Aquatic Chaoborus midge larvae (IMAGE) University of British Columbia Caption Aquatic Chaoborus midge larvae are the only insect that can control their buoyancy. Their tracheal air-sacs act as a pH-powered mechanochemical engine. Credit Philip Matthews Usage Restrictions No restriction License Original 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.