... : (1) artificial playbacks, (2) relatively brief, live agonistic dyadic encounters, and (3) long-term overnight recordings. We also measured circulating levels of two androgens, 11-ketotestosterone and testosterone. Chirp structure varied within and across individuals in response to artificial playback...

...Eric R. Schuppe; Daniel Tobiansky; Franz Goller; Matthew J. Fuxjager ABSTRACT Androgens mediate the expression of many reproductive behaviors, including the elaborate displays used to navigate courtship and territorial interactions. In some vertebrates, males can produce androgen-dependent sexual...

... and development of breeding. If differences in vernal phenology were noted, then the basis for the distinctions was considered genetic. Results indicate that (1) residents had a lower threshold to vernal photoperiod with elevations of plasma androgen, growth and development of reproductive structures preceding...

...Corinna von Kuerthy; Albert F. H. Ros; Michael Taborsky ABSTRACT Alternative reproductive tactics (ARTs), which can be plastic or fixed for life, may be characterized by distinct hormonal profiles. The relative plasticity hypothesis predicts flexible androgen regulation for adult males pursuing...

...; apteronotid species express every pattern of sexual dimorphism in EODf (males>females; males<females; males=females). The direction and magnitude of sex differences in EODf are correlated across species and populations with the responsiveness of EODf to androgens and/or estrogens, which suggests...

...Maria I. Sandell; Michael Tobler; Dennis Hasselquist SUMMARY Maternally derived androgens have been shown to influence offspring phenotype in various ways. In birds, the benefits of prenatal androgen exposure, such as increased competitiveness and accelerated growth in nestlings, have been...

...Diego Gil; Claudia Heim; Elena Bulmer; Milagros Rocha; Marisa Puerta; Marc Naguib SUMMARY Female birds incorporate in the yolks of their eggs significant concentrations of a number of different androgens. Yolk androgen has been shown to positively affect several fitness components at the embryo...