Relyea, R. A. 2001. The lasting effects of adaptive plasticity: Predator-induced tadpoles become long-legged frogs. Ecology 82:1947-1955.

Changes in environmental conditions often alter the traits of individuals; however, we have a poor understanding of how changes in phenotypically plastic traits early in development may affect traits later in life. Such effects are of particular interest in organisms with complex life cycles in which early and late life stages can have drastically different morphologies and occupy different habitats. In this study, I examined how differences in the mass, morphology, and larval period of wood frog tadpoles (Rana sylvatica) subsequently affected the mass and morphology of metamorphic frogs. I found three major patterns: (1) larval mass and larval period were positively related to metamorphic mass; (2) larval period was positively related to metamorph hindlimb and forelimb length and negatively related to metamorph body width; and (3) larval body length was positively related to metamorph forelimb size. I then used these correlations to interpret the connection between the traits of predator-induced tadpoles and the subsequent traits of metamorphic frogs. Tadpoles reared with caged predators (aeshnid dragonflies) developed relatively deeper tail fins and had shorter bodies, lower mass, and longer developmental times than tadpoles reared without predators. Metamorphs emerging from larval predator environments exhibited no differences in mass but developed relatively large hindlimbs and forelimbs and narrower bodies than metamorphs emerging from predator-free larval environments. These differences arose primarily due to predator-induced changes in larval development time and not due to the predator-induced changes in larval morphology. By focusing on a large number of traits and a wide range of trait values, one can readily generate predictions about how a variety of environments, which alter traits early in development, can subsequently alter traits later in development.

环境条件的改变常会改变个体的性状，但目前我们对发育早期的表型可塑性性状（phenotypically plastic traits）变化如何影响生命后期的性状，仍缺乏深入认知。这类效应在具有复杂生活史的类群中尤为受关注——这类生物的早期与后期生活阶段形态差异悬殊，且栖息生境截然不同。本研究以美洲林蛙蝌蚪（Rana sylvatica）为研究对象，探究其幼虫期的体重、形态及发育时长的差异，后续将如何影响变态幼蛙的体重与形态。本研究共发现三大规律：（1）幼虫体重与幼虫期均与变态幼蛙体重呈正相关；（2）幼虫期与变态幼蛙的后肢、前肢长度呈正相关，而与变态幼蛙的体宽呈负相关；（3）幼虫体长按正相关关系影响变态幼蛙的前肢尺寸。随后，本研究利用上述相关性，解析了捕食者胁迫诱导的蝌蚪的性状与后续变态幼蛙性状之间的关联。与未设置捕食者的对照组蝌蚪相比，饲养在笼养捕食者（蜓科蜻蜓，aeshnid dragonflies）环境中的蝌蚪，其尾鳍相对更深，体长短、体重更低，且幼虫期更长。从捕食者胁迫的幼虫环境中发育而来的变态幼蛙，其体重与无捕食者环境下发育的变态幼蛙并无差异，但后肢与前肢相对更大，体宽更窄。上述差异主要源于捕食者诱导的幼虫期变化，而非幼虫形态的捕食者诱导改变。通过聚焦大量性状及宽泛的性状值范围，我们可以轻松预测：多种会改变发育早期性状的环境，后续将如何影响生命后期的性状。