Are Crane Flies Attracted to Light? Debunking Common Myths

Crane flies, often mistaken for gigantic mosquitoes, are members of the fly family Tipulidae.

These slender, long-legged insects are typically found around water and have a short adult lifespan of about one to two weeks.

While they may seem like a nuisance, crane flies are actually harmless creatures.

Are Crane Flies Attracted to Light
Mating Tiger Craneflies

Adult crane flies have a natural affinity for light sources, frequently causing inconvenience to inhabitants as they inadvertently enter homes and make contact with walls or ceilings.

Despite their superficial resemblance to oversized mosquitoes, these flies do not engage in human biting or blood-feeding behaviors due to the absence of the specialized sucking mouth structures found in mosquitoes.

Crane Fly Characteristics

Crane flies are large, tan-colored insects with long legs belonging to the Tipulidae insect family.

Key features include:

  • Slender mosquito-like body
  • Extremely long legs
  • Wingspan ranges up to 2 inches

Crane flies and mosquitoes differ in various ways:

Crane FlyMosquito
FeatureHarmlessDisease vector
SizeLargerSmaller
LegsLongerShorter
SpeedSlow-flyingFaster flying

Life Cycle of Crane Flies

The life cycle of a crane fly comprises of:

  1. Egg stage
  2. Larval stage
  3. Pupal stage
  4. Adult stage

Egg: Crane fly females deposit eggs in moist environments, which hatch into larvae, marking the initial phase of the life cycle.

Larvae: The larvae stage is the most prolonged phase, during which they consume organic matter and sometimes damage grass roots.

Pupa: During the pupal stage, transformation occurs within the soil or nearby areas, where larvae metamorphose into adult crane flies, completing their development.

Adults: Crane flies live for approximately one to two weeks as adults, during which they mate and scatter eggs.

Crane Fly Habitats

Crane flies are commonly found in North America and Europe, including the common crane fly and the European crane fly.

They usually inhabit wet areas and are often found near water.

Crane Flies and Light

Crane flies are attracted to light like some other insects, such as moths. They are often seen near light sources at night, like exterior lights or windows.

For example, crane flies might be seen near:

  • Doors with exterior lights
  • Window screens
  • Indoor lights visible from outside

Colors and Wavelengths

Crane flies might not be as particular about the colors or wavelengths of light as some other insects.

However, some research suggests that insects are generally less attracted to red or orange lights compared to brighter colors like white or blue.

A comparison of lights and their attraction levels to insects might look like this:

Light ColorAttraction Level
RedLow
OrangeLow
WhiteHigh
BlueHigh

To minimize the chance of crane flies and other insects being attracted to your home or outdoor area, you can consider using red or orange exterior lights.

These colors might be less likely to draw in insects, creating a more comfortable environment.

Benefits and Dangers

Crane flies are large, gangly insects with a slender mosquito-like body and long legs. They are often found around water and are attracted to light.

They can be both beneficial and detrimental to lawns. Their adult presence is harmless, while their larvae can cause damage to grass and its roots.

Leatherjacket Larvae

Leatherjackets are crane fly larvae, which are worm-like and live in the soil. They feed on the roots and crown material of turfgrass, causing brown patches and even killing off grass in certain areas.

These larvae typically hatch in the fall and cause the most damage during spring and winter.

Lawn Care and Prevention

Mowing and Watering

  • Regular mowing: Maintain your lawn by mowing it at the correct height regularly, which helps to promote a healthy root system and resist infestations.
  • Proper watering: Provide adequate water for your lawn, as dry or stressed grass is more susceptible to leatherjacket larvae damage. Be careful not to overwater, as leatherjackets thrive in damp conditions.

Monitoring and Maintenance

Inspect your grass regularly for signs of leatherjacket larvae, particularly in the fall or winter months. Keeping a healthy lawn will aid in preventing infestations in the first place.

If signs of leatherjacket larvae are present, such as brown patches, try to remove as many larvae as possible by hand. In more severe cases, professional help may be necessary.

Infestations and Management

Chemical treatments can be used to eliminate leatherjacket larvae infestations. However, consider the following pros and cons before resorting to chemicals:

Pros:

  • Effective in eliminating existing infestation
  • Provides immediate relief to lawns

Cons:

  • May harm beneficial organisms in the soil
  • Possible negative impact on the environment

An alternative to chemical treatments is biological control, which involves using beneficial organisms like nematodes to manage pest species.

This pesticide-free method helps suppress fly larvae and is considered more environmentally friendly.

Natural Predators and Control Methods

Birds and Bats

  • Birds: Several bird species such as robins and swallows feed on crane flies.
  • Bats: Bats consume crane flies during night flights.

These predators help control crane fly populations by eating them in their larvae and adult stages.

Insectivorous Animals

  • Skunks: They dig up crane fly larvae (worms) from soil.
  • Worms: Earthworms consume organic matter, outcompeting crane fly larvae.
  • Nematodes: A biological control method, a specific parasite targets crane fly larvae.

Insectivorous animals are useful for curbing crane fly infestations in lawns and gardens.

Chemical Control Methods

MethodProsCons
ImidaclopridEffective insecticideHarmful to bees; not organic
Neem oilOrganic, safe for beneficial insectsLess effective than synthetic options
PyrethroidFast-acting insecticideToxic to aquatic life

In addition to chemical control methods, using repellents like garlic and essential oils can help deter crane flies without causing harm.

Remember to always follow proper guidelines when using chemical controls and opt for eco-friendly solutions when possible.

Crane Flies and Human Interaction

Crane flies are often misunderstood due to their appearance and behavior. Some common misconceptions include:

  • Giant mosquitoes: Crane flies, also known as mosquito hawks or mosquito eaters, do not bite humans or feed on blood.
  • Mosquito predators: Despite their nickname, crane flies do not eat mosquitoes.
  • Harmful: These insects are actually harmless and do not transmit diseases.

Do Crane Flies Bite?

Crane flies are not known to bite humans or animals. Though they have a proboscis, they use it for feeding on decayed organic matter, not for biting.

Mating Tiger Crane Flies

Minimizing the Presence of Crane Fly Indoors

To minimize the presence of crane flies indoors, it is essential to consider some preventive measures:

  • Seal entry points: Check for cracks around windows and doors and make sure to seal them.
  • Install window screens: Installing window screens helps in preventing the entry of crane flies and other insects.
  • Proper lighting: As crane flies are attracted to light, using yellow or sodium-vapor outdoor lights can help reduce their presence near buildings.

By understanding crane fly characteristics and taking preventive measures, one can minimize the crane fly’s presence indoors.

Conclusion

Crane flies have a distinct inclination towards light sources, a behavior shared by some other insects like moths. Their natural behavior makes them gather around sources of light, such as doors with exterior lights and indoor lamps that are visible from outside.

By adopting measures such as using red or orange exterior lights and sealing entry points, you can effectively manage the presence of crane flies indoors.

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 – Wingless Winter Crane Fly or Snow Fly

unknown insect
Mon, Dec 29, 2008 at 8:07 AM
I don’t even know what order to start searching. On a winter day (30degreesF) I found this insect crawling on the sidewalk near the entrance to a storage area in our nature center. I had just been in the storage area so it is possible that I displaced it from the heated area into the cold.

It caught my eye because a.) it was a bug crawling around on a cold winter day, b.) it looked/moved like a spider but wasn’t. As you can see from the photos, its about 1/4 inch long, not including legs.

Also, it occasionally pulled its legs in very tight to its body in a posture that seemed defensive. I was unable to get a photo of that because it never stayed that way for long.
Thanks for your awesome website. You might want to create some forum/support group for WTB addicts like me who check your site 3 times a day.
Vince
Northern Indiana

Wingless Winter Crane Fly
Wingless Winter Crane Fly

Hi Vince,
Thanks so much for your kind letter. We were a bit stumped by this image as well, so we contacted Eric Eaton before posting. Here is what we wrote to Eric and how he responded
Hi Eric,
I didn’t want to appear to be a total moron on this one, so I didn’t
want to post it until I contacted you. It sure looks like a fly to me, possibly
a type of crane fly, but I’m not having any luck with the ID. Can you
assist?
Daniel

Wingless Winter Crane Fly
Wingless Winter Crane Fly

Daniel:
Oh, wow, what a cool find! This is a wingless crane fly, probably in the genus Chionea (known as snow flies). We could use this image over at Bugguide where Chen Young could probably ID it to species.
Eric
P.S. insects can make a moron out of ANYBODY! LOL!

So Vince,
We are hoping you will post these images to BugGuide as well and we will contact Dr. Chen Young at the Crane Flies of Pennsylvania website to see if he can provide a species identification. He may also request permission to post your images.

Vince wrote back, but we missed it
I found it…
Tue, Dec 30, 2008 at 7:05 AM
Yesterday I sent a pic of a mystery insect. Later in the day, after emails to entomologists around the world, I found out that the insect is a wingless snowfly. It’s related to craneflies and is in the genus Chionea. Here are two good links about snowflies:
http:// somethingscrawlinginmyhair.com/2008/01/19/snow-fly/
http://iz.carnegiemnh.org/cranefly/limoniinae.htm
and one more picture, with the brightness enhanced.
Vince
Northern Indiana
Thanks a million. Check your INBOX for a follow up submission I sent. I was able to ID it, and found some links to some good info on it. I’ll be sure to contact Eric Eaton and Dr. Young about it.
As a naturalist, I do school programs and public programs for thousands of people every year. Insects are my favorite topic and whenever I do an insect program I am sure to tell people about your website.
Keep up the good work.
Vince

Letter 2 – Crane Fly: male Ctenophora nubecula

possible ichneumon wasp?
June 10, 2010
Hi Bugman,
I was wondering if you could help me identify this insect–I was thinking it was some sort of ichneumon wasp? I found it fluttering around on the ground; it was around 1.5″ long. I think the antennae are fascinating!
Dakota
Western North Carolina

Crane Fly:  male Ctenophora nubecula

Hi Dakota,
This is sure an interesting Crane Fly.  The feathered antennae are very distinctive.  We are going to begin searching the Crane Flies of Pennsylvania website in the hopes of properly identifying this spectacular Crane Fly.  The closest match we found, but one that is definitely not your species, is Limonia (Rhipidia) duplicata (Doane) on the Limoniinae subfamily page.

BugGuide has an image of a Crane Fly from Alaska in the genus Ctenophora that also has pectinate antennae, but again, it is not a match.  We went back and looked at the genus Ctenophora on the Crane Flies of Pennsylvania website and we believe it must be the correct genus, but still no hit on species.  We will try to write to Dr. Chen Young for assistance.

Dr. Chen Young provided identification
Hi Daneil,
This is a male Ctenophora nubecula  http://iz.carnegiemnh.org/cranefly/tipulinae.htm#Ctenophora_(Ctenophora)_nubecula and here is a key http://iz.carnegiemnh.org/cranefly/idkeys.htm#23A to tell all the Ctenophora species apart in east North America.
Daneil, I was wondering if you would ask the person submitted the images if it would be okay for me to post these two images on the PA crane fly website.  The second image truely showed the characters of the structure of the antennae of this species.  A higer resolution of the images would be much appreciated.
Thanks,
Chen

Thanks so much for all the information, and the speedy response! I would love to have my photos on the crane fly website. If he or any of his crane fly brethren come around again, I’ll try to capture a few shots.
Thanks again,
Dakota

Hi Daniel,
Thank you for all of your efforts and the images.  Please also give my regards to Dakota.
Best wishes,
Chen

Letter 3 – Unknown Fly from Malaysia

Subject: What kind of bug is this?
Location: Malaysia
December 10, 2013 3:38 am
I found this weird-looking insect during my holiday in Malaysia. What is this? I think, this is possibly a type of mosquito.
Signature: Lanzz

What's That Bug???
Possibly Crane Fly

Dear Lanzz,
We have no idea what this insect is, but we do not believe it is a Mosquito.  Our best guess is a Crane Fly, but it is a very unusual Crane Fly.  Perhaps one of our readers will be able to supply a comment with an answer.  We apologize, but our allotted time for research has expired and we have to head for work to give a final examination.

Erwin provides an interpretation
Subject: unknown Malaysian insect
December 11, 2013 3:12 am
Hi,
I would like to give an interpretation of the strange photo presented by Lanzz.
In my eyes there is a dead stick insect lying on the ground, with two legs missing. A tiny part of one of these missing legs can be seen near the insect. And I see another planarium-like creature or maybe a slug attached to the body of the stick insect and maybe feeding on it.
(I know my English is not 100% perfect, but I hope I can make myself understand)
Signature: Erwin Beyer

Close up showing hidden antennae
Close up showing hidden antennae

Update:  December 11, 2013
We are posting an enlarged view in response to Erwin’s comment.  In a lower resolution image, Erwin’s explanation seems possible, however, we took a vertical image of the insect on a wall and rotated it to maximize its size on our site.  The original file was reduced in resolution to be web compliant. 

This appears to be a pair of wings held above the body.  At the right of the image, partially obscured by the leg, is the head with tiny antennae.  We do not believe this is a dead Stick Insect being eaten by a Planarium.  We are not certain that it is a Crane Fly, but we do believe it is a flying insect.

Letter 4 – Brachypterous Crane Fly

Subject: Orthopteran? Wingless Crane Fly? in Alameda, California
Location: Alameda, California USA
March 14, 2015 9:59 pm
I have been trying to figure out what bug this is all day. Body and legs seem vaguely Orthopteran, but then the back legs aren’t really bigger like they are in grasshoppers and crickets.

The head looks a bit like a crane fly, but then where are the wings? I’m stumped. This bug is approximately one inch long, spotted bayside in Alameda, California.
Signature: msLaura

Wingless Crane Fly
Brachypterous Crane Fly

Dear msLaura,
This is most definitely not an Orthopteran, and we agree with you that it appears to be a Crane Fly.  We have posted images of wingless Crane Flies also known as Snow Flies in the past, but your individual does not look much like a member of the genus
Chionea.

Your individual may have experienced some type of trauma causing the loss of wings, or there may be another explanation.  We will attempt to contact Dr. Chen Young of The Crane Flies of Pennsylvania to see if he has any ideas.  We will also contact Eric Eaton.

Dr. Chen Young responds
Hi Daniel,
This is a normal brachypterous form (small winged, short winged) female crane fly, most likely in the Tipula (Triplicitipula) group, it will need a male specimen to know the identity of this female.

Thanks,
Chen

Fantastic, thank you very much!
Warmly,
Laura

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.

    View all posts
  • 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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6 thoughts on “Are Crane Flies Attracted to Light? Debunking Common Myths”

  1. Hi, this is not a dead Stick Insect being eaten by a Planarium.

    It have six leg , and it can fly. The size of this insect is approximately 10 mm long. I found many of these on the wall of my house.

    Reply
    • This insect is not missing any legs. It legs is in a weird position.
      – Two legs in front (straight position).
      – Two legs in the middle near the head (in the bent position)
      – Two legs behind (straight position).

      Reply
    • Though Dr. Chen Young did not fully explain this variant on normal Crane Flies, we got the impression it was genetic variation rather than genetic mutation, but we may be wrong.

      Reply

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