Page 32 - The Book of Caterpillars: A Life-Size Guide to Six Hundred Species From Around the World

CATERPILLARS AND PEOPLE

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above left Thousands CATERPILLARS AS SILK-PRODUCERS
of white cocoons
formed by Mulberry Sericulture, the farming of the Mulberry Silkworm (Bombyx mori) species
Silkworms (Bombyx
mori) are collected for its silk, has been practiced in China for more than 5,000 years and in
and treated so that
the precious silk Europe from around 550 ce, when legend has it the first silkworm eggs
produced by their
salivary glands— were smuggled by monks into Constantinople. Originally transported
a long, continous
filament enclosing along the Silk Roads , which connected East and West, silk was for centuries
each pupa—can
be unwound. the most luxurious fabric available—beautiful but practical, lightweight
above right Before the yet strong, cool in hot weather, and with excellent dyeing properties.
silk can be spun, the
cocoons are briefly At the start of the silk-making process, the larvae are fed mulberry
steamed or boiled
to soften the natural leaves and develop through each instar until they spin their silken cocoons.
gum also secreted by
the silkworm to bind Each cocoon is made up of a continuous filament up to 4,000 ft (1,200 m)
its silk together. In the long, composed of fibroin protein, held together with a gummy fluid called
traditional process,
the pupae perish. sericin. To soften the gum, the cocoons are treated with hot air, steam,
A new, though more
expensive, technique or boiling water, then several cocoons are carefully unwound
allows the silkmoth
to eclose before its simultaneously to create a single strand of raw silk. It takes as many as
cocoon is used.
2,500 silkworm cocoons to produce just 1 lb (around 450 g) of silk.
Significant “wild” silk production is also obtained from the Chinese Tussah

Silkmoth (Antheraea pernyi) and the Suraka Silkmoth (Antherina suraka).
A more esoteric use of silk is the lost art of cobweb painting that
originated in the sixteenth century. The intricate process involved
collecting caterpillar or spider silk, layering it over a frame, then painting

it with a fine-tipped, woodcock feather brush. The transparent effect of
the webbing gave the images an ethereal glow. For its elasticity and tensile
strength, artists in the Tyrolean Alps favored webbing produced by
Yponomeuta evonymellus larvae. A fine, 200-year-old Tyrolean cobweb
painting of the Virgin Mary can be seen at Chester Cathedral in England.