Do cultural evolutionary processes shape the long-distance vocalisations of wild chimpanzees (Pan troglodytes)?

在过去的几十年里，文化进化理论获得了越来越多的支持（Boesch和Tomasello，1998年; Noad等人，2000; Whiten，2000，2017 a; Boesch，2003; Whiten等人，二〇一七年; Aplin，2019），许多人认为文化进化是许多物种遗传进化的另一层（Mesoudi，Whiten和Laland，2004; Whiten，2017 a）。文化进化理论预测，当个体在群体中创新新的行为时，这些行为可能会通过社会学习传播到当地的同类（Whiten，2000; Whiten和货车de Waal，2018）。如果这些行为提供了显著的健身益处，尽管没有遗传基础，但它们可能会随着时间的推移而持续存在（Boesch和Tomasello，1998; Laland和Janik，2006; Whiten等人，2017年）。这种文化进化的过程被认为能够在动物的共同行为实践中产生种群水平的差异（Boesch，1996; Whiten，2005; Mesoudi，2016，2017; Aplin，2019）。经验证据在很大程度上支持黑猩猩（Pan troglodytes）进食、自我维持和社会行为是由文化进化塑造的理论（Boesch和Tomasello，1998年; Biro等人，2003; Luncz，Mundry和Boesch，2012; Gruber等人，2015; Mesoudi和Thornton，2018）。很少有人注意到黑猩猩的发声也可能表现出文化驱动的变化。在雀形目鸟类（Jenkins，1978; Lynch，1996; Aplin，2019）和鲸目动物（Deecke，福特和Spong，2000; Noad等人，2000年;加兰Ellen C.例如，2017; Mahaffy等人，2018年）。来自圈养黑猩猩种群的证据表明，裤-呼叫声的声学结构（马歇尔，Wrangham和Arcadi，1999年; Crockford等人，2004）和食物咕噜声（沃森等人，2015）也可以通过从同种的声音学习来塑造。然而，灵长类动物发声学习途径的证据仍然存在争议，沃森等人（2015年）等出版物因其分析中忽略了关键的环境和心理变量而受到批评（Fischer，惠勒和希格姆，2015年）。鉴于黑猩猩的社会学习能力得到了充分的证明（Biro等人，2003; Hobaiter等人，二〇一四年Whiten，2017 b; Whiten和货车de Waal，2018年）-包括报告的发声学习证据（马歇尔，Wrangham和Arcadi，1999年;沃森等人，2015）-以及喂养，梳理和社会行为中文化差异的普遍性（Boesch和Tomasello，1998; Biro et al. 2003; Luncz，Mundry和Boesch，2012; Gruber et al. 2015）我建议调查黑猩猩发声中可能归因于文化进化过程的种群水平差异的存在。这种长距离的“pant-hoot”展示为文化比较提供了一个新的机会。Pant-hoot呼叫是多用途的长途呼叫，在野生黑猩猩种群中普遍存在，因此可以从广泛的研究地点进行采样（Fedurek et al. 2013，2016; Fedurek，Donnellan和Slocombe，2014）。此外，长时间的pant-hoot显示，以及它们复杂的声音结构，提供了许多光谱，时间和行为元素，可以在种群间比较中加以利用（Fedurek，Zuberbuhler和Semple，2017）。出于这些原因，有人建议，panthoot调用作为一个案例研究，以评估塑造黑猩猩发声的文化进化过程。

Cultural evolutionary theory has gained increasing levels of support over past decades (Boesch and Tomasello, 1998; Noad et al., 2000; Whiten, 2000, 2017a; Boesch, 2003; Whiten et al., 2017; Aplin, 2019), with many citing cultural evolution an additional layer to genetic evolution for many species (Mesoudi, Whiten and Laland, 2004; Whiten, 2017a). Cultural evolutionary theory predicts that when individuals innovate new behaviours within a population, these may then spread to local conspecifics through social learning (Whiten, 2000; Whiten and van de Waal, 2018). If these behaviours offer significant fitness benefits, they may persist over time, despite having no genetic basis (Boesch and Tomasello, 1998; Laland and Janik, 2006; Whiten et al., 2017). This process of cultural evolution is theorised to be able to produce population-level differences in the common behavioural practices of animals (Boesch, 1996; Whiten, 2005; Mesoudi, 2016, 2017; Aplin, 2019). Empirical evidence largely supports the theory that chimpanzee (Pan troglodytes) feeding, self-maintenance and social behaviours are shaped by cultural evolution (Boesch and Tomasello, 1998; Biro et al., 2003; Luncz, Mundry and Boesch, 2012; Gruber et al., 2015; Mesoudi and Thornton, 2018). Little attention has been given to the possibility that chimpanzee vocalizations may also show culturally driven variation. Vocal learning pathways have been identified in generating culturally distinct calls of passerine birds (Jenkins, 1978; Lynch, 1996; Aplin, 2019) and cetaceans (Deecke, Ford and Spong, 2000; Noad et al., 2000; Garland Ellen C. et al., 2017; Mahaffy et al., 2018). Evidence from captive chimpanzee populations suggests that the acoustic structure of pant-hoot calls (Marshall, Wrangham and Arcadi, 1999; Crockford et al., 2004) and food grunt calls (Watson et al., 2015) may also be shaped by vocal learning from conspecifics. However, evidence for vocal learning pathways within primates remains controversial, with publications such as Watson et al. 2015 being criticised for omitting key environmental and psychological variables within their analysis (Fischer, Wheeler and Higham, 2015). Given the well documented capacity for social learning in chimpanzees (Biro et al., 2003; Hobaiter et al., 2014; Whiten, 2017b; Whiten and van de Waal, 2018) - including reported evidence of vocal learning (Marshall, Wrangham and Arcadi, 1999; Watson et al., 2015) - and the prevalence of cultural variation in feeding, grooming, and social behaviours (Boesch and Tomasello, 1998; Biro et al. 2003; Luncz, Mundry and Boesch, 2012; Gruber et al. 2015) I propose to investigate the existence of population-level differences in chimpanzee vocalisations which may be attributed to cultural evolutionary processes. The long-distance 'pant-hoot' display offers a novel opportunity for cultural comparison. Pant-hoot calls are multi-purpose longdistance calls which are ubiquitous within wild chimpanzee populations, and therefore can be sampled from a wide range of study sites (Fedurek et al. 2013, 2016; Fedurek, Donnellan and Slocombe, 2014). Moreover, the extended durations of pant-hoot displays, as well as their complex vocal structures, provide many spectral, temporal and behavioural elements that can be exploited in inter-population comparisons (Fedurek, Zuberbuhler and Semple, 2017). For these reasons, it is proposed that panthoot calls are used as a case study to assess for cultural evolutionary processes shaping chimpanzee vocalisations.