Caterpillars of the silk moth, Bombyx mori, are the most common species used for silk production. Thousands of years of selection have created an insect that can efficiently produce silk. However, all caterpillars produce silk and some other species are used for commercial silk production. Madagascar independently developed its own silk production using several species of moth but most commonly Borocera cajani. This moth is widespread and abundant in Madagascar. Males are white and females brown (photo left). The caterpillars are polyphagous and feed on many plant species. The moth is numerous in the U. bojeri (Tapia) forest that consists of primarily one species, the Tapia tree, a food for the caterpillars.
Perhaps 10,000 families in Madagascar participate in silk production which is a major addition to their income. Silk production has trended downward for several decades. Increase in population and deforestation have eliminated silk production from some areas of Madagascar and reduced the numbers of caterpillars that can be produced. Efforts at reforestation and removal of invasive tree species could boost silk production.
Borocera cajani has urticating hairs that adds to the challenge of rearing them. Processing silk from the cocoons is more complex and time consuming than silk production from Bombxy mori cocoons. Borocera cajani is more expensive than commercial silk but it is prized for its unique qualities. The silk is used in burial rituals which is a source of demand.
Borocera cajani is in the family Lasiocampidae, the same family as the invasive pest in North America, the gyspy moth. Gypsy moth was imported into the US as a potential silk producer, perhaps based on silk production from Madagascar. Unlike its Madagascar relatives, gypsy moth was not suited to silk production.
*BASE Tsiresy M. Razafimanantsoa, Gabrielle Rajoelison, Bruno Ramamonjisoa, Noromalala Raminosoa, Marc Poncelet, Jan Bogaert, Éric Haubruge & François J. Verheggen. Silk moths in Madagascar: A review of the biology, uses, and challenges related to Borocera cajani. Accueil volume 16 (2012) numéro 2.