INFORMATIONAL ITEM

Mosquito Hawk Toxyrhynchites spp.

A Useful Biological Control Agent

Against Immature Mosquitoes

· A large genus with nearly 100 species and one of the few types of mosquitoes that does not suck blood and are harmless to humans. Rather, the adults subsist on nectar and other natural carbohydrates. Their larvae prey on the larvae of other mosquitoes.

· They are mostly occurring in tropical regions of both the Old and New worlds, with a few species occurring in the warmer parts of the North Temperate Zone. The tribe includes the single genus.

· Toxyrhynchites rutilus septentrionals (Dayr and Knab) is distributed in eastern United States, north to New Jersey and Pennsylvania and west to the great plains of Kansas, Oklahoma, and Texas.

· Toxyrhynchites are brilliantly colored and unusually large mosquitoes; the wingspan may exceed 12 mm; the body length may exceed 7 mm. Adults are frequently covered with iridescent scales and the proboscis has a pronounced 90 degree downward curve.

· Larvae are generally dark brown or reddish in appearance with very conspicuous hairs on the abdomen. The head capsule is quite thick and contains powerful mandibles. Fourth in-star larvae may be more than 2 cm in length.

· Larvae feed on macro-invertebrates inhabiting flooded tree holes and man-made containers, such as plant saucers and tires, but are more successful in feeding on other mosquito larvae (as many as 400) during their larval development periods.

· These predatory mosquitoes are the most common arthropods which have been used for control of “container breeding” mosquitoes. The combination of carnivorous larvae and innocuous adults is very attractive in biological control and has been reported as having reasonable success.