the majority of self-secreted materials are produced by insects and selection acts on this characteristic of production of self-secreting materials and increases the fitness of the animal. in some cases, the self-secreted material is directly applied, as in the case of ecribellate silk, spun by ecribellate spiders, to form sticky traps for prey, or it may be processed, as in the case of salivary excretion used for creation of paper by paper wasps, by blending it directly with wood pulp. self-secreted materials may be processed in some cases. in cribellate spiders, silk produced by the spider are reworked in the cribellum to form fine sticky strands used for capturing prey. in other cases, the scale wax, produced on the bodies of honey bees, is gathered and blended with saliva, to form comb wax, the building material. not all self-secreted materials are developed specifically for that purpose. for example, bird feathers are used for lining and insulation, a typical example being that of the female common eider duck ("somateria mollissima"), which produces down feathers for lining its nest.