Ian Keesey, Max Planck Institute for Chemical Ecology (image) Max Planck Institute for Chemical Ecology Share Print E-Mail Caption Ian Keesey analyzes the odor of single flies using GC/MS (gas chromatography -- mass spectrometry). Sick flies emit significantly increased amounts of pheromones. Credit Anna Schroll Usage Restrictions None 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.