When a Mantis Isn’t a Mantis

Mantises are some of the most distinctive insects, with their elongated bodies and grasping claws. They are big, a bit clumsy, and curiously human, with their large eyes and partially erect posture. They’re famous for a much-exaggerated quirk of their mating behavior, in which females eat males after mating, and also for the multitude of highly camouflaged versions found among them, looking like grass, flowers, leave, and more.

The thing is, mantises are not alone.

This, for example, is not a mantis.

Water strider eating a fly, showing the raptorial limbs holding the fly in place

And this is not a sideways mantis.

Giant water bug, showing raptorial limbs

And this is not a sideways mantis with a snorkel.

Water scorpion, showing raptorial limbs.

And, believe it or not, this is not a mantis, either

A mantidfly, showing the raptorial limbs.
Gilles San Martin from Namur, Belgium [CC BY-SA 2.0 (https://creativecommons.org/licenses/by-sa/2.0)]
The grasping limbs that all of these insects have are called raptorial limbs, and they work by grasping prey with pointed barbs. Fairly basic geometry underlies the latching mechanism they all use, making it a relatively easy thing for all of these groups to evolve independently. Notice that all four are very similar but are also each distinct in their own ways.

Mantidflies, also known as mantis lacewings, are perhaps the most curious of these. Unlike water striders, water scorpions, and giant water bugs, they actually look like mantises, and the most obvious distinguishing features are fairly subtle: the lack of walking tarsi on their claws and the way their wings fold. Those who watch these animals develop throughout their lives can see one other striking difference. Mantises have incomplete metamorphosis, with a nymph stage that resembles a smaller, wingless adult, but mantidflies have complete metamorphosis, with a distinct larva and pupa stage. Mantidflies are in the order Neuroptera, alongside antlions, and their larvae are similarly imposing in appearance. And, of course, many mantidflies are also wasp mimics, taking on wasp-like color patterns to deter predators.

Climaciella brunea, a North American mantidfly and wasp mimic.
Ilona Loser [CC BY-SA 3.0 (https://creativecommons.org/licenses/by-sa/3.0)]
The overall difference in body shape between mantises and mantidflies hints at how the two could become so similar while also living in many of the same habitats. Mantises are, by and large, built for stealth. Many of them are highly camouflaged, and most of them are relatively weak and slow fliers. Mantidflies, with their overall more insect-like body shapes, are a little more adroit in the air than mantises, while being a little less adept at lurking in narrow crevices. Mantidflies are much more active hunters than the mantises they resemble, much like their kin the lacewings, dobsonflies, and antlions, sometimes taking their prey in the air.

Mantidflies aren’t nearly as widely known as they deserve to be, given that they’re found in North America and Europe as well as places better-known for unusual insects, so it seems fair to give these 400 species their due. Next time you see an insect with a triangular face and big claws, take a closer look and see if it isn’t a mantidfly instead of the mantis you probably thought it was. Happy hunting!

When a Mantis Isn’t a Mantis

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