Crane flies are large, gangly insects that might look intimidating due to their size and resemblance to mosquitoes. However, contrary to popular belief, crane flies do not bite or suck blood. In fact, most adult crane flies don’t even have mouths! Their main focus is on reproduction and, for some species, drinking nectar from flowers.
These insects spend a significant portion of their life as larvae, living in water bodies or damp soil. Crane fly larvae might cause damage to lawns by chewing through grass roots, but the adults are harmless to humans. So, next time you see a crane fly, there’s no need to worry about being bitten.
Crane Flies Overview
Characteristics of Crane Flies
Crane flies are members of the insect family Tipulidae, belonging to the order Diptera. They are characterized by their:
- Long legs
- Large eyes
- Antennae
- Ocelli (simple eyes)
Crane Flies vs Mosquitoes
Crane flies are often mistaken for mosquitoes due to their similar appearance. However, there are key differences:
| Crane Flies | Mosquitoes |
|---|---|
| Do not bite | Bite humans and animals |
| Harmless to humans | Transmit diseases |
| Adults do not eat | Feed on blood, nectar, or other liquids |
Role in Ecosystem
Crane flies play an important role in the ecosystem. Their larvae, known as leatherjackets, feed on decaying plants, contributing to nutrient cycling. Although some species’ larvae can be lawn pests, it’s important to note that adult crane flies are harmless, as they do not bite or sting.
Do Crane Flies Bite or Pose a Threat?
Are Crane Flies Harmful to Humans?
Crane flies, often mistaken for mosquitoes due to their slender body and long legs, are in fact harmless to humans. Although they share a similar appearance to giant mosquitoes, they do not bite or sting people.
Some key features of crane flies include:
- Slender mosquito-like body
- Extremely long legs
- Slow-flying insects
Are Crane Flies Dangerous to Pets?
Like humans, pets are safe from crane flies as they do not pose any threat or danger. These creatures are not venomous insects and primarily feed on plant nectar.
Comparison of Crane Flies and Mosquitoes
| Features | Crane Flies | Mosquitoes |
|---|---|---|
| Appearance | Slender body, long legs | Similar to crane flies |
| Biting behavior | Do not bite or sting | Bite and can transmit diseases |
| Threat to humans | Harmless | Can be harmful due to disease transmission |
| Threat to pets | Harmless | Can be harmful due to disease transmission |
| Feeding habits | Feed on plant nectar | Feed on blood (female mosquitoes) |
In summary, crane flies do not bite or pose a threat to humans or pets. They are harmless insects with no venomous properties, making them safe to coexist with in our environment.
Crane Flies Life Cycle and Habitat
Eggs and Larvae
Crane flies, also known as daddy long legs or leatherjackets, begin their life as eggs. They usually lay their eggs in:
- Moist soil
- Water bodies (rivers, lakes, and ponds)
- Wet leaves
Larvae emerge from the eggs, living in these environments for about 95% of their life, which can last up to three years or more1. They are small, brown, and tend to feed on roots and stems in moist areas.
Pupal and Adult Stages
After the larval stage, crane flies enter the pupal stage, transforming into gray to brown, non-feeding pupae2. Once they emerge as adults, they have two functional wings and a delicate, slim body about 1 inch long3. Crane flies are often found around water, thriving in:
- Gardens
- Pastures
- Meadows
Comparison Table
| Features | Larval Stage | Adult Stage |
|---|---|---|
| Size | 25.5-32 mm (1-1.25 inches)2 | About 1 inch3 |
| Feeding Habits | Feed on roots, stems, and leaves[^5^] | Do not bite or harm humans |
| Preferred Areas | Moist soil, water bodies, and wet leaves1 | Gardens, pastures, and meadows[^5^] |
As crane flies develop, they adapt to living in different habitats. Although adult crane flies resemble mosquitoes, they do not bite, thus posing no harm to humans.
Diet and Predators
What Do Adult Crane Flies Eat
Adult crane flies have a simple diet. They primarily consume:
- Nectar: Crane flies use their long mouthparts to sip nectar from flowers.
- Water: Adult crane flies don’t feed much but do drink water to stay hydrated.
While they may appear to be mosquitoes, they do not bite or feed on blood. In their larval stage, crane flies feed on decomposing plant matter, grass, and plants, which can sometimes cause damage to lawns or crops Oregon State University.
What Eats Crane Flies
Crane flies serve as a food source for various wildlife and insects, including:
- Birds: Many bird species prey on crane flies for a quick snack.
- Bats: Attracted by their flight, bats feed on crane flies.
- Skunks: Digging for crane fly larvae, skunks can damage lawns.
- Other insects: Predatory insects like spiders and predatory beetles hunt crane flies.
| Crane Flies | Mosquitoes | |
|---|---|---|
| Diet | Nectar, water | Blood, nectar |
| Predators | Birds, bats, skunks, insects | Birds, bats, insects |
Crane flies are not harmful to humans, unlike mosquitoes that can spread diseases. Their primary role is to serve as food for other species and to aid in the decomposition of plant matter in their larval stage.
Crane Flies as Pests
Damage to Lawns and Gardens
Crane flies (Tipulidae) are often mistaken for mosquitoes due to their similar appearance, but they are actually harmless insects that do not bite1. Despite being harmless to humans, crane fly larvae can cause damage to lawns and gardens. They are known for chewing through patches of grass, damaging roots as the grass starts growing in spring2.
Damage caused by crane fly larvae:
- Patchy grass
- Damaged roots
How to Prevent Infestations
To prevent crane fly infestations, here are some simple maintenance and irrigation practices that can help:
- Mow your lawn regularly: Regular mowing can discourage crane flies from laying eggs.
- Irrigation management: Overwatering your lawn can create a favorable environment for crane fly larvae. Ensure proper drainage and avoid excessive watering.
- Pesticides and nematodes: Apply insecticides or beneficial nematodes as a preventive measure. These can help control crane fly larvae populations in your lawn2.
Preventive measures:
- Lawn mowing
- Proper irrigation
- Use of pesticides/nematodes
Implementing these practices can help keep infestations at bay, ensuring a healthier lawn and garden.
Crane Flies and Disease
Crane flies, also known as mosquito hawks or daddy longlegs, are large, gangly insects that resemble mosquitoes. They are members of the fly family Tipulidae, order Diptera, meaning two-winged insects source. Crane flies have delicate, slender bodies and extremely long legs source. But, despite their mosquito-like appearance, they are not dangerous to humans.
Adult crane flies do not have the ability to bite or spread diseases. They are gentle insects, mostly found around water bodies and damp soil. Crane fly larvae, however, can cause damage to grass and plant roots, but they do not pose any threat to humans or pets source.
Unlike mosquitoes which can transmit diseases such as malaria, dengue fever, and Zika virus, crane flies are not vectors for any disease source. Therefore, there is no need to worry about health risks from crane flies.
Here is a comparison table between crane flies and mosquitoes:
| Feature | Crane Flies | Mosquitoes |
|---|---|---|
| Appearance | Slender body, extremely long legs | Smaller body, shorter legs |
| Biting | Do not bite | Bites and sucks blood from humans and animals |
| Disease | Harmless; do not transmit diseases | Can transmit various diseases |
| Larval stage | Damages grass and plant roots | Larvae do not typically harm plants; breed in standing water |
In summary, crane flies are distinctive insects that are often mistaken for mosquitoes. However, they pose no risk of disease to humans or animals, and there is no reason to be concerned about them from a health perspective.
Footnotes
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 – Tiger Crane Fly
Subject: wasp?
Location: Canby, Oregon
April 6, 2014 9:34 pm
This was sitting just outside my door. I live in Canby, OR (just south of Portland) and we’ve had wasps in our yard, but none ever looked like this. It looks similar to certain types of wasps, but this one seems more slender and with longer legs.
Signature: Bill
Hi Bill,
This really is a magnificent Crane Fly. We quickly located a matching image on BugGuide of a Tiger Crane Fly, Ctenophora vittata. Crane Flies are benign creatures that neither sting nor bite. Many years ago we received an interesting account of the mating activity of Tiger Crane Flies.
Interesting. Certainly haven’t seen any crane flies that look like that before.
Thank you very much for the info.
Bill
Letter 2 – Crane Fly
Orange wasp – interesting abdomen shape and stinger
Hello bug enthusiasts!
While rock climbing in Memorial day Rumney, NH, we spotted this wasp (?) on a backpack clip. It was pretty lethargic and about 1.25 – 1.5 inches long. It’s bright color pattern, curved stinger, and interesting abdomen shape caught our eye. My friend who referred me to your site looked it up but didn’t find a match – he thought maybe it was a pregnant wasp of some kind…any thoughts? Thanks,
Julie (Somerville, MA)
Hi Julie,
Though it resembles an Ichneumon, this is not a wasp. It is a Crane Fly. We have scoured the Crane Flies of Pennsylvania website and believe this is a species in the genus Ctenophora. It might be Ctenophora apicata, or possibly, Ctenophora dorsalis. We will contact the author of the site, Dr. Chen W Young, to see if he can provide a species identification. Here is Dr. Young’s response: “Hi Daniel, The image shows a female crane fly of Ctenophora dorsalis. This female does not have the typical coloration of most of the Ctenophora dorsalis, but as we have leaned that this species is highly variable in their body size and body color (See notes in website http://iz.carnegiemnh.org/cranefly/tipulinae.htm#Ctenophora_Tanyptera. However, the shape of the ovipositor on this images shows the typical shape of ovipositor in this species. I hope this answer your question. Thanks, Chen ”
Letter 3 – Giant Western Crane Fly
Subject: What is this bug!!!???
Location: Portland, Oregon
May 16, 2013 12:26 pm
Hi Bugman..
My friend took a pic of this in Portland, Oregon. People are saying it’s a spider, but it has 6 legs! Looks like it has wings and a snout~
Signature: Thanks, Clancy
Hi Clancy,
This is a Crane Fly. Those black “knees” look distinctive, so we attempted a web search to determine a species identity and we found a similar photo on the Fontenelle Nature Association Nature Search website that is identified as Tipula dorsimacula. Though the images on BugGuide also have black knees, we are not certain of the species being correct for your Crane Fly, so we are contacting Chen Young, a Crane Fly expert for his opinion.
Dr. Chen Young responds
Daniel,
This one is Holorusia haspera, the largest crane fly species in the western states.
Chen
Letter 4 – Crane Fly
Subject: Some sort of wasp?
Location: Unionville, IN
June 7, 2014 8:25 pm
My kids and I found this bug by our creek. We live at the base of a wooded ridge in a rural area. We are surrounded by both farms and forests in South Central Indiana. Got a clue?
Signature: Heather D
Hi Heather,
While it does look quite wasp-like, this is actually a harmless Crane Fly. We just posted a similar looking Crane Fly from the UK, but North America has its own distinct species. Your Crane Fly is Ctenophora dorsalis. According to BugGuide: “larvae develop in soft dead wood” and we believe the female uses her ovipositor to deposit her eggs in rotting wood.
Hi Daniel,
Thank you for getting back to me so quickly. I did see the picture of the Crane Fly on your site after I posted my question, but I am yet to find a picture in any of the American sites. All the Crane Flies I see here are the typical “Mosquito Hawk”. Now that you have given me the species name, I’ll look again. Where are you in the UK? I studied at the University of Kent for a year in college. … Thank you so much for your help!
Best
… Heather
Hi again Heather,
The offices of What’s That Bug? are located in beautiful Mount Washington, Los Angeles, California, but we field identification requests from all over the world.
Letter 5 – Crane Fly
Subject: Unknown bug
Location: St Paul inside kitchen
December 31, 2014 1:20 pm
Dead of winter in St Paulwhen this creature appears on the kitchen floor barely able to fly to the wall but he does! Body an inch long and
Beautiful variegated wings…what is it?
Signature: Frankie
Dear Frankie,
This harmless insect is a Crane Fly in the infraorder Tipulomorpha. We will attempt a species identification for you and we are quite curious about its appearance in late December.
Letter 6 – Crane Fly
Subject: Fly on door
Location: Near hedgesville wv
May 29, 2016 8:41 am
Just curious what kind of insect this is.
Signature: Chuck Becker
Dear Chuck,
This is a Crane Fly in the Infraorder Tipulomorpha. We are not certain of the species. Crane Flies are harmless.
Letter 7 – Crane Fly
Subject: Hornet?
Location: Holt, Michigan
May 28, 2016 5:35 pm
Found in mid-Michigan in a wood pile. He was disoriented and walking in the grass, and let us move him without any issue. Looks like it has a very large stinger.
Signature: Melissa
Dear Melissa,
We believe we have correctly identified this female Crane Fly as Tanyptera dorsalis, formerly Ctenophora dorsalis, thanks to images posted to BugGuide where it states: “larvae live in decaying wood of recently dead deciduous hardwood trees, often in prostrate trunks that are fairly sound.” This BugGuide image illustrates the female ovipositing using her egg-laying organ that you have mistaken for a stinger. The coloring and shape of this Crane Fly likely provides the species with some protection as it seems to mimic the markings on many stinging wasps.
Letter 8 – Crane Fly
Subject: Red and black mosquito eater
Location: Ben Lomond, CA 95005
March 19, 2017 7:31 pm
Had this bug land on my garage door and have never seen one like it. Looks similar to a mosquito eater crossed with a wasp?
Signature: Jeff whiting
Dear Jeff,
This is a Crane Fly, group of insects commonly, though falsely, called Mosquito Hunters. We believe your species is Phoroctenia vittata based on BugGuide images.
