Reichard Dustin G, Atwell Jonathan W, Pandit Meelyn M, Cardoso Gonçalo C, Price Trevor D, Ketterson Ellen D
Department of Zoology, Ohio Wesleyan University, Delaware, OH, U.S.A.
Department of Biology, Indiana University, Bloomington, IN, U.S.A.
Anim Behav. 2020 Dec;170:33-41. doi: 10.1016/j.anbehav.2020.10.007. Epub 2020 Nov 2.
Environmental changes caused by urbanization and noise pollution can have profound effects on acoustic communication. Many organisms use higher sound frequencies in urban environments with low-frequency noise, but the developmental and evolutionary mechanisms underlying these shifts are generally unknown. We used a common garden experiment to ask whether changes in minimum song frequency observed 30 years after a songbird colonized an urban environment are a consequence of behavioural flexibility. We captured male juvenile dark-eyed juncos, , from two populations (urban and mountain) soon after they reached independence (aged 25-40 days), raised them in identical indoor aviaries and studied their songs at an age of 3 years. We found that the large population difference in minimum frequency observed in the field persisted undiminished in the common garden despite the absence of noise. We also found some song sharing between the common garden and natal field populations, indicating that early song memorization before capture could contribute to the persistent song differences in adulthood. These results are the first to show that frequency shifts in urban birdsong are maintained in the absence of noise by genetic evolution and/or early life experiences.
城市化和噪音污染所导致的环境变化会对声学通讯产生深远影响。在低频噪音的城市环境中，许多生物会使用更高的声音频率，但这些变化背后的发育和进化机制通常尚不明确。我们进行了一项共同花园实验，以探究鸣禽在殖民城市环境30年后观察到的最小鸣唱频率变化是否是行为灵活性的结果。我们在雄性暗眼灯草鹀幼鸟刚达到独立年龄（25 - 40天）后，从两个种群（城市和山区）捕获它们，将它们饲养在相同的室内鸟舍中，并在它们3岁时研究它们的鸣唱。我们发现，尽管没有噪音，但在共同花园中，在野外观察到的最小频率的巨大种群差异依然存在且未减弱。我们还发现共同花园中的鸟与出生地野外种群之间存在一些鸣唱共享，这表明捕获前的早期鸣唱记忆可能导致成年后持续存在的鸣唱差异。这些结果首次表明，城市鸟鸣中的频率变化在没有噪音的情况下通过基因进化和/或早期生活经历得以维持。
