Meeting Abstract

P2.132  Jan. 5  The expiration data is today: Diversity of convective insect respiratory behavior visualized by synchrotron x-ray imaging WESTNEAT, M. W.; SOCHA, J. J.; WATERS, J. S. *; HALE, M. E. ; LEE, W. K. ; Field Museum of Natural History; Argonne National Laboratory; Arizona State University; University of Chicago; Argonne National Laboratory mwestneat@fieldmuseum.org

The motions of internal respiratory structures of insects and other small animals have been difficult to see due to a lack of high-resolution imaging approaches at the micron scale. We examined respiratory function in a wide range of insects using x-rays from the Advanced Photon Source to obtain high-resolution phase-enhanced x-ray videos of breathing behaviors. Air filled tracheae and air sacs are readily visible using this x-ray technique. We observed tracheal and/or air sac inflation and deflation in insects from many groups of insects, including dragonflies, earwigs, crickets, grasshoppers, cockroaches, termites, mantises, bugs, beetles, ants, bees, lacewings, flies, and butterflies. We observed natural active respiratory behaviors such as abdominal compression of airsacs, autoventilation of air sacs and tracheae during body motions, and rapid tracheal compressions in the head and thorax of many species that often were not associated with observable body motions. Not all insects were observed to collapse portions of the tracheal system, but active small species and most larger insects exhibited this phenomenon in various forms. We show high resolution x-ray images of many of these animals during breathing, quantify local volume changes in the tracheae of many species, and present a phylogenetic survey of the respiratory characters observed. We conclude that there are a diversity of active, convective gas exchange modes in insects, for which the musculoskeletal mechanisms can be better understood using x-ray imaging.