Question

Which pest passes winter in the plains and migrate to hill region during summer

• A. Cabbage butterfly
• B. Diamond back moth
• C. Cabbage aphid
• D. Cabbage borer

Hint:

Remember that Pieris brassicae (cabbage butterfly) is a classic example of an altitudinal migratory pest in India, moving between the plains and the Himalayas.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
Certain insect species exhibit seasonal migration patterns, traveling between geographic regions to avoid unfavorable temperatures and secure host plant availability.
This migratory behavior is highly distinct from simple hibernation or diapause.

Step 2: Detailed Explanation:
The Cabbage butterfly (Pieris brassicae) is a well-known migratory insect pest of cruciferous crops in the Indian sub-continent.
Its migration pattern is strongly driven by seasonal temperature changes between the plains and the Himalayan hill regions:
1. Winter Season: The pest remains active and breeds extensively in the northern plains of India, where winter temperatures are moderate, and cruciferous crops (like cabbage, cauliflower, and mustard) are abundant.
2. Summer Season: As summer approaches and temperatures in the plains rise to unfavorable levels (often exceeding \(35\text{--}40^{\circ}\text{C}\)), the adults migrate northwards into the cooler Himalayan hill regions.
In the hills, they continue to breed on summer crucifers.
As winter returns, the subsequent generations migrate back to the plains.
This cyclical, altitudinal migration enables the cabbage butterfly to maintain active breeding populations year-round.

Step 3: Final Answer:
Therefore, the pest that exhibits this migratory pattern is the Cabbage butterfly.