Silkworm Biodiversity, Conservation, Threats, and Sustainable Utilization in Indian Subcontinent

Abstract

Biodiversity has been recognized as the most important component of natural resources for providing sustainable livelihood, health, and nutritional security. India is the only country where all the five commercially raised silkworms—Bombyx mori, Antheraea myllitta, Antheraea royli, Antheraea perni, Antheraea assama, and Philosomia ricini—are found. Of these, Antheraea assama is endemic to India and produces the much-valued golden silk. Rich food plant flora distributed in the majority of the Indian states support all types of silkworms year-round. For the mori silkworm (Bombyx mori), there are three geographical races—univoltine, bivoltine, and multivoltine—whereas, the tasar silkworm has three distinct species—Antheraea mylitta, Antheraea perni, and Antheraea royli, which are popularly known as tropical tasar and are have both wild and domesticated populations. Antheraea assama is popularly known as the muga silk and confined only to Northeastern and Central Himalayan region. Antheraea assama has both wild and domesticated populations. Philosomia ricini, popularly known as the eri silkworm is totally domesticated and very common in the tribal regions of Northeastern Indian states. Due to continuous selective pressures over several thousands of years, a large amount of variability has been created in all stages of the life cycle (egg, larva, pupa, and moth). Further, several landraces, especially in tasar and muga silkworms, have been identified and used in direct rearing and also for the purpose of hybridization. Natural variability and also the variability created by researchers in several sericulturally advanced countries are discussed in this paper. Besides, the germplasm maintained in different countries of the world, including varieties developed for commercial use to produce silk, is also discussed.Biodiversity has been recognized as the most important component of natural resources for providing sustainable livelihood, health, and nutritional security. India is the only country where all the five commercially raised silkworms—Bombyx mori, Antheraea myllitta, Antheraea royli, Antheraea perni, Antheraea assama, and Philosomia ricini—are found. Of these, Antheraea assama is endemic to India and produces the much-valued golden silk. Rich food plant flora distributed in the majority of the Indian states support all types of silkworms year-round. For the mori silkworm (Bombyx mori), there are three geographical races—univoltine, bivoltine, and multivoltine—whereas, the tasar silkworm has three distinct species—Antheraea mylitta, Antheraea perni, and Antheraea royli, which are popularly known as tropical tasar and are have both wild and domesticated populations. Antheraea assama is popularly known as the muga silk and confined only to Northeastern and Central Himalayan region. Antheraea assama has both wild and domesticated populations. Philosomia ricini, popularly known as the eri silkworm is totally domesticated and very common in the tribal regions of Northeastern Indian states. Due to continuous selective pressures over several thousands of years, a large amount of variability has been created in all stages of the life cycle (egg, larva, pupa, and moth). Further, several landraces, especially in tasar and muga silkworms, have been identified and used in direct rearing and also for the purpose of hybridization. Natural variability and also the variability created by researchers in several sericulturally advanced countries are discussed in this paper. Besides, the germplasm maintained in different countries of the world, including varieties developed for commercial use to produce silk, is also discussed.