Institute of Evolutionary Biology and Environmental Sciences, University of Zürich, Zürich, Switzerland.
PLoS One. 2011 Mar 30;6(3):e17399. doi: 10.1371/journal.pone.0017399.
It is often assumed that larval food stress reduces lifetime fitness regardless of the conditions subsequently faced by adults. However, according to the environment-matching hypothesis, a plastic developmental response to poor nutrition results in an adult phenotype that is better adapted to restricted food conditions than one having developed in high food conditions. Such a strategy might evolve when current conditions are a reliable predictor of future conditions. To test this hypothesis, we assessed the effects of larval food conditions (low, improving and high food) on reproductive fitness in both low and high food adults environments. Contrary to this hypothesis, we found no evidence that food restriction in larval ladybird beetles produced adults that were better suited to continuing food stress. In fact, reproductive rate was invariably lower in females that were reared at low food, regardless of whether adults were well fed or food stressed. Juveniles that encountered improving conditions during the larval stage compensated for delayed growth by accelerating subsequent growth, and thus showed no evidence of a reduced reproductive rate. However, these same individuals lost more mass during the period of starvation in adults, which indicates that accelerated growth results in an increased risk of starvation during subsequent periods of food stress.
通常认为，幼虫期的食物压力会降低成虫的终生适应度，而不论其随后所面临的环境条件如何。然而，根据环境匹配假说，对不良营养的可塑性发育反应会导致成虫表型更适应有限的食物条件，而不是在高食物条件下发育的表型。当当前条件能够可靠地预测未来条件时，这种策略可能会进化。为了验证这一假设，我们评估了幼虫期食物条件（低、改善和高食物）对低食物和高食物成年环境中生殖适应度的影响。与这一假设相反，我们没有发现证据表明，在幼虫期的瓢虫中限制食物会产生更适应持续食物压力的成虫。事实上，无论成虫是否得到充分的喂养或受到食物压力的影响，在低食物中饲养的雌性的繁殖率始终较低。在幼虫期遇到改善条件的幼虫通过加速随后的生长来弥补生长延迟，因此没有证据表明其繁殖率降低。然而，这些个体在成年期的饥饿期内损失了更多的体重，这表明加速生长会增加在随后的食物压力期内饥饿的风险。
