Well, I hope everyone enjoyed their weekend as much as I did. I really do love this time of year! It has been awhile since I did a fact about an insect so I thought I would devote today’s Wild Fact to the Dobsonfly.
If you look at the picture, this looks like the most vicious insect in the world. They are a large insect that can reach up to 12.5 cm (5″) in length. For the record, that is almost half a foot! Even crazier is the fact that the male dobsonfly will grow tusks (or mandibles) that can reach about 1″ in length. The females also have mandibles but they are substantially smaller than the males. Like a lot of insects, the adult version (pictured above) do not actually feed and are fairly short lived. They spend most of their life in the aquatic larvae form where they can live up to 3 years and are very predacious.
So if the adult dobsonfly does not feed then what the heck is the purpose of the huge mandibles. Obviously, they are used to scare people into thinking they are the most deadly insect on the face of the earth. Actually, they are used to impress the ladies. That’s right, the dobsonfly studs will show off their impressive tusks to their mating partner. They are also used to hold the female during copulation. I wanted to write about this insect to illustrate that mating adaptations are common throughout the animal kingdom. Not only with mammals or reptiles but with the more primitive animals such as crustaceans and insects. Mating plays such an important role in evolution since it can decide the fate of an entire species. You may have noticed that most of the adaptations presented so far have to do with self defense or mating. If it is the survival of the fittest then these are the strategies that need to be perfected in order for a species to make it to the next generation.
Dobsonfly Fast Fact: The mandibles on the male dobsonfly are so large that they are actually incapable of biting a human. They are not able to get enough leverage to do any harm. The female dobsonfly, on the other hand can use her pincers to inflict a painful bite.
Hi Nathan, just thought I would drop by and say hello. Love your Pee Wee Herman analogy when you commented on my blog. Take care and keep up the good work.
Walt AKA All Sports on the Web
Thanks for stopping by, Walt!
I love reading your blog and your take on everything sports related!
O.K.now you have me curious. If the dobson fly stays as a larvae (and doesn’t feed) for about 3 years. How long does he last once he becomes a male adult (that resembles the picture above) if he doesn’t feed?
Thanks!
I am sorry if I was confusing in my fact. When the dobsonfly is in the larvae form they are very predacious and feed often. Only in the adult form to they take their diet and stop feeding. This would be why they only live about 7 days as an adult.
I hope this clears it up.
Have a great day!
I recently encountered a male dobsonfly and got a surprise defensive move when i attempted to hold a wing in order to keep it still while i studied it.the insect squirted a stream of yellowish clear fluid from the end of its tail between a pair of smaller mandibles. Please ellaborate thanx, science guy
Hey Science Guy,
Thanks for the great question and for sharing your story. Here is a little bit more information on the defense mechanisms of the dobsonfly. First of all it is important to know that the large mandibles of the male dobsonfly are pretty much harmless and are used for mating purposes. The mandibles of the female are much smaller and less impressive but can offer a pretty good pinch and will be utilized for self defense. Both males and females will usually raise their heads high and spread their mandibles as wide as they can. Basically, they are trying to scare the pants off of the incoming predator. If this doesn’t work than they will resort to their last line of defense. You were “lucky” enough to experience this. They will spray this irritating, foul-smelling chemical. Fortunately, this substance is not poisonous and won’t really hurt humans. This would probably irritate the heck out of another predator though.
I hope this helps.
Thanks again for stopping by Wild Facts.
Have a female clinging to my door frame at the present time. Very ominous looking creature. Can’t wait for my grandkids to have a look at it.