Flies

Fly Identification Guide

Physical Characteristics

Flies belong to the order Diptera, meaning “two wings.” Unlike most flying insects that have four wings, flies have only one pair of functional wings. Their hind wings have evolved into small knob-like structures called halteres that help with balance during flight. Flies have large compound eyes, short antennae, and sponging or piercing mouthparts depending on the species.

Common Household Fly Species

• Drain Flies: Small, fuzzy, moth-like flies that breed in the organic film inside drains. They hold their wings roof-like over their bodies and are weak fliers.

• Fruit Flies: Tiny tan flies with red eyes that hover around overripe fruit, fermenting liquids, and garbage. They reproduce extremely quickly in warm conditions.

• House Flies: Medium-sized gray flies with four dark stripes on their thorax. They are strong fliers and commonly land on food and surfaces.

• Blow Flies: Metallic blue or green flies attracted to decaying animal matter. Their presence often indicates a dead animal nearby.

• Cluster Flies: Larger, slower flies that enter homes in fall to overwinter. They are often found in attics and wall voids.

Fly Behavior and Biology

Flies undergo complete metamorphosis with four life stages: egg, larva (maggot), pupa, and adult. Most pest flies complete their life cycle in one to four weeks depending on temperature and species. Females can lay hundreds of eggs near suitable food sources for their larvae.

Different fly species have distinct breeding preferences. Drain flies breed in the gelatinous film inside pipes. Fruit flies prefer fermenting fruits and vegetables. House flies lay eggs in garbage, manure, and decaying organic matter. Understanding these preferences is key to controlling infestations.

Flies are most active during warm months but can persist year-round indoors if breeding sites and food sources are available. They are attracted to light and often congregate near windows.

Treatment Methods for Flies

Effective fly control focuses on source elimination and environmental management:

• Sanitation: Remove breeding sources by cleaning drains, disposing of overripe produce, securing garbage containers, and eliminating standing water.

• Exclusion: Repair window screens, seal gaps around pipes and vents, and keep doors closed to prevent fly entry.

• Drain Treatment: For drain flies, cleaning drain pipes with enzymatic cleaners or a stiff brush removes the organic film where larvae develop.

• Traps: Various fly traps including sticky traps, UV light traps, and vinegar traps can reduce adult populations while addressing the underlying breeding issue.

• Professional Assessment: Persistent fly problems may indicate hidden breeding sources that require professional inspection to locate and eliminate.