Ecological energetics of the grasshopper Poecilocerus pictus in Bangalore fields

Abstract

The structure and biomass of Poecilocerus pictus population in four fields in Bangalore were estimated by direct observation method. Results on the density of P. pictus, the survivorship curve of the grasshopper and the growth of the population are reported. The data on feeding rates, assimilation and conversion obtained in the laboratory were applied to the size and structure of the P. pictus populations in the different fields to estimate the rate and efficiency of energy flow through the population. The results indicate the defensive mechanism developed by the plant against predation. Efficiencies of exploitation, assimilation and production by the populations averaged 3·4, 34 and 15% respectively. Factors like predation, food and space do not appear to regulate the size of the population. Probably it is controlled by intrinsic population factors.