Blow Flies
Blow flies are medium to large flies with distinctive metallic blue, green, or bronze coloring. They are among the first insects to arrive at decomposing animal matter and are strongly attracted to garbage, pet waste, and animal carcasses. Their presence indoors, particularly in large numbers, often indicates a dead animal in a wall void, attic, or crawl space. Several species are common including the green bottle fly and blue bottle fly. They are important in forensic entomology for estimating time of death.
Species in This Group (2)
Green Bottle Fly
Lucilia sericata
The Green Bottle Fly is a metallic green blow fly attracted to decaying organic matter, especially animal carcasses and garbage.
Blue Bottle Fly
Calliphora vomitoria
The Blue Bottle Fly is a large, noisy blow fly associated with decaying organic matter.
Key Behaviors
Blow flies are strongly attracted to the odors of decomposition and can detect a carcass within minutes of death. Females lay eggs in clusters on dead animals, rotting meat, and wet garbage. Larvae develop rapidly in warm conditions. Adults are strong fliers attracted to odors from garbage cans, pet waste, and compost. Their sudden appearance indoors in numbers is a reliable indicator of a hidden animal carcass.
Risks & Concerns
Blow flies mechanically transmit bacteria from decaying material to food surfaces. Their most significant impact is as an indicator of a sanitation issue or dead animal. In food service, their presence suggests inadequate waste management. In homes, their sudden appearance in large numbers almost always points to a dead rodent, bird, or other animal in an inaccessible area.
Identification Tip
Distinguished from house flies by their metallic coloring. Unlike house flies that breed in various decaying materials, blow flies are primarily associated with animal carcasses and meat. Their sudden indoor appearance in numbers is diagnostic for a hidden dead animal.
Quick Comparison
| Species | Size | Color | Key Trait |
|---|---|---|---|
| Green Bottle Fly | 8-10 mm | Metallic green to copper-green | Brilliant metallic green body; associated with decaying animal matter and garbage. |
| Blue Bottle Fly | 10-14 mm | Metallic blue with a slightly hairy thorax | Metallic blue body; slightly larger than green bottle fly; buzzes loudly. |
Need Help With Blow flies?
If you're seeing signs of blow flies in or around your home, professional treatment is the fastest way to stop the problem. Lotus Pest Control offers free inspections to identify the issue and recommend the right solution.