Chaoboridae

Adults distinguished from Chironomidae by specific wing venation patterns and 15-segmented antennae (males plumose, females bristly). Larvae identified by near-transparency, paired thoracic and abdominal air sacs, and raptorial antennae—unique among aquatic Diptera larvae. Chaoborus larvae are the most commonly encountered; Corethrella, Promochlonyx, and Australomochlonyx are regionally restricted (Australia, southern North America).

Lacustrine (lake-dwelling) habitats, including sublittoral and profundal zones. Larvae occur in standing freshwater bodies; Chaoborus punctipennis has been documented at 8 m (sublittoral) and 30 m (profundal) depths in reservoirs. Some species form large larval swarms in open water.

Cosmopolitan. Documented from North America (Lake Norman, North Carolina; Vermont; Quebec, Canada), Australia (nine species in four genera), Scandinavia (Denmark, Norway, Sweden), and Asia (Ryukyu Islands). Australian fauna includes endemic genera Promochlonyx and Australomochlonyx, plus Chaoborus and Corethrella.

Chaoborus punctipennis exhibits two generations annually: an overwintering spring generation and a summer generation. Activity period February through January in North Carolina populations.

Adults: primarily nectar if feeding occurs at all. Larvae: predatory, feeding on small aquatic insects including mosquito larvae, and crustaceans such as Daphnia. Corethrella brakeleyi adults are haemophagous (blood-feeding)—exceptional within family.

Two generations per year observed in Chaoborus punctipennis (overwintering spring generation and summer generation). Larvae aquatic; pupae aquatic; adults terrestrial but closely associated with water bodies.

Larvae swim actively and sometimes form large swarms in lacustrine habitats. Larval feeding involves impaling or crushing prey with raptorial antennae before bringing to mouth. Adults of most species have reduced or non-existent feeding; Corethrella brakeleyi actively blood-feeds.

Important predators in freshwater food webs, controlling populations of mosquito larvae and zooplankton such as Daphnia. Contribute significantly to secondary production in lakes—Chaoborus punctipennis biomass reached 30.9 mg·m⁻² (profundal) with annual production of 170.8 mg·m⁻². P/B ratios of 5.5–6.3 indicate moderate turnover. Some species serve as indicators of deep, stratified lake conditions.

Larvae may reduce mosquito populations through predation on larvae. Corethrella brakeleyi is a blood-feeding pest. Chaoboridae larvae are sometimes used as bioindicators in limnological studies. No significant economic damage documented.

• ChironomidaeAdults closely resemble chironomid midges; distinguished by wing venation details and 15-segmented antennae structure
• CorethrellidaeHistorically closely related and sometimes confused; now treated as separate family but shares aquatic larval habits and some morphological features

The common name 'glassworm' refers specifically to the transparent larval stage, not to any worm-like adult form. Not all Chaoboridae are predatory as adults—only Corethrella is known to blood-feed; most adults have reduced mouthparts and do not feed.

• aquatic
• predatory
• transparent larvae
• lake indicator
• zooplankton predator
• blood-feeding exception

• BugGuide
• Wikipedia
• GBIF taxonomy match
• iNaturalist taxon
• NCBI Taxonomy
• Catalogue of Life
• The Australian Chaoboridae (Diptera)
• The life history and production of Chaoborus punctipennis (Diptera: Chaoboridae) in Lake Norman, North Carolina, U.S.A.
• FIRST CANADIAN RECORD OF CORETHRELLA BRAKELEYI (DIPTERA: CHAOBORIDAE)
• Ecology of Chironomidae, Chaoboridae, and Other Benthos in Fourteen Wisconsin Lakes1