Development and food consumption of some lepidopteran pests under increased temperature conditions

Abstract

Climate change has direct influence on the development and survival of herbivores in addition to indirect effects through trophic interactions. The present studies were carried out to observe the effect of increase in minimum temperature on development and food consumption of Helicoverpa armigera Hubner, Pieris brassicae Linnaeus and Spodoptera litura Fabricius. The mean food consumptionincreased by 12.78 and 32.64 per cent with increase in minimum temperature of 30C and 60C, respectively accompanied by decrease in larval duration by 10.37 and 27.97 per cent. Similarly, observations on P. brassicae larvae at four temperature ranges indicated that the mean food consumption increased by 4.87 with rise in minimum temperature by 30C accompanied by faster development. Likewise, effect of temperature ranges viz. 21°C: 7°C and 21°C: 10°C for 16: 8 hrs on biology of S. litura was estimated. The observations revealed faster growth when the mean minimum temperature was raised from 7 to 10°C. The rise in minimum temperature by 3°C resulted in decrease in larval and pupal duration by 5.36 and 10.43 per cent, respectively. The survival per cent was also increased by 1.44 per cent when rise in minimum temperature by 3°C.