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 :

The correct option is (c). Explanation Butterflies are integral components of terrestrial ecosystems. They function primarily as pollinators in their adult stage and as primary consumers (herbivores) in their larval stage. Their population dynamics directly influence plant reproduction and the stability of higher trophic levels. Statement-wise Analysis: - Statement 1 is Correct: Butterflies are key agents of pollination (entomophily). As they move from flower to flower foraging for nectar, they transfer pollen, facilitating the reproduction of many flowering plants. A significant decline in their population would adversely affect the pollination and subsequent fruit/seed set of these plants. - Statement 2 is Incorrect: There is no direct or generalized ecological evidence to suggest that a fall in butterfly population leads to a "drastic increase" in fungal infections of cultivated plants. While butterflies interact with plants, they are not the primary biological control agents for fungal pathogens. - Statement 3 is Correct: Butterflies and their larvae (caterpillars) serve as a crucial food source in the food web. They are preyed upon by various secondary and tertiary consumers, including wasps, spiders, and insectivorous birds. A huge fall in butterfly abundance would reduce the food supply for these predators, potentially causing a decline in their populations. Key Takeaway: The removal of a species from an ecosystem can trigger a trophic cascade, disrupting critical services such as pollination and affecting the survival of predators dependent on that species for food.

IAS 2017 — Environment & Ecology Environment & Ecology

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Due to some reasons, if there is a huge fall in the population of species of butterflies, what could be its likely consequence/consequences ?

Pollination of some plants could be adversely affected.
There could be a drastic increase in the fungal infections of some cultivated plants.
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 :

Official previous-year question

Verified 2 Aug 2026.

Options

A1 only
B2 and 3 only
C1 and 3 only
D1, 2 and 3

Did you get this right?

Solution

The correct option is (c).

Explanation

Butterflies are integral components of terrestrial ecosystems. They function primarily as pollinators in their adult stage and as primary consumers (herbivores) in their larval stage. Their population dynamics directly influence plant reproduction and the stability of higher trophic levels.

Statement-wise Analysis:

Statement 1 is Correct: Butterflies are key agents of pollination (entomophily). As they move from flower to flower foraging for nectar, they transfer pollen, facilitating the reproduction of many flowering plants. A significant decline in their population would adversely affect the pollination and subsequent fruit/seed set of these plants.
Statement 2 is Incorrect: There is no direct or generalized ecological evidence to suggest that a fall in butterfly population leads to a "drastic increase" in fungal infections of cultivated plants. While butterflies interact with plants, they are not the primary biological control agents for fungal pathogens.
Statement 3 is Correct: Butterflies and their larvae (caterpillars) serve as a crucial food source in the food web. They are preyed upon by various secondary and tertiary consumers, including wasps, spiders, and insectivorous birds. A huge fall in butterfly abundance would reduce the food supply for these predators, potentially causing a decline in their populations.

Key Takeaway:

The removal of a species from an ecosystem can trigger a trophic cascade, disrupting critical services such as pollination and affecting the survival of predators dependent on that species for food.

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The correct option is (c).

Explanation

Statement-wise Analysis:

Statement 1 is Correct: Butterflies are key agents of pollination (entomophily). As they move from flower to flower foraging for nectar, they transfer pollen, facilitating the reproduction of many flowering plants. A significant decline in their population would adversely affect the pollination and subsequent fruit/seed set of these plants.
Statement 2 is Incorrect: There is no direct or generalized ecological evidence to suggest that a fall in butterfly population leads to a "drastic increase" in fungal infections of cultivated plants. While butterflies interact with plants, they are not the primary biological control agents for fungal pathogens.
Statement 3 is Correct: Butterflies and their larvae (caterpillars) serve as a crucial food source in the food web. They are preyed upon by various secondary and tertiary consumers, including wasps, spiders, and insectivorous birds. A huge fall in butterfly abundance would reduce the food supply for these predators, potentially causing a decline in their populations.

Key Takeaway: