Tolerance of pupae and pharate adults of Callosobruchus subinnotatus Pic (Coleoptera: Bruchidae) to modified atmospheres: a function of metabolic rate

Three developmental stages (pupae, early pharate and late pharate adults) of Callosobruchus subinnotatus (Pic.) were investigated for their tolerance or susceptibility to four modified atmospheres. Two of these atmospheres were hypercarbic and two were hypoxic. The hypercarbic atmospheres were found to cause mortality earlier than hypoxic atmospheres. Late pharate adults died earlier than pupae or early pharate adults. Late pharate adults that survived the exposure took a longer time to eclose than the pupae or early pharate adult. Using high resolution microrespirometric techniques, it was possible to record the oxygen consumption rate and CO 2 output of different developmental stages in air. The metabolic rate was determined manometrically as the oxygen uptake rate at an ambient temperature of 25°C. The oxygen uptake rate differed significantly between groups of 20 individuals of different stages ( p