Dung Fly: All You Need to Know in a Nutshell

The Dung Fly, known scientifically as Scathophaga stercoraria, is a small yet fascinating insect that inhabits farmlands and pastures. These flies are an essential part of the ecosystem due to their unique role in manure decomposition. They are commonly found in cow dung where they breed and contribute to breaking down the waste, helping to maintain a healthy farm environment.

While not considered pests, Dung Flies can appear in large numbers when wet manure is abundant, and they play a vital role in controlling other insects. Adult Dung Flies feed on other flies attracted to dung, as well as consuming nectar when necessary. Their appearance may vary depending on factors such as geographical location, season, and larval food availability.

Despite their unappealing name and association with waste, Dung Flies are fascinating creatures that provide numerous benefits to both agriculture and the broader environment. Their presence is vital for breaking down dung and controlling other insect populations, making them an essential component in a healthy ecosystem.

Dung Fly Basics

Classification of Scathophagidae

The Scathophagidae family, commonly known as Dung Flies, contains various species that find animal dung as their primary habitat for reproduction and feeding.

Notable Species: Yellow Dung Fly and Black Fly

  • Yellow Dung Fly: Scathophaga stercoraria is a non-pest species, often found in cow manure. These flies help in the removal of manure on farms (source).
  • Black Fly: A general term for species that typically breed in running water and are considered pests due to their bites and disease transmission.

Physical Characteristics and Size

Dung flies are small, with varying appearances. Some key features include:

  • Often covered in hairs or spines
  • Colors range from yellow to black
  • Size ranges from 2-15 mm in length

Geographical Distribution

Dung flies, especially Yellow Dung Flies, are widely distributed across the Northern Hemisphere, with variations in appearance influenced by factors like geography, season, and food availability (source).

Comparison of Yellow Dung Fly and Black Fly:

Feature Yellow Dung Fly Black Fly
Habitat Cow manure, dung Running water
Pest status Non-pest Pest
Diet Other flies, nectar Blood of host animals (in females)
Size 2-15 mm Varies, typically smaller than Yellow Dung Fly

Yellow Dung Fly characteristics:

  • Light yellow to golden color
  • Spines throughout the body
  • Prefers cow manure for reproduction and feeding
  • Non-pest species

Black Fly characteristics:

  • Black or dark coloration
  • Typically smaller than Yellow Dung Fly
  • Breeds in running water
  • Pest status due to biting and disease transmission

Life Cycle and Feeding Habits

Breeding Site Selection

  • Dung flies primarily select cow pats as their breeding sites.
  • These sites provide a rich source of organic matter and decaying plant material for the larvae to feed on.

Development from Larvae to Adult

  1. Eggs are laid in cow pats or rotting vegetation.
  2. After a short period, eggs hatch into larvae that feed on organic matter.
  3. As they grow, larvae eventually pupate and then transform into adult dung flies.

Feeding on Organic Matter and Parasites

  • Apart from decaying plant material, dung flies also feed on pests and diseases within their breeding sites.
  • They specifically feed on fruit flies and house flies, which helps maintain a healthy ecosystem balance.

Natural Decomposition Role

  • Dung flies play a critical role in the natural decomposition process by consuming organic matter within their surroundings.
  • Their feeding habits promote the breakdown of cow pats, rotting vegetation, and other decaying plant material.

Comparison: Dung Fly vs. House Fly

Dung Fly House Fly
Breed in cow pats Breed in a variety of decaying organic materials
Feed on fruit flies and house flies Feed on a wide range of food sources, including human food
Contribute to natural decomposition Can transmit multiple diseases through contact with food and surfaces

Some key features of dung flies:

  • Breed in cow pats and rotting vegetation
  • Aid in the decomposition of organic matter
  • Help maintain a balance in the ecosystem by feeding on other pests

Characteristics of dung flies:

  • Can be found in agricultural areas and fields
  • Have a relatively short life cycle, developing rapidly from larvae to adults
  • Play a significant role in breaking down waste and recycling nutrients in the ecosystem


  • Promote the breakdown of organic waste
  • Contribute positively to the ecosystem by controlling pests and diseases


  • May not be appreciated by people who find insects unappealing or view them as a nuisance

Role in Ecosystem

Influence on Mammal Population

Dung flies play a vital role in controlling the population of large mammals, as they help to break down and decompose animal waste. This process benefits the ecosystem by:

  • Recycling nutrients: Dung flies help return nutrients to the soil, promoting plant growth
  • Reducing disease: By breaking down waste, they prevent the buildup of harmful bacteria

Symbiotic Relationships

Dung flies form symbiotic relationships with some species, such as:

  • Parasitic wasps: Dung flies serve as hosts for parasitic wasp larvae, providing food and shelter
  • Dung beetles: Both species work together to break down animal waste and maintain ecosystem health

Natural Predators

Some examples of dung fly predators include:

  • Birds, such as swallows and flycatchers
  • Insect-eating mammals, like bats
  • Other insects, such as predatory beetles and spiders

Control Methods

Dung flies can sometimes become pests. Common control methods include:

  • Habitat modification: Reducing dung buildup in areas where large mammals are kept
  • Biological control: Introducing beneficial predators or parasites to help control dung fly populations
Aspect Pros Cons
Habitat modification Non-toxic, improves overall hygiene Requires ongoing maintenance
Biological control Targets specific pests, eco-friendly Requires careful planning, may take time

Reproduction and Mating Behavior

Sexually Dimorphic Traits

Dung flies exhibit several sexually dimorphic traits. These include:

  • Males: Larger body size, more robust forelegs
  • Females: Smaller body size, streamlined body shape

The larger body size in males is related to their aggressive and competitive mating behavior, while females are adapted for efficient foraging and egg-laying.

Mating Process and Sperm Competition

The mating process in dung flies involves a sequence of events:

  1. Finding a mate: Males and females find each other on dung pads
  2. Male competition: Males fight to establish dominance over their preferred mating spot
  3. Courtship: The winning male courts a female, who may either accept or reject his advances
  4. Copulation: If accepted, the male and female mate

Dung flies also exhibit sperm competition. A female’s spermatheca, or sperm storage organ, can contain sperm from multiple males, meaning that successful reproduction relies on a male’s ability to outcompete rivals’ sperm.

Impact of Body Size on Reproduction

In dung flies, body size plays a significant role in mating success, with bigger males generally having higher reproductive success. The benefits of a larger body size in dung flies include:

  • Increased dominance: Larger males can better defend their mating spots
  • Mating preference: Females may prefer bigger males as mates
  • Greater sperm production: Bigger males can produce more sperm, increasing their chances of successful fertilization
Body Size Mating Success Dominance Sperm Production
Larger Males High Strong High
Smaller Males Low Weak Low

However, larger body size might also have some negative impacts, such as increased energy demands during fights or foraging.

Comparative Analysis

Dung Flies in Contrast with Mosquitoes and Fruit Flies

Dung flies, particularly the Sphaeroceridae family, are often found in infested areas with mud or decaying matter. They don’t consume nectar, unlike mosquitoes and fruit flies.

Feature Dung Flies Mosquitoes Fruit Flies
Habitat Mud, feces Stagnant water Fruit, vegetables
Main food source Decaying organic Nectar, blood Fruit, yeast
  • Mosquitoes breed in stagnant water, like streams or ponds.
  • Fruit flies are drawn to fermenting fruits and veggies.

Potential Hazards Posed by Dung Flies

Dung flies can indirectly harm humans, animals, and plants.

  • They may carry drugs or chemicals from their habitat.
  • Infestations can disrupt ecosystems.

For example, dung flies could potentially spread harmful substances found in their breeding grounds, like animal feces or polluted mud, to nearby areas. This transmission may occur when they land on food sources, potentially contaminating them with harmful substances.

Species Interactions Overview

Effects of Climate and Weather

Dung flies thrive on warm and sunny days, as they are day-time feeders. These flies are sensitive to fluctuations in weather, particularly when it comes to rain and temperature changes:

  • Rain: Too much rain may limit their food sources and breeding opportunities.
  • Temperature: Dung flies prefer warmer climates, but extreme heat can adversely affect their survival rates.

Interaction with Humans and Livestock

The dung fly’s affinity for feces brings them into close proximity with humans and livestock:

  • Livestock: Dung flies are essential for breaking down the feces of livestock and enriching the soil with nutrients.
  • Humans: Although not a direct threat, these flies can become pests when they populate areas near human habitations.

Influence of Environmental Factors on Colony Success

Various factors impact dung fly colony success, including the nutritional quality of dung and the availability of suitable breeding sites.

Dung quality:

Dung Quality Parameter Golden Dung Fly Dark Brown Dung Fly
Water content Prefer dung with high water content Prefer dung with low water content
Nutritional content Favor nutrient-rich dung Less selective in terms of nutritional content

Feeding times and locations:

  • Dung flies adjust their activity patterns based on the availability of food. They are usually found near rivers, as the damp and humid conditions help them thrive.
  • The different dung fly species have differing feeding habits, with some primarily feeding during sunny hours while others feast throughout the day.

Physical appearance:

  • The dark brown dung fly is easily recognizable due to its dark brown appearance.
  • The golden dung fly is aptly named for its distinctive golden color.

Dung fly species may engage in competition for resources such as dung, which can affect their overall colony success. The flies’ ability to adapt to environmental stressors, such as migratory behavior in response to unsuitable conditions, plays a crucial role in their survival.

Common symptoms resulting from Simulium fly bites on humans or livestock include swelling, soreness, and potential irritation or infection.

While dung flies have an essential ecological role, it is crucial for humans and livestock owners to be aware of their potential impact on health and well-being. To aid in identification, image galleries are available for various dung fly species, providing valuable resources for comparison and recognition.

Reader Emails

Over the years, our website, whatsthatbug.com has received hundreds of letters and some interesting images asking us about these insects. Scroll down to have a look at some of them.

Letter 1 – Golden Dung Flies


Subject: Fuzzy wasps?
Location: Brunswick, NY (outside Albany)
April 24, 2017 7:23 am
Found these on goat poop in the pasture this morning. Upstate New York, end of April. It’s been reliably warm for a couple of weeks now.
Signature: Deb at Whimsey Acres Farm

Golden Dung Flies

Dear Deb at Whimsey Acres Farm,
These are NOT wasps.  They are Flies, and we quickly identified them as Golden Dung Flies,
Scathophaga stercoraria, thanks to images posted to BugGuide where it states:  “adult males are bright yellow or golden; females are usually grayer; both sexes very hairy on body and legs.”  BugGuide also states:  “larvae found in/on dung of domestic and wild animals adults found in the neighborhood of larval development sites (dung) which can be just about anywhere – pastures, meadows, woodlands, beside standing or running water, parks, gardens, etc.”  Your image represents a new category for our site as it is the first submission we have had for Dung Flies in the family Scathophagidae.

Golden Dung Flies
Thank you!  They’re quite beautiful, actually, and now I can learn more about them.

Letter 2 – Yellow Dung Fly from South Africa


Subject:  Bug identification
Geographic location of the bug:  Klipheuwel, Cape Town, South Africa
Date: 10/01/2018
Time: 06:52 AM EDT
Your letter to the bugman:  I photographed this insect at a wetland in Klipheuwel, near Cape Town.  It is an agricultural area. Farming practices include wheat, oats and live stock farming (cattle and sheep).
How you want your letter signed:  Tania Morkel

Yellow Dung Fly

Dear Tania,
It is a Fly, order Diptera. Not sure of family.  We need more time to research.

Yellow Dung Fly
Many thanks Daniel
An entomologist from my University just confirmed that it is Scathophaga stercoraria (Yellow dung fly).
Kind regards
Tania Morkel
Hi again Tania,
Thanks for getting back to us with a correct identification.  We found images of the Yellow Dung Fly on Wildlife Insight, but we also found the species, with the common name Golden Dung Fly, on BugGuide, a North American site, where it states the range is “throughout North America and the world.”


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    Bugman aka Daniel Marlos has been identifying bugs since 1999. whatsthatbug.com is his passion project and it has helped millions of readers identify the bug that has been bugging them for over two decades. You can reach out to him through our Contact Page.

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