samedi 30 juin 2012
Post-copulatory sexual selection in the houbara bustard
A three year PhD position is available to work on a collaborative project dealing with the post-copulatory sexual selection in the houbara bustard.
In most animal species, females mate with multiple males giving rise to the potential for sperm competition and cryptic female choice. These post-copulatory components of sexual selection add to those acting on males to attract mates (pre-copulatory sexual selection).
Although the study of post-copulatory sexual selection has flourished in the last decade, there are very few biological systems that are amenable to the experimental study of sperm competition and cryptic choice.
Houbara bustards are endangered bird species living in North Africa (Chlamydotis undulata), Middle East and Central Asia (Chlamydotis macqueeni). In order to restore and reinforce natural populations of houbara in Middle East, the National Avian Research Center (NARC) has promoted a captive breeding program in Abu Dhabi (EAU) under the leadership of the International Fund for Houbara Conservation. This breeding program is based on the collection of sperm which is subsequently used to artificially inseminate females under standardized conditions (Saint Jalme et al. 1994). This allows investigating several aspects related to sperm competition and cryptic choice, in a species where both pre- and post-copulatory sexual selection is supposed to be a strong selective force. Indeed, males harbor extravagant sexual displays (Chargé et al. 2010, 2011; Preston et al. 2011) and females have been shown to mate with multiple males in the wild, where the proportion of clutches sired by multiple fathers is fairly high (60%) (Lesobre et al. 2010).
In the first stage of the PhD thesis, we expect to better characterize sperm traits that determine the likelihood to successfully fertilize eggs. Then, experimental work could be conducted to explore the following questions:
1) Is there a trade-off between pre- and post-copulatory components of sexual selection?
2) Is fertilization success mostly driven by sperm competition or cryptic choice?
3) Is there a scope for sexual conflict in this system?
In addition to their fundamental interest, the obtained results could also be valuable with respect to the genetic management of the captive breeding. On one hand, inseminating with a mix of semen could facilitate insemination procedure by reducing the time spent to select precise pedigree and by optimizing semen utilization (mixture of small ejaculates that are usually discarded could be easily used). On the other hand, sperm competition might result in severely biased paternity with a potential for strong involuntary selection acting on breeding males.
This is a collaborative project involving the NARC (Yves Hingrat, Loic Lesobre, Tony Chalah) where all the experimental work will be carried out and where the successful applicant will spend most of the time, the French CNRS in Dijon (Gabriele Sorci) and the Museum of Natural History in Paris (Michel Saint Jalme).
Interested applicants should send a CV and the name of three references to Gabriele Sorci (firstname.lastname@example.org) and Michel Saint Jalme (email@example.com).
Salary: 1,250 euros per month. Accommodation and food is provided by the NARC with no fees for the student.
Selected articles published by the group related to the project
Chargé R. et al. 2011. Immune-Mediated Change in the Expression of a Sexual Trait Predicts Offspring Survival in the Wild. PLoS ONE 6: e25305.
Preston B. et al. 2011. Sexually extravagant males age more rapidly. Ecology Letters 14: 1017-1024.
Chargé et al. 2010. Male health status, signalled by courtship display, reveals ejaculate quality and hatching success in a lekking species. Journal of Animal Ecology 79: 843-850.
Lesobre L. et al. 2010. Conservation genetics of Houbara Bustard (Chlamydotis undulata undulata): population structure and its implications for the reinforcement of wild populations. Conservation Genetics 11: 1489-1497.
Lesobre L. et al. 2010. Absence of male reproductive skew, along with high frequency of polyandry and conspecific brood parasitism in the lekking Houbara bustard Chlamydotis undulata undulata. Journal of Avian Biology 41: 117-127.
Saint Jalme M. et al. 1994. Artificial insemination in Houbara bustard (Chlamydotis undulata): influence of the number of spermatozoa and insemination frequency on fertility and ability to hatch. Journal of Reproduction and Fertility 100: 93-103.
Catégories PhD à l'étranger