Mantidfly looks as if built out of spare parts

Mantidfly, Dicromantispa interrupta

COLUMBUS DISPATCH
September 27, 2015

NATURE
Jim McCormac

Scotsman John Hunter was an inveterate explorer and officer in Great Britain’s Royal Navy. A natural scholar, Hunter was sent to then largely unknown Australia in 1788. He spent much of the next 12 years there. In 1798, he was made privy to the discovery of a bizarre Australian mammal and promptly sent a specimen to the British Museum.

Curator George Shaw, upon examining the specimen, felt it might be a hoax, as did several of his contemporaries. Their skepticism was understandable. The duck-billed platypus looks like a hodgepodge of various animals sewn together — a seemingly impossible anomaly.

The mantidfly is an entomological counterpart to the platypus. The bugs look like the work of a mad scientist. It’s as if the wings of a dragonfly were bolted to a wasp’s body, and a long skeletal neck was welded to the front. Capping the latter is a small head dominated by huge jewellike eyes. Powerful forelegs are armed with stiff spines, and the creature is held erect by long spindly legs. The mantidfly shown above is Dicromantispa interrupta, one of five species found in Ohio.

If one didn’t know better, he might think the mantidfly is the product of an ornate prank.

Adult mantidflies are predatory, stalking other insects and seizing them with their praying mantislike forelegs. The larvae also are predatory, with a life cycle almost too freakish to believe.

Female mantidflies lay up to 1,000 tiny eggs on the lower surfaces of leaves. The eggs dangle from threads. She places the egg cluster in an area frequented by spiders.

The tiny, freshly emerged larvae are capable of crawling and leaping. When a spider passes by, they attempt to jump aboard. If successful, the mantidfly larva nestles into a crevice and commences to feed on the spider’s hemolymph for sustenance.

Their primary purpose is to hitch a ride to the spider’s nest. If a male spider is boarded, the mantidfly larva will cross over to the female spider when the spiders come together to mate. When the female spider deposits her eggs, the larva debarks and attaches to an egg. It feeds on the contents of the egg via specialized mandibles.

Once the larva matures, it forms a cocoon and pupates within the husk of the spider egg. Later, it morphs into the strange-looking adult mantidfly.

Mantidflies are rare — and with such a life cycle, it’s easy to see why.
Naturalist Jim McCormac writes a column for The Dispatch the first, third and fifth Sundays of the month. He also writes about nature at www.jimmccormac.blogspot.com

Mantidfly: They don't make 'em much more bizarre than this!

One can only imagine the fits of rapturous ecstasy that washed over me when I saw this thing flutter by on a recent trip to Adams County, Ohio. Well, that may be overstating the case a bit, but I truly was pleased to see this mantidfly, and all the more happy in that it cooperated for photos. I have only seen a handful of these six-legged oddities in my years afield, and this time I was armed with an excellent macro rig.

Mantidflies look like the result of a mad scientist's experiment gone awry. It's as if Igor were sent to the spare parts bins, drunk, and returned with the wings of a dragonfly, the body of a paper wasp, the head of a damselfly, and the raptorial forelegs of a praying mantis. Then, the evil doctor welded them all together, and Voila! This is what we've got.

These insects have a lifecycle as bizarre as their appearance, and the hoops that they've got to jump through to make it to the adult stage may account for their seeming scarcity. I don't know of anyone who claims to see tons of mantidflies. There are only about four or five species in this part of the world, in about as many genera. Mantidflies are in the Order Neuroptera, along with lacewings, owlflies, antlions and that sort of thing. I believe this species is Dicromantispa interrupta.

As you may have inferred from the mantidfly's powerful-looking thickened forelegs, it is a predator. Hapless lesser bugs that wander too near are seized, and unceremoniously gutted and eaten with the mantidfly's odd little beak. I don't imagine they miss much, either, given the proportionately massive size of its eyes. The entire dangerous front end of this thing is attached to a strange-looking thorax that resembles a bone.

Things only get weirder as one drills into the mantidfly lifecycle. A female carpet bombs the plants with clusters of hundreds of eggs. She needs to dump a lot of them, as the chances of an egg making it to the adult stage are slim indeed. After a few weeks, a tiny larval mantidfly pops out, and lurks in the foliage awaiting a suitable host. When an appropriate spider (other mantidflies use bees or beetles) comes along, the fledgling mantidfly leaps aboard and firmly attaches itself to the underside of the arachnid.

If all goes well, the spider eventually hauls her dangerous cargo to the nest. Should the larval mantidfly mistakenly board a male spider, it'll realize its error and attempt to cross over to the female when and if the male finds a partner and commences mating. The larva's relationship with the adult spider is phoretic: it is just using the spider to hitch a ride. If by some minor miracle the larval mantidfly makes it to the Holy Land - a spider nest - it will then hop off and ensconce itself with the arachnid eggs. There it will morph into a grublike form and feed on the spider's eggs, eventually pupating and transforming to the strange adult insect seen in these photos.