Cooperative breeding in marmots [Coopération au cours de la reproduction chez les marmottes].

Résumé

Whenever individuals live in stable social groups and not all individuals breed, group members may breed cooperatively. While well-documented in a variety of birds and mammals, there is some controversy over whether, and to what degree, sciurid rodents breed cooperatively. We identified cooperative breeding when: individuals delay dispersal beyond reproductive maturity, reproduction in mature individuals is suppressed, and when non-breeders provide alloparental care. In this paper we note that the 14 species of marmots (Marmota sp., large ground)dwelling sciurid rodents found throughout the Northern Hemisphere, provide an excellent taxon in which to study the evolution of cooperative breeding. Marmot species fit none, some, or all of the attributes of cooperative breeding. marmot interestingly, delayed dispersal and alloparental care may be de-coupled interspecifically, and possibly intraspecifically, making marmots an excellent taxon for additional study. Environmental harshness increases maturation time and is associated with dispersal delayed beyond reproductive maturity. The opportunity to gain direct fitness may be associated with gaining indirect fitness by alloparental behavior. In addition to its theoretical attraction, cooperative breeding has profound implications for conservation and management of species that breed cooperatively. To maximize marmot production, managers and breeders need to pay particular attention to social group structure to prevent the expression of reproductive suppression. If cooperative breeding results from an environmental constraint, habitat modifications may increase the percent of female that breed.