Seasonal variation of the forewing in polyvoltine whites <Emphasis Type="Italic">Pieris rapae</Emphasis> L. and <Emphasis Type="Italic">P. napi</Emphasis> L. (Lepidoptera: Pieridae) in the forest-steppe zone of the Southern Urals

The seasonal variation of forewing size and shape was analyzed in adults of different seasonal generations of two polyvoltine species of whites: Pieris rapae and P. napi (Lepidoptera: Pieridae). Particular morphological features of the forewing are characteristic of each seasonal generation of adults independently of their sex and species. Adults of the spring generations have the smallest wings, elongate and pointed. Adults of the summer generation have the largest, broad and rounded wings over the entire summer season. Adults of the autumn generation have wings similar in shape and size to those of the summer generation, but somewhat smaller and more elongate. Differences between seasonal generations in forewing shape are linked to differences between adults of each generation in adaptation to dispersal.