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.
29 Comments. Leave new
Thank you so much for responding is such a timely manner on my insect query. Now that my knowledge of this type of insect is a little broader, I was shocked to see how common it was. Once again thank you.
James B.
WOW, I HAVE FOUND BOTH THE HELLGRAMMITE AND THE MATURE DOBSONFLY THIS YEAR. I THOUGHT I HAD SEEN ABOUT EVERYTHING IN OHIO, BUT THIS BUG REALLY SHOCKED ME AT IT’S SIZE. GREAT TO HAVE FOUND SUCH A NEAT SITE WITH OTHERS SO INTERESTED IN THE LITTLE CREATURES.
I found one in molalla river oregon.
We were fishing with them and one of the guys with us thought he had a bite but when he got it on land the hellgrammite had a bluegill pinched right between its eyes, he walked around showing all the other fishers and the hellgrammite wouldn’t let go.
Wow, so the Hellgrammite’s grasp was the only thing holding the bluegill on the line?
We had one of these crawling on our tent the other night near the Colorado River, 7 miles NW of Moab, UT. Scary looking guy.
I found somthing simular in color and species here in iowa back when we had very bad flooding eccept we caught one and it had hind pincers and was very fast and aggressive it might have been a hellgrammite species.
Found one under the rocks in the water in Stxy River Alabama of Co Rd 64. It was about 21/2 or 3 inches. I have been swimming in the river most of my life. I am almost 50. First one I ever saw. Took a bit to research and find out what it was. Nice to know they indicate whether water is polluted which is what I read on another bug site. Freaky lookin bug. Nice to know they are good for fishing…just think I may have a hard time finding enough. Thanks CJ
Dear friends, I have encountered that exact same insect and had video of it. I will dig it up if you ask it was 4 years ago and I have been searching ever since. Only thing is I saw it along the Delaware river just north of Easton Pennsylvania with my family. I took note because it seemed aggressive and it ran near my stepson. It’s size was large to me at the time, seemed to be rough guess 6 to 8 inchest long but looks exactly like the picture.
I’m 64 and as far back as I can remember my family gathered these for bait. The critter has skin tougher than shoe leather. Accordingly it’s not unusual to catch several fish on just 1. They were also referred to as rock lice. But regardless of the name..they are hands down one of ..if not the best .. bait in the stream.
Thanks so much for that information.
I saw one of these in vermont while trying to find a crayfish to use as bait…..it was under a rock tried to get a pic but lost it in the Rapids I didn’t want to touch it cause didn’t know what the he’ll it was
We always called them leatherheads where I grew up in northern California. They are great for catching trout in the creeks. We always called salmonfly nymphs hellgermites.
Thanks for providing an alternative spelling for Hellgrammite, a name with a murky origin, though the sound of the name is quite fitting for the creature.
They live under rocks along the South Branch of the Potomac in WV. The big ones are ugly and scary. They fly toward flourescent lamps in gas stations at night.
So is it a Hellgramite? We just caught one in my garage and I need to know if I should just burn down the garage or if it would be safer to burn down the entire block. So far it is still alive because none of us have the fortitude required to enter into battle with it. Really would like a solid answer as to what this thing is.
Update: As I was typing this up my friend Taco Dave went after it with a blow torch and a throwing axe. It is still alive and well but Taco Dave is not. Well he’s alive but he is not the same person he was going into this. He is pacing around outside repeating the phrase “Ive seen things man”. Taco’s little brother Burrito Bob is suiting up next. He has chosen a garden shovel and a 5lb sledge hammer. Update coming once the battle has ended. Send help if I dont post a reply within 45 minutes. There is a school 500 yards away ,the ball field can handle helicopters and some jets with short take off and landing capabilities. If we dont reply to people yelling within 5 minutes let the napalm fly. Godspeed
Omg!!! LMAO!! This was hysterical!???? I live in NE PA and just found a dead hellgrammite in my carport. Not sure how it got there? We do live near wetlands so it may have washed down the road during a heavy rain and wandered the 30ft to my carport??? Not sure what insect got to it first but it was filled with very large maggots! All that was left was the outer shell and the head!! Would’ve really liked to find it alive!!
So is it a Hellgramite? We just caught one in my garage and I need to know if I should just burn down the garage or if it would be safer to burn down the entire block. So far it is still alive because none of us have the fortitude required to enter into battle with it. Really would like a solid answer as to what this thing is.
Update: As I was typing this up my friend Taco Dave went after it with a blow torch and a throwing axe. It is still alive and well but Taco Dave is not. Well he’s alive but he is not the same person he was going into this. He is pacing around outside repeating the phrase “Ive seen things man”. Taco’s little brother Burrito Bob is suiting up next. He has chosen a garden shovel and a 5lb sledge hammer. Update coming once the battle has ended. Send help if I dont post a reply within 45 minutes. There is a school 500 yards away ,the ball field can handle helicopters and some jets with short take off and landing capabilities. If we dont reply to people yelling within 5 minutes let the napalm fly. Godspeed
Our readers are dying to know if there are any survivors.
Omg!!! LMAO!! This was hysterical!? I live in NE PA and just found a dead hellgrammite in my carport. Not sure how it got there? We do live near wetlands so it may have washed down the road during a heavy rain and wandered the 30ft to my carport??? Not sure what insect got to it first but it was filled with very large maggots! All that was left was the outer shell and the head!! Would’ve really liked to find it alive!!
We found two of these in Dinosaur National Monument this past weekend. We were in Utah and on the Green River. They were both long, fast and somewhat agressive. we do have a picture but its very similar to the one you have.
They are also called eastern Dobson fly, they do bite if threatened, and it can hurt.
I saw them a lot in Virginia Madison Heights/Monroe area, especially further up in the mountains. There it’s teeming with them, and they get massive. We used to fight them lol they were pretty aggressive. I just moved to Clayton, NC, and saw one got in the house, so I think I’ll he seeing more!
I was surprised when nobody else I showed knew what it was.
Also I learned I was taught wrong by that kid at camp (mountains, where it was teeming haha). He told me they were “Hellkemites” and another said “Hellgamites”.
Most everyone there did call them Hellkemites though.
I was confused when the search engine was like wtf is this?
I saw them a lot in Virginia Madison Heights/Monroe area, especially further up in the mountains. There it’s teeming with them, and they get massive. We used to fight them lol they were pretty aggressive. I just moved to Clayton, NC, and saw one got in the house, so I think I’ll he seeing more!
I was surprised when nobody else I showed knew what it was.
Also I learned I was taught wrong by that kid at camp (mountains, where it was teeming haha). He told me they were “Hellkemites” and another said “Hellgamites”.
Most everyone there did call them Hellkemites though.
I was confused when the search engine was like wtf is this?
I just found one crawling across my garage floor. New Hampshire. Slow moving .
They are called Helljamites…grandpa told us kids if one bites you you may live and helljamite not !!!
I’ve encountered a hellgrammite in the Virgin River within Zion National Park. I’ve got pictures.
I just saw one for the first time in 20 years of swimming in the virgin river at zion. Took a while to find out what it’s called
Similar seen along a river in Roswell, GA 5/1/2022.