Phantom midge
Chaoborus crystallinus
Phantom midges belong to the family Chaoboridae and are primarily known for their nearly transparent larvae, often called 'glassworms'. The adults possess characteristic plumose antennae in males and do not bite humans. They are found worldwide in stagnant and slow-moving waters, where they play a crucial role in the aquatic food web.
Details
Identification
Larvae are almost entirely transparent with two pairs of dark air sacs; adults have hairy wing venation and no biting proboscis.
Social behavior
Adults often form large, dancing mating swarms during twilight hours.
Diet
Larvae are predators feeding on zooplankton like Daphnia; adults mostly consume liquids like nectar or do not feed at all.
Hunting strategy
Ambush predators: Larvae float motionlessly in the water and strike rapidly at prey using modified antennae.
Spawning substrate
Eggs are laid in gelatinous masses directly on the water surface.
Overwintering
Overwintering usually occurs as larvae in the bottom sediment or deeper open water.
Ecology
Ecological role
Important consumer of zooplankton and simultaneously a significant food source for many fish species.
Natural predators
Fish, predatory aquatic insects (e.g., backswimmers), dragonfly larvae, birds.
Competitor species
Other zooplanktivorous organisms such as predatory water fleas or juvenile fish.
Ecosystem service
Regulation of zooplankton populations; larvae are used as high-quality fish food in the aquarium hobby.
Threats
Eutrophication of water bodies, pesticide runoff, and lake acidification.
Scientific profile
Profile
Distinguishing features
Males possess strongly plumose, tufted antennae. Larvae are characterized by two pairs of kidney-shaped, dark air sacs (hydrostatic organs) in the thorax and the seventh abdominal segment. The larval head bears hook-shaped prehensile antennae for prey capture.
Role in food web
Important top predator in the pelagic food web of fish-free waters; regulates zooplankton populations.
Protection & threats
Main threats
Loss of small water bodies through drainage or infilling; excessive fish stocking in small ponds; input of insecticides from agriculture.
Population trend
Stable; the species is widespread in Central Europe and common in suitable habitats.
Conservation measures
Protection and restoration of stagnant water bodies; promotion of fish-free pools; reduction of nutrient and pesticide inputs into aquatic ecosystems.