Problem 87 - Objective Biology for NEET

Question

The nymph of cockroach is grown by moulting for about times to reach the adult form. (a) 12 (b) 11 (c) 13 (d) 10

Step-by-Step Solution

Answer

(c) 13

Step 1: Identify the correct information

One must know the number of times a nymph of cockroach moults to become an adult. This is a piece of biological knowledge, typically found in textbooks or educational materials about cockroach development. According to factual biological information, a nymph of cockroach molts 13 times to reach adulthood.

Key Concepts

Insect Metamorphosis

Insect metamorphosis is a fascinating process that allows insects to transition through different life stages. This transformation is highlighted by the remarkable changes in form and function. Generally, metamorphosis can be divided into two broad types: complete and incomplete.

• Complete Metamorphosis: This involves four distinct stages—egg, larva, pupa, and adult. Examples include butterflies and beetles.
• Incomplete Metamorphosis: This consists of three stages—egg, nymph, and adult. Cockroaches fall into this category.

Understanding metamorphosis helps explain how insects grow, adapt, and survive in their environment. For instance, cockroaches, undergoing incomplete metamorphosis, do not have a pupal stage. Instead, they develop gradually through nymphal stages until they reach their adult form.

Nymphal Stages

The nymphal stage in cockroaches is crucial to their development. Nymphs resemble miniature versions of the adult but lack wings and reproductive ability. As they grow, they undergo several moults, where they shed their exoskeleton to accommodate their increasing size.
Nymphal stages help cockroaches efficiently transition from newly hatched nymphs to fully grown adults. Throughout this period, cockroaches experience significant physiological changes, enabling them to thrive in various environments.
Key aspects of nymphal stages include:

• The exoskeleton: This is protective and helps prevent desiccation.
• Size increase: Each moulting process results in a larger, more developed nymph.
• Gradual development: Unlike larvae in complete metamorphosis, nymphs develop incrementally until maturity.

Understanding the nymphal stages provides insight into the cockroach's ability to adapt and survive.

Moulting Process

The moulting process is a vital part of a cockroach's development. It allows them to grow by shedding their old exoskeleton, which does not expand as they increase in size.
The moulting process in cockroaches involves several key steps:

• Hormonal Changes: Special hormones trigger the moulting process.
• Exoskeleton Softening: The old exoskeleton is softened and eventually split open.
• Shed Exoskeleton: The nymph exits the old shell, revealing a new, larger exoskeleton underneath.
• Hardening: The new exoskeleton initially remains soft to allow room for growth, then hardens to offer protection.

Cockroaches typically undergo this process 13 times during their nymphal stage before reaching adulthood. Each moulting is a step closer to achieving their mature form, making moulting an essential aspect of their life cycle and survival.