Culicomorpha

Adults are small to medium-sized nematoceran flies with reduced wing venation and long, slender legs. Larvae are aquatic with specialized morphological adaptations: Culicidae and Chaoboridae possess a posterior respiratory siphon; Simuliidae have cephalic fans for filter feeding; Chironomidae exhibit diverse body forms with plumose or reduced antennae; Ceratopogonidae larvae are typically elongate with pigmented head capsules; Thaumaleidae are flattened and adapted to madicolous habitats.

Immature stages are obligate aquatic or semi-aquatic. Chironomidae larvae occupy virtually all aquatic habitats including lentic and lotic waters, brackish environments, and intertidal zones. Other families exhibit more specialized habitat preferences: Simuliidae larvae require flowing water with attached substrates; Thaumaleidae are restricted to thin water films on wet rocks and splash zones (madicolous habitats); Chaoboridae and Corethrellidae frequent standing waters; Culicidae larvae develop in diverse standing water bodies from clean to polluted conditions.

Cosmopolitan distribution with all eight extant families occurring across multiple continents. Specific distributional patterns vary by family: Chaoboridae show Holarctic dominance with some tropical affinities; Simuliidae are globally distributed with island endemism documented in the South Pacific; Thaumaleidae exhibit disjunct distributions across the Holarctic, southern South America, Australia, and isolated regions including Iceland and the Canary Islands.

Adult females of Chironomidae do not feed on blood. Adult females of Simuliidae, Ceratopogonidae, Thaumaleidae, and Culicoidea (Dixidae, Corethrellidae, Chaoboridae, Culicidae) feed on vertebrate blood. Larval feeding modes vary: Simuliidae are passive filter feeders using cephalic fans; Chironomidae exhibit diverse feeding strategies including deposit feeding, filter feeding, and predation; Chaoboridae are predatory; Culicidae larvae filter feed or scrape organic matter.

Holometabolous development with egg, larval, pupal, and adult stages. Eggs are laid on or near water surfaces. Larvae are aquatic with four instars; pupation occurs in water or at water margins. First instar larvae of Corethrella appendiculata possess a prothoracic proleg. Pupal morphology is highly distinctive across families and includes family-specific autapomorphies in respiratory and locomotory structures.

Adult females exhibit diel periodicity in blood-feeding activity, with some species feeding diurnally and others nocturnally. Simuliidae larvae display coordinated cephalic fan movements for filter feeding, with fan closure initiated by torma rotation and adduction occurring approximately every 0.23 seconds. Larval body form and behavior are adapted to maintain laminar water flow over cephalic fans even in turbulent habitats.

Chironomidae larvae function as primary consumers and ecosystem engineers in aquatic food webs, colonizing virtually all aquatic habitats and achieving high abundance and biomass. Competitive exclusion by Chironomidae appears to restrict other Culicomorpha families to specialized aquatic niches where Chironomidae are absent or marginal. Blood-feeding by adult females of Simulioidea and Culicoidea provides a reliable protein source that correlates with elevated diversification rates in these lineages. Many species serve as biological vectors of pathogens affecting humans and domestic animals.

Multiple families transmit pathogens of medical and veterinary significance. Culicidae transmit malaria, West Nile virus, and numerous arboviruses. Simuliidae transmit Onchocerca volvulus (causative agent of river blindness). Ceratopogonidae transmit Akabane virus, bluetongue virus, Schmallenberg virus, African horse sickness virus, epizootic hemorrhagic disease virus, and bovine ephemeral fever virus. Studies have confirmed that mosquitoes and biting midges are not biological vectors of SARS-CoV-2.

• BibionomorphaAnother nematoceran infraorder; distinguished by more robust body form, shorter antennae with fewer flagellomeres, and typically terrestrial larval habits in soil or decaying organic matter rather than aquatic habitats.
• PsychodomorphaNematoceran infraorder including moth flies and sand flies; distinguished by densely hairy wings held roof-like over the body, and larvae typically in moist terrestrial or semi-aquatic habitats rather than the diverse aquatic specializations of Culicomorpha.

• BugGuide
• Wikipedia
• iNaturalist taxon
• NCBI Taxonomy
• Catalogue of Life
• Another Study Confirms Mosquitoes, Midges Don't Transmit Coronavirus
• World Catalogue of the family Thaumaleidae (Diptera: Culicomorpha)
• The Pupae of Culicomorpha—Morphology and a New Phylogenetic Tree
• The Pupae of Culicomorpha—Morphology and a New Phylogenetic Tree
• Simuliidae (Diptera: Culicomorpha) of Rarotonga, Cook Islands, South Pacific
• Filter feeding in larvae of Simuliidae (Diptera: Culicomorpha): aspects of functional morphology and hydrodynamics
• Innervation and fine structure of antennal sensilla of Simuliidae larvae (Diptera: Culicomorpha)
• The distribution and habitat preferences of the Chaoboridae (Culicomorpha: Diptera) of the Holarctic Region
• Redescription of immatures of Dasyhelea flavifrons Guérin-Méneville (Culicomorpha: Ceratopogonidae) and new contribution to the knowledge of its larval habitats