Design of a computer controlled pressure chamber for insect behavioral studies

A cylindrical chamber was designed and built to evaluate the effects of barometric pressure on insect behavior. The chamber, 200 mm diameter by 550 mm high, is made of an acrylic pipe and two acrylic covers. The system is computer controlled using an electronic barometer, solenoid valves, a vacuum pump, and compressed air connected to a data acquisition unit. The chamber is pressurized and maintained using compressed air; a vacuum pump is used to decrease pressure. The performance of the system was tested by lowering the pressure from 1050 to 950 mbar and then increasing it to 1050 mbar within 1 h, following a sinusoidal pattern. The maximum difference between the instantaneous set point pressure and the recorded pressure was 1.1 mbar, which represents a maximum error of 1.1% over the range tested. This system was able to simulate adequately the range of pressure to which insects are normally subjected in their natural environment.