Franco Alo

Concordia University
Candidat M.Sc.

superviseur(e): Robert Weladji
Début: 2014-09-02
Fin: 2016-08-31
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The influence of operational sex ratio (OSR) on the intensity of competition and male mating tactics in reindeer (Rangifer tarandus)
Sexual selection not only results in an array of adaptations which organisms harbor to increase their mating success, but may also influence the mating type of said organism. In reindeer, a polygynous species, the outcome of male mating tactics is dictated by such adaptations evolved like antlers, as well as a sole or combined effect of age, social status and experience. Females are left with the aspect of mate choice and hence males must compete between each other for access to a harem (aggregation of females). The intensity of agonistic behaviours are said to be influenced by the ratio of reproductively active males to fertilizable females (OSR: operational sex ratio). We will thus manipulate OSR on three levels to measure its influence on the intensity of this intra-sexual competition. We will investigate the predictions that: (i) male-male aggression will increase with OSR whereas female-female aggression will decrease (ii) courtship rate and duration will either decrease with OSR because of increased male-male competition or increase if males adopt alternative mating tactics (e.g. follow) (iii) a heavily biased operational sex ratio can alter the mechanisms of competition ultimately affecting reproductive effort and the mating tactics of individuals


Rangifer tarandus, Animal behaviour, Polygyny, Mating systems, Operational sex ratio