Department of Biology, University of North Carolina, Chapel Hill, NC 27599-3280, USA.
Biol Lett. 2012 Oct 23;8(5):751-3. doi: 10.1098/rsbl.2012.0481. Epub 2012 Jul 18.
The environmental conditions under which signals are perceived can affect receiver responses. Many songbird populations produce a song chorus at dawn, when, in cold habitats, they would experience thermal challenge. We recorded temperature and the song activity of Lincoln's sparrows (Melospiza lincolnii) on a high-elevation meadow, and determined that song behaviour is concentrated around the coldest time of the day, at dawn. We hypothesized that this is because male song in the cold is more attractive to females than song in the warm. To test this, we exposed laboratory-housed Lincoln's sparrow females to songs at 1°C and 16°C, which they naturally experience in the wild. Females spent 40 per cent more time close to the speaker during playback at 1°C than at 16°C. When tested at 16°C 1-2 days later, females biased their movement towards the speaker playing songs previously heard at 1°C over 16°C. Thus, female Lincoln's sparrows remembered and affiliated with songs they heard under thermal challenge, indicating that the thermal environment can affect the attractiveness of a sexual signal.
信号被感知的环境条件会影响接收者的反应。许多鸣禽在黎明时分会发出合唱声，而在寒冷的栖息地，它们会面临热应激的挑战。我们在一个高海拔的草地上记录了林肯雀（Melospiza lincolnii）的温度和歌声活动，并确定它们的歌声行为集中在一天中最冷的时间，即黎明时分。我们假设这是因为在寒冷中雄性的歌声对雌性比在温暖中更有吸引力。为了验证这一点，我们让实验室饲养的林肯雀雌性在 1°C 和 16°C 下听歌曲，这是它们在野外自然会经历的温度。雌性在 1°C 时比在 16°C 时更接近扬声器，时间延长了 40%。当它们在 16°C 下 1-2 天后再次接受测试时，雌性会更倾向于移动到播放之前在 1°C 下听到的歌曲的扬声器，而不是 16°C 下的扬声器。因此，雌性林肯雀记住了并认同了它们在热应激下听到的歌曲，这表明热环境会影响性信号的吸引力。
