A battle-scarred mantis

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Sometimes, blemishes on a subject tell a story. I didn’t notice the pair of thick scars on the mantis’s face until I brought the images up for processing.

Tenodera sinensis

While we can’t know for certain what happened, it looks like an old prey insect fought back. Perhaps a carpenter bee managed to grab hold of her killer’s face, or an ant retaliated. In any case, this insect isn’t a picture-perfect specimen. It’s more interesting than that.

Incidentally, the image is among the most heavily photoshopped files I’ve ever uploaded to my galleries. It is a focus-stacked composite of two photographs taken at slightly different focal depths, combined manually using the clone tool in photoshop. The focus-stacking technique produces an optically impossible result, yet one that is pleasingly crisp, with the illusion of being larger than life.

Here are the unedited originals:

These photos were taken at different focal planes.

12 thoughts on “A battle-scarred mantis”

  1. These are not necessarily battle scars. Old mantids often get necrotic spots for no apparent reason (if I were a lazy medical doctor I would call them “idiopathic necrosis”). If these happen to be in places that the insects can reach with their mandibles then they try to eat them – I have seen old individuals that progressively consumed one of their front legs. This happens both in captive and wild-living individuals.

  2. For image stacking, you pretty much have to use a tripod, correct? I’ve never tried it, but I imagine the images need to line up exactly. I’m guessing mantids work pretty well for this since they’ll stay still for long periods of time. I want to try that, but I haven’t had much luck collecting insects in the wild lately. I’m kind of… not scared, but easily startled.

    1. Most stacking software goes thru an alignment step and then the actual image composite creation step (or some additional pre-processing step(s) prior to the composite stacking).

      The stacking software often allows for either manual or automatic selection of alignment points on the photos. There are obviously real limits to the alignment capabilities so YES, using a tripod or motorized stage will make a better result.

      Usually one would use many more than 2 photos in the stacking process.

  3. Piotr – that is interesting to hear! One of my students was keeping a mantis and said it had eaten two of its hind tarsi. He was quite alarmed! Thinking it was ill, he decided to kill the mantis for his collection. I had not heard of mantids eating themselves before.

    1. When I was a Post Doc in Entomology at U. of Arizona, someone in the lab asked Reg Chapman if he thought insects felt pain. He said “No” and listed several reasons, including no evidence that insects ever ‘limp’ or favor a wounded limb, a lack of homology between insect sensory cells and sensory cells in other taxa known react to pain and etc. I suspect, the a capacity to eat part of your living body might be another piece of circumstantial evidence for no sense of pain in the insects.

  4. I once found a mantis that was missing an eye. The eye socket was black and almost looked spongy/burnt. It was full grown, and it seemed to be doing well and acting fine. I didn’t collect it, just photographed it. Makes you wonder about the life of the insect… it’s trials and tribulations.

  5. Although I use motorised stages myself, not everyone does and some stacking software copes with misalignment better than others. A good one to have a look at is zerene stacker

    1. There is a pretty good list of focus stacking software and functionality at “Focus stacking” in wikipedia.

      I have used free “CombineZP” and gotten excellent results and other software with lesser capabilities.

      For an in depth discussion, you can check out Laurie Knight’s review.

  6. Thanks for this nice post on focus stacking Alex. It really makes a difference! Is this the same model we used?

  7. Interesting how the stacking appears to bring into focus even areas that aren’t perfectly focused in either of the parent images (or whatever they’re called), or is that from further sharpening after the “cloning”? (Stupid term – It’s more like hybridization, or at least, outbreeding.)

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