Previous Year 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?
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:
1 only
2 and 3
1 and 3
1, 2 and 3
Correct Answer: C
Detailed Solution
Butterflies are important pollinators in many natural and agricultural ecosystems.
While obtaining nectar from flowers, pollen grains adhere to their bodies.
When they visit another flower, these pollen grains can reach its stigma and assist in pollination.
A substantial decline in butterfly populations can affect the pollination of plants that depend on them.
This can reduce fruit and seed formation and natural regeneration in such plants.
Therefore, Statement 1 is correct.
Butterflies and their larvae, or caterpillars, also occupy an important position in food webs.
Butterfly eggs, larvae, pupae and adults are a source of food for many organisms.
Wasps may depend upon butterfly caterpillars as parasitoids or predators.
Spiders may prey upon adult butterflies and their other life stages.
Many birds consume butterflies and particularly their caterpillars as food.
A substantial decline in butterfly populations can reduce food availability for the wasps, spiders and birds that depend upon them.
Consequently, the populations of some species of these organisms may also decline; therefore, Statement 3 is correct.
There is no necessary direct relationship between a decline in butterfly populations and a drastic increase in fungal infections of cultivated plants.
Therefore, Statement 2 is incorrect and the correct answer is 1 and 3.