Iowa Cooperative Fish and Wildlife Research Unit, Iowa State University, Ames, IA 50011, USA.
Proc Biol Sci. 2010 Jun 7;277(1688):1659-65. doi: 10.1098/rspb.2010.0022. Epub 2010 Feb 3.
Developmental plasticity can be integral in adapting organisms to the environment experienced during growth. Adaptive plastic responses may be especially important in prioritizing development in response to stress during ontogeny. To evaluate this, I examined how developmental conditions for mourning doves related to early growth and how this affected fledging age, an important life-history transition for birds. The life history of mourning doves is consistent with strong selective pressure to minimize fledging age. Therefore, I predicted that in the face of nutritional stress associated with experimental brood-size increases, young would prioritize growth to structures that promote early fledging to reduce the effect of slowed overall growth on fledging age. Increasing brood size slowed overall structural growth of nestlings and affected the relative allocation of growth among different body parts. Total wing area was the best predictor of fledging age and individuals from larger broods had larger wings relative to overall body size. Although nestlings from larger broods fledged at later ages owing to slower overall growth, prioritization of wing growth reduced this effect by an estimated 1.6 days relative to the delay if plasticity among body parts had not occurred. This was an 11 per cent reduction in the predicted developmental time it took to reach this important life-history transition. Results demonstrate that preferential allocation to wing growth can affect the timing of this life-history transition and that morphological plasticity during development can have adaptive near-term effects during avian development.
发育可塑性对于生物体适应生长过程中所经历的环境至关重要。适应性的可塑性反应在应对个体发育过程中的压力以优先发育方面可能尤为重要。为了评估这一点，我研究了哀鸽的发育条件与早期生长的关系，以及这如何影响离巢年龄，这是鸟类重要的生活史转折点。哀鸽的生活史符合最小化离巢年龄的强烈选择压力。因此，我预测，在面临与实验性巢大小增加相关的营养压力时，幼体会优先考虑生长，以促进早期离巢的结构，从而减少整体生长减缓对离巢年龄的影响。增加巢的大小会减缓雏鸟的整体结构生长，并影响生长在不同身体部位之间的相对分配。总翼面积是离巢年龄的最佳预测指标，来自较大巢的个体相对于整体身体大小，其翅膀更大。尽管由于整体生长较慢，来自较大巢的雏鸟离巢较晚，但翅膀生长的优先化估计可将这种影响减少 1.6 天，与如果身体部位之间没有发生可塑性的延迟相比。这相当于达到这个重要的生活史转折点所需的发育时间减少了 11%。研究结果表明，优先分配给翅膀生长可以影响这个生活史转折点的时间，并且发育过程中的形态可塑性可以在鸟类发育中产生适应性的近期影响。
