Schwabl H, Kriner E
Max-Planck-Institut für Verhaltensphysiologie, Andechs, Federal Republic of Germany.
Horm Behav. 1991 Jun;25(2):180-94. doi: 10.1016/0018-506x(91)90049-n.
Male robins aggressively defending a feeding territory in winter have low levels of testosterone, while males defending a breeding territory in spring have elevated levels of testosterone. Song is an integrated part of territorial defense during both phases. We investigated whether testosterone is involved in the expression of these behaviors by treating free-living and captive male robins during both phases with the antiandrogen flutamide. Results suggest that, similar to species in which territoriality is restricted to the reproductive phase, aggressive defense of a breeding territory by male robins is facilitated by androgens. Territorial defense during the nonbreeding season, however, does not require androgenic activity. Singing frequency, on the other hand, was not significantly reduced during either phase by flutamide application. Since the quality of male song changes with season we suggest that the incorporation of sexual signals into male song during breeding depends on testosterone, but that the year-round production of territorial "keep out" signals is independent of testosterone.
冬季积极捍卫觅食领地的雄性知更鸟睾酮水平较低，而春季捍卫繁殖领地的雄性知更鸟睾酮水平升高。鸣叫是这两个阶段领地防御的一个组成部分。我们通过在这两个阶段用抗雄激素氟他胺处理自由生活和圈养的雄性知更鸟，研究了睾酮是否参与这些行为的表达。结果表明，与领地行为仅限于繁殖阶段的物种类似，雄激素促进了雄性知更鸟对繁殖领地的积极防御。然而，非繁殖季节的领地防御并不需要雄激素活性。另一方面，在任何一个阶段，氟他胺处理都没有显著降低鸣叫频率。由于雄性鸣叫的质量随季节变化，我们认为繁殖期间雄性鸣叫中融入性信号取决于睾酮，但全年发出的领地“禁止进入”信号与睾酮无关。
