Abstract
In aerobic condition, a phosphine-susceptible strain of the rust red flour beetle, Tribolium castaneum, at the larval, pupal and adult stages, absorbed more phosphine than a resistant strain, although no phosphine uptake was observed in both strains in anaerobic condition. And both strains showed same uptake of phosphine in the tissues of the homogenized insects in glycine buffer. The supernatant fraction at 100, 000×g contained a main factor responsible for the intake of phosphine. The activity of this factor was promoted by the presence of molecular oxygen and was stable at pH 5-9 and temperatures up to 50°C. The results led to a scheme for the insect's resistance mechanism to phosphine.
