EAGER: Acoustic Differentiation of Northern Red-legged Frog Populations

了解自然界的一个主要问题是，每个物种如何能够成功地识别配偶，以确保物种的持久性，以及不断变化的环境条件如何影响其繁殖成功。在许多物种中，雄性的广告叫声对于吸引雌性交配和在一个区域内多个物种共存时用于物种识别是必不可少的。研究人员发现了一种新的系统，可以量化太平洋西北部北部红腿蛙群在水下发出的广告和识别叫声是如何改变的。这项关于声音传播和交配的研究将通过对该蛙物种在其地理范围内种群间遗传分化的调查来补充。这项研究将通过波特兰州立大学的“更好地了解实验室”的外展倡议进行分享，该倡议将周边社区和研究实验室聚集在一起，共同进行数据收集，直到展示他们的发现。此外，我们计划与当地教师建立联系，帮助设计跨学科课程，突出交流、生态学和声音科学的作用，让学生了解交配策略和动物交流在物种成功生存中所起的重要作用。感觉驱动假说认为，感觉条件（环境生物物理学）和感觉系统驱动配偶信号向特定方向分化，从而最终通过最终的繁殖成功优化信号传播。这项研究在测试感官驱动假说方面是独一无二的，研究对象是一只陆地无尾熊，它(1)在水下鸣叫，(2)在浅池塘里鸣叫，这可能会极大地改变“正常”的声音衰减。声信号分量的衰减一般与声音频率的平方成正比；更高的频率衰减得更快。然而，已有研究表明，在浅池中，基材和深度可以显著增加低频的衰减。因为雌性选择所依据的能量优势频率落在信号的较低范围内，一个低频可能急剧衰减的系统比以前研究过的系统更有可能在青蛙种群中造成生殖隔离。该项目将测试异域北方红腿蛙种群的声学和遗传分化，并在大地理范围内比较不同池塘的声学特征。雄性广告叫声与繁殖地点的频率分布匹配程度将决定繁殖成功率，并根据频谱特征进行定向选择，并通过利用水下叫声为感官驱动假说提供第一个测试。

A major question in understanding the natural world is how each species is able to successfully identify a mate to assure persistence of the species and how changing environmental conditions might influence its reproductive success. In many species male advertisement calls are essential for attracting a female to mate with as well as being used for species recognition when more than one species co-occurs within an area. The researchers have identified a novel system to quantify how male advertisement and recognition calls are altered when the calls are performed underwater among populations of northern red-legged frogs in the Pacific North West. This research on sound transmission and mating will be complemented by an investigation of the genetic differentiation among populations of this frog species throughout its geographic range. The research will be shared via an outreach initiative at Portland State University's "Better Know a Lab" that brings together the surrounding community and research labs to jointly conduct data collection all the way through to the presentation of their findings. Furthermore, networking is planned with local teachers to help design interdisciplinary curricula highlighting the role of communication, ecology, and the science of sound to engage students in learning about mating strategies and the important role animal communication plays in species successful persistence in nature. The sensory drive hypothesis asserts that sensory conditions (environmental biophysics) and sensory systems drive divergence in mate signaling in a particular direction, one that optimizes signal propagation ultimately through resultant reproductive success. This research is unique in testing the sensory drive hypothesis with a terrestrial anuran that (1) calls underwater and (2) calls in shallow ponds that may dramatically alter "normal" acoustic attenuation. Attenuation of acoustic signal components is generally proportional to the square of sound frequency; higher frequencies attenuate much more quickly. However it has been shown that in shallow ponds, substrate and depth can dramatically increase the attenuation of lower frequencies. Because the energetically dominant frequencies upon which female choice is based fall in the lower range of the signal, a system where low frequencies may be dramatically attenuated is far more likely to create reproductive isolation among frog populations than the previous systems studied. The project will test the acoustic and genetic differentiation of allopatric northern red-legged frog populations compared across ponds with significantly differing acoustic profiles across a large geographical scale. How well male advertisement calls are matched to the frequency profile of the breeding site should determine reproductive success and create directional selection on spectral characteristics, and provide a first test for the sensory drive hypothesis through the utilization of underwater calling.