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NO-SEE-UM

SCIENTIFIC NAME: Ceratopogonidae

NUMBER OF SPECIES/DISTRIBUTION
There are over 4,000 known species of no-see-ums in the Ceratopogonidae family.
  • Within the genus Culicoides, there are over 1,000 species, and there are 676 known species over 39 different genera across North America.
  • No-see-ums can be found throughout the world.
No-see-um
DIET/FEEDING
No-see-ums are mostly predatory, although some are also collectors, gatherers, and scrapers.
  • The predatory species feed on a range of benthic macroinvertebrates, such as roundworms.
  • Those species that are collectors and gatherers tend to feed on algae, fungi, and decomposing organic material from plants, soil, bacteria, and feces.
  • Adult no-see-ums feed on flower nectar, and females also need blood from insects, reptiles, or mammals in order to reproduce.
HABITAT
No-see-ums are generally found in standing or slow-moving waters in lakes, ponds, marshes, and streams, but can also be in water-filled tree holes or other water filled cavities.
  • Some species can even be found in salt water or brackish habitats, where fresh and salt water mix.
  • They usually live in soft sediments or among algal growths along the substrate.
  • Most species cannot live more than a few inches below where the water meets the air at the surface of the water.

LIFE CYCLE
No-see-ums undergo complete metamorphosis, which involves passing through four complete life stages. These are the egg, larval, pupal, and adult stages.

Eggs
  • Adult females can lay up to 450 eggs per batch, and can sometimes lay up to seven batches during a lifetime.
  • The eggs come in a variety of shapes and can look like bananas or sausages.
  • When the eggs are first deposited, they are white, darkening over time as they mature.
  • The eggs may be deposited either as a large mass or individually on rocks within the water or on aquatic vegetation.
  • Some eggs are laid along the river banks, but if the banks dry up, these eggs will not survive.
  • Eggs typically hatch within two to ten days of being laid, although some can survive as eggs for up to a year.
  • The amount of development time needed before hatching depends on the type of species and on environmental conditions such as water temperature.
Larvae
  • The larvae are very small (2-5 mm), worm-like in appearance and often creamy white.
  • They typically go through 4 stages of development, called 'instars'.
  • The no-see-um larvae develop out of the water in moist or wet sand, mud, or any other moist, protected area near the water's edge.
Pupae
  • No-see-ums pupate underwater.
  • The pupal stage typically lasts about two to three days, and the pupal colour can range from pale yellow to dark brown.
  • The pupae use special structures called 'respiratory horns' to breathe.
  • These structures allow them to breathe by acting as snorkels, and also keep the pupae hanging just below the water's surface.
Adult
  • As adults, no-see-ums are very small; often less than 3 mm long (hence the name).
  • They are grey in colour and have wings that are patterned and covered in hairs.
  • Adult males attract females for mating by flying in large swarms, and mating occurs mid-air when females enter the swarm of males.
  • In some species, adult males may seek out females of the same species by finding animals on which the female may feed for her blood meal.
  • In these species, mating occurs after the female has finished feeding.
  • In the natural environment, the adult lifespan is a few weeks; in the lab, however, adults can live up to seven weeks.
  • The complete lifecycle of a no-see-um can occur in two to six weeks, or can take up to a year.
  • The length of the life cycle depends on the type of species, the time at which eggs were deposited, and on environmental conditions.
  • The complete cycle can occur in two to six weeks, but is dependent on the species and environmental conditions.
INTERESTING FACTS
  • The scientific name Ceratopogonidae is from the Greek words 'Keratos', meaning horns, and 'Pogon', meaning beard. The name may refer to the adult male's hairy antennae.
  • The adult stage is most prevalent in the months of June and July.
  • Many species of the Ceratopogonidae genera, especially the Culicoides genus, tend to bite humans. The bites can be very irritating, painful, and can even leave lasting lesions on some people.
  • Due to their small size, they can often climb through screen doors and get into homes; this makes them very troublesome for some people.
  • They are commonly known as 'biting midges'.
  • A few species are parasites that live on the outside of their host's body (making them 'ectoparasites'), and some species may also transmit diseases.

Sources
California State University (2001). Ceratopogonidae. Available here.
Iowa State University Entomology (2010). Family Simuliidae - Black Flies. Available here.
Murray Darling Freshwater Research Centre (2006). Simuliidae Simulinae. Available here.
University of Florida (2005). Common name: biting midges, no-see-ums. Available here.
Univeristy of Minnesota; Guide to Aquatic Invertebrates of the Upper Midwest (2004). Diptera. Available here.

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