Sexual selection and sexual dimorphism in plants
(Post-doc in Prof. John Pannell’s group 2015-2019)
Sexual selection is recognized in animals as a force promoting divergence of phenotypic characters in males and females. Particularly, male-male competition have been shown to sometimes trigger extreme cases of sexual dimorphism in many animal species. But, to what extant such male-male competition also explain the evolution of sexual dimorphism in dioecious plants is still poorly understood. Using experimental evolution and selection gradients, I am currently studying whether increased male-male competition can affect the evolution of the degree of sexual dimorphism in wind-pollinated plants. In the model herb species Mercurialis annua, I produced experimental populations that are grown each generation either at a low density or at high density, thus enhancing male-male competition as I was able to show thanks to a paternity analysis. In herbs, males are typically smaller than females while plant height is supposed to enhance male competitive abilities by dispersing pollen from higher heights. I am also studying the evolution of protein expression in pollen coat thanks to proteomics to identify proteins involved in pollen adhesion and re-hydratation. Using experimental evolution and selection gradients produced thanks to genotype data and spatially explicit models, we are testing ideas about selection of male traits allowing to improve mating success. We also are investigated the evolution of protein expression associated with a possible increase in male gametophyte performance during the pollen-pistil interaction phase thanks to proteomics.
Collaborators: John Pannell, Patrice David, Etienne Klein
Sex-specific requirements and sexual dimorphism in plants
(Post-doc in Prof. John Pannell’s group 2015-2019)
Most literature on the plant sexual system evolution consider the existence of one single resource limiting similarly all plant functions. However, several studies highlighted that ovule and fruit production are mostly limited by carbon while pollen production mostly requires nitrogen. Using optimal control theory, we are theoretically studying the optimal sex-specific resource allocation of both carbon and nitrogen and the effect of limitation in these currencies on sexual dimorphism evolution. Using Mercurialis annua as a model species, we also investigated sex-specific plastic responses to carbon limitation.
Collaborators: John Pannell, Mauricio Gonzalez-Forrero, Patrice David
Evolution of sex-specific selection gradients in a natural population of Leucadendron rubrum
(post-doc with Dr. Ophelie Ronce and Prof. Agnès Mignot 2013-2014)
To further understand how male and female morphologies are shaped through natural, fecundity and sexual selection, it is critical to evaluate selection on male and female morphologies in natural populations using life-time estimation of fitness. In one of the most dimorphic wind-pollinated angiosperm species Leucadendron rubrum, we are quantifying the strength and direction of selection acting in male and female morphologies using molecular data combined with spatial data. We specifically developed a spatially explicit model to estimate jointly both pollen and seed dispersal kernels and the variance in reproductive success of males and females.
Collaborators: Etienne Klein, Alexandre Courtiol, Sylvie Oddou-Muratorio, Isabelle Olivieri, Ophélie Ronce, Agnès Mignot
