Where can moth flies breed?

• A. Around garbage cans
• B. Around drains
• C. On dead animals
• D. In soil

Answer: (B)

Moth flies breed where there is moist, organic-rich material that forms a slimy biofilm. In buildings, that environment is most often the inside of plumbing drains, where wastewater and debris create a warm, damp, food-rich film for eggs and larvae to develop. Eggs are laid in that film, larvae feed on it, and the continuous moisture in drains supports multiple life cycles.

That’s why breeding around drains is the best answer. Garbage cans can have organic matter, but they don’t provide the same sheltered, consistently moist biofilm found in drains. Dead animals are typically associated with other flies that feed on carrion, and soil isn’t a favorable habitat for drain flies because it lacks the standing moisture and film they require.