Toxorhynchites – mosquito hawk or elephant mosquito
Mosquitoes of the genus Toxorhynchites are sometimes called mosquito hawks, because their larvae eat larvae of other mosquitoes, or elephant mosquitoes – because of their exceptional size. The wingspan of Toxorhynchites may exceed 12 mm (0.4 inches) and the body length may exceed 7 mm (0.2 inches).
There are around 90 species of these mosquitoes worldwide, mainly distributed in forested tropical regions. Due to the hostile nature of their larvae, Toxorhynchites are uncommon.
Adults are frequently covered with iridescent scales and the proboscis has a pronounced 90 degree downward curve. Adults of mosquito hawks are active during the day.
Adult Toxorhynchites feed exclusively on sugary substances (such as nectar) and are not involved in the transmission of human or animal pathogens. Larvae inhabit mainly treeholes, bromeliads and other natural pools of water or different man-made containers. The larvae of all species of elephant mosquitoes are predacious, feeding on the living macroinvertebrates, mainly on the larvae of other mosquitoes. They may eat as many as 400 larvae of other mosquitoes during their development. This feature is being employed in controlling economically important mosquitoes and successful biological control has been reported using Toxorhynchites from Japan, Southeast Asia, the Caribbean and the United States. However, problems using Toxorhynchites for biocontrol include the high labor costs of mass rearing, the quick hatching of the eggs and the high labor costs of distribution.
All known species produce multiple generations per year and in the United States, Toxorhynchites generally overwinter as late larval instars. Several species of Toxorhynchites were deliberately introduced into Hawaii in the 1950s as potential biocontrol agents.