Dark-Winged Fungus Gnat

Bradysia coprophila — the dark-winged fungus gnat — is one of about 2,000 species in family Sciaridae (the dark-winged fungus gnats) and one of the most-encountered indoor pest insects worldwide. Adults are small (2-4 mm), dark gray-black, with characteristic Y-shaped wing venation. Females lay 100-200 eggs in moist organic substrate (potting soil, compost, mushroom production beds, decaying plant matter); larvae are translucent white legless maggots with prominent black head capsules and feed primarily on fungi and decaying organic matter in soil. In dense populations, larvae also feed on living plant root hairs and fine roots, causing significant damage to seedlings, houseplant root systems, and greenhouse crops (especially Begonia, Cyclamen, and other ornamental nursery production). The species is also a major vector of fungal plant pathogens (Pythium, Fusarium, Phytophthora) between greenhouse plants — adult flies pick up spores on their bodies and transfer them between plants during oviposition visits. Modern greenhouse and houseplant pest management uses Bacillus thuringiensis israelensis (Bti), parasitic Steinernema feltiae nematodes, and beneficial predatory mites (Stratiolaelaps scimitus) for biological control. The Sciaridae family is also famous for one of the most spectacular bioluminescent species on Earth: the New Zealand glowworm Arachnocampa luminosa is a fungus gnat whose larvae hang from cave and forest cliff ceilings producing blue-green bioluminescence to attract small flying prey (midges, moths). The larvae spin a tubular silk web with sticky dangling silk fishing-line snares; flying insects attracted by the light fly toward the bioluminescence and become entangled. The Waitomo Caves of New Zealand are famous for the 'starry sky' effect of thousands of glowworm larvae illuminating the cave ceilings — one of the most-visited natural-history attractions in the country.