Biting midges also called as ‘no-see-ums’ are insects that breed in wet soils in the tidal zones such as sandy shores. The female midges are attracted to human habitation and rest on screens, fences and vegetation while waiting to take a blood meal. They prefer dull calm days with high humidity when seeking a meal as they are weak fliers and are easily blown out on windy days because of their small size. Biting midges can be a nuisance to campers, fishermen, hunters, hikers, gardeners, and others who spend time outdoors during early morning and evenings, and even during the daytime on cloudy days when winds are calm. They will readily bite humans; the bites are irritating, painful, and can cause long-lasting painful lesions for some people.
Identification: Biting midges are very small, ranging in size from 1-3 mm in length. They are greyish in colour but more turns more reddish when filled with blood.
Habitat: Biting midges live around freshwater creeks, intertidal estuaries, saltmarsh and mangrove swamps, on shores of streams and ponds, and in muddy substrates.
Feeding and diet: In general biting midges feed on plant sap and nectar, the primary energy sources for flight and for increased longevity of females. As with mosquitoes and most biting flies, it is only the females that is attracted to vertebrate blood and bite as they need blood to produce eggs and they usually lay eggs on a moist surface, such as muddy salt marsh areas and/or soil found in agricultural operations with high manure content. Victims are usually unaware of the fly’s presence until it has already started to feed. Male biting midges are not attracted to vertebrates, and their mouthparts are not capable of biting.
No-see-ums usually bite during the hours of dusk and dawn and rarely bite during daytime hours. Females primarily blood feed on mammals, but they may also blood feed on other animals such as birds, amphibians and reptiles.
Midge bite identification: A common observation upon experiencing a bite from this insect is that something is biting, but the person suffering cannot see what it is. The bite of a no-see-um can cause a burning sensation accompanied by a small red welt. Allergic reactions, including itching, may also occur.
Biting midges are sometimes incorrectly referred to as sand flies. Sand flies are insects that belong to a different biological group and should not be confused with the biting midges.
Life cycle: After hatching, flies go through four instars during the larval stage which can last from two weeks to one year, depending on environmental conditions, species of fly, and region. This is followed by the pupal stage (two to three days) and adulthood. The typical lifespan of an adult midge is two to seven weeks.
Prevention and Control
Some of the preventative measures are:
- Avoid swampy, wet sand during dawn and dusk. Scheduling outdoor activities to avoid daily peaks of biting midges is the most effective way of preventing midge bites.
- Cover your skin with clothing.
- Before going outside, use tropical strength insecticide spray/lotions or apply baby oil before going outside
- Homeowners can instal screens (mesh must be smaller than 16-mesh insect wire) on porches and windows.
- Biting midges are generally weak fliers, so ceiling and other types of fans can also help keep them away from areas where humans congregate.
- Controlling midges can be difficult due to the widespread areas where eggs can be laid in moist substrates. Currently, the preferred method of control is using carbon dioxide-baited traps (the insects use this as a signal to find hosts) to attract and eliminate the host-seeking pests.
- Insect repellent containing DEET or one marked for use against no-see-ums can be used. Campers should consider using tents equipped with “biting midge screening.”
- Avoid scratching the bites of biting midges.
- Treatment with cortisone or prescription topical steroids can help.
- For natural remedies, you can apply aloe vera topically.