Tuesday, July 31, 2012

Dobsonfly: Bit of a horrorshow, this one

Ah, the legendary hellgrammite, many a bass fisherman's dream bait. This multi-legged larva looks like a mini dragon, and has a powerful set of pinchers to boot. Mishandle one of these aquatic beasts, and it'll nip you, too. I caught this one on a darter-hunting expedition in Big Darby Creek a few years back. Hellgrammites are strictly aquatic, and lurk in the substrate of streams, capturing whatever they can. Ugly as this insect may be, their presence is in a waterway is a nice thing - hellgrammites are indicators of good water quality.

If you are an entomophobe, you'll not find the dobsonfly any more appealing than its hellgrammite larval stage. Corydalus cornutus is a whopper of a bug, and males such as the one in this photo measure several inches in length.

We lured a few of these beasts to our lights last week in Adams County. We were after moths, but they're not the only critters attracted to bright lights at night, and I was pleased to spot this bruiser on the wall. It's a male dobsonfly, as can easily be told by the incredibly long scimitar-shaped mandibles (females' mandibles are much shorter). They use the swordlike mandibles for self defense, and typically fly suddenly at a person invading their space, quickly thrusting each mandible deep into the person's eyes. With an abrupt reversal of its flight coupled with a fierce jerk of the mandibles, the dobsonfly rips the victim's eyes from the sockets, and flies off to feed them to its mate.

Just kidding. Ferocious as the dobsonfly may appear, it is actually utterly harmless. While one may try to give a pinch with its mandibles if mistreated, they're too long and flimsy to gain much purchase, and would cause no harm. All visual bark and no real bite.

We were intrigued to see this Carolina mantis sneaking up on the huge dobsonfly. I watched this drama for a while, my camera's video function at the ready, hoping the mantid would attack. It bobbed, weaved, cocked its pointy triangular head, waved its legs and swayed side to side, but wouldn't get any closer to the dobsonfly than this. Fierce as the mantids are, this dobsonfly was apparently too much and the would-be predator chickened out. Can't say as I blame it.



A.L. Gibson said...

Bass fisherman's dreams, no doubt! I catch these by the dozens in Ohio Brush Creek in the riffles along our property. Few other baits work as well as these fresh from the water. It's no wonder the word 'hell' is included in their name; they are fierce looking creatures.

Elaine said...

When I was younger, my Dad and I waded out into the Huron River in Michigan. We carried a small metal creel on our waists and turned over rocks to capture the hellgrammites. Then we hooked them by the hard shelled necks and use them for fly fishing.