Mixture models as a method for comparative sociality: social networks and demographic change in resident killer whales
Mixture models as a method for comparative sociality: social networks and demographic change in resident killer whales
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DOI：
10.1007/s00265-021-03006-3
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发表时间：
2021-04-01
影响因子：
2.3
通讯作者：
Croft, Darren P.
中科院分区：
文献类型：
--
作者：
Ellis, Samuel;Franks, Daniel W.;Croft, Darren P.
在社会行为的研究中，社会联系通常是从互动或联系的比率中推断出来的。这种方法揭示了许多重要的见解动物社会结构的近似形成和最终功能。然而，它仍然具有挑战性，比较系统或时间点之间的社会结构，因为外在因素，如抽样方法，也可以影响观察到的关联率。由于这些方法上的挑战，很难分析社会联系模式如何随着人口统计过程（如主要社会伙伴的死亡）而变化。在这里，我们开发并说明使用二项式混合模型来定量比较网络之间的社会关联模式。然后，我们使用这种方法来研究虎鲸的社会偏好模式如何应对人口变化。当地的虎鲸是雌雄同体的，成年后，两性都与母亲保持密切联系。我们发现，母亲和女儿的社会交往减少后，出生的女儿的第一个后代，但不是出生后的后代的母亲。我们还发现，母亲死亡的鲸鱼比母亲活着的鲸鱼更容易与异性兄弟姐妹和祖母联系。我们的工作证明了使用混合模型来比较网络之间和物种之间的社会偏好的实用性。我们还强调了这种方法的其他潜在用途，例如识别动物种群中强大的社会联系。由于抽样和方法差异的混杂效应，比较不同系统之间或不同时间相同系统之间的社会关联模式具有挑战性。在这里，我们提出了一种方法，允许社会协会进行稳健的分类，然后使用二项式混合模型的网络之间进行比较。我们通过展示虎鲸如何改变它们的社会联系模式来说明这种方法，以应对幼崽的出生和母亲的死亡。我们发现，在她的小牛出生后，女性与母亲的联系较少。我们还发现，母亲死亡的鲸鱼比母亲活着的鲸鱼更容易与异性兄弟姐妹和祖母联系。这清楚地表明，这种方法可以用来研究动物社会系统中的细尺度时间过程。
In studies of social behaviour, social bonds are usually inferred from rates of interaction or association. This approach has revealed many important insights into the proximate formation and ultimate function of animal social structures. However, it remains challenging to compare social structure between systems or time-points because extrinsic factors, such as sampling methodology, can also influence the observed rate of association. As a consequence of these methodological challenges, it is difficult to analyse how patterns of social association change with demographic processes, such as the death of key social partners. Here we develop and illustrate the use of binomial mixture models to quantitatively compare patterns of social association between networks. We then use this method to investigate how patterns of social preferences in killer whales respond to demographic change. Resident killer whales are bisexually philopatric, and both sexes stay in close association with their mother in adulthood. We show that mothers and daughters show reduced social association after the birth of the daughter's first offspring, but not after the birth of an offspring to the mother. We also show that whales whose mother is dead associate more with their opposite sex siblings and with their grandmother than whales whose mother is alive. Our work demonstrates the utility of using mixture models to compare social preferences between networks and between species. We also highlight other potential uses of this method such as to identify strong social bonds in animal populations. Significance statement Comparing patters of social associations between systems, or between the same systems at different times, is challenging due to the confounding effects of sampling and methodological differences. Here we present a method to allow social associations to be robustly classified and then compared between networks using binomial mixture models. We illustrate this method by showing how killer whales change their patterns of social association in response to the birth of calves and the death of their mother. We show that after the birth of her calf, females associate less with their mother. We also show that whales' whose mother is dead associate more with their opposite sex siblings and grandmothers than whales' whose mother is alive. This clearly demonstrates how this method can be used to examine fine scale temporal processes in animal social systems.