Jaws with Wings

What on earth is this thing? It’s huge! It has gigantic wings! It has massive… ANTLERS coming off its face! Has someone had a nightmare that’s come to life or what?

~Joseph Jameson-Gould on dobsonflies from his blog, Real Monstrosities 

Dobsonfly male

Adult male Eastern Dobsonfly (click photos to enlarge)

On my daily wander in the yard yesterday, I happened to look up at the right moment and was surprised to find something that would end up occupying me for the next hour – an Eastern Dobsonfly, Corydalus cornutus. It blended in surprisingly well, given its huge size (this guy was a little over 4 inches in total length). It was in the shade, along one of the branches of a Redbud tree about ten feet off the ground. I ran and grabbed my camera and a tall stepladder to try to get a few images.

Dobsonfly male head with my finger for scale

Eastern Dobsonfly male head with my finger tip for scale

The large, sickle-shaped mandibles of the male are over an inch long and look like they could put a real hurt on you, but they are totally harmless. The females and larvae (known as Hellgrammites) can give a painful bite, but the males’ tusks cannot be closed hard enough to inflict pain. Males use them during the mating ritual (they lay them across the wings of the female. perpendicular to the axis of her wings) and they are presumably also used in jousting matches with other males. Seabrooke Leckie, a naturalist/writer (and one of my inspirations for why I finally started blogging) describes the mating ritual in one of her posts.

Dobsonfly male head 3

Eastern Dobsonfly close up of head

These really are impressive-looking creatures, especially the males, so I strained at getting close enough for photos while hanging off the stepladder, sweat pouring down over my glasses in the tropical climate we have been having this week. This is the only species of dobsonfly in the eastern United States, with three other species in the west. There has been a recent discovery in China of what is thought to be the largest known aquatic insect alive today, a giant dobsonfly, with a wingspan of eight inches!

Dobsonfly wings

The wings have a dense network of intersecting veins

Speaking of the wings, they are huge as well, and are folded over the back when at rest. When viewed up close, they have a prominent network of ridged veins and are speckled with light and dark spots. After standing on the ladder for almost an hour, I realized I needed to finish some of the errands on my list, so I left the beast in the tree, hoping it would be there on my return.

Dobsonfly male head 1

Dobsonflies are not cooperative photography models

About an hour later when I returned, the giant insect had not moved. I decided to try to get it down off the branch for some easier, and, hopefully, better photos. Turns out that dobsonfly-wrangling is not an easy task. It did not want to let go of its branch. As I gently tried to coax it onto a broken branch I had in hand, it spread its impressive wings and fluttered to the ground. I got off the ladder and let it grab onto the twig. It is such a large insect that I had to hold it at arm’s length to try to fit it all into the frame for my 100mm macro (and I usually still didn’t manage it). It showed some fearsome behavior as I tried to get it onto a white background for a photo, rearing back its head, opening those jaws widely, thrashing back and forth, and flapping its impressive wings. My brain kept repeating…it can’t hurt you, it can’t hurt you.

Dobsonfly male on white background

One last image before it took off

I finally just placed the stick down on the white background and fired a couple of shots. The subject was irritated with me now and even sprayed out some foul-smelling yellow droplets onto the white background as I tried to position the branch for the photos. He had had enough for one day, and finally spread his wings and flew off, circling around me, and landing on my back! Now my brain was having trouble repeating…he can’t hurt you, he can’t hurt you, and was sneaking in…it’s going to bite you, it’s going to bite you, get it off your back!! I reached around and brushed him off, and off he went, into the trees. Funny how some things can just override what you know to be true.

This guy probably spent his larval stage (which can be up to three years) in the rocky substrates of the nearby Haw River. In contrast, the adult stage lasts only a few days, long enough to find a mate and reproduce. They are attracted to lights at night, so perhaps I will see him again when I put out my moth light this week.


3 thoughts on “Jaws with Wings

  1. Once again you have me completely intrigued, Mike. I often see some insect (like a dobsonfly) and wonder just how badly they could hurt me. :<) But I seldom find time (or remember) to try to look them up. And now here you've been presenting me with answers for so many questions!

    I've seen a dobsonfly once or twice by day, but more often at night when I take Dante out for his pre-bed prep. They are very impressive zipping by with a whir before disappearing out of the light. Very good to know that "he can't hurt you"…

  2. well, the male Dobsonfly has mandibles that are too long to deliver a real bite..but here’s the bad news, the female can put a real hurting on you. The female has short powerful mandibles, and she will use them. Love your photos of this guy….and glad you didn’t do any experimenting with one of the mean Mommas!

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