Relative density of Neurostrota gunniella larvae in branches of giant sensitive plant, Mimosa pigra at the edge and interior of thickets was estimated by measuring characteristic feeding damage. the proportion of branches attacked by N. gunniella was high throughout and indistinguishable by location in the thicket. However, edge branches were more heavily damaged by larvae than branches in the interior, in both wet and dry seasons. Edge branches also had more leaves and leaflets at the end of the dry season, but not at the end of the wet season. Implications for biological control of M. pigra are discussed.