How to Get Rid of Mayflies: Effective and Safe Methods

Mayflies are fascinating insects with a unique life cycle. These delicate creatures have an adult lifespan of just a few hours to a couple of days, primarily focusing on reproduction before dying. However, due to their large numbers when they emerge, they can become a nuisance, especially if they invade your home or garden.

To tackle a mayfly infestation, it’s crucial to understand their biology and habits. They are usually found near water sources, such as rivers, lakes, and ponds, as they lay their eggs in water. When they emerge as adults, they swarm over land, searching for mates. After mating, the females return to the water to lay their eggs before dying, beginning the cycle anew.

Getting rid of mayflies can be challenging, but there are practical steps homeowners can take to minimize their presence and prevent them from becoming a major problem. In this article, we will explore various methods and techniques that will help you keep mayflies at bay and maintain a comfortable living environment.

Understanding Mayflies

Lifecycle

Mayflies have a unique lifecycle among insects, as they possess a subimago stage between their larval and adult forms 1. This stage is active and mobile, marking the transition to the mature adult, or imago.

Appearance

Mayfly larvae, also known as naiads or nymphs, are slender and soft-bodied, with notable differences from adults 2. These differences include:

  • No wings
  • An array of leaf-like or feathery gills on their abdomen
  • Smaller eyes than adults
  • Often, a flattened head for adherence to rocks in fast-flowing water

Habitat

These delicate insects are found in freshwater environments worldwide, except for Antarctica and a few remote islands 3. They play a crucial role in the aquatic ecosystems they inhabit.

Diet

In their larval stage, mayflies consume a variety of organic matter, including decaying leaves and other debris. Adult mayflies lack functional mouthparts and do not feed 4.

Characteristics Larval Stage (Nymphs) Adult Stage (Imago)
Feeding Habits Eat organic matter Do not eat
Appearance No wings, gills Presence of wings
Habitat Freshwater Freshwater
Importance to Ecosystem Food for predators, recycle nutrients Mate and reproduce

Footnotes

  1. (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6628430/)

  2. (https://education.mdc.mo.gov/discover-nature/field-guide/mayfly-larvae)

  3. (https://pubmed.ncbi.nlm.nih.gov/31207933/)

  4. (https://www.entm.purdue.edu/mayfly/)

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 – Mayfly Exuvia

 

Subject: what in the world…
Location: i am in a small farm town, 60 miles west of chicgo, in Minooka, it’s August 7,2015 about 4:30 in the evening, and the weather is nice,no raim
August 7, 2015 2:47 pm
Hi there, I live in Minooka , Illinois and right now it is about 81 degrees, no rain, today is August 7, 2015 and it is about 4:30 pm
My daughter saw this bug and came to me and said look….so I have taken a pretty good close up of it and we were wondering if you, the bug man,could please tell us what is it??? Thanks for your time, hope to hear from you soon
Signature: From Becca and her mommy

Mayfly Exuvia
Mayfly Exuvia

Dear Becca and her mommy,
Is there a body of water nearby?  This appears to be the exuvia of a Mayfly, the only insect to molt twice while in a winged form, so it is possible that this individual flew a short distance from the water, alighted on your highly reflective wooden wall, and molted, leaving behind the shed exoskeleton or exuvia.

Yes,I am right by a little river

Letter 2 – Mayfly and Exoskeleton

 

What’s this bug
We are in Missouri, woke up to let the dog out and the yard was swarming with these. When I mean swarming I mean swarming. The entire yard, the neighbors yard as far as the eye could see they were everywhere. I left at about 9 am to take my daughter to camp. The entire subdivision was covered in them!! Any ideas? When we came back at about 10 there is significantly less of them but they are still out there. They are on the west side of the house only though not the east. Maybe they don’t like the sun? Thanks
Nikki Hickman

Hi Nikki,
You have been graced with witnessing the mass emergence of a species of Mayfly in the order Ephemeroptera. Adults only live a few days, their sole purpose in life being to mate and provide food to a vasy aray of other creatures higher up the food chain, like birds, fish and predatory insects. Larval Mayflies are aquatic, and live near a water source. Mayflies also are unique in that their are two adult forms, the subimago and the reproductive adult, known as the imago. We are also including a comment letter we got on a previous posting. You have pictures of a sloughed off exoskeleton and an adult. Perhaps one of our more knowledgeable readers can clarify if the adult is an imago or reproductive adult. If you are far from the water source, we are confident this is a reproductive adult.

Further Update: (04/26/2008)
Hi Daniel,
I sent in the comment several days ago about the mayfly imago and subimago; I’m a fly fisherman, among other things, and the mayfly picture with the shed exoskeleton jumped out at me. Interestingly, fly fisherman call the subimago stage of mayflies “duns” and the imago stage “spinners”. These are British terms, and I don’t know why they picked those words. … Your website is interesting, informative and fun, all at the same time, and I read it regularly. Thanks for your help.
Bob

Clarification: (07/19/2008)
Hi Daniel,
The picture of the adult mayfly from Missouri posted on July 16 is almost surely that of an imago rather than a subimago: the wings are clear, the tails are very long, and there is a shed exoskeleton. Mayfly subimagos typically have cloudy wings and relatively short tails, although no doubt there are exceptions to the rule. This insect is probably a species of the genus Tricorythodes. Fly fishermen refer to them collectively as “tricos”. They’re tiny, and it’s a challenge to tie a fly to imitate them and to fish it successfully. Tricorythodes emergences typically occur at night or early in the morning and the subimagos rapidly metamorphose into imagos; they mate, lay eggs, and die and it’s all over by noon.
Bob

Letter 3 – Mayfly

 

Reptile Insect
Location: Gladwin County, Michigan
July 27, 2011 8:19 am
Ok…I live in Gladwin County Michigan, and I saw this weird looking thing. My family and I are wondering what it is? It looks like a cross between a reptile, insect and rino.
Thanks,
Jeff
Signature: Thanks

Mayfly

Hi Jeff,
Your insect is a Mayfly.

Letter 4 – Mayfly

 

this bug is cute but scary
Location: Troy IL
September 7, 2011 6:34 pm
i want to know what kind of bug this is because my friend has passed away and we had a great memory with this bug i have a picture i would really appreciate it if i could get what bug it is as soon as possible
Signature: bug lover kindof

Mayfly

Dear bug lover kindof,
We are sorry to hear about your friend.  This is a harmless Mayfly, a member of the order Ephemeroptera.  Mayflies do not feed as adults, and many only live for a few days, long enough to mate and lay eggs.  Mayflies sometimes appear in tremendous numbers, swarming around street lights and other sources of light near bodies of water that serve as the habitat for the aquatic larvae.

Letter 5 – Mayfly

 

Intriguing Bug… intriguing behavior
Location: Fraser Valley, BC, Canada
September 27, 2011 9:13 pm
Hello Mr. Bugman,
I have had this very interesting little bug on my window since around mid June (it is now the end of September). I just checked before I took these pictures today and he/she is very much alive still. Do you know what it is so that I can look further into why it is behaving this way? I gently picked him/her up and placed her on a plant and within an hour he/she was right back on my window. Sometimes he/she is brownish and sometimes he/she is a brilliant light green color.
Thank you tons.
C.T.
Signature: Thank you Tons. C.T.

Mayfly

Dear C.T.,
This is a Mayfly in the order Ephemeroptera.  You can see the U.C.  Berkeley website for more information on Mayflies.  We can tell you that the name Ephemeroptera is a reference to the very short life of the adult or imago that often lives for a single day.  Adult Mayflies do not feed.  We are certain that the Mayfly you photographed is not the same as the individual you noticed in June.  The light green individuals you have seen are the subimagos or subadults.  Mayflies are unusual in that they molt twice in the final winged stage of their life.  

That is awesome info!  Thank you so greatly.  I often get interesting bugs on my deck.  If I find them in the future, can I contact you again?
Thank you also for you quick response.  I was excited to see your email and surprised and how fast you got back to me.
Smiles,
Cheryl

We have many contributors who send us multiple identification requests, but we cannot guarantee that our small staff will be able to respond to every request.

Letter 6 – Mayfly and a Mystery!!!!!

 

Mayfly???
I found this bug on my apricot tree and was really intrigued about its odd appearance. I am pretty sure it is a mayfly, but am not 100% sure. I live in northern CA about 2 1/2 hours north of Sacramento. Any help would be appreciated. Thanks.

This is a Mayfly, but your photo and letter pose a great mystery for us. The cast off skin of the aquatic naiad is visible in your photo, but we are curious how this aquatic nymph got into your apricot tree.

Explanation: (04/21/2008)
Mayflies, unlike other insects, have two adult stages (subimago and imago), and it is likely that the shed exoskeleton in the picture is that of the subimago.
Bob

Further Update: (04/26/2008)
Hi Daniel,
I sent in the comment several days ago about the mayfly imago and subimago; I’m a fly fisherman, among other things, and the mayfly picture with the shed exoskeleton jumped out at me. Interestingly, fly fisherman call the subimago stage of mayflies “duns” and the imago stage “spinners”. These are British terms, and I don’t know why they picked those words. … I enjoyed the back and forth between you and Johanna and her nails. Your website is interesting, informative and fun, all at the same time, and I read it regularly. Thanks for your help.
Bob

Letter 7 – Mayfly Exuvia

 

Subject: What on Earth?
Location: Southwestern PA
August 18, 2015 5:20 pm
Hello bugman! I saw this little beauty on the side of my brothers house. I’ve never seen anything like it! Can you tell me what it is?
Signature: Kyra Bergman

Mayfly Exuvia
Mayfly Exuvia

Dear Kyra,
This is the cast off exoskeleton or exuvia of a Mayfly, an insect that because its nymph is aquatic is generally found near water.  We just finished posting an image of an adult Mayfly.

Letter 8 – Mayfly Exuvia

 

Subject: What is this?
Location: Pennsylvania
April 25, 2016 6:39 pm
Saw this on my deck today. What is it?
Signature: NB

Mayfly Exuvia
Mayfly Exuvia

Dear NB,
This is the shed exoskeleton or exuvia of a Mayfly.  You must live near a body of water.

Authors

    by
  • 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.

  • 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.

8 thoughts on “How to Get Rid of Mayflies: Effective and Safe Methods”

  1. The reason there are wings on the shed exuvia is because mayflies are the only insect with a winged sub-adult stage, called a subimago, or dun. The subimago emerges from the aquatic larva, then flies to a resting place, and shortly after (hours to a day) emerges as a full adult, also called an imago or spinner. Subimagos can be distinguished from the adults by their hairy, cloudy wings, while adults have clear, transparent wings.

    Reply
  2. YES!! Thank you bug man.. we have always had mayflies in New England, but clearly, very few of us have seen them as adults, or ever adult enough to shed during their second molt.. Yup, You ROCK!!
    Thank you again,
    Paula

    Reply
  3. YES!! Thank you bug man.. we have always had mayflies in New England, but clearly, very few of us have seen them as adults, or ever adult enough to shed during their second molt.. Yup, You ROCK!!
    Thank you again,
    Paula

    Reply
  4. Okay, correct me if I am wrong, but the Mayflies only molt once as Adults, yes? Once from the larvae into an adult winged form (Dun form), and then the second molt into the full adult form (Spinner form). So only one molt as a winged “adult” entity. No?

    But still the only insect to molt after achieving wings…

    http://www.mayflynews.net/facts.html

    Reply
    • You are correct. Mayfly naiads emerge from the water and molt into winged Duns and shortly afterwards, they molt a second time into full adults, which do not feed and only live a few days, hence the name of the order Ephemeroptera. This is a very curious double winged molting, and one can only wonder why the need to have two molts in rapid succession evolved. Molting occurs in insects because insects feed and grow and their exoskeleton does not grow with them. Once they leave the water, Mayflies no longer feed, so they no longer grow.

      Reply
  5. Okay, correct me if I am wrong, but the Mayflies only molt once as Adults, yes? Once from the larvae into an adult winged form (Dun form), and then the second molt into the full adult form (Spinner form). So only one molt as a winged “adult” entity. No?

    But still the only insect to molt after achieving wings…

    http://www.mayflynews.net/facts.html

    Reply

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