Appleby Daniel, Langmore Naomi, Heinsohn Robert, Crates Ross
Fenner School of Environment and Society, Australian National University, Acton, Australian Capital Territory, Australia.
Research School of Biology, Australian National University, Acton, Australian Capital Territory, Australia.
R Soc Open Sci. 2024 Oct 16;11(10):240766. doi: 10.1098/rsos.240766. eCollection 2024 Oct.
Animal cultures can undergo rapid changes associated with innovations, revolutions or population decline. Where a rapid shift results in reduced complexity of cultural behaviours, it may have fitness consequences for individuals. Here, we report a dramatic shift in the dominant song type of critically endangered wild regent honeyeaters . Between 2015 and 2019, most males in the Blue Mountains sang a typical regent honeyeater song (typical Blue Mountains song), but 5%-10% sang an abbreviated version of the song with half the number of syllables (the clipped Blue Mountains song), which was associated with lower pairing success. Since 2020, the proportion of males singing the clipped Blue Mountains song has increased to 50%-75% each year. The likelihood of successful pairing in these males showed a significant concomitant increase, suggesting that the fitness costs associated with the abbreviated song decreased as it became the dominant song type. Our results suggest that the fitness consequences of loss of song complexity in declining and fragmented populations may be ameliorated by frequency-dependent shifts in song type preference.
动物文化可能会经历与创新、变革或种群衰退相关的快速变化。当快速转变导致文化行为的复杂性降低时，可能会对个体的适应性产生影响。在此，我们报告了极度濒危的野生丽色食蜜鸟占主导地位的鸣唱类型发生的显著转变。2015年至2019年间，蓝山地区的大多数雄性丽色食蜜鸟唱一种典型的丽色食蜜鸟鸣唱（典型蓝山鸣唱），但有5% - 10%的雄性唱一种音节数量减半的简化版鸣唱（缩短的蓝山鸣唱），这种鸣唱与配对成功率较低有关。自2020年以来，唱缩短的蓝山鸣唱的雄性比例每年增加到50% - 75%。这些雄性成功配对的可能性显著随之增加，这表明随着简化版鸣唱成为主导鸣唱类型，与该鸣唱相关的适应性成本降低了。我们的结果表明，在数量减少且碎片化的种群中，鸣唱复杂性丧失对适应性的影响可能会因鸣唱类型偏好的频率依赖性转变而得到缓解。
