Wing Variation in Passionvine Butterflies and Peppered Moths (image) Smithsonian Tropical Research Institute Share Print E-Mail Caption These are museum specimens of passionvine butterflies (Heliconius melpomene) and peppered moths (Biston betularia) showing two different wing pattern variants in each species. The cortex gene controls pattern variation. Taken at the Muséum National d'Histoire Naturelle in Paris. Credit Violaine Llaurens Usage Restrictions None Share Print E-Mail Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.