Monarch Caterpillar on a Leaf (IMAGE) DOE/Argonne National Laboratory Caption A monarch caterpillar on a common milkweed leaf. Credit (Image by Argonne National Laboratory/Lee Walston.) Usage Restrictions Original content License Original content 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.