UPSC Prelims 2024 Q28: Environment & Ecology – Ecosystems & Ecology Concepts
Which one of the following shows a unique relationship with an insect that has coevolved
with it and that is the only insect that can pollinate this tree ?
- (a) Fig
- (b) Mahua
- (c) Sandalwood
- (d) Silk cotton
Answer: (a) Fig
Explanation
Fig and fig wasp — classic obligate mutualism
| Partner | What it gets | What it gives |
|---|---|---|
| Fig tree (Ficus) | Pollination — only the fig wasp can enter its closed flower (the syconium) | Safe place for wasp larvae to grow |
| Fig wasp (Agaonidae) | Food and nursery for its young inside the fig | Carries pollen from fig to fig |
Each fig species usually has its own wasp species.
Neither can complete its life cycle without the other — a textbook case of coevolution.
Other trees in the options:
| Tree | Pollinated by |
|---|---|
| Mahua | Bats and birds |
| Sandalwood | Many insects; it is a root hemiparasite |
| Silk cotton (Semal) | Birds and bats |
Answer: (a) Fig.
Why each option is right or wrong
- (a) CORRECT. Figs are pollinated only by fig wasps, which breed inside them — a coevolved, one-to-one relationship.
- (b) Incorrect. Mahua flowers are pollinated mainly by bats, not a single insect.
- (c) Incorrect. Sandalwood has many pollinators; it is famous for being a root parasite.
- (d) Incorrect. Silk cotton has large red flowers visited by birds and bats.
Key point
Fig–fig wasp = obligate mutualism and coevolution: each depends completely on the other.
Remember
Only the fig wasp can pollinate the fig — a coevolved mutualism.
Common mistakes
- Not knowing the fig's flowers are hidden inside the fruit-like syconium, so only tiny wasps can reach them.
- Choosing sandalwood because it is linked to special relationships; that relationship is parasitism with host roots.
- Thinking mutualism means occasional help; here the partnership is obligatory for both.
Exam tip
NCERT's mutualism examples: fig and wasp; orchid Ophrys and bee; lichens; mycorrhiza. Learn all four.
Sources
- NCERT Class XII — Biology, Ch 13 (Organisms and Populations — Mutualism)
- Cook and Rasplus (2003) — Mutualists with attitude: coevolving fig wasps and figs