Question

Phase theory of locust was proposed by

• A. Boris Uvarov
• B. R. E. Snodgrass
• C. A. D. Imms
• D. M. L. Roonwal

Hint:

Associate the name "Sir Boris Uvarov" directly with "Locusts" and "Phase Theory" (1921).
He is recognized globally as the father of modern acridology (locust science).

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
Locusts are unique species of grasshoppers that can transition between two distinct behavioral, physiological, and morphological phases: the solitary phase and the gregarious phase.

Step 2: Detailed Explanation:
The "Phase Theory of Locusts" was proposed in 1921 by the Russian-British entomologist Sir Boris Uvarov.
Prior to his discovery, the solitary and gregarious phases of locusts were classified as separate species because of their different body colors, shapes, and behaviors.
Uvarov demonstrated that when solitary locusts are crowded together under favorable environmental conditions (such as high rainfall leading to abundant vegetation), they undergo physiological changes.
This results in a transition to the gregarious phase, where they change color, develop longer wings, aggregate, and form highly destructive migratory swarms.
This theory laid the foundation for modern locust forecasting and management programs.
Other scientists listed:
R.E. Snodgrass is famous for insect morphology.
A.D. Imms authored the classic textbook of entomology.
M.L. Roonwal is famous for his work on Indian termites.
Thus, Boris Uvarov is the pioneer who proposed the Phase Theory.

Step 3: Final Answer:
The phase theory of locusts was proposed by Boris Uvarov.