Dissertation Research: Bird Song Divergence, Interspecific Territoriality, and Biogeography within a Sky Island Species Complex

领地动物在识别和应对竞争对手构成的威胁方面面临挑战。特别有趣的研究领域的情况下，两个密切相关的动物在激烈的竞争资源使用显着不同的信号，以阻止入侵者。这种情况发生在最近分化的莫罗太阳鸟和Fuelleborn太阳鸟之间的狭窄边界上，它们在领土歌曲方面存在显着差异，并且似乎对彼此表现出高度不同的领土性水平。有趣的是，这两个物种的地理分布表明，一个是扩大其范围的代价，另一个在整个'天空岛'森林隔离的Udzungwa山脉，坦桑尼亚。这项研究整合了实验和分子方法来研究人群之间攻击性不对称的原因和后果。为了检验解释明显的攻击性不对称的替代假设的支持，该研究将采用一系列回放实验，其中领土主体通过播放竞争对手的歌曲引起模拟入侵。使用DNA序列数据，该研究将检查：1）一个物种最近是否以牺牲另一个物种为代价入侵了乌宗瓦山脉，以及2）物种之间基因流动的程度。这项研究利用了物种之间不寻常的'天空岛'接触区来测试信号进化和领土性如何相互作用，以及这种相互作用如何影响生态相似物种之间竞争的长期结果。很少有可能研究行为差异如何扩大到影响岛屿状分布的防御-防御动力学。

Territorial animals face challenges in recognizing and responding to the threat posed by competitors. Particularly interesting for studies of territoriality are circumstances where two closely related animals in strong competition for resources use dramatically different signals to deter intruders. Such a situation occurs at the narrow boundary between the recently diverged Moreau's and Fuelleborn's sunbirds, which differ dramatically in territorial song and appear to show highly disparate levels of territoriality towards one another. Intriguingly, the geographical distribution of these two species suggests that one is expanding its range at the expense of the other across the 'sky island' forest isolates of the Udzungwa Mountains, Tanzania. This study integrates experimental and molecular approaches to examine the causes and consequences of aggressive asymmetries between populations. To examine support for alternate hypotheses that explain apparent aggressive asymmetry, the study will employ a series of playback experiments in which territorial subjects incur a simulated intrusion via the broadcast of a competitor's songs. Using DNA sequence data, the study will examine: 1) whether one species has recently invaded the Udzungwa Mountains at the expense of the other, and 2) the extent of gene flow between species.This study takes advantage of an unusual 'sky island' contact zone between species to test how signal evolution and territoriality interact, and how such interactions may influence the long-term outcomes of competition among ecologically similar species. It is rarely possible to examine how behavioral differences might scale up to impact extinction-recolonization dynamics in island-like distributions.