Male courting chain (IMAGE) Max Planck Institute for Chemical Ecology Caption Courting chain of four male Drosophila flies. Male flies exhibited unusual courting behavior towards other males that had been exposed to increased ozone levels as they are nowadays often found in cities in the summer. Credit Benjamin Fabian, Max Planck Institute for Chemical Ecology Usage Restrictions Credit must be given to the creator. Adaptations must be shared under the same terms. License CC BY-SA 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.