Lancaster Environment Centre, Lancaster University, Lancaster, UK.
J Evol Biol. 2010 Jun 1;23(6):1302-11. doi: 10.1111/j.1420-9101.2010.01997.x. Epub 2010 Apr 23.
Maternal and environmental effects can profoundly influence offspring phenotypes, independent of genetic effects. Within avian broods, both the asymmetric post-hatching environment created by hatching asynchrony and the differential maternal investment through the laying sequence have important consequences for individual nestlings in terms of the allocation of resources to body structures with different contributions to fitness. The purpose of this study was to evaluate the relative importance of post-hatching environmental and maternal effects in generating variation in offspring phenotypes. First, an observational study showed that within blue tit, Cyanistes caeruleus, broods, late-hatched nestlings allocated resources to tarsus development, maintained mass gain and head-bill growth and directed resources away from the development of fourth primary feathers. Second, a hatching order manipulation experiment resulted in nestlings from first-laid eggs hatching last, thereby allowing comparison with both late and early-hatched nestlings. Experimental nestlings had growth patterns which were closer to late-hatched nestlings, suggesting that within-brood growth patterns are determined by post-hatching environmental effects. Therefore, we conclude that post-hatching environmental effects play an important role in generating variation in offspring phenotypes.
母体和环境的影响可以在独立于遗传效应的情况下深刻影响后代的表型。在鸟类的巢中，孵化的不同步所产生的孵化后环境的不对称性以及通过产卵顺序的差异母体投资，都会对个体巢雏在资源分配到对适应度有不同贡献的身体结构方面产生重要影响。本研究旨在评估孵化后环境和母体效应在产生后代表型变异方面的相对重要性。首先，一项观察性研究表明，在蓝山雀（Cyanistes caeruleus）的巢中，晚孵化的雏鸟将资源分配到跗跖发育上，保持体重增加和喙-额生长，并将资源从第四根初级飞羽的发育中转移开。其次，通过孵化顺序操纵实验，使得第一批产卵中最晚孵化的卵孵化，从而可以与晚孵化和早孵化的雏鸟进行比较。实验巢雏的生长模式更接近晚孵化的雏鸟，这表明巢内的生长模式是由孵化后环境的影响决定的。因此，我们得出结论，孵化后环境的影响在产生后代表型变异方面起着重要作用。
