Study of phenotypic variability in silk gland characters in three ecoraces of tropical tasar silkworm Antheraea mylitta Drury

Abstract

The wild silkworm, tropical tasar Antheraea mylitta Drury being mainly culturing in central and eastern parts of India and produces famous tasar silk. This insect species expresses divergent phenotypic characters in response to varying ecological and climatic conditions thus exists as ecoraces. Hence, in the present study, three ecoraces viz., Daba, Sukinda (Semi-domesticated) and Sarihan (wild) have been selected for the assessment of the variability in silk gland related traits. The parameters of the silk glands studied like comparative length, weight and silk gland to larval body mass index. Besides, some biochemical contents of the silk gland tissue were also studied in three ecoraces. The results showed significant variations at p<5% in all the parameters among the three ecoraces studied, also showed the sexual dimorphism in expression of silk gland features and economic traits. The semi-domesticated Dab a ecorace showed higher performance in most of the parameters with comparatively greater in silk gland weight (22%) and in body mass index (>16%). Apart from this, wild ecorace Sarihan cocoons showed higher shell ratio (>10% over the value of other ecoraces). The study infers that, there is wide variability in the expression of phenotype with respect to silk gland related traits among the different ecoraces of tropical tasar silkworm A. mylitta. Since the silk glands are site of biosynthesis of silk proteins, these may be considered for the assessment of diversity or characterization of different ecoraces of tropical tasar silkworm. © 2012 Academic Journals Inc.