title: Masculinized females produce heavier offspring in a group living rodent.
abstract: Alternative morphotypes have been reported less frequently in females than in males. An exception to this rule is the gradient of phenotypical masculinization reported in some female mammals, in which feminized and masculinized females represent two opposite ends along this gradient. These phenotypical differences originate during prenatal development as the consequence of maternal effects. Feminized and masculinized females differ in several traits, including morphological, physiological, behavioural and reproductive traits. Differences previously reported in reproductive traits between feminized and masculinized females come mostly from mechanistic studies performed in the laboratory, and not necessarily on social species. As a result, it is unclear to what extent these reported differences between female alternative morphotypes materialize in wild, natural populations. We quantified the effect of female alternative morphotype on female reproductive traits in a natural population of Octodon degus, a highly social rodent. We assessed female alternative morphotype through a continuous gradient of anogenital distance. Thus, feminized females were close to the short end of anogenital distance, while masculinized females were close to the long end of this gradient. We also tested the hypothesis that the social environment interacts with female morphotype to influence female reproductive traits. In female degus, only body weight affected litter size, where heavier females weaned more offspring. Masculinized females delivered male-biased litters and weaned heavier offspring. Lastly, masculinized females gave birth later in the breeding season compared to feminized females. Contrary to previous claims, our findings do not support that masculinized females are less fertile than feminized females. Moreover, masculinized females produced heavier, potentially higher quality offspring compared with feminized females.
authors: Departamento de Ecología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile. lcorreak@bio.puc.cl.
authors: Loreto A
authors: LA
authors: Correa
authors: Departamento de Ecología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile.
authors: Cecilia
authors: C
authors: León
authors: Departamento de Ecología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile.
authors: Juan
authors: J
authors: Ramírez-Estrada
authors: Facultad de Ciencias, Instituto de Ciencias Ambientales y Evolutivas, Universidad Austral de Chile, Casilla 567, Valdivia, Chile.
authors: Mauricio
authors: M
authors: Soto-Gamboa
authors: Facultad de Ciencias, Instituto de Ciencias Ambientales y Evolutivas, Universidad Austral de Chile, Casilla 567, Valdivia, Chile.
authors: Roger D
authors: RD
authors: Sepúlveda
authors: Departamento de Ecología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile.
authors: Luis A
authors: LA
authors: Ebensperger
mesh_terms: D000818:Animals; D001835:Body Weight; D002677:Chile; D008098:Litter Size; D046329:Octodon / Q000502:physiology*; D036801:Parturition; D012098:Reproduction; D012621:Seasons; D012744:Sex Ratio; D012919:Social Behavior; D013739:Testosterone / Q000378:metabolism*
chemical_list: D013739:Testosterone
keywords: female alternative morphotype; female masculinization; maternal effects; reproductive traits; social context