1. Study of some economically important insects.
Honey bee
Systemic position
Kingdom: Animalia
Phylum: Arthrpoda
Class: Insecta
Order: Hymenoptera
Family: Apidae
Genus: Apis
Habit and habitat:
The honey bees are social insects which live in large colonies. original habitats of the honey bee are tropical
climates and heavily forested areas. They can survive in natural or domesticated environments though they
prefer to live in gardens where flowering plants are abundant. The commercial rearing of honey bee is called
Apiculture.
Morphological structure
The honey bees are trimorphic as they are found in three different forms in a colony namely queen, drones and
workers.
5. The life cycle of silkworm consists of four stages viz, egg, larvae , pupa and adult.
Egg: Female silkworm lays eggs on the mulberry leaves around 300 at a time and dies. The eggs are very small
in size and stay idle in cold temperature. As soon as the temperature reaches 18-25 degree Celsius, the larvae
are hatched. Larva is developed in around 10- 12 days.
larvae: It is the most active and feeding age of the silkworm. It feeds a lot of mulberry leaves and walks a lot
during the feeding. It secrets saliva and changes its skin four times staying stationary and do not eat anything for
24 hours which is called instar. Larva stage lasts for a month. At the last stage of instar, it rolls itself into the
jelly secreted itself to form a silk rolled pupa-cocoon.
Pupa: It is the most inactive stage of the silkworm. It lasts for 12-14 days. It is called cocoon which is ready for
silk to be obtained. This is the stage where we take the silk from the silkworm by immersing them into hot
water by killing the pupa inside the cocoon. Some of the pupa are left alive for the reproduction further.
Adult: After the maturity of pupa, the cocoon is immersed into hot water and the silk is obtained. Some of the
pupa are left alive for the reproduction of silkworm. The adult lives for about 6-7 days. The life cycle is
completed in around 45 days.
Economic importance of silkworm
1. It is used for making clothes, curtains etc.
2. Surgical strings, fishing strings, insulation coil of telephone can be made from silk.
3. The dead pupae while extracting silk is highly nutritious and can be feed to livestock.
4. Silk clothes are lighter in weight and warmer than other clothes.
Notes compiled by: Bharat Pangeni
