Question

The larva which is the hatch from eggs of the silk moth is called:
(a) Caterpillar
(b) Silkworm
(c) Both A and B
(d) Butterfly

Answer 1

Hint:  In this stage, the larvae of silk moths are called ‘eating machines’. They are nocturnal (i.e.,) they hide in the plant base during the day and will feed only during the night time.

Complete answer:
Caterpillar/silkworm is the larval stage of the silk moth. 
There are 4 stages of development for the egg to develop into the silk moth. They are the egg stage, the larvae stage, the pupa stage, and the adult stage.
- Egg stage: The female moth will lay the eggs near the plant region. The embryo formation occurs inside the egg for over 30 days. The larvae develop within the egg and it will grow for 7 to 10 days. When there is appropriate temperature, humidity, and other environmental conditions, the larvae will develop into the caterpillar embryo.
- The larvae stage (caterpillar): The caterpillar will feed on the shell to obtain proteins. After this, they will feed on the plants and this is one of the reasons behind the female silk moth laying the eggs in the plant area.  The caterpillar will undergo molting and shedding of their skin to develop into an adult.  Both molting and shedding seem to be a similar process. But, Molting is the process by which the animals cast off their body part to grow into the adult whereas shedding is the process by which the animals will prepare its skin for the seasonal changes. Here, the caterpillar will feed on its cuticle that will remain after the molting process. The feeding as well as the molting process will happen until the caterpillar reaches the pupa stage.
- Pupa stage:  The caterpillar produces a protein that will produce a type of silk. The caterpillar will now spin a layer of silk around its shell. This stage is called the cocoon. The tissues of these organisms will be broken down and this process is called histolysis. In the pupa stage, the moth will not eat and is static (i.e., it does not move). Two weeks later, the caterpillar will develop wings and will come out of the cocoon. This is called the moth. 
- Adult stage: The pupa later gets converted to the adult moth. The female moth lays eggs after mating and the life cycle starts again.
So, the correct answer is ‘Both a and b’.

Note:  The cultivation of silkworms to produce silk is called sericulture. There are different types of silkworm species that are available to make silk but the most widely used is the Bombyx mori which is the caterpillar stage of the domestic silk moth. Furthermore, India and China are accountable for nearly 60% of the world’s annual silk production.