Data from: Cooperative breeding influences the number and type of vocalizations in avian lineages

Although communicative complexity is often predicted to correlate with social complexity in animal societies, few studies have employed large-scale comparative analyses to test whether socially complex species have more complex systems of communication. I tested this social complexity hypothesis in birds (Class: Aves) using the large amount of natural history information that describes both vocal repertoire and social system in these species. To do so, I marshalled data from primary and secondary records of avian vocal repertoires (n = 253), and for each of the species in the dataset I recorded the reported repertoire size and associated species information. Using phylogenetic comparative methods, I found that cooperative breeding was a strong and repeatable predictor of vocal repertoire size, while other social variables, e.g. group size and group stability, had little or no influence on repertoire size. Importantly, repertoire sizes expanded concurrently with the evolution of cooperative breeding, suggesting a direct link between these two traits. Cooperatively breeding species devoted significantly more of their repertoire to contact calls and alarm calls. Overall, these results therefore lend support to the hypothesis that social complexity via behavioural coordination leads to increases in vocal complexity.

尽管动物社会中交流复杂度常被预测与社会复杂度存在关联，但目前鲜有研究采用大规模比较分析方法，检验社会复杂度更高的物种是否拥有更为复杂的交流系统。本研究以鸟类（鸟纲：Aves）为研究对象，依托已积累的大量同时涵盖该类群鸣唱曲目库（vocal repertoire）与社会系统特征的自然历史数据，对上述社会复杂度假说展开检验。为此，本研究整理汇编了来自253项（n=253）鸟类鸣唱曲目库的一手与二手记录数据，并为数据集中的每个物种记录了其已报道的曲目库大小及相关物种信息。通过系统发育比较分析方法，本研究发现合作繁殖（cooperative breeding）是鸣唱曲目库大小的强且可重复的预测因子；而其他社会变量（如群体规模与群体稳定性）对曲目库大小几乎无影响。尤为关键的是，曲目库大小随合作繁殖的演化同步扩张，这表明二者之间存在直接关联。实行合作繁殖的物种，其鸣唱曲目库中分配给联系叫声与警戒叫声的比例显著更高。综上，本研究结果支持如下假说：通过行为协调实现的社会复杂度提升，会推动交流复杂度的增加。