Meeting Abstract

P3.143  Sunday, Jan. 6  How hoppers breathe HARRISON, J.F.*; WATERS, J.S.; CEASE, A.J.; VANDENBROOKS, J.M.; CALLIER, V.; KLOK, C.J.; SHAFFER, K.; SOCHA, J.J.; Arizona State University; Arizona State University; Arizona State University; Arizona State University; Arizona State University; Arizona State University; Arizona State University; Virginia Tech j.harrison@asu.edu

Insect tracheal-respiratory systems achieve high fluxes, great dynamic range and are light-weight and energetically efficient. Because they have been improved by natural selection for millions of years, they represent new and potentially important models for bioengineers interested in developing microfluidic systems. Here we focus on the best-known insect respiratory system, the abdominal pump of the locust. Functional valves of unknown mechanisms appear to allow hemolymph to resist gravity and permit segment-specific pressures. Each segment contains two fluids with very different properties (air and water) separated by a flexible membrane. Muscle-driven volume changes in abdominal segments generate volume changes in the tracheal system of that segment, producing pressure changes that drive flow both within the body and through spiracles. Differential compression of air sacs and tracheae create local regional flows. Velocities through the major longitudinal tracheae are high and convection dominates over diffusion as a transport mechanism in these parts of the tracheal system, but Reynolds numbers suggest viscous effects remain important. This research was partially supported by NSF EFRI BSBA 0938047 to JJS and JFH.