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UPSC Prelims 2016 · Environment · Species Watch
Due to some reasons, if there is a huge fall in the population of species of butterflies, what could be its likely consequence/consequences? Select the correct answer using the code given below:
- 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.
- (a) 1 only
- (b) 2 and 3 only
- (c) 1 and 3 only
- (d) 1, 2 and 3
Show the answer and explanation
Answer: (c) 1 and 3 only
Pollination falls and so do the predators that eat butterflies.
Statement by statement
1. ✓ YES Butterflies pollinate many flowering plants.
2. ✗ NO Butterflies don’t protect plants from fungi — their fall doesn’t raise fungal infections.
3. ✓ YES Their eggs, caterpillars and adults are food for wasps, spiders and birds.
The idea
Every species is tied to others in two directions: to what it feeds on or serves, and to what feeds on it. Remove butterflies and both sides feel it: the plants they pollinate, and the animals that eat them.
Fewer butterflies → Below: flowers they visited set fewer seeds → Above: wasps, spiders and birds that eat caterpillars and adults go hungry
The trap
Statement 2 sounds like a chain reaction. There is no butterfly–fungus link.
Also know
Butterflies react quickly to changes in plants, temperature and pesticides, so they are used as indicators of the health of a habitat. Each kind lays eggs only on certain host plants; lose the plant and the butterfly goes too.
🔒 A species’ loss hits what it pollinates (below) and what eats it (above).