Black Flies

Simuliidae

Classification

Phylum: Arthropoda
Subphylum: Hexapoda
Class: Insecta
Order: Diptera
Infraorder: Culicomorpha
Family: Simuliidae

Pronunciation

How to pronounce Simuliidae: /sɪˌmjuˈliːɪdiː/

These audio files are automatically generated. While they are not always 100% accurate, they are a good starting point.

Summary

Black flies, or buffalo gnats, belong to the family Simuliidae and are known for their distinctive appearance and biting behavior. Most species are blood-feeders, which can make them a significant nuisance to humans, especially in outdoor settings. They have complex life cycles and ecological roles in aquatic ecosystems, with many species associated with the transmission of serious diseases like river blindness.

Physical Characteristics

Adults are black to various shades of gray or yellow, with a shiny, strongly convex thorax giving a humpbacked appearance. They have clear, broad wings with heavy veins near the anterior wing margin and weak veins posteriorly. Larvae are brown, gray, or black with a light brown head, cylindrical body somewhat club-shaped, and possess a prominent pair of mouth brushes for filtering food from water.

Identification Tips

Look for small size (1-5.5 mm), black or gray coloration, and the distinctive humpbacked thorax of adults. Larvae can be identified by their cylindrical shape and mouth brushes.

Habitat

Black flies thrive in running water of all types, including small seepages and streams as well as larger rivers and waterfalls. Larvae attach to underwater rocks and objects.

Distribution

Widespread globally, most diverse in Eurasia and the Neotropics. In North America, they are most abundant in northern regions and are present across many states and provinces.

Diet

Larvae filter small aquatic organisms and detritus from flowing water; adults feed on the blood of birds, with some species also feeding on mammals, including humans. However, many species do not take blood meals.

Life Cycle

Black flies can be univoltine or multivoltine, depending on the species. They undergo a typical insect life cycle with eggs laid in running water; larvae develop and pupate underwater before emerging as adults.

Reproduction

Eggs are laid in running water. Females feed on blood before laying eggs; some species exhibit different reproductive strategies based on environmental conditions.

Predators

Larvae are often preyed upon by fish such as trout, while adult flies may be consumed by various predators depending on their habitat.

Ecosystem Role

Black flies play critical roles in aquatic ecosystems, filtering and recycling organic materials through their feeding habits as larvae, while adults serve as food sources for various predators.

Economic Impact

They are a significant nuisance for humans during outdoor activities, and cause economic losses in livestock due to weight loss and potential death from bites.

Cultural Significance

Black flies are known for their problematic bites, leading to lore and cultural references in several regions, particularly in areas where they are prevalent.

Health Concerns

Bites can cause local swelling, inflammation, and in some cases may lead to intense reactions known as 'black-fly fever.' They can transmit diseases such as river blindness through their feeding habits.

Collecting Methods

Using light traps to capture adult flies
Collecting larvae from substrates in running water using nets

Preservation Methods

Ethanol for adult specimens
Freezing for live specimens
Mounting in entomological display cases

Evolution

Over 2,200 species of black flies have been described, with significant diversity within the family Simuliidae. They are closely related to families such as Ceratopogonidae and Chironomidae, indicating a shared ancestral lineage within the order Diptera.

Similar Taxa

Misconceptions

Black flies are often confused with midges or other small biting flies, though they are distinct in their feeding and ecological roles.