My research

I am broadly interested in behavioural ecology and evolutionary conservation. Specifically, I investigate fertility and genetic benefits gathered by females from mate choice, mating decisions according to individual mating history, and how sexual selection theories could help improving supportive breeding programs for endangered species.

SEXUAL SELECTION

My work has primarily been focused on secondary sexual traits as honest signal of male’s quality. I focus my research on both direct fertility benefits and indirect genetic benefits for the offspring that females might gather by mating with attractive males.

Courtship display of the male Houbara bustard

    More specifically, I revealed in a lekking bird (the Houbara bustard) that choosy females gain fertility benefits by mating with males that display more (Chargé et al. 2010), produce more fertile and attractive sons and fertile daughters (Chargé et al., 2013). We also showed in experimental studies that more fertile and “sexy” captive males (able to maintain high courtship activity and sperm quality following an immune challenge) sired offspring  with a better survival once released in the wild, compared to low quality males (Chargé et al., 2011, 2010). I have also explored in birds post-copulatory female cryptic choice for optimal kinship. Based on artificial insemination of females with a mixture of semen collected from three males differing in their relatedness with the female, I found evidence for cryptic female choice for optimal kinship, while embryo survival was strongly affected by inbreeding level (paper in prep).

Main collaborators:

Dr. Céline Teplitsky, Dr. Gabriele Sorci, Dr. Michel Saint Jalme, & Dr. Yves Hingrat

 





Female of the Wood Tiger moth

   In insects, I investigated fertility benefits from mate choice in the specific context of aposematism. Surprisingly, colour polymorphism in aposematic species is quite common despite the assumed directional selection by predators for signal uniformity and conspicuousness. Yet, very few studies have examined the role of sexual selection to explain this polymorphism. I am thus questioning whether fertilisation aspects are important for female mate choice in the Wood Tiger moth and whether mating success of white males explains its coexistence with the more conspicuous yellow coloured males (more efficient in predator avoidance). Contrarily to my expectations, fertilisation benefits seem not to explain the maintenance of colour polymorphism in the Wood Tiger moth. However, fertilisation aspects are important for mating decisions. I found, for instance, that female mate choice could be based on male’s ability to transfer large ejaculate. Mate choice decisions based on securing eggs fertilisation are not unique to females. Males are able to modulate the amount of sperm transferred in relation to females ability to produce eggs, which is signalled by females body mass (paper in prep).

An exciting implementation of the project we are currently investigating is to explore oxidative damages in the moth semen and its relationship with sperm production, courtship behaviour, and ageing.

 

Main collaborators:

Prof. Johanna Mappes, Prof. Nina Wedell, Dr. Jonathan Blount, Dr. Carita Lindstedt & Dr. Swanne Gordon

EVOLUTIONARY CONSERVATION

Can sexual selection theory inform genetic management of captive populations?

Captive breeding for conservation purposes presents a serious practical challenge because several conflicting genetic processes (i.e. inbreeding depression, random genetic drift and genetic adaptation to captivity) need to be managed in concert to maximise captive population persistence and reintroduction success probability.

Houbara bustard from a supportive captive breeding

      During my PhD, I investigated the outcome of a genetic management in a supportive breeding for the Houbara Bustard. At the phenotypic level, we found an increase in several fitness-related traits over generations. Phenotypic changes resulted from genetic changes driven by selection acting on gamete production and to a lesser extent on courtship display. Selection decreased over years for female gametes, emphasizing the effort of managers to increase the contribution of poor breeders to offspring recruited in the captive breeding. Our results shed light on very fast genetic changes in an exemplary captive programme that follows worldwide used recommendations and underlies the need for more empirical evidence of the effects of genetic guidelines on the prevention of genetic changes in supportive breeding (Chargé et al. 2014).
     Following this investigation, one of my current interests is to explore the implications of sexual selection theories for captive breeding programs. The application of female mate choice to captive breeding is in its infancy, but it shows promise as a tool in captive breeding under certain conditions. Providing clear guidelines that would guarantee positive fitness outcomes and avoid conflicts with other genetic goals is however still challenging (paper in review in Evolutionary Applications).

Main collaborators:

Dr. Céline Teplitsky, Dr. Gabriele Sorci, Dr. Matthew Low & Dr. Mikael Puurtinen

Effects of agricultural intensification on biodiversity

    During my first postdoctoral position, I had the opportunity to explore the effects of the agricultural changes related to the intensification of farming practices and the simplification of landscape elements on biodiversity. The associated synergistic effects are poorly understood because of the difficulty to disentangle the underlying multi-facet and multi-scale of the ecological processes. The main focus of that project is to assess the relative contribution of each component of agricultural intensification on taxonomic and functional diversity in birds and small mammals communities.

  Using large-scale bird monitoring and practice surveys in 200 agricultural fields in France, we showed that pesticide doses were related to measurable negative effects on the proportion of habitat specialists. The proportion of generalists increased and landscape simplification was associated with a loss of bird species diversity and an increase in the specialisation at the communities level (Chiron et al. 2014). In addition, we found that landscape homogenisation and opening had effects on taxonomic and functional diversities of birds at field and farm levels, but not at the region level, emphasizing the scale-dependence of agriculture-biodiversity relationships. Chemical intensification had negative impacts on bird diversity especially at the farm level affecting both bird specialisation to farmland and the community trophic level (Jeliazkov et al., in prep).

      Our results highlight the importance of combining taxonomic and functional diversity indices at different spatial scales to fully understand changes in communities that occur in response to agricultural intensification.

      We are currently investigating similar aspects of agricultural intensification on small mammals populations.

Main collaborators:

Dr. Francois Chiron, Dr. Romain Julliard & Aliénor Jeliazkov