Toxorhynchites aurifluus is a large beneficial insect that does not suck blood; its larvae prey on mosquito wrigglers.

Toxorhynchites aurifluus is a large mosquito in the genus Toxorhynchites of the family Culicidae, named for the golden-red sheen on its abdomen. Its body is noticeably larger than that of ordinary house mosquitoes, and its thorax often carries a blue-green metallic luster; together with its slender build and downward-curving mouthparts, it is often mistaken for a very aggressive mosquito.

In fact, the adult Toxorhynchites aurifluus does not suck blood. Its mouthparts cannot pierce the skin, and it normally feeds on plant juices such as nectar and tree sap, resting by day among forest edges, shrubs or grass. This large mosquito therefore poses no direct threat to humans and is instead often classified as a beneficial insect.

What is truly valuable is its larval stage. The wrigglers of Toxorhynchites aurifluus live in small bodies of water such as tree holes, bamboo tubes, leaf axils or water collected in containers; they are fierce by nature and prey on other wrigglers in the same water, including the larvae of vector mosquitoes such as Aedes albopictus and Aedes aegypti. Because they eat a great deal and move quickly, a single Toxorhynchites larva can eliminate many vector wrigglers over the course of its development, and so this species is regarded in the field of vector control as having potential for biological control.

Toxorhynchites aurifluus is mainly distributed in the tropical and subtropical regions of Asia; it has been recorded in the mountain forests and countryside of Taiwan, China and South China, and adults mostly appear near clumps of plants close to water sources. In recent years some areas have tried using it to help control vector mosquito numbers, as a supplement to spraying-based control. The next time you see this brightly colored large mosquito in the wild, there is no need to swat at it in haste; it is most likely just passing by to feed.