Updated: Jun 11, 2021
The silkworm is commonly known due to the silk fabric that is created from them. That said, not many people know that silkworms are just the larval form of a moth. But what more can we find out about them? And how is silk itself harvested?
Physical Description and Behavior
Silkworms can grow to be up to 4 cm long, including a spikey tail. They are off-white with brown markings, turning yellow soon before they start weaving their cocoons. After hatching from their pupae, they are moths that are off-white and fuzzy with a wingspan of about 4 cm.
Fun fact: Female silk moths lay very small eggs, weighing just 1/30,000ths of an ounce each. After laying upwards of 300 eggs at once, the female then dies.
Silkworms have been bred and harvested due to their silk in China for at least 5000 years, a practice referred to as sericulture. This practice later spread out to India, Japan, Nepal, and more through the Silk Road. But how do you get silk from a silkworm?
Well, the silkworm hatches from an egg after 14 days and starts to eat ferociously. They mainly consume white mulberry leaves but will consume the leaves of other species of mulberry as well. After growing for 6 weeks, they are then ready to spin their cocoon, which is made from a single thin fiber ten times thinner than that of a human hair.
While in the cocoon, their own digestive juices kill off parts of their body, known as histolysis, to make room for the metamorphosis. Two weeks after being in a cocoon, they come out in the form of a moth. However, if they are bred for silk, this stage never happens.
After they get into the cocoon, they are then boiled alive to kill off the worm. The silk thread is then captured and unraveled to retrieve the silk. Many people consider this to be an inhumane act due to evidence that silkworms can feel pain, as well as the fact that silk is not needed in modern times.
Habitat and Location
The silkworm can be found in many parts of the world due to them being used for their silk, as well as being used for teaching purposes in schools around the world. They are found in the US, China, Japan, Southern Australia, South Africa, and Europe. In some cultures they are even seen as cuisine, being consumed in Japan, Thailand, Vietnam, and Korea.
Originally, they existed only around Asia. However, it is unlikely that any wild silkworms survive to this day.
Click on the video below to see the lifecycle of this insect