A double cocoon is spun by two worms, producing a filament, which does not unwind smoothly and tangles easily. As these cannot be reeled along with normal cocoons, double cocoons are used for manufacture of a coarse, non-uniform, stubby yarn called "doupion".
Double cocoons may be caused by crowded mounting conditions, high temperatures, high humidity and mutation of silk species.
Double cocoons may be caused by crowded mounting conditions, high temperatures, high humidity and mutation of silk species.