Scuttle Flies Identification Guide

Scuttle Fly Identification Guide

Physical Characteristics

Scuttle flies are small insects. They measure 1 to 4 millimeters long, about the size of a fruit fly. The easiest way to spot them is by the hump on their upper body. When you look at them from the side, you can see an arched shape on the thorax. This is why people also call them humpbacked flies. Their color ranges from tan to dark brown or black. Many have darker bands or stripes on their abdomen.

These flies have short antennae that are partly hidden by tiny bristles on the head. Their eyes are dark, not bright red like fruit fly eyes. The back legs are larger and flatter than the front legs. This shape helps them jump and run fast.

The wings show a simple vein pattern. Thick veins run along the front edge. Thinner veins spread across the rest of the wing. This pattern can help tell scuttle flies apart from other small flies when seen up close.

The Scuttling Behavior

The best way to identify scuttle flies is by watching how they move. Most flies take off right away when you get close. Scuttle flies do not. They run fast across surfaces in short, jerky bursts. After running for a bit, they may then fly away.

This running habit is very unique. Pest control experts can often spot an infestation just by watching how the flies react. No other common household fly runs across surfaces the way scuttle flies do.

Common Species in North America

The most common species found in homes is Megaselia scalaris. People sometimes call it the coffin fly because it can breed in buried remains. This species can live in many different types of rotting matter. Other species you might find indoors include Dohrniphora cornuta and other Megaselia types.

The Phoridae family has over 4,000 known species around the world. Most live outdoors and help break down dead plants and animals. Only a few types become pests inside buildings.

Scuttle Fly Behavior and Biology

Life Cycle and Reproduction

Scuttle flies go through four life stages: egg, larva, pupa, and adult. How fast they grow depends on temperature. In warm weather around 75 to 80 degrees Fahrenheit, the full cycle from egg to adult takes about 14 to 21 days. Cooler weather slows growth to 30 days or more.

Female scuttle flies lay many eggs. One female can lay 20 to 40 eggs at a time. Over her month-long life, she may lay 500 to 1,000 eggs total. The tiny, pale eggs look like small boats. Females place them at the edge of rotting material.

Larvae hatch within 24 hours when conditions are warm. These small, legless, whitish maggots eat decaying matter for 8 to 16 days. Then they crawl to a drier spot to change into pupae. The pupae are small, oval, and slightly flat. Adults come out about one week later and can start laying eggs within a few days.

Breeding Habits and Habitat

Scuttle flies can breed in many different materials. This makes them hard to control. They can grow in places that homeowners might not think to check.

Common breeding sites include:

• Slime and buildup inside drain pipes
• Rotting fruits and vegetables, especially potatoes and onions
• Garbage cans and recycling bins with food scraps
• Dirty garbage disposals and grease traps
• Pet waste and spilled pet food
• Dying plant material in potted plants
• Wet areas with mold or mildew
• Dead animals in wall spaces or crawl spaces
• Broken sewer lines and septic tank leaks
• Damp soil mixed with rotting matter

These flies need both moisture and rotting material to breed. Dry conditions stop larvae from growing. This is why scuttle fly problems often come with plumbing issues, water leaks, or damp areas in buildings.

Flight and Movement Patterns

Even though they prefer running, scuttle flies can fly well. With wind help, adults can travel up to six miles in 24 hours. But they usually fly short distances and prefer to walk or run on surfaces. They are most active during the day and are drawn to light. You may often see them near windows.

Adults eat many types of organic material. This includes rotting matter, fungi, and sweet foods. Their diet means they may touch dirty materials and then land in food prep areas. This is why seeing them in kitchens is a concern.

Treatment Methods for Scuttle Flies

The key to scuttle fly control is finding and removing their breeding sources. Killing adult flies only helps for a short time. New flies will keep coming out as long as larvae have a place to grow. Here are methods that work well for treating scuttle fly problems:

Finding the Breeding Source

The first step is finding where the flies breed. Start by checking common spots:

• Check all stored produce, especially root vegetables like potatoes and onions
• Look at floor drains, sink drains, and garbage disposals for buildup
• Look under and behind fridges, stoves, and other appliances
• Check trash cans and recycling bins
• Check pet feeding areas for spilled food or waste
• Look at potted plants for too much water or rotting plant matter

Sticky traps placed around the home can help find where flies are most active. Put traps near places you think might be breeding sites. Watch which traps catch the most flies over a few days. More catches mean you are closer to the source.

Sanitation and Source Elimination

Once you find breeding sites, clean them well and remove all rotting matter.

For drains, use enzyme drain cleaners instead of bleach or harsh chemicals. Enzyme products break down the slimy film where larvae feed. Regular cleaners may only kill what is on the surface. A drain brush can also scrub away buildup.

Throw away all rotting fruits and vegetables. Clean storage areas and bins well. Check hidden spots like the back of pantry shelves.

Clean under and behind appliances where food bits collect. Focus on areas that are not part of your normal cleaning routine. Wash trash cans often. Make sure lids fit tight. Take out the garbage more often during warm months.

For pet areas, clean feeding spots daily. Remove pet waste from indoor areas right away.

Addressing Hidden or Persistent Sources

If scuttle flies keep showing up after you clean, there may be a hidden breeding source. Broken sewer lines under floors are a common cause of ongoing problems. Watch for these warning signs:

• Flies coming from the same spot on the floor over and over
• Sewer or musty smells, especially near floor drains
• Past problems with slow drains or plumbing
• Wet spots on floors or walls with no clear cause

A plumber can use a camera or smoke test to find damaged pipes. Fixing these hidden sources means repairing broken lines and removing dirty soil. This usually requires a professional.

Monitoring and Prevention

After getting rid of an infestation, keep up with prevention to avoid future problems:

• Treat drains with enzyme cleaners once a month
• Store produce the right way and throw away overripe items quickly
• Keep trash cans clean and sealed
• Fix water leaks and moisture problems right away
• Clean under appliances and in hidden spots on a regular basis
• Use sticky traps to catch early signs of new activity

Insect light traps can catch adult flies but will not stop an infestation by themselves. They work best as a way to spot new activity before fly numbers grow.

References

• Phorid Flies - NC State Extension
• Phoridae - Wikipedia
• Phorid Flies - Penn State Extension
• Megaselia scalaris - LSU AgCenter
• Phorid Fly Information - Insects Limited