UPSC Prelims 2008 Q137: Environment & Ecology – Sustainable Agriculture & Forestry
The release
of which one of the following into ponds and wells helps in controlling the mosquitoes?
- (a) Crab
- (b) Dogfish
- (c) Gambusia fish
- (d) Snail
Answer: (c) Gambusia fish
Explanation
Which organism helps control mosquitoes when released into water bodies
A specific fish species is widely used as a biological control method against mosquito breeding.
| Option | Verdict | Reason |
|---|---|---|
| (a) Crab | Incorrect | Not the standard biological control organism for mosquitoes |
| (b) Dogfish | Incorrect | A type of shark, unrelated to freshwater mosquito control |
| (c) Gambusia fish | Correct | Gambusia fish (mosquito fish) feed on mosquito larvae, making them an effective biological control agent |
| (d) Snail | Incorrect | Not the standard control organism for mosquitoes |
Gambusia fish facts:
| Point | Detail |
|---|---|
| Role | Biological control of mosquito larvae |
| Common name | Mosquito fish |
Answer: (c) Gambusia fish.
Why each option is right or wrong
- (a) Incorrect. Crabs are not the standard mosquito-control organism.
- (b) Incorrect. Dogfish (a shark) is unrelated to freshwater mosquito control.
- (c) CORRECT. Gambusia fish feed on mosquito larvae, controlling their population.
- (d) Incorrect. Snails are also not the standard control organism.
Key point
Gambusia fish (mosquito fish), released into ponds and wells, help control mosquitoes by feeding on their larvae — a classic biological control method.
Remember
Gambusia fish helps control mosquitoes when released into ponds and wells.
Common mistakes
- Confusing Gambusia fish's specific mosquito-larvae-eating role with unrelated aquatic organisms.
- Mistaking dogfish (a marine shark) for a freshwater mosquito-control species.
- Not knowing the common name 'mosquito fish' for Gambusia.
Exam tip
Gambusia fish ('mosquito fish') = classic biological control for mosquito larvae in ponds/wells.
Sources
- National Vector Borne Disease Control Programme — Operational Manual for Malaria Control: larvivorous fish (Gambusia)
- Encyclopaedia Britannica — mosquitofish