Date of this Version
Journal of Economic Entomology 59:3 (1966), pp. 550–552.
The concentration of plant pigments in excreta vs. food provided a measure of digestibility of most plants by grasshoppers. Digestibility values obtained with the chromogen-ratio method and consumption-excretion ratios were highly correlated (r = 0.789**). Greatly disparate results were obtained in 4 cases. The chromogen method, when applicable, gave better duplicability and eliminated many of the errors and much labor associated with consumption-excretion ratios.