Chaput-Bardy Audrey, Ducatez Simon, Legrand Delphine, Baguette Michel
Muséum National d'Histoire Naturelle, UMR 7205 Institut Systématique Evolution Biodiversité, Paris, France ; INRA, Equipe Ecotoxicologie et Qualité des Milieux Aquatiques, UMR 985 Ecologie et Santé des Ecosystèmes, INRA-Agrocampus, Rennes, France.
Muséum National d'Histoire Naturelle, UMR 7205 Institut Systématique Evolution Biodiversité, Paris, France ; Department of Biology, McGill University, Montreal, Quebec, Canada.
PLoS One. 2014 Feb 27;9(2):e90026. doi: 10.1371/journal.pone.0090026. eCollection 2014.
The large white butterfly, Pieris brassicae, shows a seasonal polyphenism of wing melanisation, spring individuals being darker than summer individuals. This phenotypic plasticity is supposed to be an adaptive response for thermoregulation in natural populations. However, the variation in individuals' response, the cause of this variation (genetic, non genetic but inheritable or environmental) and its relationship with fitness remain poorly known. We tested the relationships between thermal reaction norm of wing melanisation and adult lifespan as well as female fecundity. Butterflies were reared in cold (18°C), moderate (22°C), and hot (26°C) temperatures over three generations to investigate variation in adult pigmentation and the effects of maternal thermal environment on offspring reaction norms. We found a low heritability in wing melanisation (h(2) =0.18). Rearing families had contrasted thermal reaction norms. Adult lifespan of males and females from highly plastic families was shorter in individuals exposed to hot developmental temperature. Also, females from plastic families exhibited lower fecundity. We did not find any effect of maternal or grand-maternal developmental temperature on fitness. This study provides new evidence on the influence of phenotypic plasticity on life history-traits' evolution, a crucial issue in the context of global change.
大白蝶（粉纹夜蛾）呈现出翅膀黑化的季节性多型现象，春季个体比夏季个体颜色更深。这种表型可塑性被认为是自然种群中一种用于体温调节的适应性反应。然而，个体反应的差异、这种差异的原因（遗传、非遗传但可遗传或环境因素）及其与适合度的关系仍然鲜为人知。我们测试了翅膀黑化的热反应规范与成虫寿命以及雌虫繁殖力之间的关系。将蝴蝶在寒冷（18°C）、适中（22°C）和炎热（26°C）的温度下饲养三代，以研究成虫色素沉着的变化以及母体热环境对后代反应规范的影响。我们发现翅膀黑化的遗传力较低（h(2) = 0.18）。饲养的家族具有不同的热反应规范。来自高度可塑性家族的雄性和雌性成虫，在发育温度较高的个体中寿命较短。此外，来自可塑性家族的雌虫繁殖力较低。我们没有发现母体或祖母发育温度对适合度有任何影响。这项研究为表型可塑性对生活史特征进化的影响提供了新的证据，这在全球变化的背景下是一个关键问题。
