Influence of temperature on food consumption and utilization parameters of the common cutworm, Spodoptera litura (Fab.) (Lepidoptera: Noctuidae)

Abstract

Laboratory experiments were conducted to assess the influence of controlled temperature regimes (20, 25 and 30 oC) on the nutritional parameters of different host plants (castor, cabbage and tomato) by the last larval instar of Spodoptera litura (Fab.) on dry weight basis. The results of the present study indicated that the temperature (30 °C) was favourable for the food consumption and utilization of castor, cabbage and tomato by the 6th instar S. litura larva. The pattern of the nutritional indices on the three host plants at 30 oC revealed high feeding and food assimilation activities as characterized by significantly higher values for relative consumption rate (RCR), relative growth rate index (RGR), the efficiency of conversion of ingested food (ECI) and digested food (ECD). The values of larval approximate digestibility (AD) on the three host plants were significantly higher at 2 5oC and least at 30oC. The reduced food consumption and utilization by 6th instar S. litura at 20 oC was evidenced by the low feeding activity as well as the relatively reduced capacity to assimilate the food materials.