Extraction of Natural Silk Fibre from Cocoons of Argema mimosae (Lepidoptera: Saturniidae)

Abstract

Abstract:In recent years, numerous actions for sustainable exploitation of forest resources have been undertaken, but few deal with commercialization of forest insects. Several tree based insect products, like wild silk, can be linked with forest conservation activities to provide livelihood services of different economic scales to forest dependent people. African wild silkmoth, Argema mimosae Boisduval, is one of the forest insects, a moth in the family of Saturniidae producing wild silk, but there is need for definite procedures for extracting silk fibre from its cocoons. This study evaluated physical characteristics of the A. mimosae cocoons and outlined a procedure to extract viable silk fibre for use in silk industry. Cocoons of the A. mimosae were collected from natural forest of Arabuko-Sokoke, Kenya (3°20′ S, 39°55′ E), and others obtained by semi-captive rearing of the silkmoth larvae. The cocoons of A. mimosae were described to be silvery in colour, tough and thick with distinctive perforations on the surface and a prominent valve-like opening with loose filaments at one end. The study recorded 120 min as the optimum boiling time for the cocoons to yield silvery brown silk floss using sodium carbonate (Na 2 CO 3 ) as the degumming agent. Cocoons boiled in distilled water could not be deflossed into floss, but remained hard and intact, as compared with those of the control, Bombyx mori. This reveals that A. mimosae cocoons can be processed for natural silk fibre production and offer communities adjacent to forests an excellent opportunity to engage in production of natural wild silk.