Doctoral Dissertation Research: Endocrine Mediation of Alternative Reproductive Tactics in Anurans

摘要：在鱼类和爬行动物中，对雄性选择性交配策略表达的生理机制进行了最广泛的研究，这些鱼类和爬行动物通常使用视觉信号进行宣传。尽管在无脊椎两栖动物（青蛙和蟾蜍）中普遍存在替代策略，但关于调节声音信号产生的过程知之甚少。例如，雄性蟾蜍通常用声音来吸引配偶，但有些个体采用另一种不叫的“卫星”策略。卫星雄性的特点是靠近发出声音的雄性，并试图拦截被发出声音的个体吸引的雌性。理论预测，这些可塑的成人行为表型应该受到激素的影响，这些激素调节一种行为对另一种行为的表达。在无尾猿中，鸣叫和不鸣叫行为之间的交替被认为与“应激”类固醇激素皮质酮和性类固醇（雄激素）循环水平之间的相互作用有关，这种相互作用是由发声过程中能量储备的消耗所驱动的。初步数据支持皮质酮水平与发声期间能量储备消耗之间的关系，但表明呼叫和卫星行为之间的交替与雄激素无关。拟议的研究将测试另一种模型，以确定雄性蟾蜍生殖行为的生理基础。

Proposal 0308958 - Endocrine mediation of alternative reproductive tactics in anurans PIs: Rosemary Knapp and Christopher J. LearyLay SummaryPhysiological mechanisms contributing to the expression of alternative male mating tactics have been studied most extensively in fishes and reptiles that typically advertise using visual signals. Less is known regarding processes regulating vocal signal production in anuran amphibians (frogs and toads), despite the pervasiveness of alternative tactics in this group. For example, male toads typically vocalize to attract mates, but some individuals adopt alternative non-calling "satellite" tactics. Satellite males characteristically remain in close proximity to calling males and attempt to intercept incoming females attracted to vocalizing individuals. Theory predicts that these plastic adult behavioral phenotypes should be subject to effects of hormones that mediate the expression of one behavior over the other. In anurans, it is thought that alternation between calling and non-calling behavior is related to a reciprocal interaction between circulating levels of the "stress" steroid hormone corticosterone and sex steroids (androgens) that is driven by depletion of energy reserves during vocalization. Preliminary data support a relationship between corticosterone levels and depletion of energy reserves during vocal bouts but indicate that alternation between calling and satellite behavior is independent of androgens. The proposed studies will test an alternative model to determine the physiological basis for male reproductive behavior in toads.