UPSC CSE Prelims 2008
Gambusia fish, commonly known as mosquitofish, is a larvivorous species. It primarily feeds on mosquito larvae, making it an effective agent for biological control of mosquito populations. Introducing Gambusia fish into stagnant freshwater bodies such as ponds and wells helps reduce mosquito breeding, thereby aiding in the control of mosquito-borne diseases.
Crabs (a) are not typically found in freshwater ponds and wells in a role that would control mosquito larvae. They are not primarily larvivorous.
Dogfish (b) are marine species and are therefore unsuitable for introduction into freshwater environments for mosquito control purposes.
Snails (d) do not prey on mosquito larvae. Furthermore, some snail species can serve as intermediate hosts for various parasites, potentially contributing to the spread of certain waterborne diseases rather than controlling mosquito populations.