Dobsonflies are aquatic insects that spend nearly all their lives in water. But when they come out – are Dobsonfly dangerous? Their huge size and pincers certainly indicate so, but let’s be sure.
Huge pincer-like jaws on a giant insect are a clear indicator of how dangerous it is, right? Wrong.
The jaws may look dangerous, but the bigger the jaws are, the more effort it takes to generate a sharp, biting force.
Dobsonflies are the best example of this. These insects have extremely long jaws, but surprisingly, they can barely cause any damage to humans through their bites.
But the same is not true for all kinds of dobsonflies. Confused? Well, don’t be. In this article, we will discuss which dobsonflies can hurt humans and how dangerous they are.
What Are Dobsonflies?
Dobsonflies are one of the largest insects found in various regions of North America. They have pincer-like mandibles that can almost grow up to an inch in length.
However, if you look closely, adult males have comparatively bigger mandibles than females. This gives them a scarier appearance.
The various species of dobsonflies are aquatic insects; they prefer to stay near clean water bodies.
Also, they are nocturnal in nature and are active throughout the spring and summer.
If we exclude the size of the jaws, an adult dobsonfly can easily range from 2-4 inches in length. The Eastern Dobsonfly has an enormous wingspan of 5 inches.
The overall appearance of the body adds to the frightening factor. They are usually dark in color and have grayish-brown wings with distinct vein-like patterns.
Are Dobsonfly Dangerous To Humans?
Male adult dobsonflies might look fearsome with their enormous mandibles, but these jaws are just for show.
The chewing muscles are not strong enough to transfer a strong enough force to the tip of the mandibles to generate a strong bite force.
The female has shorter mandibles and can hurt humans by biting.
Can They Bite Or Sting?
Yes, they can bite, but as mentioned above, the males are not capable of delivering painful bites. The female dobsonflies have smaller jaws and can generate enough biting force to break past the human skin and trigger pain.
Are They Poisonous?
No, dobsonflies are not poisonous. Yes, the bites from the female can be a little too painful to handle, but they won’t show any long-term fatal effects on your body.
Are They Dangerous To Pets or Other Animals?
No, these types of insects are not harmful to pets. The bites can be an alarming factor here, but they won’t have any long-term effects.
Since these insects live mostly around clean aquatic bodies, the chances of your pet encountering one are less.
Are Dobsonfly Larvae Dangerous To Humans?
Larvae of dobsonflies are called hellgrammites. These aquatic insects are underwater predators and are found in clean and cool bodies of water.
Hellgrammites prefer to hunt in high water currents. Unlike adult males, hellgrammites have small and sharp pincers.
Adding to that, they are blessed with strong chewing muscles that help them to generate strong biting forces.
This means dobsonflies, during their larval stage, can hurt humans through their bites.
But again, these bites are not poisonous, and moreover, you are unlikey to meet one unless you steup into water.
Symptoms of Larval Bites?
When a hellgrammite bites, you will feel a strong surge of pain near the wound. The bites are strong enough to cause bleeding, irritation, swelling, and redness.
Thankfully, these symptoms are temporary; the pain will subside quickly.
What To Do If You Get Bitten?
If you get bitten by a dobsonfly, there is no need to panic. Yes, you will feel pain, but it won’t last long. Wash the wound with clean water and apply some antiseptic to avoid allergic reactions.
How To Get Rid Of Dobsonflies?
We have already mentioned that these aquatic insects are not dangerous for humans. Therefore if you find them near your house, it is okay to leave them be.
They won’t cause any damage, and since they have a short life cycle as adults, they will disappear quickly.
Also, dobsonflies prefer to lay egg masses near water bodies. The chances of them laying eggs indoors are close to zero.
If you are hell-bent on driving them out instantly, you can use the and powdered insecticide.
Create a solution of it by mixing an ounce of the insecticide with one-gallon water. Put the solution in a spraying bottle and sprinkle it on areas where you spot these insects.
Also, they are attracted to light sources. Therefore try to keep the porch lights off at night to avoid them.
Frequently Asked Questions
What Is A Dobsonfly Good For?
Dobsonfly larvae can be used to determine the quality of water in various streams, ponds, lakes, and more. The insects prefer to live in clean waters and well-oxygenated waters.
If the water is polluted, the larvae won’t be able to survive. A good dobsonfly population in water is an indicator that the water is clean.
Why was a Dobsonfly in my house?
Dobsonflies usually do not enter homes, but if you find one loitering inside your house, it must have been lured in by lights.
These insects are nocturnal and get instantly attracted to a light source in the dark. As soon as they spot a source, they start flying toward it.
What does a Dobsonfly eat?
Adult dobsonflies do not eat. They prefer to survive using the fat storage built during the larval stage. The immature dobsonflies, on the other hand, are great hunters.
They live in fast-flowing water and are excellent at hunting small aquatic insects and fishes. They, too, have sharp pincers-like jaws to clamp the prey and tear to tear it down.
How painful is a dobsonfly bite?
Male dobsonflies are harmless. Despite having enormous mandibles, they can’t generate strong enough biting force to cause pain.
Female dobsonflies have shorter mandibles but can produce enough biting force to break past the human skin and cause bleeding.
The bites are painful, but they don’t cause any long-term fatal effects.
Lastly, the larvae, ie, hellgrammites, can bite and yes, their bites are painful as well piercing to the human skin.
Where do dobsonflies lay their eggs?
They always lay eggs near water bodies. Female dobsonflies prefer to lay eggs on various structures or objects flowing above the water surface.
Sometimes if they don’t find a nearby floating object, they switch to the rock near different clean water bodies like streams.
Wrap Up
Dobsonflies may look like tiny demons, but they are a classic example of why appearances can be deceptive.
The males in particular, are entirely harmless. The female can have the capacity to deliver painful bites, but these bites won’t cause any fatal injuries or illness.
Adding to that, these aquatic insects barely invade homes and will cause no damage to household items and crops.
In fact, they are great for determining the water of various streams and lakes.
Use the information given in the article to identify which dobsonflies can bite and try to be careful around them. Thank you for taking the time to read the piece.
Reader Emails
Female dobsonflies can leave a major pinch on your skin, and many of our readers have experienced it over the years.
Read through some of the emails, watch the pics, and also learn about some of these experiences that we have learnt from the precious letters from our audience.
Letter 1 – First Male Dobsonfly posting of the season
Geographic location of the bug: Connecticut
Date: 06/25/2021
Time: 07:41 AM EDT
Your letter to the bugman : Found this in our yard, near our woods.
How you want your letter signed: Dogmom
Dear Dogmom,
Because of their large size and frightening appearance, Dobsonflies are one of our most common summer identification requests. Despite his scimitar-like mandibles, this male Dobsonfly is perfectly harmless. The much smaller mandibles on the female Dobsonfly are more functional and she can produce a painful pinch that might even draw blood.
You rock!!!
Thanks so much!
Ellen
You are most welcome Ellen, and thanks for acknowledging that we rock.
Letter 2 – Male Dobsonfly Corpse found in Maryland
Geographic location of the bug: Maryland back yard Harford co
Date: 10/04/2021
Time: 08:15 AM EDT
Your letter to the bugman: Found this dead bug in the yard never seen one before looks like it came from nars
How you want your letter signed: G8R8RALL
Dear G8R8RALL,
Your image of a male Dobsonfly corpse is quite impressive, but living male Dobsonflies are even more impressive. Despite their fierce appearance, they are perfectly harmless, though the female Dobsonfly can bite (no venom) with her considerably smaller mandibles. The larvae of Dobsonflies are known as Hellgrammites, and they might also bite. They are considered prize bait by fishermen.
Thank you so much are They prevalent in Maryland literally this is the first one I’ve ever seen definitely never seen a live one how do they where do they hang out and how can you find them and thank you very much again
Hello again G8R8RALL,
Our original response contained links to additional postings on our site that should answer your questions.
Letter 3 – Dobsonfly from El Salvador
We found this on our window sill the other day here in San Salvador. Can you help me identify it? I’ve never seen anything like it.
Thanks,
Scotty
Hi Scotty,
You have an impressive specimen of a male Dobsonfly. I don’t know the exact species as I am only familiar with the species found in the continental U.S. We have gotten reports of male Dobsonflies that reach four inches in length. The males have the scary looking pincher jaws, but the smaller mandibles on the female are more capable of delivering a bite.
Thanks for the information. We do run across all sorts of strange stuff here that we can’t identify. Since we live up in a coffee plantation both my wife and I have been bitten by scorpions. Talk about a pop. 
The Dobsonfly that we had was the length of a key. I’ll forward you another photo that shows his size. Again, thanks for the help.
Scotty
Letter 4 – Dobsonfly from India
Mon, Apr 6, 2009 at 10:08 PM
Hi! This 14 cm long creature was calmly resting at the verandah of our hotel in Shillong, Meghalaya state (North-East India). Apparently he came attracted by very bright lights at night. He stayed at the same spot overnight, lazily responding to our attention with very slow motions of his head. In the morning, we took a piece of paper and managed to make him move and step on it, so that we could put him under a tree in the pine-tree forest which’s around. Half an hour later he was still there, but looked more jovial and was climbing over some grass.
Tatiana
Shillong, Meghalaya state; altitude: 1800 m.
Hi Tatiana,
Wow!!!! That is an impressive Dobsonfly. Beginning in May and continuing for a few months, We get reports of smaller Dobsonflies from North America. We have also had Central and South American specimens submitted to our site, but to the best of our recollection, this is the only Asian submission. Dobsonflies are impressive insects. Your specimen is a male, as evidenced by his greatly developed mandibles. The female Dobsonfly, though her mandibles are not as impressive, is a more adept biter, and she will bite if threatened, but all that will result is a pinching sensation. The insect is quite harmless. The aquatic larval stage is known as a Hellgrammite. According to the New World Encyclodedia online, there are numerous species in India, and we cannot provide you with an exact species name.
Letter 5 – Dobsonfly from Ecuador
Jul 11, 2009
Large winged moth like thing with big pincery bits
This is Arnold, who is larger than the palm of my hand and turned up every night at about 8pm when it was dark and the light was on, and seemed to really like landing on me. The pincery bits don’t appear to be mandibles, and are quite hard to the touch. Arnold brought his wife along one night, and she lacked the pincers. I have never seen anything like this, and would love to know what you think!
Leigh McIvor
Cloud Forest, 2000m.a.s North Western Ecuador
Hi Leigh,
Arnold is a male Dobsonfly. Though we are uncertain of the exact species in Ecuador, it seems that Dobsonflies from around the world are quite easily identified. Your photo showing the spread wings is quite impressive.
Letter 6 – Dobsonfly from Costa Rica
January 20, 2010
Hello a friend of mine who lives in Costa Rica took this photo while seeing a patient. He said it kept tapping the window cause it was trying to get in. He also said he could sense evil from it…
Alex Anico
Costa Rica
Hi Alex,
Despite looking diabolical, this male Dobsonfly is perfectly harmless. The female with her smaller mandibles, on the other hand, might deliver a painful pinch if carelessly handled.
Letter 7 – Dobsonfly from Japan
Geographic location of the bug: Fussa, Japan
Date: 07/14/2018
Time: 02:29 AM EDT
Your letter to the bugman: I saw this big insect at church today. A Japanese man told me they call it a dragonfly and that it bites.
How you want your letter signed: Ms. Beth
Dear Ms. Beth,
This is not a Dragonfly. It is a Dobsonfly or Fishfly in the family Corydalidae, and females have formidable mandibles that might even draw blood if they bite, but they are not considered dangerous. We believe we identified the species as Protohermes grandis on The Royal Society Publishing site. We verified that on Minden Pictures.
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