Impact of temperature on food consumption and nutritional indices of tomato fruit borer, Helicoverpa armigera (Hübner) (Noctuidae: Lepidoptera)

Abstract

Rising temperatures under changing climatic conditions results in the increase in food intake by the insect pests. The present studies on effect of different alternating temperatures on food consumption and nutritional indices of Helicoverpa armigera (Hübner) on tomato crop were conducted during 2013-14. The total food consumption by H. armigera larvae during total (third to fifth instar) larval duration increased from 2.457±0.048 g/larvae at 25:10oC to 3.545±0.021 g/larva at 30:16oC. This suggests that with increase in temperature there is increase in food consumption by H. armigera larvae. The share of food consumption by fifth instar larvae was e” 80 per cent of total food consumption by H. armigera larvae in all the treatments.Nutritional indices for total larval duration of H. armigera such as consumption Index (CI) rose from 0.929±0.020 at 25:10oC to 1.495±0.014 at 30:16oC, The relative growth rate (RGR) of total larval period varied from 0.139±0.002 at 25:10oC to 0.174±0.003 at 30:10oC. The rise in alternating temperature from 25:10oC to 30:10oC resulted in increased RGR of H. armigera larvae.