What Attracts March Flies: Unveiling the Mystery Behind Their Behavior

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March flies, also known as horse flies or deer flies, are notorious for their painful bites and annoying nature. But have you ever wondered what attracts these pesky insects to us? Understanding the factors that attract march flies can help you take measures to avoid them, and ultimately make your time outdoors much more enjoyable.

It turns out that march flies are primarily attracted to warmth and movement. When you’re outdoors, your body heat and the way you move can catch their attention. Additionally, these insects are drawn to the carbon dioxide you exhale, as well as the scent of your sweat or other body odors.

Understanding March Flies

March flies belong to the Diptera family and are known by various names like Plecia nearctica, Bibionidae, or lovebugs. These small insects are quite fascinating, and understanding their behavior and characteristics can be helpful when dealing with them.

Physical Features:

  • Antennae: March flies have prominent antennae that help in navigation and mating
  • Males vs. Females: Adult males have larger eyes than females, while the females have a more rounded abdomen tip

Life Cycle:
The life cycle of March flies consists of four stages – eggs, larvae, pupae, and adults. The larvae stage is particularly important for these flies, as they play a crucial role in the decomposition of organic matter.

Mating Behavior:
March flies are known for their unique mating behavior, where couples can be seen flying in copula. This is why they are also called lovebugs.

Here’s a comparison table of male and female March flies:

Features Males Females
Eye Size Larger Smaller
Abdomen Tip Tapered Rounded

In summary, March flies are intriguing insects belonging to the Diptera family. Their antennae, life cycle stages, and mating behaviors set them apart from other flies. Knowing these features can help you identify and understand these unique creatures.

Life Cycle of March Flies

Egg-Larvae Stage

March flies, scientifically known as members of the insect order Diptera and the family Bibionidae, lay their eggs in small clutches in the soil. The tiny eggs are rarely seen, but once they hatch, the larvae, or maggots, emerge and begin feeding on decaying organic matter in damp soil. You may find these grayish maggots, measuring between 1/4 to 1 inch long, in areas with enriched organic soils. During this stage, the larvae contribute to breaking down organic matter, which helps in nourishing the soil.

Adults and Mating

As the larvae grow and complete their development, they transform into pupae. The pupae then mature into adult March flies, which are dark gray with male and female variations visible in their appearance. The females have smaller eyes, while males generally have larger eyes, assisting them in locating their mates.

Once the adult March flies emerge, they focus on mating and reproducing. The mating process, often referred to as a copula, usually takes place in swarms in the spring or early summer. Here’s a quick comparison of male and female March flies:

Feature Male Female
Eyes Large Smaller
Body Color Dark gray Dark gray

After mating, the females lay their eggs in damp soil, thus continuing the cycle of life for March flies.

During the life cycle of March flies, these insects can create somewhat of a nuisance to people, but they play an important role in breaking down decaying organic matter and maintaining healthy soil. By understanding their life cycle, you can better appreciate the unique role they play in the ecosystem.

Attractants of March Flies

March flies are attracted to various elements in their environment. Some of the factors that draw them are:

  • Nectar: Adult March flies feed on nectar, pollen, and honeydew, often found on flowers. They play a role in pollination, especially in orchards and specific species of irises and orchids.
  • Seasons: These flies are mostly active during the spring and late spring months but can extend into the summer season. Their activity relies heavily on daylight, as they are most active during calm and sunny afternoons.
  • Soil and plants: March fly larvae feed on organic matter in the soil and plant roots, making them drawn to areas with abundant vegetation.

Apart from their natural attractants, March flies can also be lured by human-related factors:

  • Overripe fruit, spilled soda, and alcohol: The sweet and fermenting scents from these can catch the attention of March flies.
  • Animal carcasses, manure, and pet feces: Organic matter and decomposing substances attract these insects in search of food.

Keep in mind that while March flies could be near highways or homes, they mainly prefer wooded areas. To prevent attracting March flies to your property, limit activities such as leaving out overripe fruit, and maintain proper sanitation for better control of their population.

Attractant Relevant Environment
Nectar Wooded areas, flowers
Seasons Spring, late spring, summer
Soil and plants Areas with abundant vegetation
Human-related factors Homes, highways

Impact of March Flies

Effects on Humans

March flies can be quite a nuisance due to their painful bites. When they bite, their needle-like mouthparts pierce the skin, injecting a small amount of venom. This can cause pain, itching, and sometimes allergic reactions for some individuals. For example, you might experience:

  • Redness and swelling around the bite area
  • Itching or burning sensation
  • Mild fever (in rare cases)

Effects on Environment

March flies, like other pests, can have an impact on the environment. They can act as vectors for various diseases, which can affect both humans and animals. Additionally, their presence can disrupt the natural balance of ecosystems. Some potential environmental impacts include:

  • Spreading disease among plants, livestock, and wildlife
  • Disrupting the food chain by affecting the population of their prey and predators

While they can be a nuisance for humans and have some negative impacts on the environment, it is worth noting that March flies also play a role in pollination. In some cases, their presence can be beneficial for certain plants and ecosystems.

Geographical Distribution

March flies can be found in various parts of the world. In this section, we’ll briefly discuss their distribution in Australia, the Southeastern United States, and Florida.

In Australia, you may encounter march flies across the continent. They are known to be particularly prevalent in coastal regions, grasslands, and open forests. Keep in mind that their presence may vary depending on seasonal patterns and local ecosystems.

Moving on to the Southeastern United States, these flies also make their presence known. This includes areas such as Georgia, South Carolina, and Alabama. They are attracted to warmer and wetter climates, which are common in this region.

Lastly, let’s talk about Florida. As a part of the Southeastern United States, Florida also has a significant march fly population. They are attracted to the subtropical climate and abundant vegetation found throughout the state.

To better understand the march flies’ distribution in these regions, consider the following points:

  • March flies are more commonly found in warm, humid environments.
  • They thrive in areas with abundant vegetation, such as forests and grasslands.
  • Their distribution may vary across seasons and different ecosystems.

Remember, understanding the geographical distribution of march flies can help you better prepare for and deal with their presence in your local area.

Methods of Control

Using Repellents

A variety of insect repellents can help you keep march flies at bay. DEET is a popular and effective ingredient found in many repellents. To protect yourself, you can:

  • Apply a repellent containing DEET on your skin and clothing.
  • Choose a product with 20% or higher DEET concentration for longer-lasting protection.

For example, a repellent like Off! Deep Woods contains around 25% DEET making it more effective at warding off march flies. However, remember that using DEET-based repellents may have some drawbacks, such as causing irritation in sensitive skin or having a strong odor.

Physical Methods

Besides repellents, physical methods can also help in controlling march flies. Some effective physical methods include:

  • Installing insect screens on windows and doors to prevent the flies from entering your home.
  • Using fly traps, which lure and capture the insects. Some common types of traps are sticky traps and UV light traps.

A comparison of the two methods:

Method Pros Cons
Insect screens Non-toxic, reusable, provides fresh air flow Can be expensive, needs regular maintenance
Fly traps Can be highly effective, available in different types May be unsightly, requires regular cleaning and disposal of trapped flies

By combining the use of repellents and physical methods, you can effectively reduce the number of march flies around your environment and minimize their annoyance.

Managing March Flies in Homes

Keep your home clean: To prevent March flies from invading your home, maintain cleanliness. Keep your garbage cans covered and regularly dispose of waste. For example, empty the garbage cans at least weekly to avoid attracting the flies.

Seal entry points: Homeowners should seal all possible entry points to their homes, such as gaps in doors or windows. Install screens on windows and doors to keep these flies out.

Regular pest control service: Scheduling regular pest control services, such as Orkin, can help eliminate not only March flies but other pests like bed bugs and fleas too.

Avoid standing water: March flies can breed in stagnant water, so it’s crucial to check your home’s drains and ensure there are no areas collecting water. Clear any standing water in planters or objects around your home.

Here are some key measures to take in managing March flies:

  • Keep home clean and maintain proper garbage disposal
  • Seal entry points in doors and windows
  • Schedule regular pest control services
  • Eliminate areas of standing water

While implementing these methods, it is essential to remember that no single solution will be perfect. However, combining these tactics will increase your chances of successfully managing March flies in your home.

Similar Insect Problems

Issue with Fruit Flies

Fruit flies are small insects attracted to overripe fruit, spilled soda, and alcohol. They can become a nuisance in your home by infesting your fruit bowl and nearby areas. To prevent fruit fly issues, you can:

  • Store fruits in the refrigerator
  • Clean up spills promptly
  • Use fruit fly traps

Issue with Drain Flies

Drain flies are another common pest attracted to drains and scum. They breed and lay eggs in organic matter found inside drains. To manage drain flies, you can:

  • Regularly clean your drains
  • Use a drain cleaner to break down organic matter
  • Install drain covers to prevent entry of flies

Issue with Cluster Flies

Cluster flies tend to overwinter in your home, seeking warm and sheltered areas. They can become a problem in large numbers and cause discomfort. To minimize cluster fly issues, you can:

  • Seal cracks and gaps around your home
  • Use insecticides to control their population
  • Install window screens to prevent their entry

Issue with Horse Flies

Horse flies are known for their painful bites as they seek a blood meal. They are usually found around livestock and wetlands. Protect yourself from horse flies by:

  • Wearing long sleeves and pants when outdoors
  • Applying insect repellent
  • Using appropriate fly traps
Insect Attracted To Prevention Methods
Fruit Flies Overripe fruit, spilled soda, alcohol Refrigerate fruits, clean spills, use traps
Drain Flies Drains, scum Clean drains, use drain cleaner, install drain covers
Cluster Flies Overwintering indoors Seal cracks, use insecticides, install window screens
Horse Flies Blood meal Wear protective clothing, apply repellent, use fly traps

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 – March Fly


Subject:  March fly?
Geographic location of the bug:  Tampa bay fl
Date: 02/19/2018
Time: 04:17 PM EDT
Your letter to the bugman:  We were on the beach and everyone assumed it was a love bug but it was solid black the size of  my Fingernail.   They were in a swarm landing on people some people were covered in about 20 of them .
How you want your letter signed:  Nicole

March Fly

Dear Nicole,
This is indeed a female March Fly.  The Love Bugs that are well known in parts of Florida and the South are also March Flies, but Love Bugs,
Plecia nearctica, which are pictured on BugGuide, are red and black.  So, all Love Bugs are March Flies, but there are many species of March Flies that are not Love Bugs.

Letter 2 – March Fly


Subject: Love bug?
Location: Brevard County Florida
April 26, 2017 12:45 pm
I live in Florida and we usually get a ton of love bugs around this time of the year but instead of your typical black bodied bug with a red head they’re all black? Is this a love bug? I have yet to see a red headed love bug anywhere.
Signature: Stephanie

March Fly

Dear Stephanie,
This is an excellent question.  The image you submitted is of a March Fly in the family Bibionidae and the small eyes indicate it is a female.  Lovebugs are members of the genus Plecia within the family Bibionidae.  So all Lovebugs are March Flies, but not all March Flies are Lovebugs.  As you stated, Lovebugs have red heads.  You may read more about March Flies on BugGuide where it states:  “Adults emerge synchronously in huge numbers and often form dense mating aggregations. Males form loose ‘swarms’ and copulate immediately with females as they emerge from the soil. After mating, female bibionines dig a small chamber in the soil with their fossorial fore tibiae, lay eggs, and die within the chamber (
Plecia lay eggs on the soil surface). Adults are short-lived (3-7 days).”

Letter 3 – March Flies on Goldenrod


Subject:  Many found on goldenrod
Geographic location of the bug:  Greenport, LI, NY  eastern end of Long Island ny
Date: 09/14/2019
Time: 07:59 PM EDT
Your letter to the bugman:  Photographed these today and cannot identify
How you want your letter signed:  Amy

March Flies

Dear Amy,
Based on this BugGuide image, these appear to be March Flies in the genus
Dilophus.  There are numerous images of Dilophus spinipes on goldenrod on BugGuide.

Thank you so much!   I truly appreciate your help!

Letter 4 – March Fly


Location: Mid-Missouri
October 26, 2010 12:50 pm
A friend of mine suggested that I submit some of my photos to your site (love the site by the way). I found these a few days ago all over the Amur Honeysuckle berries that line my woods. I believe it to be a Lovebug and they are sure interesting looking creatures. These were the first that I have seen this year
Signature: Nathanael Siders

March Fly

Hi Nathaneal,
This is definitely a March Fly in the family Bibionidae which includes the Love Bugs in the genus
Plecia, but we haven’t the necessary skills to identify the genus or species.  That would require an expert and most likely a physical specimen.  We can say that she is a female because the eyes of the male are much larger.   Presumably, if he could speak, he would inform his mate that they are:  “All the better to see you with, my dear.”  You may see some additional examples of March Flies on BugGuide.

March Fly

Update:  October 2, 2016
In creating a new March Fly posting, we realized that this fall flying species is probably
Bibio longipes based on BugGuide information that it is a fall flying species.

Letter 5 – March Fly


Subject: Black bug with orange belly
Location: Charleston, SC
May 5, 2014 5:07 pm
I live in Charleston, SC and just today have seen many black flying bugs (1/2 inch long) with orange bellies all around town…literally everywhere I go.
Signature: -Evan

March Fly
March Fly

Hi Evan,
This appears to be a March Fly in the family Bibionidae, but there is not enough detail in your images to provide a more specific identification.  See BugGuide for more information on the family.

That’s what I thought too (“love bug” but they don’t have the orange behind their heads. Perhaps just a different type.
Thanks Daniel!

Lovebugs, which generally live further South, are one type of March Fly.

Letter 6 – March Fly


Subject: March fly?
Location: Myrtle Beach, SC
May 6, 2014 11:20 am
I have a bug that is the same as these:
I’m hoping with the pictures I’m attaching, we can get the species figured out!
Signature: Courtney

March Fly
March Fly

Dear Courtney,
This is a female (small head) March Fly in the family Bibionidae, as you suspect.  We are not certain of the species.

March Fly
March Fly

Letter 7 – March Fly


Subject: Need to identify this bug
Location: Rhode Island
May 15, 2015 9:14 am
for two days now there has been a huge number of these bugs suddenly appear in my back yard. No standing water. It is the middle of May here in Rhode Island
Signature: Sylvia

March Fly
March Fly

Hi Sylvia,
This looks like a March Fly in the family Bibionidae to us, and the large eyes indicate it is a male.  The March Fly family includes the infamous Love Bugs that are found in the south.  According to BugGuide:  “Adults emerge synchronously in huge numbers and often form dense mating aggregations. Males form loose “swarms” and copulate immediately with females as they emerge from the soil. After mating, female bibionines dig a small chamber in the soil with their fossorial fore tibiae, lay eggs, and die within the chamber (Plecia lay eggs on the soil surface). Adults are short-lived (3-7 days).”


  • 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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Tags: March Fly

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