Université de Lyon, UMR5023 Ecologie des Hydrosystèmes Naturels et Anthropisés, Université Lyon 1, ENTPE, CNRS, 6 rue Raphaël Dubois, 69622, Villeurbanne, France.
Anim Cogn. 2019 Nov;22(6):1095-1103. doi: 10.1007/s10071-019-01301-1. Epub 2019 Aug 17.
When they detect a predator, many species emit anti-predator vocalizations. In some cases, they emit mobbing calls, which are associated with the caller approaching and harassing the predator while attracting others to join it. Surprisingly, although mobbing has been widely reported in adults of numerous species, there has been no test of the role of learning in mobbing call recognition, especially during ontogeny. Here, we exposed wild great tit (Parus major) nestlings to playbacks of an unthreatening novel sound either associated with conspecific mobbing calls (experimental treatment) or with another unthreatening novel sound (control treatment). We then tested them as nestlings and fledglings to see how they respond to the novel sound compared to conspecific mobbing calls. Results revealed that fledglings in the experimental treatment behaved similarly to conspecific mobbing calls and the novel sound associated with conspecific mobbing calls. Because mobbing efficiency is often linked to interspecific communication, associative learning should be used by heterospecifics as mobbing calls recognition mechanism. Regardless of treatment during the nestling phase, fledglings always were sensitive to the playback of conspecific mobbing calls. However, fledglings from the control group were more likely to approach the loudspeaker than those from the experimental group when mobbing calls were played suggesting that overexposure during the nestling phase altered mobbing learning. Overall, these results suggest that learning could play a role in the recognition of calls, like heterospecific mobbing calls, when paired with conspecific mobbing, and that mobbing is perceived as a threatening stimulus from a very young age.
当它们察觉到捕食者时，许多物种会发出防御性叫声。在某些情况下，它们会发出驱赶叫声，这与呼叫者接近并骚扰捕食者的行为有关，同时也吸引其他同类加入。令人惊讶的是，尽管驱赶行为在许多物种的成年个体中被广泛报道，但在幼体发育过程中，对学习在驱赶叫声识别中的作用，尤其是在发育过程中的作用，还没有进行过测试。在这里，我们让野生大山雀（Parus major）的雏鸟暴露在一个无害的新声音的播放中，这个声音要么与同种的驱赶叫声相关（实验处理），要么与另一个无害的新声音相关（对照处理）。然后，我们在雏鸟和幼鸟时期测试它们，观察它们对新声音的反应与对同种驱赶叫声的反应有何不同。结果表明，实验处理组的幼鸟与同种驱赶叫声和与同种驱赶叫声相关的新声音表现出相似的行为。由于驱赶效率通常与种间通讯有关，因此，种间学习应该被异源物种用作驱赶叫声识别机制。无论在雏鸟阶段接受哪种处理，幼鸟总是对同种驱赶叫声的播放有反应。然而，与实验处理组相比，对照组的幼鸟在播放驱赶叫声时更有可能接近扬声器，这表明在雏鸟阶段过度暴露会改变驱赶学习。总的来说，这些结果表明，在与同种驱赶声配对时，学习可以在叫声识别中发挥作用，就像异源驱赶声一样，而且从很小的时候起，驱赶就被视为一种威胁性刺激。
