Department of Entomology, College of Agriculture, Orissa University of Agriculture & Technology, Bhubaneswar-751 003, Orissa (India).
*A part of approved Ph.D. thesis submitted by B.N. Mohanty to the Orissa University of Agriculture and Technology, Bhubaneswar, India.
The life-budget analysis of the rice hairy caterpillar, Nisaga simplex Walker, was studied in Kalahandi district of Orissa, India in 1989–90. The key mortality factors in each age-interval were identified and in the egg stage were infertility, parasitization and egg sterility due to high temperature. The hymenopterous parasitoid, viz., Anastatus sp. and Telenomus sp. together accounted for 25.5 per cent parasitisation of eggs. The effect of rain, water current, intra-colonial competition and displacement from food plants, starvation, and predation by ants on field bunds were the major mortality factors in the first and second instar larvae. In the late instars, mortality was caused due to the attack of a tachinid parasitoid (Palexorista sp.) and infection by muscardine fungi (Beauveria sp.). In the pupal stage, arthropod predation and desiccation were the chief causes of mortality, whereas reptile and avian predation was in the adult stage. K-factor analysis revealed that the highest mortality occurred in the larval stage (54.52%) followed by that in pupal (25.65%), egg (14.87), adult (3.18%) and pre-pupal stage (1.78%) considering total mortality as 100% in one generation.
