Soutenance de Thèse : Thomas Aubier

: Publication : 28 août 2018

Avis de Soutenance
Thomas AUBIER
Soutiendra publiquement ses travaux de thèse intitulés
Diversity of warning signals, speciation and clade diversification
Soutenance prévue le vendredi 14 septembre à 14h
Lieu : l'Amphithéâtre de la Délégation Languedoc-Roussillon du CNRS

The display of warning signals by unpalatable (or otherwise defended) prey provides a wonderful opportunity for estab-lishing an integrative view of biological diversification. Warning signals are known to be under strong natural and sexual selection. On the one hand, the sampling strategy of predators, characterized by a learned avoidance of signals associated with unpalatability, generates natural selection in favour of warning signals in high frequency in the prey community. Such positive frequency-dependent selection favours phenotypic uniformity and causes unpalatable species to converge on common warning signals (mutualistic "Müllerian" mimicry), as seen in a large panel of taxa. On the other hand, warning signals are used as a phenotypic cue for mate choice, generating sexual selection with important consequences for repro-ductive isolation and speciation.

Paradoxically, despite powerful selection favouring phenotypic convergence, warning signals are fantastically diverse, both within and between species, and this morphological diversification is often associated with extensive species diversification at the clade level. In this thesis, I tackle this apparent paradox from the ground up and I thereby refine our understanding of the role of positive frequency-dependent selection and mutualistic interactions for evolutionary diversification at micro- and macroevolutionary scales. First, I show that the predator sampling strategy can favour the emergence of diversity of warning signals despite positive frequency-dependent selection. Second, I dissect the conditions allowing the evolution of strong and stable reproductive isolation, necessary for speciation to occur, in a number of ecological situations where warning signals are under natural and sexual selection. Third, I highlight important indirect effects of frequency-dependent selection on diversification at macro-evolutionary scale via spatial constraints and by-product ecological convergence.

Keywords: frequency-dependent selection, mutualism, predator cognition, speciation, clade diversification, theory

Membres du jury:

M. Michael KOPP        Aix Marseille Université - CNRS UMR 7373 (I2M)        Rapporteur
M. Christophe THÉBAUD       Université Paul Sabatier - CNRS UMR 5174 (EDB)      Rapporteur
Mme Emmanuelle PORCHER       Museum National d'Histoire Naturelle - CNRS UMR 7204 (CESCO)      Examinatrice
Mme Carole SMADJA       Université de Montpellier - CNRS UMR 5554 (ISEM)      Examinatrice
M. Mathieu JORON      Centre d'Ecologie Fonctionnelle et Evolutive - CNRS UMR 5175      Directeur de these
Mme Marianne ELIAS       Museum National d'Histoire Naturelle - CNRS UMR 7205 (ISYEB)      Co-directrice de these

Yong ZHENG

: Publication : 26 janvier 2018

Yong ZHENG

Biocultural approaches to indicators of well-being and sustainability: bridging local to global scales

: Publication : 26 octobre 2017

Eleanor STERLING

Center for Biodiversity and Conservation, American Museum of Natural History, New York, USA

Le vendredi 10 novembre 2017 - 11h30 Grande Salle CEFE (1919 Rte de Mende, 1e étage, aille C)

(Seminar in English)

Pacific Island communities are facing unprecedented challenges in conserving natural resources and maintaining human well-being. In these place-based communities, biocultural connections, or the integrated social, economic, cultural and environmental linkages between people and nature are widely believed to play a critical role in improving and maintaining the resilience of both human and ecological communities. However, indicators of human or ecological well-being rarely reflect the integrated nature of these systems. Based on visioning exercises across multiple Pacific Island archipelagoes (Hawaiʻi, Fiji, Solomon Islands, Marshall Islands) on characteristics of vibrant biocultural landscapes and seascapes, we have identified key dimensions that describe a resilient biocultural state for Pacific Island communities and developed example indicators that measure the state of these dimensions. Additionally, we have assessed the United Nation's Sustainable Development Goals and the Convention on Biological Diversity's Aichi Targets to determine which of these goals or targets are relevant to Pacific Island communities. For goals or targets that were not obviously relevant, we have come up with recommendations for how they can be adjusted to be relevant or translated between local and global needs, in order to better resonate with communities and better reflect important connections between people and nature.

Recent publications:

Sterling et al. 2017 Biocultural approaches to well-being and sustainability indicators across scales. Nature Ecology & Evolution

Sterling et al. 2017 Culturally Grounded Indicators of Resilience in Social-Ecological Systems Environment and Society: Advances in Research.

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Virginie MOLINIER

: Publication : 19 janvier 2018

CEFE/CNRS Campus du CNRS

Aile C, bureau 214

1919, route de Mende

34293 Montpellier 5

Tél : +33/0 4 67 61 32 31

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Mots clés (par ordre alphabétique) : Biologie des organismes, Biologie évolutive, Biologie moléculaire, Biologie végétale, Composés organiques volatils, Écologie, Génétique des populations, Génotypage, Microsatellites, Mycologie, Phylogénie, Phylogéographie.

Lire la suite : Virginie MOLINIER

Conférences EUREKA 2017: Les insectes et la santé

: Publication : 31 août 2017

Jeudi 21 Septembre 2017, à 18h30 - Amphithéâtre de Genopolys

Gérard Duvallet: " Les insectes et la santé "

Résumé:

La grande majorité des insectes jouent un rôle fondamental dans le fonctionnement des écosystèmes et nous rendent des services très importants : pollinisation, contrôle par prédation ou parasitisme des populations nuisantes, élimination des cadavres et des déjections, ressources alimentaires, etc. Un certain nombre cependant sont particulièrement néfastes soit par leur action pathogène directe : envenimation, allergies diverses, myiases, soit par la transmission potentielle d’agents infectieux : virus, bactéries, protozoaires ou filaires. Ce sont ces différents aspects qu’étudie l’entomologie médicale et vétérinaire.

L'orateur:

Gerard Duvallet trombi

Professeur des universités, entomologiste médical menant ses recherches au Centre d’Ecologie Fonctionnelle et Evolutive (www.cefe.cnrs.fr), Gérard Duvallet est également Président de la Société d'Horticulture et d'Histoire Naturelle de l'Hérault (https://s2hnh.org/), une association pluridisciplinaire qui œuvre pour l'étude et la diffusion des sciences naturelles.