Department of Biology, University of North Carolina, Chapel Hill, NC 27599, USA.
Integr Comp Biol. 2017 Oct 1;57(4):891-901. doi: 10.1093/icb/icx080.
A sexual signal can indicate not only the signaler's attractiveness as a potential mate but also the signaler's competitiveness relative to rivals. As the attractiveness or competitiveness of the prevailing signaling environment increases, individuals prospecting for mates should change their choice threshold, whereas competing individuals should shift resources toward elevating their own competitiveness. Previous studies show that experimental elevations of song competition increase male competitive behavior in Lincoln's sparrows (Melospiza lincolnii) and European starlings (Sturnus vulgaris). Through a series of experimental manipulations using laboratory-housed Lincoln's sparrows, we have also discovered that females change the strength of their song preferences depending on the attractiveness of the song environment to which they have recently been exposed; compared to a less-attractive environment, a highly-attractive environment elevates the threshold for releasing phonotaxis behavior toward male song. These behavioral adjustments are associated with changes in forebrain monoaminergic activity that are triggered by experimental manipulations of the quality of the song environment. Findings from these studies suggest possible neural mechanisms for the regulation of adaptive behavioral plasticity associated with dynamic sexual signaling environments.
一个性信号不仅可以表明信号发出者作为潜在配偶的吸引力，还可以表明信号发出者相对于竞争对手的竞争力。随着当前信号环境的吸引力或竞争力的增加，寻找配偶的个体应该改变他们的选择阈值，而竞争的个体应该将资源转移到提高自己的竞争力上。先前的研究表明，实验中增加竞争歌曲会增加林肯雀（Melospiza lincolnii）和欧洲椋鸟（Sturnus vulgaris）雄性的竞争行为。通过对实验室饲养的林肯雀进行一系列实验操作，我们还发现，雌性会根据其最近暴露于的歌曲环境的吸引力来改变其歌曲偏好的强度；与吸引力较低的环境相比，吸引力较高的环境会提高对雄性歌曲释放鸣叫行为的阈值。这些行为调整与前脑单胺能活性的变化有关，这些变化是由歌曲环境质量的实验操作引发的。这些研究的结果为与动态性信号环境相关的适应性行为可塑性的调节提供了可能的神经机制。
