Larval and cocoon characters of eri silkworm, Samia cynthia ricini boisduval (Lepidoptera: Saturnidae) as influenced by different hosts

Experiments were carried out during 2011–12 to study the larval and cocoon characters as influenced by five different hosts, viz. castor (Ricinus communis), kesseru (Heteropanax fragrans), barkesseru (Ailanthus excelsa), tapioca (Manihot esculenta) and gulanch (Plumeria rubra). The order of suitability of five host plants based on larval weight and cocoon weightwas castor> barkesseru> tapioca> kesseru> gulanch. Incase ofshellweight, the orderofsuitabilitywascastor > tapioca and kesseru > barkesseru > gulanch. Larval duration varied significantly between 21–26 days, it being lowest on castor and highest on gulanch. The length of silk gland of 5^th instar larvae followed a pattern: castor (12.73 cm) > kesseru(12.47 cm)> barkesseru(11.42 cm)> gulanch(10.47cm). Among different chemical constituentsof theselected hosts, castor exhibited higher amount of crude protein, crude fat, total soluble sugar and reducing sugar. This had contributed in enhancing cocoon and pupal weight of the eri silkworm compared to other host plants; it was followed by tapioca. Therefore, leaves of tapioca may serve as alternative feeds to tide over castor off-season, yet kesseru and barkesseru can also fill the void in extreme conditions.