Dobsonfly Defense Mechanism: Explained

folder_openInsecta, Megaloptera
comment12 Comments

How do dobsonflies ward off their predators? Does their large size keep others away, or do these insects also fall prey to bigger animals and bugs? Here are some interesting dobsonfly defense mechanisms that are unique to them.

 

The Dobsonflies are one of the most fascinating aquatic insects, with over thirty species found in North America, Canada, and Mexico. 

These large creatures (some of them can grow up to five inches) with scary-looking pincers on their front can be enough to make you run away from an average Dobsonflies. 

But in their natural habitat, how do they protect themselves? In this article, let us explore the life and behavior of the Dobsonflies. 

 

Dobsonfly Defense Mechanism: Explained

 

Dobsonfly Defense Mechanisms

Like any other type of insect or animal in the wild, Dobsonflies have a wide range of special defenses against predators. 

These creatures are built differently, with pincers, jaws, and wings that help them survive and keep natural hunters away. 

Their Large Mandibles

The first thing you will notice about adult male dobsonflies is their large mandibles in front of their head. These are shaped like sharp sickles. 

These mandibles are used during mating or as a defense against other males. The mandibles make up almost the whole head and can grow up to 1 inch in length

Adult males have mandibles larger than females. They use these to attract and hold the females during mating. However, these are not powerful enough to pierce animal skin. 

On the other hand, the mandibles of the females are short and sharp. These do not contain any venom but are enough to inflict painful bites on predators, including unsuspecting humans.

 

Dobsonfly Defense Mechanism: Explained

 

Foul Odors

Dobsonflies have a chemical defense to their advantage, common to many other insects. 

The insects have Malpighian tubules as part of their excretory system, which releases a foul-smelling anal spray. 

This mechanism is often used as a last resort to ward off their enemies. 

Their Size

Humans, as well as animals, are intimidated by the large size of these creatures. For natural predators of the Dobsonflies, their size itself becomes a defense mechanism. 

These insects can grow up to 5 inches long, with a wingspan about twice the size of their bodies. 

The larva of Dobsonflies, commonly called Hellgrammites, also grows between 2-3 inches

These insects are considered one of the largest insect predators in the water, eating worms, different types of flies, and small fish. 

The size of Dobsonflies is one of the reasons that most predators stay away from hunting them. 

Hellgrammite Defense Mechanisms

Hellgramites are the larval form of Dobsonflies. These are comparatively smaller than adults but are still one of the largest aquatic insects. 

The larvae have their own defense mechanisms, which are effective in protecting themselves from their predators. 

 

Dobsonfly Defense Mechanism: Explained

 

Eggs laid out like bird droppings

Birds are one of the major predators of Dobsonflies and Hellgramites, so the insects have found a unique way to protect themselves in plain sight. 

Dobsonflies lay eggs in clusters, arranged in three layers, and the mass is covered by a clear fluid that turns white over time. 

The eggs resemble bird droppings which most birds or predators ignore. Therefore, making it the perfect hiding spot for the eggs and newly hatched larvae. 

Sharp Pincers

Hellgramites resemble adult Dobsonflies in terms of the structure of their mouth. These insects have very sharp mouthparts that can easily pierce the skin of animals. 

Like adults, the male larvae do not have sharp pincers to pierce. Female hellgramites have pincers that can pinch, cause painful bites to animals, and even draw blood. 

Frequently Asked Questions

Can a dobsonfly hurt you?

Yes, there is a chance that female dobsonflies can hurt you if you handle them incorrectly.

These insects have sharp pincers that can pierce the skin of humans and animals. 

Female dobsonflies are the only ones that have these sharp mandibles, however, and can cause painful bites. The males cannot do it.

 

Dobsonfly Defense Mechanism: Explained

 

How does the dobsonfly fight?

Dobsonflies use their large mandibles if they have to defend themselves against other potential mates of their love interest. 

For females, the mandibles are the greatest defense mechanism they have. They use these to keep away any threat and pierce the enemy, causing painful bites. 

What do dobsonflies turn into?

Dobsonflies are the final life cycle of the insect. They hatch into larvae called Hellgramites which live underwater for two to three years. 

After pupating for a brief period, they hatch into winged insects called Dobsonflies. The adult dobsonflies live for only about a week, and their only purpose is to mate and produce their offspring.

Why dobsonflies are called hellgrammites?

There is no specific answer to the etymology of Hellgrammites. 

Historically, fishermen are known to call aquatic bait hellgramites. 

These insects are used to this day as effective bait to catch fish. However, the origin of their names is unknown. 

Wrap Up

Whenever we find a scary-looking insect, our first resort is to get them out of the way and avoid them. It works as a defense mechanism against something we consider a threat. 

Similarly, a threatening appearance or chemical release is the defense mechanism for creatures like the Dobsonflies. 

The important thing to remember is that it is all part of nature’s fascinating way of protecting every creature in its unique manner. 

Thank you for reading, and look out for bug bites around the water! 

 

 

 

Dobsonfly from Peru

 

Dobsonfly from Peru

 

 






 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Hellgrammites captured for bait

 

 

Authors

  • 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.

    View all posts
Tags: Dobsonflies

Related Posts

12 Comments. Leave new

  • I live on the Delaware River and each year we have the hellgramites crawling up to our house, sometimes even in our house (we have found them in our bed).Someone left the screen on the slider open a crack. The way this man described the crawling is exactly as we see it each year, and then when they metamorphasis into the adult dobsonfly is a sight to behold, hundreds of these creepy critters flying in the night. As I write this letter I have a dozen adults on the side of my house. AS WE SAY EACH YEAR THERE HERE!!!

    Reply
  • The mandibles are very megalopteran (like a dobsonfly or fishfly), but it’s difficult to decipher the appendages that should be at the end of the abdomen. Definitely need more info on the kind of water the leaf pack was placed in, where the leaves came from, etc. Megalopterans need oxygen from flowing water, so this critter may actually be an aquatic beetle larva of some kind, which can tolerate lower oxygen levels.

    Reply
    • Thank you for your input. We never received any further information, and we are still quite curious what this “experiment” was expected to produce.

      Reply
  • Kristy Jeffries
    July 12, 2015 1:30 pm

    Great info – thanks. We found a large female on our garage door – we live in Northern Virginia near DC. I remember a huge swarm of these on my grandparents farm in Monroe County, WV and also recall them when we fished at Smith Mt Lake, but this is the first one I’ve seen in the DC area. Our house backs to a Potomac River tributary with a dam but it does have moving water. Should we anticipate a large hatch of these coming out of the water this summer? Hoping not.
    Thanks again!
    Kristy

    Reply
    • Insect populations vary from year to year, but if conditions are right, you can experience large numbers.

      Reply
  • Kristy Jeffries
    July 12, 2015 1:30 pm

    Great info – thanks. We found a large female on our garage door – we live in Northern Virginia near DC. I remember a huge swarm of these on my grandparents farm in Monroe County, WV and also recall them when we fished at Smith Mt Lake, but this is the first one I’ve seen in the DC area. Our house backs to a Potomac River tributary with a dam but it does have moving water. Should we anticipate a large hatch of these coming out of the water this summer? Hoping not.
    Thanks again!
    Kristy

    Reply
  • that bug is giant

    Reply
  • What time of year can these be found in the meramac river in Missouri

    Reply
  • Is it rare to find in durham nc? Have pics if needed. Weirdest thing ive seen in awhile. Tyvm for the info. Very helpfull

    Reply
  • looking to purchase hellgrammites, do you sell them and ship to places in wisconsin?
    what do you charge if you do sell and ship them?

    Reply
  • looking to purchase hellgrammites, do you sell them and ship to places in wisconsin?
    what do you charge if you do sell and ship them?

    Reply

Leave a Reply

Your email address will not be published. Required fields are marked *

Fill out this field
Fill out this field
Please enter a valid email address.
You need to agree with the terms to proceed

keyboard_arrow_up