New York Science Journal 2015;8(8) http://www.sciencepub.net/newyork 92 Consumption and Utilization of Food by Different Instars of Oak Tasar worm Antheraea proylei (jolly) Fed on Quercus serreta (Thunb) Leaves Pashupati Nath 1 and P.C. Joshi 2 1, 2 Dept. of Zoology & Environmental Science, Gurukula Kangri Vishwavidyalaya, Haridwar, 7398864034 1 , 9837062992 2 1 nathpashupati53@gmail.com , 2 prakash127@yahoo.com Abstract: During this study the ecological efficiencies of Antheraea proylei (Jolly) was studied in the laboratory. Total duration of instar stages is 4.80±0.418, 4.00±Nil, 4.80±0.418, 8.00±Nil, 11.46±1.12 days for 1st, 2 nd , 3 rd , 4 th and 5 th larval instars, respectively. The food consumption was 0.612±0.33, 1.05±0.155, 1.405±0.2383.212±0.789and 5.923±1.38 g insect -1 day -1 in 1 st , 2 nd , 3 rd , 4 th and 5 th larval instars, respectively. In all five stages leaf assimilation was 0.600±0.33, 1.03±0.154 1.329±0.2270, 2.88±0.800, and 5.066±1.26 g insect -1 day -1 , respectively. The tissue growth was 0.0112±0.002, 0.053±0.072, 0.213±0.068, 0.359±0.21 and 0.536±0.20 g insect -1 day -1 in all respective stages. The maximum value (97.518±0.476) of approximate digestibility was recorded for 2 nd instar larvae, while the minimum value (85.726±0.286) was recorded for fifth instar larvae. The value of ECD was minimum (1.899±0.99) in 1 st instar and maximum (16.126±1.320) for 3 rd instar larvae. The minimum value (1.863±0.97) of ECI was recorded in 1 st instar larvae, while maximum value (15.243±1.09) was recorded in 3 rd instar larvae. [Pashupati Nath and P.C. Joshi. Consumption and Utilization of Food by Different Instars of Oak Tasar worm Antheraea proylei (jolly) Fed on Quercus serreta (Thunb) Leaves. N Y Sci J 2015;8(8):93-97]. (ISSN: 1554- 0200). http://www.sciencepub.net/newyork . 14 Keywords: Antheraea proylei; Q. serreta, Consumption; Approximate digestibility; Conversion of ingested food; Conversion of digested food. Introduction Order Lepidoptera is the most diverse and large group of insects and includes butterflies and moths. It is among the most successful groups of insects and inhabits all terrestrial habitats (viz desert to rainforest, lowland grasslands, montane plateaus).These insects are associated with higher plants or flowering plants (Gullan and Cranston 2004). Some species of Lepidoptera damage plants, which are useful to humans, like fruit trees, crops, fabrics, fodder, and timber. The larval stages of many species of moths are very injurious, and damage the leaves, stems, roots, or fruits. Many species of this order are valuable in biological research, including work in physiology, systematics, ecology, biogeography and genetics. Many factors like quantity and quality of food, various climatic conditions and presence of predators, parasites and disease can be regarded as the index of the physiological potential of life performance of the insect (Slansky and Scriber 1985). The vital physiological activities viz. metabolism, enzyme synthesis, nutrient storage etc. are influenced by consumption and efficiency of utilization of consumed food. Studies on ecological energetics and feeding potential of different insects have been carried out by many workers (Slansky and Scriber 1985; Kaushal et al. 1988; Kaushal and Joshi 1991; Joshi et al. 2003; Sharma and Joshi 2010,Sudhansu 2010). Tasar, the commercial silk is produced by a variety of species of Antheraea. In the present study, energy budget of Antheraea proylei has been studied using its natural food plant, Quercus serreta (Thunb). Materials And Methodology The eggs of Antheraea proylei were collected from Regional Tassar Research Station, Bhimtal and placed in different petridishes, covered with plastic sieves of 12 meshes/cm to maintain a stock culture in the laboratory. These were kept at a room tempetrature of 20-25 0 C and a relative humidity of 60- 65%. On emergence, the larvae were transferred to the food plants. Ecological efficiency of 1st , 2 nd , 3 rd , 4 th and 5 th instar of oak tasar moth were determined. Larvae of this insect feed on leaves of oak plant Quercus serreta (Manipuri banjh). For removal of faecal matter from alimentary canal, actively feeding caterpillars were kept away from food source for about one hour before the start of the experiment. Before the start of experiment, each larva was weighed and kept in petri dish covered with plastic seives. After that larvae were allowed to feed on preweighed portion of oak leaves for 24 hrs, thereafter, the remaining portion of leaves and faeces were dried to a constant weight at 80 o C. A wet/dry mass ratio was determined for the leaves and the amount of leaves ingested by each larva was estimated. Food consumption was calculated as the difference between the initial weight of the leaves