DISSERTATION RESEARCH: Aggressive Signaling and Fitness Consequences in a New World Warbler

动物之间为了争夺有限的资源经常发生争执。 在这种情况下，动物可能会通过使用刻板的通信信号（如视觉或声音显示）来避免直接战斗。 co-PI之前对鸣禽黑喉蓝莺的声音信号的研究表明，两种声音显示特征是特别“诚实”的威胁信号，就预测未来的攻击而言。 特别是，产生非常安静的歌曲（“软”的歌曲）和一定的歌曲类别（“II型”歌曲）都可靠地预测鸟是否会随后攻击模型对手。 拟议研究的第一部分将测试这两个信号特征是否传达不同程度的威胁，以及鸟类是否以及如何通过单独或顺序调制这两个歌曲特征来升级攻击性互动。 为此，一个现场实验将模拟互动歌曲比赛的强度升级。 在低水平的升级与II型歌曲响应的鸟类预计会在升级的更高阶段，每个更高的阶段成为一个更可靠的预测最终的攻击，给软的歌曲。 这个实验将表明动物纠纷是否会像最近的理论工作所预测的那样，沿着一个等级“阶梯”升级。 拟议研究的第二部分是询问动物是否以及如何通过使用威胁展示而受益。男性在威胁展示使用中的自然变化将被记录下来，声音互动的“赢家”和“输家”将根据谁先退缩进行编码。遗传亲子关系分析将提供威胁显示和繁殖成功之间的相关性的估计。 更频繁地使用威胁显示和“赢得”更多的互动对对手的男性预计将更成功地繁衍后代。 这个项目将为本科生提供实地研究经验，并将在面向小学生的外展活动中展示。

Disputes often arise among animals competing for limited resources. In such circumstances, animals may avoid direct combat through use of stereotyped communication signals, such as visual or vocal displays. Prior studies by the co-PI on vocal signaling in a songbird, the black-throated blue warbler, showed that two vocal display features are particularly "honest" signals of threat, in terms of forecasting future aggression. Specifically, the production of extremely quiet songs ("soft" songs) and a certain song category ("type II" songs) both reliably predict whether a bird will subsequently attack a model opponent. The first part of proposed research will test whether these two signal features convey differing levels of threat, and if and how birds may escalate aggressive interactions by modulating these two song features either alone or in sequence. Towards this end, a field experiment will simulate interactive song contests that escalate in intensity. Birds that respond with type II songs during low levels of escalation are predicted to give soft songs during higher stages of escalation, with each higher stage becoming a more reliable predictor of eventual attack. This experiment will indicate whether animal disputes follow a hierarchical "ladder" of escalation, as has been predicted in recent theoretical work. The second part of proposed research asks if and how animals benefit through their use of threat displays. Natural variation among males in threat display use will be documented, and "winners" and "losers" of vocal interactions coded based on who backs down first. Genetic paternity analysis will provide estimates of correlations between threat displays and reproductive success. Males that more frequently use threat displays and "win" more interactions against opponents are predicted to be more successful at siring offspring. This project will provide field research experience for undergraduates, and will be showcased in outreach activities to elementary school students.