...James C. Mouton; Renée A. Duckworth; Ryan T. Paitz; Thomas E. Martin ABSTRACT Maternal hormones can shape offspring development and increase survival when predation risk is elevated. In songbirds, yolk androgens influence offspring growth and begging behaviors, which can help mitigate offspring...

..., melanocortins and androgens, underlie the short-term and long-term modulation of signal amplitude and duration observed during social interaction. Population density drives signal amplitude enhancement, unexpectedly improving the reliability with which the signal predicts the signaler's size. The signal's...

... ) 24 5 2011 © 2011. 2011 androgen condition dark-eyed junco Junco hyemalis migration phenology During the transition from the non-breeding to breeding life history stages, migratory animals may be forced to balance the physiological demands of preparing for and maintaining...

... also significantly altered androgen and corticosterone profiles of snakes,providing a potential mechanism to explain reported annual variation in steroid hormones. Although previous studies indicate that male red-sided garter snakes exhibit a dissociated reproductive strategy, we demonstrate...

...Pierre Deviche; Luis Cortez SUMMARY The immunocompetence handicap (ICH) hypothesis predicts that elevated levels of the gonadal androgen testosterone (T) entail obligatory costs, such as immunosuppression, but evidence supporting this immunosuppressive influence is equivocal. To investigate...

... that physiological concentrations of androgens, 17β-estradiol and cortisol rapidly (<10 min) enhance inotropism (30–40%) in a sex-specific manner. These effects were specific to the hormones studied, absent if animals were anesthetized chemically and dependent upon steroid concentration and contraction frequency...

... and fatigue resistance for the production of long mating calls. Type II (floater) males show characteristics that are intermediate, but statistically not significantly different, between type I males and females. Six weeks after castration and androgen (testosterone and 11-ketotestosterone) replacement...

... pacemaker neuron NMDA receptor Na + channel K + channel androgen estrogen phosphorylation Weakly electric fish are useful neuroethological subjects because their electrical signals are stereotyped and quantifiable, and the circuitry that generates and receives these signals is simple...