Question

The carnivorous fish Gambusia, introduced in the lakes, ponds, etc., control a deadly disease in India, feeds on the larvae of
a. Nephantis
b. Dragonfly
c. Anopheles
d. All of the above

Answer 1

Hint: Gambusia is a large genus of viviparous fish which belongs to the family Poeciliidae. Gambusia species are also known as mosquitofish, which refers to two species, G. affinis and G. holbrooki which are often introduced into ponds in order to eat mosquito larvae. Therefore, they are introduced widely outside their native range and frequently become invasive, threatening local species.

Complete answer:
Gambusia affinis, of coastal waters of the United States from New Jersey southwards, was introduced into India about forty years ago from Italy and Thailand.
The species can successfully survive in overcrowding conditions. They are found in freshwater, brackish water and salt marshes with high salinity. It feeds on aquatic and terrestrial insects. A single carnivorous fish that can consume mosquito larvae of Anopheles is equal to its own weight each day and hence it is known as mosquito fish.
Nephantis serinopa is found in Sri Lanka. The forewings are pale greyish-ochreous, with some scattered blackish scales and with the extreme coastal edge whitish.
Dragonflies can be mistaken for damselflies which are similar in structure. Even though dragonflies are swift and agile fliers, some predators can catch them due to their high speed, they include falcons such as the American kestrel, the merlin, nighthawks. In the water, various species of ducks and herons eat dragonfly larva.

So, the correct answer is option C which is 'Anopheles'.

Note:
The introduction of fishes such as Gambusia in ponds can selectively devour mosquito larvae is a type of biological control where pests such as insects, mites, weeds and plant diseases are controlled using other organisms. Gambusia are only occasionally kept in aquariums due to their lack of color and the highly aggressive nature of the mosquitofish species.