Females with Increased Costs Maintain Reproductive Output: A Field Experiment in a Common Songbird
Females with Increased Costs Maintain Reproductive Output: A Field Experiment in a Common Songbird
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成本增加的雌性保持繁殖能力：对常见鸣禽的现场实验
DOI：
10.1093/icb/icad042
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发表时间：
2023
影响因子：
2.6
通讯作者：
Safran, Rebecca J.
中科院分区：
文献类型：
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作者：
McDermott, Molly T.;Madden, Sage A.;Laubach, Zachary M.;Ayala, Marina J.;Safran, Rebecca J.
繁衍和自我维持是涉及经典生活史权衡的耗费精力的活动。然而，很少有研究衡量野生生物对繁殖和自我维持成本同时变化的反应，这可能会产生交互影响。在自由生活的雌性谷仓燕子(Hirundo Rustica)中，我们同时操纵了繁殖成本(通过增加或移除两只雏鸟)和自我维护成本(通过将∼1 g重量以全球定位系统标签的形式附加到我们研究的一半鸟类上)，并测量了质量、免疫状态、血糖、羽毛生长和繁殖产量(第二胎的可能性、卵子数量和产卵间隔时间)。GPS标签使我们能够分析移动范围大小如何影响对雏鸟大小操纵的反应。标记改变了雌性的免疫功能，表现为异嗜性细胞与淋巴细胞(H：L)比率的升高，但所有雌性都同样有可能产卵更多。没有证据表明标记和孵化大小处理之间存在交互作用。范围大小变化很大，范围大的鸟羽毛生长较慢，但在考虑范围大小变化的同时，分析孵化规模控制的效果并没有导致任何生理反应。我们的结果支持了理论预测，即短寿命脊椎动物确实面临着繁殖和自我维持之间的权衡，当面临成本增加时，往往会以牺牲亲代条件为代价来保存对繁殖的投资。这项实验也有助于我们理解运动模式如何与野生鸟类的生活史权衡相关。
Reproduction and self-maintenance are energetically costly activities involved in classic life history trade-offs. However, few studies have measured the responses of wild organisms to simultaneous changes in reproductive and self-maintenance costs, which may have interactive effects. In free-living female Barn Swallows (Hirundo rustica), we simultaneously manipulated reproductive costs (by adding or removing two nestlings) and self-maintenance costs (by attaching a ∼1 g weight in the form of a GPS tag to half of our study birds) and measured mass, immune status, blood glucose, feather growth, and reproductive output (likelihood of a second clutch, number of eggs, and time between clutches). GPS tags allowed us to analyze how movement range size affected response to brood size manipulation. Tagging altered females’ immune function as evidenced by an elevated heterophil to lymphocyte (H:L) ratio, but all females were equally likely to lay more eggs. There was no evidence of interactive effects of the tagging and brood size treatment. Range size was highly variable, and birds with large ranges grew feathers more slowly, but analyzing the effect of brood size manipulation while accounting for variation in range size did not result in any physiological response. Our results support the theoretical prediction that short-lived vertebrates do face a trade-off between reproduction and self-maintenance and, when faced with increased costs, tend to preserve investment in reproduction at the expense of parental condition. This experiment also helps us to understand how movement patterns may be relevant to life history trade-offs in wild birds.