Assignment maps (IMAGE) University of Ottawa Caption An example of the assignment maps for two individuals: Butterfly A (MOTF003) on the left and Butterfly B (MOTF009) on the right. For each, there are assignment maps for each of the three techniques: Hydrogen isotopes (blue), strontium isotopes (red), and a dual strontium-hydrogen assignment (green). Darker shades indicate areas where the butterfly more likely originated. Dual assignment (green) is consistently more precise (smaller area) than the single-isotope assignments. Therefore, we recommend the use of dual strontium-hydrogen assignment in future studies of monarch butterflies using isotope geolocation. Credit Megan Reich, University of Ottawa Usage Restrictions None 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.