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