Feeding biology and digestive enzymes of Buzura suppressaria Guen. and Eterusia magnifica Butl., two major defoliatingpests of Camellia sinensis from Darjeeling Plains, IndiaAbstract : The common looper caterpillar, Buzura suppressaria and the red slug caterpillar, Eterusia magnifica are serious defoliators of tea bushes (Camellia sinensis) of the Terai and Dooars areas of Darjeeling and N.E. India. While the former species prefers young leaves, the latter feeds on more mature leaves. This study aims to find the difference of the nutritional indices for the two folivores, such as relative consumption rate (RCR), relative growth rate (RGR), gross growth efficiency (ECI), net growth efficiency (ECD) and approximate digestibility (AD) and relate the same with their maintenance cost and production index (body mass). B. suppressaria has an edge over Et. magnifica as far as RCR and AD values are concerned. However, Et. magnifica could make up for the poor food quality (as they feed on mature tea leaves) by increasing their feeding period and better food conversion efficiencies. Higher value of AD in B. suppressaria may be due to higher quantity of the digestive enzymes in the midgut of this caterpillar. Significant differences in the activities of amylase, protease and lipase could be detected at salivary and midgut levels in the two folivores. The adaptive strategies in exploiting the different qualities of leaves, from two hampers of tea bushes is important for optimal food utilization by the two folivores with niche segregation.