Evening Primrose (image) University of California - Santa Cruz Share Print E-Mail Caption Varieties of evening primrose (Oenothera biennis) show variation in leaf chemistry, leading to differences in the insect communities in different fields. Credit Nash Turley Usage Restrictions For use only with news coverage of this research. 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.