Mayfly vs Mosquito: Unraveling the Differences and Impacts

Mayflies and mosquitoes are two distinct types of insects that are often found near bodies of water, but they differ in many ways. While mayflies are known for their unique life cycle and short adult lifespan, mosquitoes are infamous for their blood-sucking habits and potential to spread diseases.

Mayfly larvae, also called nymphs or naiads, have a slender and soft-bodied appearance, with leaf-like or feathery gills along their sides or on the top rear portion of their abdomen 1. On the other hand, mosquitoes are flying insects that thrive in various parts of the world and are present in over 3,500 different types 2. Their bites are known to cause itching and swelling, while some mosquitoes are vectors of serious illnesses.

Both insects play their part in the ecosystem, with mayflies contributing through their unique life cycle 3, and mosquitoes acting as indicators of environmental changes and health risks. As we explore the fascinating world of mayflies and mosquitoes, we’ll discover their distinct characteristics and better understand their roles in our environment.

Mayfly Vs Mosquito: Basic Differences


  • Mayfly:

    • Slender and soft-bodied
    • Unwinged in larval stage, sport wings as adults
    • Leaf-like or feathery gills on abdomen
    • Smaller eyes in larval stage, larger in adults
  • Mosquito:

    • Small-sized with a slender body
    • Long legs and a proboscis for feeding
    • Wings present in adult stage

Life Cycle


  • Mayfly:

    • Found in clean, oxygen-rich aquatic environments
    • Larvae often live on rocks in fast-flowing water
  • Mosquito:

    • Larval and pupal stages thrive in standing water
    • Adults found near water sources and in various climates


  • Mayfly:
    • Larvae feed on algae, detritus, and other small organisms
    • Adults do not eat
  • Mosquito:
    • Larvae consume microorganisms and organic matter
    • Adults feed on nectar, while females require blood meals for egg production

Scientific Names

  • Mayfly:

    • Order: Ephemeroptera
  • Mosquito:

    • Order: Diptera
    • Family: Culicidae

Impact on Humans

Bites and Itchiness


  • Mayflies do not bite or cause itchiness.
  • They are harmless to humans.


  • Mosquitoes bite, causing itchiness and discomfort.
  • Female mosquitoes feed on human blood for nutrients needed to produce eggs.

Diseases and Health Risks


  • Do not transmit diseases to humans.
  • Minimal health risk, mostly associated with their swarming behavior which can cause nuisance.


  • Transmit deadly diseases, such as malaria, dengue fever, and Zika virus.
  • Major health risk globally, especially in tropical and subtropical regions.
Mayflies Mosquitoes
Bites No Yes
Itch No Yes
Health Risk Minimal High (transmits diseases)

Both mayflies and mosquitoes have an impact on humans, although significantly different. While mayflies are harmless, mosquitoes can cause serious health issues through their bites. It is essential to take preventive measures against mosquito bites to protect oneself from the diseases they carry.

Environmental Roles

Role in Ecosystems

Mayflies primarily inhabit rivers and streams as larvae, consuming algae and smaller organisms. Their presence is an indicator of good water quality. Mosquitoes, on the other hand, lay their eggs in standing water and can survive in a wider range of environmental conditions, playing a role in the spread of diseases like malaria.

Comparison Table: Mayflies vs Mosquitoes

Mayflies Mosquitoes
Habitat Rivers, streams Standing water, various environments
Diet Algae, smaller organisms (larvae stage) Female mosquitoes feed on blood, males feed on nectar
Positive Impact Good water quality indicator Pollinators (some species)
Negative Impact None Disease vectors (such as malaria, dengue, and Zika virus)

Common Predators

Mayflies and mosquitoes share a wide range of predators. Examples include:

  • Fish: Many species feed on mayfly larvae and adult mosquitoes.
  • Birds: Swallows and other insectivorous birds consume both mayflies and mosquitoes.
  • Other insects: Dragonflies and damselflies are known to prey on mosquitoes and mayfly larvae.

In summary, mayflies and mosquitoes have unique roles in their respective ecosystems. Mayflies are indicators of healthy aquatic environments, while mosquitoes can be both pollinators and disease vectors. Both mayflies and mosquitoes serve as important food sources for a variety of predators, maintaining the balance of ecosystems.

Insects That Resemble Mosquitoes

In this section, we will take a closer look at three insects that resemble mosquitoes. These insects are often mistaken for mosquitoes due to their physical appearance. However, they have different characteristics and their presence in the environment can sometimes be beneficial.

Crane Flies

  • Commonly mistaken for giant mosquitoes
  • Much larger than mosquitoes, size ranging from 2-60mm
  • Possess long, slender legs with wings spanning approximately 20mm
  • Do not bite or transmit diseases
  • Larvae feed on decaying plant material, adult crane flies feed on nectar or not at all

Crane flies are a prime example of an insect often confused with mosquitoes. Despite their large size and long legs, crane flies are harmless and do not bite. They can be beneficial to the ecosystem, as their larvae help break down decaying plant material, which enriches the soil.


  • Small, delicate insects resembling mosquitoes
  • Similar in size, about 1-4mm
  • Do not bite or transmit diseases (non-biting midges)
  • Larvae can be aquatic or terrestrial, feeding on algae or decaying organic matter
  • Adult midges can form swarming patterns, mostly seen during dusk or dawn

Midges, another insect commonly mistaken for mosquitoes, have similar size and appearance but do not bite or transmit diseases. Their presence can be annoying, especially in swarming patterns, but they are generally harmless.

Fungus Gnats

  • Resemble mosquitoes with delicate bodies and clear wings
  • Size range between 2-5mm
  • Do not bite or transmit diseases
  • Larvae feed on the fungi that grow in damp, organic matter (potting soil, for example)
  • Attracted to damp, overwatered plants

Fungus gnats are yet another insect that resembles mosquitoes. They have delicate bodies and clear wings but do not bite or transmit diseases. Fungus gnat larvae feed on fungi growing in damp, organic matter, so they are primarily attracted to over-watered plants.

Insect Size (mm) Biting Behavior Larvae Habitat Benefits
Crane Flies 2-60 No Decaying plant material, soil Decompose plant material
Midges 1-4 No* Aquatic or terrestrial, algae or decaying None
Fungus Gnats 2-5 No Damp, organic matter (potting soil) Decompose fungi in soil

*Note: This refers to non-biting midges, some midge species do bite.

Mosquito and Mayfly Management

Protecting Yourself and Your Yard

To protect yourself and your yard from mosquitoes and mayflies, follow these simple steps:

  • Remove standing water: Eliminate any sources of stagnant water around your yard, as it’s a breeding ground for mosquitoes.
  • Trim vegetation: Keep your yard well-trimmed, as both insects tend to congregate near tall grass and overgrown shrubs.
  • Install screens: Place window screens and screen-enclosed porches on your property to keep pests out.

Controlling Pests

Controlling mosquitoes and mayflies can be done through integrated pest management approaches, such as mosquito control programs and integrated mosquito management.

Mosquito control example:

  • Pros: Reduces mosquito populations; prevents the spread of diseases like West Nile virus and dengue fever.
  • Cons: May require using chemicals which might have a negative environmental impact.

Mayfly control example:

  • Pros: Mayflies are generally harmless and have a short life span; natural predator of other insect pests.
  • Cons: Large swarms can be a nuisance; may cause respiratory problems for people with allergies.
Mosquitoes Mayflies
Life Span Up to several weeks Usually 1-2 days
Diet Blood (females) & nectar Algae & other small insects
Diseases Can transmit to humans None
Control Requires more effort Requires less effort

Taking these steps to protect yourself and to control pests can help your yard be a more enjoyable space during mosquito and mayfly season.

Reader Emails

Over the years, our website, 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


Bizzare unknown fly with huge eyes
Location:  Fairfield, Maine USA
August 13, 2010 2:51 pm
Dear Bugman,
I found this fly on my Cruiser and another under an apple tree leaf. The one on the car seemed very aware of my presence and at one point seemed to be doing some kind of ”defending it’s territory dance” at me! It was about a half inch long (just the body.) It had very bright green large eyes and two very long appendages coming out of its tail end. Is this a stage of life for a dragonfly, or just an adult of something entirely different? It looks like it could be related…can you identify this please?
James R


Hi James,
These are beautiful images of a Mayfly, even though it is August.  Though Mayflies are most common in the spring, especially May, they may also be found at other times of the year.  Whenever they are found, there is one thing that is constant.  They do not live long as winged adults, many dying the first day.  The name for the order, Ephemeroptera, is explained on BugGuide as:  “from the Greek ‘ephemeros’ (of or for a day; short-lived) + ‘pteron’ (wing; feather) refering to the short time that adults are on the wing
.”  Mayflies are unique in the insect world in that they molt twice once they are winged and capable of flight.  The aquatic nymphs metamorphose into subadults or subimages which are called duns by anglers.  They molt a second time into true adults or images which are called spinners by anglers.  According to BugGuide:  “Adult (imago): body delicate or “flimsy”, varying from almost transparent to white, yellow, orange, green, brown, or black; thorax and abdomen bare, often shiny; legs slender, solid color; front legs often held forward and sometimes upward in front of head when at rest; forewings large, triangular, with many cross veins; hindwings much smaller than forewings (hindwings absent in some species); both wings usually transparent but sometimes patterned, held vertically and together above thorax when at rest  Pre-adult (subimago): wings cloudy in appearance, body dull and pubescent, with appendages somewhat shorter — but otherwise similar to imago; pre-adults molt a final time to become adults  Nymph: body elongate, flattened or cylindrical, usually greenish or brownish but color varies according to the type of food eaten; legs long; antennae short; abdomen with lateral plate-like gills and usually three long thin tail projections (cerci); some species have only two cerci.”  We believe your specimen is a Common Burrower Mayfly in the family Ephemeridae, based on images posted to BugGuide.


Hi Daniel,
Thanks so much for the i.d. and detailed information!
Interesting how the body color is affected by diet.
Best wishes,

Letter 2 – Mayfly


Can you identify?
This bug landed on the outside of my office window a while back and I’ve saved the picture ever since hoping to find out what it was. I’ve never seen a bug quite like this. Any ideas?

Hi Jenn,
Even though this is a Mayfly, they appear in other months as well.

Letter 3 – Mayfly


Mystery Bug!
Tue, Mar 17, 2009 at 4:38 AM
A friend of mine who lives in Temecula, CA, is wondering what sort of bug landed near his computer, one early morning in June of 08.
I have been searching the internet trying to figure out what it might be, but am alas, at a loss. However, I am no insect expert at all, so it may be something simple….. Can you shed some light on this?
Thank you!
Temecula, CA


Dear mystery2me,
Anyone who uses the word alas in a letter is a peach for us.  Despite its appearance in June, this is a Mayfly, an insect in the order Ephemeroptera.  We are not very good at identifying the specific species of Mayflies, so we hope this general identification will suffice.  This may be a Small Minnow Mayfly in the genus Callibaetis as evidenced by images on BugGuide.  Mayflies often appear in great numbers near bodies of water when the aquatic nymphs mature into adults and swarm in their annual nuptial flight.

Letter 4 – Mayfly


Big eyed bug in PA
Tue, May 26, 2009 at 8:50 AM
What’s this bug? Thanks!
Northern PA, US


Hi Mark,
This is a Mayfly in the order Ephemeroptera.  We haven’t the skill to take the taxonomy beyond the level of order.  We absolutely love the perspective on your photograph.

Letter 5 – Mayfly


Subject: Is that a stinger?
Location: St. John’s Newfoundland
July 20, 2016 6:16 pm
Hi there,, saw this little creature tonight. I’ve lived in this area all my life and I don’t recall ever seeing one before. Any idea what this little (about 1.5 inches) guy might be? And is that a stinger on his back end? Thank you!
Signature: Curious on the Rock

Thank you for submitting your identification request.
Please understand that we have a very small staff that does this as a labor of love. We cannot answer all submissions (not by a long shot). But we’ll do the best we can!

Thank you for your quick response!  I’ve done a little research and it looks like my friend is a Mayfly!

Giant Mayfly
Giant Mayfly

We know you already identified your Mayfly, but it is such a nice image that we want to post it so our readers will learn to recognize Mayflies.  We believe your individual is a Giant Mayfly in the genus Hexagenia which we researched on BugGuide.  We also want to address your stinger question.  According to BugGuide, Mayflies have:  “usually three long thin tail projections (cerci); some species have only two cerci” but there is no further explanation.  The features of Mayflies are described on including “It also features three long cerci or tails at the end if the body.”  Once again, the purpose or function of the cerci are not explained.  We will continue to research this matter. 

Letter 6 – Mayfly


Subject: I found a weird googly eyed bug
Location: Tangent, Oregon, United states
August 7, 2016 3:34 pm
I was at a park and found this strange bug with 4 legs and big white googly eyes I can’t find any info anywhere can you help me identify it please? it was awfully cute!
Signature: Jessica


Dear Jessica,
This is a Mayfly in the order Ephemeroptera.

Letter 7 – Mayfly


Subject: Friendly winged insect
Location: South Pasadena, CA
August 12, 2017 7:19 pm
Hello Mr. Bugman,
This bug alighted on my plate this evening at dinner on the patio. Curious to know what it is.
Signature: Emily


Dear Emily,
This is a Mayfly, and we are confident it is in the genus
Callibaetis which we discovered on Wayne’s Word and we verified on BugGuide that it might be Callibaetis pallidus.  Another species in the genus pictured on BugGuide that looks quite similar is Callibaetis californicus.  Mayfly nymphs are aquatic, so there must be some nearby body of water that will allow the nymphs to develop.  Winged adults are feeble fliers that cannot travel great distances.

Letter 8 – Mayfly


Subject:  Mosquito / may fly / dragon fly with tail
Geographic location of the bug:  Long Island, NY
Date: 05/29/2018
Time: 01:43 AM EDT
Your letter to the bugman:  These long tailed flies are swarming our house.  They don’t move much. They just sit on the screens and doors -Many until they die. We’re presuming they hatched from dirty rain gutters from a house we just bought. Some seem to be coming from vents outside that lead to the attic.  Please don’t let them be in the attic… They have long curved bodies and long tails.  We have a newborn and are nervous about them getting in because there are thousands of them. It’s like a scary movie bug swarm. Hoping they hate human blood.  Are they a beneficial fly that will prey on a nuisance species or are they out to get us? Thank you.
How you want your letter signed:  Concerned new parents.


Dear Concerned new parents,
Other than being a nuisance when they are numerous, Mayflies like the one in the image you submitted are perfectly harmless and they will not harm you or your home.  The larvae of Mayflies are aquatic, so we suspect you are near some body of water.

I’m about half a mile from a river. But there was a lot of standing water all over this property before we took ownership of it.

Letter 9 – Mayfly


Subject:  Please Identify
Geographic location of the bug:  Lake Chelan, WA
Date: 09/09/2021
Time: 12:26 PM EDT
Your letter to the bugman:  Approximately 2″ from antennae to end of “stinger.”  Yellow.   Still for hours.  On shady side of pole.  Both big and little lacey wings.
How you want your letter signed:  Thanks, Beatrice


Dear Beatrice,
This is a Mayfly in the insect order Ephemeroptera, a group that does not feed as adults.  They are short lived and because they often appear in great numbers, they are an important food source for fish, birds and other insects.


  • Bugman

    Bugman aka Daniel Marlos has been identifying bugs since 1999. 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.

4 thoughts on “Mayfly vs Mosquito: Unraveling the Differences and Impacts”

  1. I never see any reference to mayflies as the greatest natural bait nature ever made, but they are. During the 1950’s through 70’s our family went almost every weekend in summer to our cabin on Pickwick Lake. My absolute FAVORITE time was when the mayflies swarmed in June and July: we loved to fly fish (not trout fly fishing, but bass and bream fly fishing with floating lines and flies), and you could anchor your boat where there were a lot of flies and you were SURE to catch your limit during the brief sunrise or sunset swarms. It was thrilling! Every time your fly hit the water you would get a strike! The water would be churning with fish going after the flies that fell in the water. The action only lasted a few minutes, but it was non-stop during that time.

    USING the mayflies as bait was my “invention.” After evening swarms, I would find the flies in spider webs the next day on our dock. I started using them to bait my hook to catch bream (my favorite fish as a child because they are plentiful and easy to catch). My family saw that I caught not only bream, but striped bass and anything else that came along. We eventually set up lights on the outside of the dock to attract the flies. This would attract the fish, so at night we could sit in our boathouse and catch our limit of striped bass. We developed a whole special rig of “striper poles” which were short (because of the rafters in the boathouse) and had light floats because the mayflies are easily stripped from the hook so you need to know as soon as the fish bumps the bait.

    Mayflies are beautiful, gentle creatures and have provided me with some of the most wonderful memories of my life: there is nothing like being in a boat on the lake before sunrise with the fog rolling along the water and no sound but the birds and the occasional fish striking at a hapless bug on the surface. This was repeated countless times with my father – conversation breaking the silence only rarely with a comment about something taking place around us.

    You could time the sunrise by the activity of the mayflies (even when there were clouds or rain): the closer it got to sunrise, the more flies there were and the farther out from shore they came (they spent the nights on tree limbs, grasses, twigs, anything that would hold them, and the tree limbs would be black and bent down by the weight of them!)

    Then all at once the sun would peek over the eastern hills and the air would suddenly be FILLED with mayflies – the sky would actually be brown-colored there were so many. They would be all around us and on us – it was wonderful!

    And the fish would go crazy. Where we had been fishing and getting absolutely no strikes, suddenly there was a strike with every cast or every move of the fly across the water: the fish know when the flies swarm and they do not bother to come to feed until that time. (And at one time we had some artificial mayflies that we tried, but they didn’t work unless there was a mayfly hatch about!)

    So if you are a live-bait fisherman, try mayflies the next time there is a swarm: I guarantee you will get a bite!

  2. Dear Stonehuntr,
    Thanks so much for the wonderful nostalgic account of your childhood experiences with Mayflies. If you have never seen the film “A River Runs Through It” with Brad Pitt, you may enjoy the swarming Mayflies lovlily backlit while Brad is fly-casting.

  3. Mayflies are organisms of venerable antiquity. The order goes back to the late Carboniferous (300 million years ago), and they or something very like them were probably the first flying animals. It’s ironic that insects with famously short lives belong to a group that has hung around so long.


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