GraduatePosition ; U. Paris 6. Evolution Of Ant Castes
PhD position (3 years starting September 1st 2011)
Equipe Evolution of Animal Societies, Laboratoire Ecologie & Evolution CNRS UMR 7625, Université Pierre et Marie Curie, 7 quai Saint Bernard, 75005 Paris
Supervisors : Mathieu Molet and Thibaud Monnin
Contact : mathieu.molet@gmail.com; +33 1 44 27 26 94
Web site : http://ecologie.snv.jussieu.fr/socialite/
Anomalous queen-worker mosaics drive the evolution of novel phenotypes in ants
Studying the mechanisms that allow for the production, survival and selection of novel phenotypes is crucial to understand biodiversity. The classic evolutionary mechanism involves random mutations and selection. Molet, Wheeler and Peeters (2010) propose an extension, only available to polyphenic organisms, i.e. exhibiting phenotypic plasticity with discrete alternative forms, where traits from existing alternative phenotypes are recycled and recombined to generate novel mosaic phenotypes. Because these traits have already been tested by natural selection in the phenotypes where they normally occur, mosaics are likely to be viable. They can be selected because they result from variability in genes that control the sensitivity thresholds responsible for the polyphenism. Molet et al. (2010) also propose that in social taxa, anomalous phenotypes have higher probability of survival since the colony buffers them against the outside environment. Accordingly, we suggest that polyphenic and/or social organisms show an enhanced potential for evolving biodiversity.
Ants are an ideal model to test these two hypotheses. They live in societies where reproduction is not shared equally. Fundamental to this division of labour is an ancestral female polyphenism with two castes: winged queens specialized in colony founding and egg-laying cooperate with wingless workers that perform all other tasks. These two adult phenotypes are environmentally-determined during larval development. Ants produce rare anomalous phenotypes called intercastes that are intermediate between winged queens and workers. These intercastes can be the first step towards the numerous novel castes that have evolved in ants, such as wingless queens and soldiers.
The PhD student will investigate the production of intercastes in colonies of *Mystrium *and *Temnothorax*. Using ethological, morphometric and dissection methods, he/she will assess whether they are mosaics that survive in the colonies where they emerge, measure the costs that they may inflict on colonies, and test whether they can occasionally bring benefits to colonies by providing new functions or performing existing functions more economically. He/She will also expose colonies to various environmental conditions in order to reveal some parameters that can influence intercaste production.
The applicant should have a B.Sc. (Hons) and a good English level. He/She should have skills in several of the following area: ecology, evolution, ethology, morphometry, social insects. Fieldwork in France or other countries (Madagascar¡) will be planned.
Email motivation letter, CV, academic records, and details of two academic referees, to Dr Mathieu Molet (mathieu.molet@gmail.com). For further information phone: +33 1 44 27 26 94. Application deadline is May 1. Interviews will take place end of May.
Molet M., Wheeler D., Peeters C. (2010) Developmental mosaics, social buffering, and the evolution of novel castes in ants. Congress of the International Union for the Study of Social Insects, Copenhague, Danemark.
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Mathieu Molet
mathieu.molet@gmail.com
http://www.mathieumolet.fr/
Laboratoire Ecologie & Evolution UMR 7625
Université Pierre et Marie Curie
7 quai St Bernard
bat A, 7ème étage
75005 Paris, FRANCE
Tel. +33 (0)1 44 27 26 94
Fax. +33 (0)1 44 27 35 16