Final answer:
The larva of a silk moth is known as a voracious eater due to its need to consume significant amounts of food, specifically mulberry leaves, to fuel its rapid growth during the larval stage. Option D is correct answer.
Step-by-step explanation:
The larva of the silk moth is called a voracious eater because it has to consume a large amount of food for its rapid growth and development. During its larval stage, which lasts around 56 days, a silkworm can increase its weight by over 4,000 times and grow in size by approximately 10,000 times since birth. This incredible growth rate requires a high-energy intake, hence the silkworm's strong appetite for mulberry leaves, which serve as its primary food source.
Unlike some insects which may have no mouthparts at all or utilize siphoning or sponging methods to feed, the larval stage of the silk moth has chewing mouthparts well-suited for consuming solid food, such as leaves. This phase is crucial as it precedes the pupa stage, where the insect does not eat and undergoes metamorphosis to transform into the adult moth. Different insects have varied feeding habits, but for the silk moth larvae, intense feeding is essential to support the energy demands of its rapidly growing body.
In conclusion, the correct option explaining why the larva of the silk moth is called a voracious eater is: 'D. Because it needs to consume a significant amount of food to grow and develop into a silk moth.'