A study of tolerance of ingested tannin in Schistocerca gregaria

A study has been made on the effects of ingestion of tannic acid on growth and development of Schistocerca gregaria. No deleterious effects were found on digestion or utilisation of food, even when food protein levels were very low. At high concentrations consumption rates were relatively low over the first day, but this effect was not sustained. The lack of ‘antidigestive’ effects is shown to be due partly to the hydrolysis of tannic acid to gallic acid and glucose, and partly to the adsorptive properties of the peritrophic membrane. Insects reared on food with high levels of tannic acid took a longer time to reach sexual maturity than did the controls, although fecundity was not affected thereafter.