Figure 1 (IMAGE) University of Vienna Caption Electron microscope image of the Robbea hypermnestra symbiont attached to its roundworm host. The proximal, host-attached pole is more invaginated that the free pole. Scale bar: 1 micrometer Credit Copyright: Nikolaus Leisch, Nature Microbiology Usage Restrictions The image may only be used with appropriate caption or 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.