Standardization of rearing protocol for sustainable Eri Silk production in India: A focus on Ricinus communis and Ailanthus grandis through age-stage, two-sex life table approach

Aim: To standardize the rearing protocol for the Eri silk worm, Samia ricini (Donovan) (Lepidoptera: Saturniidae) by studying its life history traits. Methodology: Fifty newly hatched larvae of S. ricini from disease-free layings were reared on leaves from four different host plants under controlled laboratory conditions. Observations were made on their developmental and reproductive traits. The life table parameters were constructed using the age-stage, two-sex life table method, and the analysis was conducted using the TWOSEX-MS Chart software. Results: Highest fecundity was recorded on castor (350.16 eggs/ female), followed by borpat, Ailanthus grandis Baiu (Simaroubaceae) (315.16eggs/ female). The intrinsic rate of increase was higher on castor (0.10 female/females/day), followed by borpat (0.098/ female/females/day). Similarly, the net reproductive rate is highest on castor (128.34 female/females/generation), followed by borpat (125.14/ female/females/day). The population doubles for every 6.92 days on castor and 7.26 days on kesseru, H. fragrans Roxb (Araliaceae). The fresh cocoon yield of 100 disease free laying’s larvae was highest on the castor, i.e., 78 kg, while it was 74.75 kg on the borpat. Interpretation: This study suggests that using castor and borpat host plants, either alone or in combination, benefits Eri culture. For combination feeding, castor can be used up to the chawki stage, with borpat for later stages. This method could lower production costs compared to solely using castor, which needs annual replanting, especially in North-east India, where farmers grow host plants only for ericulture. Key words: Ailanthus grandis, Castor, Demographic parameters, Eri silkworm, Kesseru, Ricinus communis, Tapioca