What Do Rat-Tailed Maggots Eat: A Friendly Guide to Their Diet

Rat-tailed maggots are the larval stage of the drone fly, which is known for mimicking the appearance of the European honey bee. These maggots are fascinating creatures with a unique diet that keeps them thriving in various environments.

One of the primary food sources for rat-tailed maggots is decaying organic material. They are commonly found in stagnant water, such as ponds and animal waste, where they consume nutrients from decomposing plants and animals. This diet not only provides sustenance but also plays a crucial role in breaking down and recycling dead matter in the ecosystem.

Another interesting aspect of their diet is their ability to breathe underwater, using a specialized structure called a siphon. The siphon acts like a snorkel, allowing the maggots to collect oxygen from the air while they remain submerged in their nutrient-rich environment. This adaptation helps them have an edge over other organisms competing for the same food source and further establishes their role as decomposers within the ecosystem.

Description of Rat-Tailed Maggots

Rat-tailed maggots are the larval stage of the drone fly, Eristalis tenax. These creatures are known for their unique appearance and interesting habitats. Let’s take a closer look at the characteristics of rat-tailed maggots.


  • Color: Rat-tailed maggots are usually a pale whitish color, which helps them blend in with their surroundings.
  • Size: The body of a mature larva is about ¾ inches long. However, their most distinctive feature is the elongated “tail” which can be several times the length of the body.
  • Breathing Tube: This “tail” is actually a breathing tube, or siphon, which allows the maggot to breathe while submerged in water.

Rat-tailed maggots can be found in shallow aquatic habitats with high levels of organic matter. In these environments, they primarily feed on decaying organic matter and bacteria. This diet helps them thrive and grow into their adult form, the drone fly.

Here is a brief comparison table of some key features:

Feature Rat-Tailed Maggot
Color Pale whitish
Size ¾ inches long (body)
Breathing Through elongated siphon (tail-like)

In summary, rat-tailed maggots are fascinating creatures with a unique appearance and feeding habits. By understanding their characteristics, we can better appreciate the role they play in their ecosystems.

Larval Life Cycle

Rat-tailed maggots are the larval stage of some species of hoverflies. During their life cycle, they go through a series of changes which include the following stages:

Eggs: Female hoverflies lay tiny eggs in shallow aquatic habitats with high levels of organic matter. These are ideal environments for the larval stage to develop and find food.

Larvae: Emerging from the eggs, the rat-tailed maggot begins its life as a small larva. Over time, it grows and feeds on decaying organic matter in its environment, such as leaves, plants, and feces. The presence of bacteria and other microorganisms in these habitats provides essential nutrients for the maggots1.

As rat-tailed maggots develop, they progress through a series of larval instars. Each instar is characterized by growth in size and other physical changes. For example, the body of a mature larva can be about ¾ inches long, with an extendable breathing tube, or siphon, which can be several times the length of the body2.

Here’s a brief overview of the larval life cycle:

  • Eggs: laid in shallow aquatic habitats with high levels of organic matter
  • Larvae: feed on decaying organic matter and microorganisms
  • Instars: growth and development through a series of larval stages

Some species of rat-tailed maggots are known to overwinter as larvae, remaining submerged in their aquatic environments until the following spring. This allows them to survive through harsh winter conditions and continue the life cycle when temperatures rise.

Pupate: Once the rat-tailed maggot has completed its larval stage, it will leave the water and find a suitable location to pupate, typically in nearby soil or leaf litter. The pupal stage is a transitional phase during which the maggot undergoes metamorphosis, eventually emerging as an adult hoverfly3.

To recap, the larval life cycle of rat-tailed maggots consists of:

  1. Egg-laying in aquatic habitats with organic matter
  2. Larval development and growth through several instars
  3. Overwintering in some species, if necessary
  4. Pupation and metamorphosis to become adult hoverflies

By understanding the complex lifecycle of rat-tailed maggots, you can gain insight into their unique survival strategies and the important role they play in the environment.

Feeding Habits

Primary Diet

Rat-tailed maggots primarily feed on organic matter in their aquatic environment. They have a penchant for decaying plants, feces, and other debris found in stagnant water bodies. For example, you may find them in sewage lagoons and cesspools. A key feature of their feeding habits is that they consume nematodes and other small organisms as well1. Here’s a look at their main sources of nutrition:

  • Decaying plants
  • Feces
  • Nematodes
  • Organic debris

Effect of Pollution

The feeding habits of rat-tailed maggots can be significantly affected by pollution. As the organic content increases due to contamination, their food sources may thrive or change. For instance, contaminating substances in water bodies may lead to an increase in the organic matter they feed on, like in sewage lagoons2. However, the opposite can also be true, with polluted food sources possibly harming the maggots’ development and well-being. Therefore, the impact of pollution on rat-tailed maggots’ feeding habits can be quite variable, depending on the nature of the contaminants and their concentration. In contaminated water, you may observe:

  • Increased organic content
  • Alteration of food sources
  • Potential harm to maggots’ development

Keep in mind these factors when studying the feeding habits of rat-tailed maggots, and remember to take into account the environment they live in, as pollution plays a crucial role in shaping their diet.


Rat-tailed maggots, the larval stage of the drone fly, can be found in various environments where there’s an abundance of decaying organic matter. Some common habitats include:

  • Lagoons: These shallow aquatic environments often contain decomposing plant material, providing an ideal food source for rat-tailed maggots.
  • Stagnant water: Ponds, puddles, or ditches with still water can accumulate decaying matter, serving as perfect habitats.
  • Manure pits: Animal waste mixed with rainwater forms a sludge that attracts rat-tailed maggots due to the high nutrient content.
  • Foul water: Sewage systems or any contaminated water bodies are also potential homes for these larvae.

In these habitats, rat-tailed maggots feed on decomposing organic material, such as plant debris, animal waste, or even dead animals. As they consume this decaying matter, they break it down and recycle nutrients, playing an important role in the ecosystem. But, don’t worry, they’re not harmful to humans.

Always remember, when you’re around these habitats, be aware that rat-tailed maggots might be present. Although they might not look pleasant, they’re an essential part of nature’s recycling process.

Common Predators

Rat-tailed maggots, the larvae of drone flies, have several natural predators that keep their population in check.

One common predator of rat-tailed maggots is the wasp. These insects hunt for the rat-tailed maggots to feed their own young, helping to control their numbers.

Other natural predators of rat-tailed maggots include:

  • Birds
  • Fish
  • Aquatic insects

Here’s how these predators compare:

Predator Hunting Strategy Preferred Habitat
Wasp Stings and paralyzes the maggot, feeds to its young Land and near water
Birds Capture maggots from the water or while they are exposed Land and bodies of water
Fish Eat the maggots as they swim in the water Aquatic environments
Aquatic insects Prey on the maggots while they are in the water Freshwater habitats

These predators play a vital role in maintaining a balanced ecosystem, as rat-tailed maggots can be found in stagnant water and decomposing organic matter. By controlling the population of rat-tailed maggots, these predators contribute to a healthier environment.


Rat-tailed maggots have fascinating adaptations to help them survive in their environment. One of their most notable features is the siphon, a long, thin respiratory appendage that extends from the rear of their body. The siphon functions like a snorkel, allowing the larvae to breathe while submerged in shallow aquatic habitats with high organic matter content.

Another remarkable adaptation is their unique mimicry skill. As they mature into drone flies, they showcase an impressive example of Batesian mimicry, resembling the European honey bee, Apis mellifera. This form of mimicry helps protect the adult flies from predators since they are mistaken for a potentially harmful or unpalatable species.

In summary, rat-tailed maggots exhibit a range of adaptations, including:

  • A siphon for breathing in aquatic environments
  • Batesian mimicry to deter predators

These adaptations are essential to their survival and success as a species. By understanding how these creatures live and adapt, you can appreciate the fascinating world of nature and its complexity.

Post-Larval Stage

After the larval phase, rat-tailed maggots undergo a significant transformation. In this stage, they transition from larvae to pupae, which eventually leads to the emergence of adult drone flies. Let’s explore this fascinating post-larval stage.

Rat-tailed maggot larvae undergo complete metamorphosis, which consists of four stages: egg, larva, pupa, and adult. As the larval stage ends, the maggots enter the pupal stage where they form a protective casing around themselves, usually in soil. This process gives them time to develop into an adult fly.

During the pupal stage, the maggot’s body structure changes significantly. Their constricted tail forms into legs and wings, while their mouthparts adapt to new feeding habits 1(https://entnemdept.ufl.edu/creatures/livestock/rat-tailed_maggot.htm). After development is complete, an adult drone fly will emerge from the pupa, with its new body ready to face its surroundings.

Adult drone flies are important pollinators 2(https://entnemdept.ufl.edu/creatures/livestock/rat-tailed_maggot.htm) and can be seen hovering around flowers, resembling honey bees. Here are some key characteristics of adult drone flies:

  • Mimic the appearance of honey bees
  • Have large compound eyes
  • Possess a single pair of wings
  • Can fly long distances in search of food

In summary, rat-tailed maggots transition from the larval stage to the pupal stage before becoming adult drone flies within the soil. This process, known as complete metamorphosis, allows these insects to adapt and succeed in their environment as pollinators.

Role in Nature

Rat-tailed maggots are interesting creatures that play a unique role in nature. Apart from their unusual appearance, they have a fascinating life cycle and diet.

These larvae of drone flies are usually found in shallow aquatic habitats with high organic content. They thrive in environments such as stagnant water, liquid manure, and sewers. You may be curious about their diet. They mainly feed on decaying organic matter and sometimes on microscopic animals.

As they mature, rat-tailed maggots transform into drone flies. These adult flies are mimics of the European honey bee and can be easily mistaken for one. Their role changes as they transition from larvae to adult flies.

Adult drone flies are beneficial insects that contribute to the ecosystem by acting as pollinators. They visit various flowers for nectar, inadvertently spreading pollen in the process. Some of the plants they visit include:

  • Dandelions
  • Buttercups
  • Wild carrot flowers

Their resemblance to bees makes them a significant part of the pollinator community. Hoverflies, a group that includes drone flies, are considered the second most essential group of pollinators after bees.

Therefore, rat-tailed maggots, despite their unsettling appearance, play an essential role in nature. Through their lives, they help break down waste materials and contribute to pollination as adult flies. So, the next time you see these creatures, you can appreciate the positive impact they have on our environment.

Special Attributes

Rat-tailed maggots are the larval stage of a type of hover fly. In this section, you will learn about their special attributes, including their diet and appearance.

These larvae have a unique appearance. They are usually yellow, orange, or brown with black bands. Their most distinctive feature is their long, tail-like appendage, which is actually a breathing tube.

What do rat-tailed maggots eat?

  • They feed on decaying organic matter.
  • They are often found in stagnant water, sewage, and manure.

Their diet and habitat make them interesting subjects in entomology. They play an essential role in breaking down and recycling nutrients in the environment. Plus, their adult form, the hover fly, is a beneficial pollinator.

In summary:

  • Rat-tailed maggots are hover fly larvae.
  • They have distinct color patterns and a long breathing tube.
  • They feed on decaying organic matter.
  • They contribute to nutrient recycling and pollination in the environment.

Their unique characteristics and environmental contributions make rat-tailed maggots an engaging topic for those interested in entomology.

BioHazard Potential

Rat-tailed maggots are larvae of drone flies, which feed on decaying organic matter. Due to their dietary preferences, these maggots can pose potential biohazards.

The most notable biohazard associated with these larvae is myiasis, where maggots infest and feed on living tissues. This condition occurs in both humans and animals, and can be further classified into accidental myiasis or true myiasis. Accidental myiasis results from the ingestion of contaminated food, while true myiasis arises from the deliberate laying of eggs in living tissues by flies.

Livestock is particularly at risk for accidental myiasis, mainly due to the conducive environment of their habitats. Some examples include:

  • Poor sanitation
  • Accumulation of manure
  • Presence of open wounds

To minimize the biohazard potential of rat-tailed maggots, it’s important to maintain clean surroundings. For instance, you can:

  • Regularly clean animal enclosures
  • Dispose of waste properly
  • Keep feed storage areas clean
  • Treat and care for wounds promptly

By taking these measures, you can significantly reduce the risk of myiasis, ensuring the health and safety of both humans and animals.

Distribution and Classification

The rat-tailed maggot, also known as the Eristalis tenax, is part of the Eristalis genus. It belongs to the Diptera order and the Syrphidae family, specifically the Eristalini and Sericomyini tribes. This insect has a cosmopolitan distribution, which means it can be found all around the world.

These fascinating creatures have some notable characteristics:

  • They resemble honey bees in their adult form, known as the drone fly
  • The larval stage is called the rat-tailed maggot due to its long, distinctive tail-like structure
  • This tail works as a breathing tube, allowing the maggot to survive in stagnant water

Eristalis tenax is often found in polluted environments with high levels of organic matter. They are particularly attracted to decaying plant material or animal waste. These maggots feed on the bacteria and other microorganisms that break down these organic materials. This feeding behavior is crucial for their survival and growth.

In summary, the rat-tailed maggot plays an essential role in breaking down and consuming organic matter in various habitats. By understanding its distribution and classification, as well as its unique features, you can better appreciate the role that Eristalis tenax plays in the ecosystem.


  1. https://entomology.ca.uky.edu/ef017 2 3

  2. https://extension.msstate.edu/newsletters/bug%E2%80%99s-eye-view/2021/rat-tailed-maggot-vol-7-no-2 2 3

  3. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7504313/

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 – Rat-Tailed Maggots


What is this larvae(?) found under the ice
Sun, Dec 21, 2008 at 8:55 AM
My son was breaking the ice in our yard pond and found hundreds of these congrgating below the ice, apparently searching for air? I’m fairly familiar with many of the local water bugs and larvae, but never seen this particular creature and was just wondering what it is. Most are approximately .75″ long with a tail 2.5-3″ long. Just trying to teach my son about these kinds of things, and I was a bit embarassed to tell him that I just don’t know what these are!
Ray Elkins
Western Kentucky

Rat-Tailed Maggot
Rat-Tailed Maggot

hi Ray,
This is the larva of a Drone Fly, known as a Rat-Tailed Maggot. Despite its unsavory sounding name, the Rat-Tailed Maggot, though it feeds on decomposing organic material in stagnant water, will eventually metamorphose into a beneficial pollinating insect, the adult Drone Fly, Eristalis tenax, a Honey Bee mimic. Interestingly, this species was introduced from Europe prior to 1874 and it has a coast to coast distribution “From Alaska to Labrador and south into California and Florida” according to BugGuide.

Rat-Tailed Maggots found under Ice
Rat-Tailed Maggots found under Ice

Letter 2 – Rattailed Maggot


Subject: Snork a pillar?
Location: Grovetown, Georgia
February 15, 2013 1:35 am
I have never seen such a bug with a snorkel. This bug was in a tub of clothing that was outside and filled up with water. The long tail or whatever it is is what made me inquire. I hope you can identify this bug?
Signature: Larry the Birdman

Rattailed Maggot

Hi Larry,
You encountered a Rattailed Maggot, the larva of a Drone Fly,
Eristalis tenax.

Letter 3 – Rat-Tailed Maggot


Subject: What’s this bug?
Location: Bathroom
July 10, 2017 3:04 am
Over the last couple of days I found two of these in the bath tub now another one on bathroom rug. I have scowerd the internet trying to identify this as would like to understand where it could be coming from. It has no legs. I’d be surprised if they entering through the high up bathroom window. Then I thought they coming through plug hole… but now I find one on the floor I’m not so sure. Would love to know if you can help. Many thanks. Jelena
Signature: Jels

Rat-Tailed Maggot

Dear Jels,
The identification is easy, but your other theoretical questions are not quite as easy.  This is a Rat-Tailed Maggot, the larva of a Drone Fly, and according to BugGuide:  “larvae of most feed on decaying organic debris. They are filter feeders in different kinds of aquatic media. They purify water by filtering microorganisms and other products.”  Since we don’t know where your bathroom is located:  on the 37th floor of a high rise, in a basement, in Singapore or in New York, speculating on the point of entry is questionable, but we suspect they are breeding in your drain.  If you are connected to a septic tank, this is even more likely.  We suspect these Rat-Tailed Maggots are now seeking a drier environment so they can initiate pupation.

Letter 4 – Rattailed Maggot


Slug with long tail
Sun, Nov 9, 2008 at 7:08 PM
I have found about 4 of these sluglike things in my home in the last couple of weeks and have no idea what they are. When I spray them with insect spray their skin seems to burn and turns a dark color. The photo attached is after I sprayed it. It is normally a brown/grey color. Should I be concerned that they are in my house?
New Zealand

Rattailed Maggot
Rattailed Maggot

Dear Unsure,
We believe this is a Rattailed Maggot, the larva of a Drone Fly in the family Syrphidae.  We aren’t really familiar with your species in New Zealand, but Drone Flies are beneficial pollinators.  Their larvae, the Rattailed Maggots, are aquatic and live in stagnant water.  The Rattailed Maggots are not troublesome, but finding our why they are in your home in another questions.  We have read that Rattailed Maggots can be found in liquid cow manure in agricultural areas.  We haven’t the time to research if Drone Flies are found in New Zealand, or if your Rattailed Maggot is from a related genus.

Letter 5 – Rat-Tailed Maggot


Subject:  Basic Beautiful Birdbath Bug
Geographic location of the bug:  Bountiful Utah
Date: 07/18/2018
Time: 11:29 PM EDT
Your letter to the bugman:  I saw these swimming in the the birdbath and was very curious as I had never seen anything like these before. I have watched them over several days, but this is the first time I could get a good picture as the camera focuses on the surface of the water. During the day they often hide under leaves in the birdbath, but seem to become active before sunset.  I can get more pictures if you like.  I will be eternally grateful if you identify these for me.
How you want your letter signed:  Dean Hirschi

Rattailed Maggot

Dear Dean,
This is a Rat-Tailed Maggot, the larval form of the Drone Fly or another Hover Fly species in the subfamily Eristalinae, and here is a BugGuide image.  According to BugGuide: “Larvae in moist, sometimes shallow aquatic environments” and “Larvae of most feed on decaying organic debris. They are filter feeders in different kinds of aquatic media. They purify water by filtering microorganisms and other products.”

Wow! That was fast!  I appreciate the links and the information.
You are the greatest!

Letter 6 – Rat-Tailed Maggot or other Fly larva


Subject:  Can’t find any info on insect
Geographic location of the bug:  South louisiana
Date: 12/13/2018
Time: 09:10 PM EDT
Your letter to the bugman:  My friend posted this picture of this bug and I’ve seen them around before but I can’t find any info on it. To me it looks like a baby graboid from the tremors movie lol please help
How you want your letter signed:  Amanda

Rat-Tailed Maggot

Dear Amanda,
Though the snorkel-like breathing tube or “tail” on the posterior appears shorter than usual, we nonetheless believe this is a Rat-Tailed Maggot, the larva of a Drone Fly.  Here is a BugGuide image for comparison.  Rat-Tailed Maggots are generally found in stagnant water rich in organic materials, like animal manure, or in very damp soil.  We wouldn’t rule out that this might be a larva of a different group of Flies, like possibly a Soldier Fly larva

Letter 7 – Rat-Tailed Maggots


Subject: Aquatic grubs
Location: Northeast Los Angeles
March 20, 2013 2:06 pm
Hello, Bugman! It turns out that I’ve been following your site for quite a while, and recently discovered that we’re neighbors, as I also live in the Mt. Washington area. So these are pretty local critters!
I have found these aquatic grubs in our (non-working) backyard water feature a few times while trying to keep the mosquito larvae population under control. I came across these two specimens yesterday and had the presence of mind to take a picture to send to you, along with a dime for scale. I have tried before to find something on the web, and today I tried the term ”aquatic grub”, and ended up here: http://www.aquatax.ca/miscdip.html – a website devoted to Saskatchewan Aquatic insects, which has a picture of a grub that looks very similar.
I realize we may not be able to nail down the species, but this looks like it could be a Dipterid grub. I love syrphid flies, and would be happy to know if that’s what they are. In any case, just wondering if you can identify or possibly confirm my conjecture. Thanks very much!
Signature: Jonathan V

Rat-Tailed Maggots
Rat-Tailed Maggots

Hi Neighbor Jonathan,
Rat-Tailed Maggots are the aquatic larvae of a large Syrphid Fly known as a Drone Fly,
Eristalis tenax.  You might be interested in our Mount Washington Tag.  We archive most of our own photos there.

Fantastic, Daniel, thanks! I don’t think I realized that maggots could have their own name, but that’s certainly an apt one.  (And, you’ll be happy to know that I returned them to the pond.)
Thanks for the tip about the Mt. Washington tag, too. If I come across more unknown insects, I’ll be sure to check there, first.
Take care!

Letter 8 – Rattailed Maggot


What kind of bug is this?
Tue, May 12, 2009 at 3:28 PM
I found this bug in a hole in a tree filled with water. Any ideas?
Natalie West
North East Ohio

Rattailed Maggot
Rattailed Maggot

Hi Natalie,
This is a Rattailed Maggot, the larva of a Drone Fly, possibly Eristalis tenax.  There are a few photos of Rattailed Maggots on BugGuide.

Letter 9 – Rattailed Maggot


Subject: Wierd bug i named Jefery
Location: Meredith, Nh
October 2, 2015 7:05 pm
Found this in a rotten tree in Nh, what is it? Mostly see thru, seemed to have a stinger at the end of its tail.
Signature: Douglas Hewitt Jr

Rattailed Maggot
Rattailed Maggot

Dear Douglas,
This is the larva of a Drone Fly, commonly called a Rattailed Maggot.
  According to BugGuide:  ” larvae feed on rotting organic material in stagnant water” so we are wondering if there was any water in the rotten tree.


  • Bugman

    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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  • Piyushi Dhir

    Piyushi is a nature lover, blogger and traveler at heart. She lives in beautiful Canada with her family. Piyushi is an animal lover and loves to write about all creatures.

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8 thoughts on “What Do Rat-Tailed Maggots Eat: A Friendly Guide to Their Diet”

  1. I found this rat tailed maggot in Tonga is that a common area to find them, first time to see them here. thank you fror your help

  2. I just found some in Billings Montana. Never seen them before, very creepy but glad to hear they are a good insect… I’m one to destroy the good insects even if I get th creepy crawlies.

  3. I have been rooting Cottonwood cuttings and these guys always show up in my buckets here in Douglas County CO. I finally decided I needed to know what they are. Thanks for letting me know they are Drone fly larvae.


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