Rajanee Mishra • 538 Reads
Silkworm: Silkworm forms a quality of fibre called silk. From the business point of view, mainly 2 kinds of silkworms are found in Nepal. They are:1. Eri silkworm (Attacus recinii) feeds on castor leaves2. Siri silkworm (Bombyx mori) feeds on mulberry leavesClassification: Kingdom: Animalia Sub-Kingdom: ...
The rearing of silk moths in order to obtain silk fibers for commercial purpose is called sericulture. Silkworm is considered as a useful insects because it produces valuable silk fiber that is extracted from cocoon and used to make comfortable silk clothes, saris, shirts, t-shirts, etc.
The name of common species of silkworms found in Nepal are:
- Seri silkworm
- Eri Silkworm
What is the food of a Seri silkworm? Name the stage of the lifecycle when the silkworm produces silk thread?
Seri silkworm eats the leaves of mulberry as its food.
In pupal stage of its lifecycle it produces silk thread of about 1500 m length.
We all know that, the leaves of mulberry are not available during winter. If available also, the silkworm cannot survive there because of coldness. And the egg of Silkworm only hatches once it get temperature of 18°C to 25°C. So, it can be stored for the desired time below 18°c. As a result, to grow the silkworm in favorable season, it kept below 18°c during winter.
The features of artificial silk are:
- It & not shiny, light and durable as natural.
Eri silkworm is the species of Silkworm that feeds on castor leaves.
a. Larva of silk moth and larva of honey bee.
|Larva of silk moth||Larva of honey bee|
|It hatches within 11 days.||It hatches within 3 days.|
|It is found on mulberry leaves.||It is found in hexagonal wax cell.|
|They search and take food themselves.||They are fee by the workers bee.|
|They have dorsal horn.||They don't have dorsal horn.|
A cocoon is the spherical cover of the pupa of a silkworm inside which pupa remains passive.
When larva is fully grown up, I develops a pair of salivary glands which secretes liquid silk. On emerging, the liquid silk hardens and forms a silk fibers. The silk fibers to wrap around the body of the caterpillar to form a cocoon. In this way, cocoon is produced.
For obtaining silk, the cocoon are treated with the hot water or placed in a hot oven to kill the pupae inside the cocoon. Because it helps to produce thread easily without breaking. Otherwise if we allowed to hatch, they would cut the silk thread on emerging that makes the hard or unwinding easy without break. In this way, silk is extracted from the cocoon.
The Importance of mulberry plants in sericulture are:
- It is need for the completion of Lifecyle of silkworm.
- It is needed for laying eggs for silk moth.
- The larvae eats a lot of mulberry leaves for growing up.
The pupa are killed inside the cocoon during extraction of the silk thread because:
- If we allowed them to hatch them they would cut the silk thread on emerging.
- It make enable to hard sericin portion to get softened.
a. Pupa and cocoon.
b. Pupa of silkworm and pupa of honey bee.
c. Natural silk and artificial silk.
a. Pupa and cocoon.
|It is the third stage of lifecycle.||It is the spherical cover of pupa of silk moth.|
|It is found inside cocoon.||It covers pupa.|
|It is living beings.||It doesn't have life.|
|It remains passive inside cocoon.||It protects the pupa from external dangers.|
|Pupa of silk moth||Pupa of honey bee|
|It is found inside cocoon.||It is found inside hexagonal wax cells.|
|This stage last for (12-14) days.||This stage last for 9 days.|
c. Natural silk and artificial silk.
|Natural silk||Artificial silk|
|It is very shiny, light and durable.||It is not shiny as natural silk.|
|It is long-lasting and elastic.||It is not long-lasting and elastic.|
|It absorbs water readily and dries fast.||It absorbs water fast and dry slowly.|
Which stage of life cycle of a silk moth will be affected immediately if mulberry plants die suddenly die?
Larva stage of the life cycle of a silk moth will be affected immediately if mulberry plants die suddenly because the larva is voracious feeder and feeding on mulberry leaves for long time as their food is clean and dry mulberry leaves.
We know that, the eggs of silk moth hatches to larva at 18°C to 25°C. After the larvae fully developed by the completion of different stages, it develops a pair of salivary gland which secretes liquid silk. The liquid silk hardens and form a cocoon. The cocoon is treated with hot water to kill the pupae inside. After this, the silk thread is extracted nearly about 1000 to 1500 m by a single cocoon.
The economic importance of sericulture are:
- It can be exported to increase the economy status of farmers.
- Employment opportunities for women.
- It can be practiced with very low hand holding.
- All things used in sericulture con be sold.
- Sericulture gets effective market.
Three precautions to be taken during sericulture are:
- The eggs should be stored below the temp 18°C for long term.
- Clean and dry mulberry leaves should be fed to larvae.
- A few cocoon of good quality should be kept as seed.
Honey bees are social organisms which live in colonies where all the individuals are of same family.
Following are the importance of honey bee:
- It produce honey which is protein rich diet.
- It is used for making medicines, healing wounds.
- It helps in pollination while collecting nectar.
- They help in environment balance.
The different stages of life cycle of honey bee are as below:
The bodies of honey bee is divided into the head, thorax and abdomen. The thorax consists of 3 pairs of jointed legs and a pair of wings. The head consists of a pair of antenna, a pair of compound eyes, and mouth parts. The mouthparts consist of a tongue or labium which can be enclosed near the head by the labial palps and maxillae. Nectar can be drawn up the grooved surface of the labium is the head. The abdomen elongated and segmented.
Honey bees are social insects which live in colonies where all the individuals are of same family. They are division of labor in which individuals carry out particular duties. They produce honey. They live in discipline and their life is very busy.
|They are workless.||They are very busy in working.|
|They don't have poison gland.||They have poison gland.|
|Their function is to fertilize new queen.||Their work is to collect nectar and feed to larva and queen.|
|They are male bees.||They are female bees.|
The division of labor in the honey bee are:
a. Queen bee
- To lay eggs
- To control and guide the colony by releasing special order.
b. Drone bee.
- To fertilize the queen.
- To keep the hive warm.
c. Workers bee.
- To be busy in outdoor works.
- To clean the cell.
- To build honey comb using wax.
The drones bee are the male bees smaller than queen and larger than the worker bee with black and hairy body.
Workers are the smallest bees in the colony which be busy on collecting the nectar and storing it.
The wax combs are built hanging vertically with a gap of about half an inch separating each one. Workers prepare the cells according to their size. For worker cells are about 5 mm across and drone cells are about 6 mm across. The egg is laid to each cell by queen and the lite life cycle of bee is completed inside cell up to pupa. In this way, they are produced.
The process of leaving the old hive in a swarm by old queen and some of the workers usually in spring or summer where the nectar flow at its greatest is called swarming.
The advantages of honey bees are:
- They produce honey which is protein rich diet.
- They are used for making medicines, healing wounds.
- They help in pollination while collecting nectars.
- They help in eco-balance.
There is only one queen found in colony. They are larger than drones and workers. The abdomen of queen is large and slender. The head is smaller and proboscis is shorter. The queen has special smell in its body. All the worker and drones identify their colony on the basis of the smell of the queen.
Yes, honey bees are very important insects for human beings. It produces honey, which is high in protein. The honey produced by it also can be used for making medicines. Also, these bees helps in pollination of the different plants & crops. They also play equal role to balance the environment. So, these insects are very important for us.