Structural equation modeling reveals determinants of fitness in a cooperatively breeding bird.
Structural equation modeling reveals determinants of fitness in a cooperatively breeding bird.
复制标题
DOI：
10.1093/beheco/arab135
复制
发表时间：
2022-03
期刊：
影响因子：
--
通讯作者：
中科院分区：
文献类型：
--
作者：
即使在经过充分研究的生物体中，揭示健康的社会和环境决定因素也常常具有挑战性。通常，适应性是由多种因素共同决定的，从而形成复杂的因果关系网络。此外，即使社会和环境条件与健身成分之间存在很强的相关性，也可能并不表明直接的因果联系，因为测量的变量可能是由未测量的（或不可测量的）因果因素驱动的。标准统计方法（例如多元回归分析）不适合理清如此复杂的因果关系。在这里，我们应用结构方程模型（SEM），这是一种专门为揭示变量之间的因果关系而设计的技术，并且还允许包含假设的因果因素。因此，SEM 似乎非常适合比较关于社会和环境因素差异如何产生适应性差异的替代假设。我们将 SEM 应用于对塞舌尔莺 (Acrocephalus sechellensis) 的长期研究中收集的丰富数据集，塞舌尔莺是一种具有兼性合作繁殖和高群体外亲子关系的鸟类。我们的分析表明，助手的存在对雌性和雄性饲养者的繁殖产出都有积极的影响。相比之下，人均粮食供应量并不影响生殖产出。我们的分析并没有证实之前关于其他物种的建议，即辅助者的存在对雄性饲养者的繁殖产出有负面影响。因此，无论食物供应情况如何，雌性和雄性饲养者都应该在其领地内容忍助手。在合作繁殖鸟类中，非父母个体帮助繁殖对抚养幼鸟。由于辅助者也会产生负面影响，目前尚不清楚繁殖对是否以及何时应该容忍它们。我们证明统计方法（因果分析）可以为这个问题提供新的线索。通过分析塞舌尔莺的数据，我们发现繁殖成功率不受食物供应的影响，但繁殖者都从助手的存在中获益。
Even in well-studied organisms, it is often challenging to uncover the social and environmental determinants of fitness. Typically, fitness is determined by a variety of factors that act in concert, thus forming complex networks of causal relationships. Moreover, even strong correlations between social and environmental conditions and fitness components may not be indicative of direct causal links, as the measured variables may be driven by unmeasured (or unmeasurable) causal factors. Standard statistical approaches, like multiple regression analyses, are not suited for disentangling such complex causal relationships. Here, we apply structural equation modeling (SEM), a technique that is specifically designed to reveal causal relationships between variables, and which also allows to include hypothetical causal factors. Therefore, SEM seems ideally suited for comparing alternative hypotheses on how fitness differences arise from differences in social and environmental factors. We apply SEM to a rich data set collected in a long-term study on the Seychelles warbler (Acrocephalus sechellensis), a bird species with facultatively cooperative breeding and a high rate of extra-group paternity. Our analysis reveals that the presence of helpers has a positive effect on the reproductive output of both female and male breeders. In contrast, per capita food availability does not affect reproductive output. Our analysis does not confirm earlier suggestions on other species that the presence of helpers has a negative effect on the reproductive output of male breeders. As such, both female and male breeders should tolerate helpers in their territories, irrespective of food availability. In cooperatively breeding birds, non-parental individuals help the breeding pair with raising the young. As helpers can also have negative effects, it is not clear whether and when the breeding pair should tolerate them. We show that a statistical method (causal analysis) can shed new light on this issue. Analyzing data on Seychelles warblers, we show that reproductive success is not affected by food availability, but that both breeders profit from the presence of helpers.
登录
查看更多内容
DOI：
10.1093/beheco/arab135
发表时间：
2022-03
期刊：
Behavioral ecology : official journal of the International Society for Behavioral Ecology
影响因子：
--
作者：
通讯作者：
--
DOI：
10.1098/rspb.2015.1086
发表时间：
2015-07-22
期刊：
Proceedings. Biological sciences
影响因子：
--
作者：
Beirne C;Delahay R;Young A
通讯作者：
Young A
影响因子：
4.8
作者：
Cubaynes, Sarah;Doutrelant, Claire;Gimenez, Olivier
通讯作者：
Gimenez, Olivier
影响因子：
4.8
作者：
Hodge, Sarah J.;Manica, A.;Clutton-Brock, T. H.
通讯作者：
Clutton-Brock, T. H.
影响因子：
4.8
作者：
Brouwer, Lyanne;Richardson, David S.;Komdeur, Jan
通讯作者：
Komdeur, Jan