Life Cycle
Life Stage 1 - Eggs:
The egg of the silk worm is generally oval shape and are laid batched of about 400-500 eggs. As silk worms no longer live in the wild the eggs can be laid on artificially placed mulberry leaves. Depending on the temperature and humidity of the area, the eggs hatch in approximately 9-11 days.
Life Stage 2 & 3 - Larvae & Pupae:
Once the larvae have hatched from the egg it is about 2 to 3 mm long. The larvae generally feed on mulberry leaves but have also been known to eat Osage orange and lettuce. Mulberry leaves are preferred as they contain a phagostimulant called flavonoid Morin which is specific to silk worm larvae. Mulberry leaves cause the cocoon of the silk worm to turn yellow and is the preferred food source due to this quality. One feature the larvae have is a posterior (caudal) horn. Over around 45 days the larvae grows to a size of 75mm where it eventually becomes a pupa. This means it is ready to spin its cocoon. The time it takes to spin its silk cocoon is around 48-72 hours. After 10 days it emerges from the cocoon as a moth.
Life Stage 4 - Adult:
Obvious physiological changes have occurred to the moth once it emerges. It not has prominent wings, antennae and compound eyes on their head, three pairs of thoracic legs and a non-functioning coiled proboscis. However it still lacks the colourings ad flight needed to survive independently in the wild. (Cabinera 2008).
The egg of the silk worm is generally oval shape and are laid batched of about 400-500 eggs. As silk worms no longer live in the wild the eggs can be laid on artificially placed mulberry leaves. Depending on the temperature and humidity of the area, the eggs hatch in approximately 9-11 days.
Life Stage 2 & 3 - Larvae & Pupae:
Once the larvae have hatched from the egg it is about 2 to 3 mm long. The larvae generally feed on mulberry leaves but have also been known to eat Osage orange and lettuce. Mulberry leaves are preferred as they contain a phagostimulant called flavonoid Morin which is specific to silk worm larvae. Mulberry leaves cause the cocoon of the silk worm to turn yellow and is the preferred food source due to this quality. One feature the larvae have is a posterior (caudal) horn. Over around 45 days the larvae grows to a size of 75mm where it eventually becomes a pupa. This means it is ready to spin its cocoon. The time it takes to spin its silk cocoon is around 48-72 hours. After 10 days it emerges from the cocoon as a moth.
Life Stage 4 - Adult:
Obvious physiological changes have occurred to the moth once it emerges. It not has prominent wings, antennae and compound eyes on their head, three pairs of thoracic legs and a non-functioning coiled proboscis. However it still lacks the colourings ad flight needed to survive independently in the wild. (Cabinera 2008).
How Silk is Created
One key feature of the silk worm is the silk gland. The silk gland is developed through a single cell type that is formed from a process called polyploidization (wang et al. 2009). The silk gland is a gland that produces silk fibrin. After 3-4 days of the larvae hatching once DNA synthesis in those cells has stopped, the gland dismisses any other proteins being made and focuses solely on the synthesis of silk fibrin (Cathrin et al. 2011). However, as well as silk, antimicrobial and flavonoid proteins are also made. These are used for defence as whilst the worm is inside the cocoon it is not mobile and thus susceptible to attack. However it has also been found that flavonoids play a role in defence of the cocoon by protecting against microbes and degradation by UV light (Cathrin et al. 2011). The silk worms cocoon is spun from a continuous strand of silk; this is why it is so easy to harvest (Cabinera 2008).