (2013) ALPES NATURE : Vanoise, objectif marmotte ! Alpes Magazine, n°142. pdf
Milleret R. (2013) . Dans le terrier des marmottes à La Grande Sassière. Le Dauphiné Libéré, 21 Juillet 2013.
Giraud M. (2009) Darwin c’est tout bête ! eds Robert Laffont.
Boone D. (2009) Rencontres au sommet. Version Femina n°384.
Kaplan M. (2007) Ain’t misbehaving. The Economist, 28 June 2007. pdf
Comby G. (2007) Comme pour les marmotte, l’adultère est-il salutaire? Le Matin Dimanche, 5 August 2007. pdf