Several common fly species have striking black and white markings, and the one you spotted likely belongs to one of three groups: tiger bee flies, pellucid hoverflies, or picture-winged flies. Each looks quite different up close, and identifying which one you’re dealing with tells you whether it’s harmless, beneficial, or a potential nuisance.
Tiger Bee Fly
The tiger bee fly is one of the most recognizable black and white flies in North America. It has a stout, fuzzy body with bold black and white patterning on its wings that resembles a tiger’s stripes. Adults are commonly found hovering around flowers, where they feed on nectar and pollen, making them useful pollinators despite their intimidating appearance.
What makes this fly especially interesting is its life cycle. Female tiger bee flies lay between 2,000 and 3,000 eggs near the entrance holes of carpenter bee nests. Once the larvae hatch, they crawl inside the tunnels and first eat the pollen stores meant for the carpenter bee’s young. Then each larva attaches to a carpenter bee larva and slowly drains it, functioning as a parasitoid, a parasite that ultimately kills its host. The carpenter bee larva is reduced to a dried husk while the fly larva grows plump enough to pupate.
If you’ve been dealing with carpenter bees boring into your deck or siding, spotting tiger bee flies nearby is actually good news. They’re a natural check on carpenter bee populations. They don’t bite or sting humans and pose no threat to your home.
Pellucid Hoverfly
The pellucid hoverfly, sometimes called the white-banded drone fly, is a European species measuring 12 to 18 mm long. It’s easy to identify: the body is mostly black, but the second segment of the abdomen is ivory white (sometimes with a thin black stripe down the middle). The wings have a distinctive dark spot in the center, the legs are black, and the antennae are reddish-yellow. Females have a reddish-brown plate behind the thorax.
These flies are active from May through September in a single generation per year. Adults visit flowers on a wide range of plants, from low-growing ground cover to shrubs and trees. Males are strong fliers that hover in sunny spots at roughly head height, defending territories and chasing off rival males or other insects. When resting, they like to sit on sun-warmed leaves.
The larval stage is where things get unusual. Females locate underground wasp nests by detecting nest odor through receptors in their antennae. They lay about 60 eggs inside the nests of social wasps, particularly the German wasp and the common wasp. The larvae live at the bottom of the nest, feeding on waste material, dead wasps, and sometimes live wasp larvae. When ready to pupate, they leave the nest entirely. Like the tiger bee fly, pellucid hoverflies are completely harmless to people.
Picture-Winged Flies
If the fly you noticed is smaller and has elaborate patterns on its wings rather than its body, it’s likely a picture-winged fly. This is a broad group that includes fruit flies in the family Tephritidae, whose wings display intricate combinations of spots, stripes, bars, and blotches in dark and clear tones. Some wings show a “stellate” pattern (clear spots against a dark background), while others have bold bars or darkened edges. The most common wing designs across the group are barred patterns and stellate patterns.
Picture-winged flies are generally small and are found on plants where they feed and breed. Males use their patterned wings as visual signals, displaying them on leaves to attract mates or warn off competitors. Many species are associated with specific host plants in the daisy family. While a few picture-winged species are agricultural pests that damage fruit crops, the ones you encounter in a garden are typically harmless.
Do Black and White Flies Bite?
None of the species above bite humans. Tiger bee flies, hoverflies, and picture-winged flies all lack the mouthparts needed to pierce skin. If you’re being bitten by a fly with dark and light markings, you’re more likely dealing with a deer fly or horse fly. These biting species rest on plants in shady areas during the day and ambush hosts they detect by sight or by sensing carbon dioxide and body odors. They’re most active in the morning and evening, and their larvae develop in moist or waterlogged soil.
Another possibility is the Asian tiger mosquito, which is dark with white banding on its legs. It’s technically not a fly in the everyday sense, but its coloring leads to frequent confusion.
Managing Biting Flies in Your Yard
If the black and white fly you’re searching about is one that bites, a few practical steps can reduce the problem. Keeping vegetation trimmed removes the sheltered resting spots that biting flies prefer during the day. For outdoor gatherings, a large fan on a patio or deck creates enough air movement to keep most biting flies away from your seating area. Burning citronella candles or torches can help in mild cases, though they’re rarely enough on their own for a serious fly problem.
When working outside in fly-heavy areas, light-colored long sleeves, long pants, and a hat with netting over the face offer reliable physical protection. An EPA-approved insect repellent containing DEET adds a chemical layer of defense for hiking, gardening, or time at the beach. Inside the home, sealing cracks, repairing torn window screens, and adding weather stripping around doors prevents biting flies from following you indoors.
Why These Flies Matter
Most black and white flies play valuable ecological roles. Tiger bee flies pollinate plants as adults while naturally controlling carpenter bee populations as larvae. Pellucid hoverflies visit a wide variety of flowers and help regulate wasp colonies. Even picture-winged flies contribute to plant ecology through their interactions with host species. Unless you’ve confirmed that the fly in question is actually biting you, it’s likely a beneficial insect worth leaving alone.