Meeting Abstract

P3.137  Sunday, Jan. 6  Effects of the larval oxygen environment on the three-dimensional branching structure of insect flight muscle tracheae KOVACEVIC, A*; BIDDULPH, T; WATERS, J/S; HARRISON, J/F; Arizona State University sandrakovacevic2010@gmail.com

While it is well-known that insects exhibit compensatory changes in their tracheal structure in response to rearing oxygen levels within the embryonic and larval stages, it is unclear how larval oxygen conditions affect the morphology of the adult tracheal system. We reared Drosophila melanogaster from egg to adult in 10, 21 or 40% oxygen, and used confocal microscopy and synchrotron x-ray phase contrast micro tomography (SR-µCT) to examine the three-dimensional structure of adult flight muscle tracheae. The flight muscles are enveloped within a dense network of tracheoles branching off from large air sacs and sac-like tracheae which open to the thoracic spiracles. We focused on one major tracheal branch that supplies about 25% of three of the longitudinal flight muscle fibers. This major branch subdivides into three main levels of tracheae, each penetrating laterally between the fibers, and so separated by approximately 45µm. Rearing oxygen level did not affect the average number of these tracheae, but there was an effect of branch location. Branches farther from the spiracle had more tracheae. The ratio of the number of branches at the level furthest away from the spiracle to the number of branches at the level closest to the spiracle was inversely proportional to rearing oxygen concentration. These findings suggest that the tracheal networks supplying the adult flight muscle are subject to developmental plasticity in tracheal organization induced by larval or pupal oxygen level. This research was partially supported by NSF 0938047 to J. Socha and J.F.H. and NSF IOS 1122157 to JFH.