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Primary sex ratio adjustments in a common vole (M. arvalis) cyclic population

2010Primary sex-ratio adjustments in a common vole (M. arvalis) cyclic populationQUAN RODAS Claudia Lorena (Guatemala)
Organisation:University of Poitiers, Poitiers (FR) - Centre d’Etudes Biologiques de Chizé, Beauvoir-sur-Niort (FR)Supervisor :Bertrand Gaufrée (CEBC)
Summary: Sex allocation is one of the most studied topics on evolutionary biology du to its important implications on individuals’ reproductive success. Despite extensive literature has been produced in this area, much research is still needed in order to reveals the mechanisms implicated in offspring sex determination. The main objective of this study was to asses the sex ratio of common vole (M. arvalis) embryos in a cyclic population of central-western France between years 2006 and 2008. Embryos of collected individuals from the micro-mammals monitoring program in this area were sexed using molecular techniques. Factors affecting litter size and sex ratio were analyzed. A slight difference in favors of males has been found in the embryos’ weight within each litter. Significant correlation between litter size and mother age is reported. Selective loss of small female-biased litters through abortions is suggested by the results but the evidence is not conclusive regarding the adaptive roll of this process. Important differences between years had been found and those are discussed at the light of variations in physical traits of the mothers. Agreements of results with the more important theories of sex allocation are also discussed.