BBC Focus

EYE OPENER

The very

hungry

caterpillars

HUANJIANG MAONAN, GUANGXI,

CHINA

These silkworms are chowing
down on their favourite food –
mulberry leaves. After about a
month of voracious feeding, the
fast maturing caterpillars begin
to spin a silken cocoon made
from proteins found in their
saliva in preparation for their
metamorphosis into silk moths.
“A molecular marvel, the
protein fibroin has a high tensile
strength and a toughness that
makes commercially produced
silk an incredibly useful and
valuable material,” explains
entomologist and BBC presenter
Adam Hart. “Another protein,
sericin, coats the fibroin and
allows it to stick together, forming
thicker and stronger fibres.”
To loosen the silk to prepare it
for being fed onto a spinning
wheel and woven into fabric, the
cocoons are thrown into boiling
water or pierced with a needle. In
China, sericulture, the rearing of
silkworms for the production of
silk, is big business. In 2015, the
industry produced 170,
tonnes of fabric, which is nearly
six times the output of India, its
closest competitor.

PHOTO: EYEVINE