Department of Biology, Franklin & Marshall College, Lancaster, PA 17604, USA.
Proc Biol Sci. 2010 Jun 22;277(1689):1881-8. doi: 10.1098/rspb.2009.2138. Epub 2010 Feb 10.
Nest microclimate can have strong effects that can carry over to later life-history stages. We experimentally cooled the nests of tree swallows (Tachycineta bicolor). Females incubating in cooled nests reduced incubation time and allowed egg temperatures to drop, leading to extended incubation periods. We partially cross-fostered nestlings to test carry-over effects of cooling during incubation on nestling innate constitutive immunity, assessed through bacteria killing ability (BKA) of blood. Nestlings that had been cooled as eggs showed a lower ability to kill bacteria than control nestlings, regardless of the treatment of their foster mother. However, there was no effect of treatment of rearing females on nestling BKA in control nestlings, even though cooled females made significantly fewer feeding visits than did control females. This suggests that the effect of cooling occurred during incubation and was not due to carry-over effects on nestling condition. Nestlings that were exposed to experimental cooling as embryos had lower residual body mass and absolute body mass at all four ages measured. Our results indicate that environmental conditions and trade-offs experienced during one stage of development can have important carry-over effects on later life-history stages.
巢微气候可能会产生强烈的影响，并延续到以后的生活史阶段。我们对树燕（Tachycineta bicolor）的巢进行了降温实验。在降温巢中孵卵的雌鸟减少了孵卵时间，并使卵温下降，导致孵卵期延长。我们部分交叉育雏，以检验孵卵期间降温对雏鸟先天固有免疫力的传递效应，通过血液的杀菌能力（BKA）来评估。无论其养母的处理方式如何，作为卵被冷却的雏鸟的杀菌能力均低于对照雏鸟，而不论育雏雌鸟的处理方式如何，在对照雏鸟中，育雏雌鸟的处理方式对雏鸟 BKA 均无影响。这表明，冷却的影响发生在孵卵期，而不是由于对雏鸟状况的传递效应。作为胚胎暴露于实验性冷却的雏鸟在所有四个测量的年龄的剩余体重和绝对体重都较低。我们的研究结果表明，在发育的一个阶段所经历的环境条件和权衡取舍会对以后的生活史阶段产生重要的传递效应。
