Food energy budget of Pieris brassicae larvae-a pest of cruciferous agro-ecosystems

Abstract

The food consumption, assimilation and tissue growth in the different instar larvae of Pieris brassicae fed on the leaves of Raphanus sativus were assessed under laboratory conditions. The data were used to calculate the various efficiencies of food utilization. The caloric value of the larvae was higher than that of the leaves of the host plant. Generally, the weight-specific food consumption, assimilation and tissue growth declined with the increase in biomass. Maximum food consumption and assimilation were exhibited by second instar larvae. The assimilation efficiency declined from the early to the last instar larvae, whereas the ecological and the tissue growth efficiencies increased up to the early stage of the fifth instar. Calculations indicate that larvae hatched from 68 eggs laid on an average by one female, with 33% mortality at each larval stage, would consume 132.10 kcal of leaves of host plant.