Holger Schielzeth

Population Ecology Group, University of Jena, Germany

Le vendredi 10 mai 2019 - 11h30 Campus Triolet Univ Montpellier: amphi 23.01 - Bât. 23

The coexistence of multiple colour morphs in natural populations has fascinated ecologists and evolutionary biologists for a long time, begging the question how such phenotypic polymorphisms are maintained in the long run. One of the most remarkable systems of widespread coexistence of discrete colour morphs is the green-brown polymorphism in Orthopterans. A large number of species, mostly those inhabiting grasslands, occur in both green and brown variants in natural populations and their coexistence appears to depend on the action of balancing selection. I will introduce the fascinating study system and present recent ecological, quantitative genetic and genomic work that aims to uncover the selective conditions that contribute to the maintenance of the polymorphisms as well as its genetic basis. Besides the specific case of grasshoppers, I will also touch upon the concept of the ecological niche that I think needs a fresh-up when viewed from the perspective of an evolutionary ecologist.

Recent publications:

Nakagawa, S., Johnson, P.C.D. & Schielzeth, H. (2017). The coefficient of determination R² and intra-class correlation coefficient from generalized linear mixed-effects models revised and expanded. Journal of the Royal Society Interface 14: 20170213.

Schielzeth, H., Rios Villamil, A. & Burri, R. (2018). Success and failure in replication of genotype-phenotype associations: How does replication help in understanding the genetic basis of phenotypic variation in outbred populations? Molecular Ecology Resources 4: 739-754.

de Villemereuil, P., Schielzeth, H., Nakagawa, S. & Morrissey, M. (2016). General methods for evolutionary quantitative genetic inference from generalised mixed models. Genetics 204: 1281-1294.

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Anton POTAPOV

University of Göttingen, Germany

Le vendredi 19 avril 2019 - 11h30 Campus Triolet Univ Montpellier: amphi 23.01 - Bât. 23

Life in soil is extremely diverse but poorly understood. There are marked differences in food-web organization between soil and other ecosystem types. To understand the interactions between organisms in soil and functioning of this ecosystem I’m applying instrumental analyses, primary stable isotopes. I’m keen to find out, how can we predict these interactions. In fact, we can learn much from traits such as body size and morphology. I will demonstrate, how soil food webs are organized (based on stable isotope analysis), how body size may shape soil food webs, from small to large organisms, and how general morphological adaptations, conserved through the evolutionary history, constrain the trophic niches in modern communities.

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Contact: Jérôme Cortet 

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