mercredi 13 mai 2015

PhD position at Université Paris 13, Laboratorie d’Ethologie Expérimentale et Comparée E.A. 4443, France

Evolutionary transition between hermaphroditism and separate sexes

Application deadline: 25 May 2015

Sex is a central topic in biology and it is often associated to male and female genders. But why males and females are so common in animals? And if there has been some selective advantage in evolving male and female genders, why is hermaphroditism almost ubiquitous among animal taxa and why are there more than 65000 species of hermaphroditic species in animals? Have males and females evolved from hermaphrodites or vice versa? Whereas other questions in the evolution of sex have been the focus of theoretical and empirical research in animals (e.g., sexual selection, the transition between sexual and asexual reproduction, etc.), the transition between hermaphroditism and separate sexes has been rarely explored and we are left with many unsolved questions. This PhD project plan to meet this goal using polychaete worms of the genus Ophryotrocha as biological models and testing the role of hermaphrodite behavioral traits (such as reciprocity and plastic sex allocation) and gonochoric behavioral traits (such as gender specialization) in stabilizing hermaphroditism and/or favoring the transition towards separate sexes.

The project requires doing behavioral experiments where worms are exposed to different conditions (e.g., density and/or mate competition) and/or used in choice tests; data on their mating behavior and mate preferences as well as measures of their reproductive investment will be analysed. Most experiments require working at the stereomicroscope.

Bibliographic references
Lorenzi M.C., Sella G. 2013. In between breeding systems: Neither dioecy nor androdioecy explains sexual polymorphism in functionally dioecious worms. Integrative and Comparative Biology 53:689-700. 
Weeks S.C. 2012. The role of androdioecy and gynodioecy in mediating evolutionary transitions between dioecy and hermaphroditism in the animalia. Evolution 66:3670-86.

The language in the lab will be French and English. The position is funded for 3 years and will start on Oct 1st 2015.

Applications for this position should be sent to Prof. Dr. M. Cristina Lorenzi ( by May 25, 2015, including: letter of interest, CV, proposed research plan and recommendation letters from previous supervisors. 
Applicants are encouraged to make an informal enquiry beforehand by contacting Prof. Dr. M. Cristina Lorenzi via email ASAP. For further information about the Laboratoire d’Ethologie Expérimentale et Comparée see