Tree swallows trade off immune function and reproductive effort differently across their range
Tree swallows trade off immune function and reproductive effort differently across their range
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DOI：
10.1890/04-1619
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发表时间：
2005-08-01
期刊：
影响因子：
4.8
通讯作者：
Ardia, DR
中科院分区：
文献类型：
--
作者：
Ardia, DR
生命史上的纬度差异被认为是由当前和未来繁殖之间权衡的差异所解释的。我报告了在一种广泛分布的鸟类物种，Tree S wallow （Tachycineta bicolor）的范围内，父母和后代之间权衡的差异。我操纵了亲代的努力，发现在阿拉斯加，年成虫回报率很低，繁殖的雌性增加生殖投资来保持后代的质量，而在田纳西州，年成虫回报率很高，繁殖的雌性要么不能，要么不愿意增加生殖投资，从而培养出质量较低的后代。我进一步研究了一个关键的自我维持机制，它可能是不同部位生存差异的基础：免疫能力。在阿拉斯加繁殖的雌性在繁殖后代时，免疫反应较弱，而田纳西州的雌性则没有，这进一步表明阿拉斯加雌性为了保持后代质量而承担成本（即减少未来的繁殖）的策略。随着繁殖季节的推进，这两个地点的昆虫可用性都有所增加，但阿拉斯加的食物比田纳西州的多。这是第一批报告免疫功能地理差异的研究之一，与生活史理论相一致，该理论预测生存概率较高的个体应该在自我维护方面投入更多。
Latitudinal differences in life histories are believed to be underlain by differences in trade-offs between current and future reproduction. I report differences in tradeoffs between parent and offspring across the range of a widespread avian species, the Tree S wallow (Tachycineta bicolor). I manipulated parental effort and found that in Alaska, where yearly adult return rates are low, breeding females increase their reproductive investment to maintain offspring quality, whereas in Tennessee, where yearly adult return rates are high, breeding females are either unable or unwilling to increase reproductive investment and, consequently, raise offspring of lower quality. I further investigated a critical mechanism of self-maintenance that may underlie differences in survival among sites: immunocompetence. Females breeding in Alaska mounted weaker immune responses when raising enlarged broods, whereas females in Tennessee did not, further suggesting a strategy in Alaskan females to incur costs (i.e., reduce future reproduction) in order to maintain offspring quality. Insect availability increased as the breeding season progressed in both sites, but more food was available in Alaska than in Tennessee. This is among the first studies to report geographic differences in immune function consistent with life history theory, which predicts that individuals with higher survival probabilities should invest more in self-maintenance.