Nematode Aggregation (IMAGE) California Institute of Technology Caption Chemical cues are used to promote aggregation among roundworms (in black) on a Petri dish. Credit Caltech/Jagan Srinivasan Usage Restrictions Okay with credit License Licensed 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.