Question 17 from UPSC CSE 2017 - Environment

Question

Due to some reasons, if there is a huge fall in the population of species of butterflies, what could be its likely consequence/consequences?
1. Pollination of some plants could be adversely affected.
2. There could be a drastic increase in the fungal infections of some cultivated plants.
3. It could lead to a fall in the population of some species of wasps, spiders, and birds.
Select the correct answer using the code given below:

IASCODEX · Accepted Answer

Correct Option: C. 1 and 3 only

Strategy: Analyze each statement by recalling the ecological roles of butterflies. Butterflies are known pollinators for many plants (Statement 1) and serve as a crucial food source in the food chain (Statement 3). There is no significant ecological role for butterflies in preventing fungal infections in plants (Statement 2). Therefore, statements about pollination and the food web are correct, while the one about fungal infections is incorrect.

Key Info: A drastic fall in butterfly populations would have significant ecological consequences:

*   **Pollination:** Butterflies are important pollinators for many flowering plants, including some cultivated crops. Their decline could lead to reduced seed and fruit set in plants that rely on them for pollination, thus adversely affecting plant reproduction and potentially crop yields.
*   **Food Web Dynamics:** Butterflies, both in their larval (caterpillar) and adult stages, serve as a food source for a variety of predators. This includes insects like parasitic wasps (which lay eggs on caterpillars), predatory spiders, and numerous bird species. A substantial reduction in butterfly numbers would directly impact the availability of food for these dependent species, potentially leading to a decline in their populations as well.
*   **Fungal Infections:** Fungal infections in plants are primarily influenced by environmental factors such as humidity, temperature, and plant susceptibility, or by vectors like wind, water, or other insects. Butterflies do not play a direct role in preventing fungal infections in plants; their decline would not lead to a drastic increase in such infections.

IASCODEX · Answer

Option A: 1 only

IASCODEX · Answer

Option B: 2 and 3 only

IASCODEX · Answer

Option D: 1, 2, and 3