Evening Primrose in Ithaca, N.Y. (image) National Science Foundation Caption This is a large natural population of evening primrose (yellow), which is a common plant in eastern North America. Agrawal's team set up 16 identical plots. During each growing season for five years, eight of the plots were treated biweekly with an insecticide; the other eight were controls. Credit Anurag Agrawal Usage Restrictions None 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.