Researchers have recently discovered that silkworms and silk spiders inhale carbon dioxide, which they use to produce silk when spinning cocoons and webs.
This marks the first proof that some insects and animals are capable of absorbing carbon dioxide. Until this discovery, it had been held that only plants and some bacteria microorganisms had this ability.
"Silkworms also use carbon dioxide in making nymphs and eggs," said researcher Jun Magoshi. "It is possible that animals that do not produce silk also absorb carbon dioxide."
The carbon dioxide used by silkworms constitutes 0.065 percent of the threads produced, members of the research group said.
According to the group's calculations, about 58.5 tons of carbon dioxide are absorbed for the annual amount of silk produced worldwide.
In experiments on four kinds of silkworms and silk spiders, carbon isotopes were found in the amino acid and aspartic acid that form the threads.
They confirmed that carbon dioxide was being used in this process.
Researchers from the National Institute of Agrobiological Sciences and the Japan Science and Technology Corp., both of which are government-affiliated bodies, took part in the project.