Contribution of genetic versus plastic responses to adaptive patterns in a widespread butterfly along a latitudinal cline

Understanding how organisms adapt to complex environments is a central goal of evolutionary biology and ecology. This issue is of special interest in the current era of rapidly changing climatic conditions. Here, we investigate clinal variation and plastic responses in life history, morphology, and physiology in the butterfly Pieris napi along a pan-European gradient by exposing butterflies raised in captivity to different temperatures. We found clinal variation in body size, growth rates and concomitant development time, wing aspect ratio, wing melanisation, and heat tolerance. Individuals from warmer environments were more heat-tolerant, had less melanised wings and a shorter development but still they were larger than individuals from cooler environments. These findings suggest selection for rapid growth in the warmth and for wing melanisation in the cold, and thus fine-tuned genetic adaptation to local climates. Irrespective of the origin of butterflies, the effects of higher develo...