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Selected Publication:

Type of publication: Journal Article
Type of document: Full Paper

Year: 2014

Authors: Rubolini, D; Fusani, L; Bonisoli-Alquati, A; Canoine, V; Caprioli, M; Romano, M; Ambrosini, R; Dessi-Fulgheri, F; Saino, N

Title: Effects of Egg and Circulating Testosterone on Ring-Necked Pheasant (Phasianus colchicus) Male Traits and Combat Outcome.

Source: Ethology (120), 1 64-76.



Authors Vetmeduni Vienna:

Fusani Leonida


Abstract:
Studies of avian species have shown that maternal effects mediated by the transfer of egg hormones can profoundly affect offspring phenotype and fitness. We previously demonstrated that the injection of a physiological amount of testosterone (T) in the eggs of ring-necked pheasants (Phasianus colchicus) disrupted the covariation among male morphological traits at sexual maturity and positively affected male mating success. Here, we investigate whether egg T exposure affected adult male circulating T levels at the onset of the breeding season (reflecting gonadal maturation), and the relationship between circulating T and male traits. Egg T exposure did not affect pre-mating plasma T. T levels were not associated with the expression of secondary sexual and non-sexual traits or socio-sexual behaviour (social rank, overall fighting ability and mating success). However, wattle brightness decreased with increasing circulating T in males hatched from T-eggs (T-males) but not among control males. In dyadic encounters during the peak mating period, control males with higher pre-mating T levels had higher chances of being dominant over other control males. However, higher pre-mating T levels did not predict success in male-male competition in encounters involving T-males. We suggest that the long-term effects of egg T on male phenotype do not originate from differential gonadal maturation according to egg T treatment. Rather, prenatal androgens may have priming effects on functioning of target tissues, translating into differential phenotypic effects according to androgen exposure during embryonic development.


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