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MOLET Mathieu - Maître de conférences
Sorbonne Université - Faculté de Sciences - iEES Paris - Bât. 44-45, 5e étage
4, place Jussieu
75252 PARIS cedex 5
Tél Pro :
+33 1 44 27 26 94
Fax :
+33 1 44 27 35 16
Département de recherche IEES
Niveau d'enseignement
- Master 2
- Master 1
- Licence
Equipe de recherche IEES
Site (campus)
- S-U - P&M Curie - Bât. 44-45 et bât. 44-34
Thèmes de recherche
The evolution of biodiversity relies on the production and selection of new phenotypes. I study these mechanisms in the context of animal societies, using ants as a model. Ants consist of 13000 species that occupy a variety of ecological niches throughout the world. One reason for this success is their morphological caste system associated with efficient division of labour. Indeed, in addition to the two ancestral castes (winged queens and wingless workers), many ant species have evolved novel castes such as wingless queens and soldiers. Wingless queens are a response to selective pressures against long range dispersal and solitary colony foundation, while soldiers allow for better colony defense, food storage or foraging. The evolutionary and developmental processes that led to this diversity are poorly known. I study them with an integrative approach that focuses on morphology, physiology, behaviour, ecology and development. My model taxa are Mystrium and Temnothorax.
 

Diversity of castes and life-cycles

The life cycle of ant colonies is mostly known from species with winged queens. Studying this in species with wingless queens reveals unexpected diversity. Wingless queens do not found colonies alone but with the help of nestmate workers. Accordingly they mate near their nest after attracting males using pheromones. We have found that, depending on species, colonies contain either one big queen specialized for egg-laying, or numerous small queens that can either mate and lay eggs or function as helpers. This entails original division of labour, conflicts for reproduction, dynamics of colony emigration and genetic structures.
 

Mechanisms for generating novelty

We compare novel castes to conspecific or congeneric winged queens and wingless workers in order to assess the evolutionary link between these phenotypes and test the hypothesis that novel castes are mosaics of ancestral castes. We use two approaches: morphometry (growth rules, morphological modules) and evo-devo (gene expression in imaginal discs of larvae).
 

Role of developmental anomalies in evolution

Ant colonies produce rare anomalies called intercastes that are morphologically very variable but look intermediate between winged queens and wingless workers. We study their morphology, behaviour and physiology and we assess the costs and benefits that they bring to colonies. We compare them to novel castes. We develop and evolutionary scenario that involves genetic accommodation and buffering properties of colonial life to connect anomalies to novel castes. We also explore how hormone applications generate anomalies.
 

Environmental pressures and evolution of colonial reproductive strategy

The replacement of winged queens by wingless queens or reproductive workers is tightly linked with selection against long-range dispersal by flight and independent colony foundation. We study why and how colonies alter their reproductive strategy in response to environmental changes.
Publications
Afficher toutes les publications
Année : 2018
Titre/Chapitre : Lack of interruption of the gene network underlying wing polyphenism in an early-branching ant genus
Revue/Livre : Journal of Experimental Zoology Part B: Molecular and Developmental Evolution
Volume : 0, pages de 0 à 0
Auteurs : Béhague J., Fisher B.L., Péronnet R., Rajakumar R., Abouheif E.& Molet M.
Année : 2017
Titre/Chapitre : Evolution of cheaper workers in ants: comparative study of exoskeleton thickness
Revue/Livre : Biological Journal of the Linnean Society
Volume : 121, pages de 556 à 563
Auteurs : Peeters C., Molet M., Lin C. & Billen J.
Lien :
Année : 2017
Titre/Chapitre : Effect of temperature and social environment on worker size in the ant Temnothorax nylanderi
Revue/Livre : Journal of Thermal Biology
Volume : 67, pages de 22 à 29
Auteurs : Molet M., Péronnet R., Couette S., Canovas C. & Doums C.
Lien :
Mots-Clefs
Ecologie - Evolution - Insectes - Socialité - Développement - Plasticité phénotypique
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