An experimental study of the influence of food quality and population density on the demographic performance of Tribolium castaneum (Herbst.)

An experiment is described in which the effect of the interaction between food quality and population density upon the demographic performance of Tribolium castaneum is determined. A soft wheat variety (Corella) and a hard wheat variety (Eagle) were used to produce flour for the experiment and densities ranging from 1 to 26 pairs of insects per replicate were used. The results showed that, at low densities, the insects in soft wheat flour produced about 15 times the progeny of those in hard wheat flour and developed significantly faster. At the highest densities, however, adult productivity was much the same for each wheat type, although the soft wheat replicates produced very many more larvae. The apparent rate of development in the soft wheat flour at the highest density was significantly slower than in the hard wheat flour. The likely cause of these apparently anomalous results appear to be high levels of larval cannibalism of pupae in the very productive soft wheat replicates.