INFLUENCE OF TEMPERATURE&RELATIVE HUMIDITY ON THE SURVIVAL OF Daphnis nerii (LEPIDOPTERA: SPHINGIDIAE) AND ITS FOOD EFFICACY ON HOST PLANTIN ARID AND SEMI-ARID REGION.

Arid region is characterized by high temperature and high evaporative demand that has made survival of insects difficult. The lepidopterous fauna of India with particular reference to arid and semi-arid region is relatively diverse and has received a very little attention by the scientists. The knowledge of food efficacy oflepidoperous species in a particular ecosystem, pertaining to their life-stages and effect of abiotic factors, is essentially required for their effective conservation. Lepidoptera normally feed on horticultural plants. The Daphnis nerii is a lepidopterous moth usually found on the host plant Nerium oleander. They defoliate the leaves,leaving veins and veinlets. An experiment has been laid down in the lab as well as in field condition, whereNerium leaves were provided to starving fifth instarslarvae of D. nerii and the food efficacywere evaluated. The coefficient of digestibility (C.D.), the efficiency of conversion of ingested food to the body weight (E.C.I.) and the efficiency of conversion of digested food (E.C.D.) of D. neriilarvae, fed on the leaves of Nerium oleander were recorded as 80.43%, 13.21%, 15.01% respectively. The Nerium oleander is found as a most suitable host plant for the rearing of D. nerii .There are 4 to 5 overlapping generations in a year. There are fiveinstar larvae. The incubation period is about 25 to 28 days. The pupal periodlasts for 20 days. The influence of abiotic factor like temperature and relative humidity on the survival of D. neriihas been studied. The most suitable period for D. nerii is from August to October with temperature ranges from 25oto 30oC and relative humidity ranges from 55 to 60 %.