The amazing bird-murdering praying mantis

First, a note. Over the years, lots of readers have spelled the animal at issue this way “preying mantis.” That’s an easy mistake to make, for they are fierce predators. But the true term is praying mantis, clearly taken from the position of its forelegs. So next time you write it, just remember how it looks.

Natalie Angier’s science articles in the New York Times are always good reads, as she has an eye not only for a good story, but also for lively prose. You can see both of these on display in the week-old article below—click on screenshot to get to it—largely about the increasing documentation of praying mantises eating birds. You may have heard about their hanging around hummingbird feeders, where they capture the little buzzers and eat them, but it’s not just hummingbirds:

James V. Remsen of the Museum of Natural Science at Louisiana State University and his colleagues documented 147 cases of mantis-on-bird predation in 13 countries representing all continents but Antarctica — not surprising, Dr. Remsen said in an interview, since there are no mantises on Antarctica.

Hummingbirds were the most common target, but mantises also went after warblers, sunbirds, honeyeaters, flycatchers, vireos and European robins. Large species like the Chinese mantis, which grows to four inches in length, were the most avid avivores, and females were responsible for virtually all the bird-killing observed worldwide.

Now here’s the disgusting part: copulating while preying:

In two reported cases, females feasted on birds while copulating with males. Sometimes the mantises would tuck in through the bird’s breastbone, but more often they went for the head, Dr. Remsen said.

“They bite in and eat the brains,” he said, “which might imply this is something they’re professionals at.”

Here’s an attack that was thwarted (would you do that? I would.):

Here’s one that wasn’t:

They take mice, too! That’s not right!

Then Angier imparts some biology; I’ll let you read that for yourself, except for this bit that was new to me:

Mantises find their prey visually, and their exceptionally sophisticated eyesight has lately caught the attention of researchers. Jenny Read of the Institute of Neuroscience at Newcastle University in Britain and her colleagues recently demonstrated that praying mantises have stereoptic, or 3-D, vision, the first definitive evidence for the talent shown in an invertebrate.

By seeing in stereo — that is, mentally triangulating the slightly different images received from two eyes into a single line of sight — an animal can get a sense of depth and distance.

“It’s a complex ability, and we’re still trying to understand the algorithms, the calculations, that our own brains use to do it,” Dr. Read said.

Yet calculate the mantis clearly does. In experiments that traded charisma for cute, the researchers outfitted praying mantises with tiny homemade 3-D glasses: filters that effectively separated the two images a mantis would see when it looked at a screen.

A mantis will ignore a glowing box on a flat screen when viewing it without the benefit of 3-D glasses, the researchers found. But once the filters were in place, the mantis’s brain was fooled into the illusion of a three-dimensional object hovering at just the right “catch range,” an inch away, and began striking out into empty space as though at potential prey.

This is why we scientists have (or had, in my case) such great jobs. Imagine getting paid to put 3-D glasses on a mantis!

Angier discusses the well-known cannibalism of mantids, reporting that if a male lets himself be eaten after copulation, the female, who lays a huge egg sac, can produce 20% more eggs from the extra nourishment she gets from her partner’s body. As the researchers who did that work concluded, if the chance of a male finding a subsequent mate is less than 20%, then it’s to his evolutionary advantage (or rather, to the genes that say “let yourself be nommed”) to sacrifice his life for his offspring. Perhaps the same is true for spiders, though males often seem to try to flee after copulation, implying that they don’t go gentle into that good bite.

One more set of facts about mantises recounted by Angier (with links):

The conclusion: If a male, after spending 3.5 hours in the typical mantis copulatory bout, has a better than one in five chance of encountering a second fertile female somewhere down the line, reproductive logic dictates that he should channel his inner Olympian and bolt.

Or jump — mantises are good at that. In another movie-themed set of experiments, Malcolm Burrows of Cambridge University and his co-workers showed that when they held a pencil vertically in front of a praying mantis at just the right distance, which varied depending on the size of the mantis, the insect couldn’t help itself: it would jump onto the pencil.

“You could see it scanning with its head, weighing how far away the target was and at what orientation, and then it would jump and land successfully,” Dr. Burrows said. “We thought, how on earth could it maneuver its body from a horizontal surface and onto a vertical one and do it so accurately every time?”

To deconstruct the movements, the researchers took high-speed videos of jumping mantises. They determined that the mantis curved its jointed abdomen up, rotated its front legs counterclockwise and its rear legs clockwise, and switched front and rear rotations once and then back again — all within 70-thousandths of a second.

The midriff bending was key. When the researchers glued the abdomen to prevent it from bending, “the mantis would crash headfirst into its target,” Dr. Burrows said.

Here’s a NYT video of that behavior; click on the screenshot to see it:


What a great job! Now there’s little practical implications for this, though the video does mention one. It’s just raw curiosity that drives us to do this kind of study. And you’re paying for it, so I hope you like it! But how can you not? What kind of stony-hearted person would be uninterested in how a praying mantis jumps, or how it kills hummingbirds?

Anyway, remember that it’s PRAYING mantis. They’re fricking awesome insects.

Oh, and their closest relatives are termites and cockroaches. Who knew?

____

And a late-arriving cartoon from Heather Hastie, especially appropriate:

27 Comments

  1. ThyroidPlanet
    Posted October 1, 2017 at 2:21 pm | Permalink

    PCC(E) said “fricking”

    My day is made.

    • Posted October 1, 2017 at 2:42 pm | Permalink

      Gizmodo recently reported an unusual amount of methane coming from a relatively small area in the Midwest.

      The reason? Fricking fracking!

      • Posted October 1, 2017 at 2:44 pm | Permalink

        (I just noticed that it’s actually it’s an old article, but something led me to it recently.)

  2. Randy schenck
    Posted October 1, 2017 at 2:32 pm | Permalink

    Just have to say, if I had the hummingbird feeder out and saw one of these climbing around on it, I would knock it off.

    • Posted October 1, 2017 at 3:16 pm | Permalink

      If I heard that horrible scream of panic coming from the poor hummingbird, I would!

    • JackbeThimble
      Posted October 1, 2017 at 4:19 pm | Permalink

      Chordate solidarity, gotta make sure the invertebrates know their place.

  3. Liz
    Posted October 1, 2017 at 2:48 pm | Permalink

    The stereoptic vision is interesting.

  4. FB
    Posted October 1, 2017 at 3:00 pm | Permalink

    We should call them priest mantis: they look like they’re praying but are actually preying.

    • BJ
      Posted October 1, 2017 at 7:28 pm | Permalink

      Brilliant.

    • Diane G.
      Posted October 2, 2017 at 4:00 am | Permalink

      😀

      • Merilee
        Posted October 2, 2017 at 12:15 pm | Permalink

        Priest mantis: +1

  5. Jenny Haniver
    Posted October 1, 2017 at 3:03 pm | Permalink

    Thanks for all this information. Heck, if I see one of ’em creeping up on me, I’m covering my head!

    • Jenny Haniver
      Posted October 1, 2017 at 3:04 pm | Permalink

      What a great horror movie this would make.

  6. yazikus
    Posted October 1, 2017 at 6:00 pm | Permalink

    We kept a mantis as a pet a couple of years ago, it was magnificent. Kiddo is especially skilled in catching (but not harming) flies, and we would drop them in and then watch her hunt. She was an excellent hunter. We kept her for about six months, and released her back into her habitat.

  7. Posted October 1, 2017 at 6:25 pm | Permalink

    I know I have spelled the name both ways. Note made.

    It seems sensible to eat the brain first, since the skull is thin and easily pierced. Brains are highly nutritious (so I have heard..) and eating it quickly immobilizes the meal.

    No surprise that they have 3-D vision. Their forward vision is most acute, and they frequently sway back and forth to triangulate distances before a strike or a jump. I always felt that 3-D vision was obvious, though it is good to have a definitive demonstration of that.

  8. dargndorp
    Posted October 1, 2017 at 6:41 pm | Permalink

    Linking to the NYT video seems to be broken.

  9. BJ
    Posted October 1, 2017 at 7:36 pm | Permalink

    “…though males often seem to try to flee after copulation, implying that they don’t go gentle into that good bite.”

    This did not go unnoticed, you scamp.

    • infiniteimprobabilit
      Posted October 1, 2017 at 7:45 pm | Permalink

      Yep, I bet PCC’s been waiting forever to use that one! 😉

      cr

  10. Merilee
    Posted October 1, 2017 at 7:50 pm | Permalink

    Sub

  11. infiniteimprobabilit
    Posted October 1, 2017 at 7:53 pm | Permalink

    I’ve always liked mantises, matrimonial diet notwithstanding. (I have to say that, after 3 1/2 *hours*, I probably wouldn’t care if I got eaten or not…)

    Eating birds is a plus so far as I’m concerned. Now if I could just find a mantis to munch on the one that habitually bombs my just-washed car… (though from the evidence it’s orders of magnitude bigger than a hummingbird).

    cr

  12. Posted October 1, 2017 at 8:45 pm | Permalink

    I had no idea that they killed hummingbirds! Thanks for the info!

  13. Posted October 2, 2017 at 7:04 am | Permalink

    Reblogged this on jtveg's Blog and commented:
    Fascinating nature. 🦂

  14. Vaal
    Posted October 2, 2017 at 10:36 am | Permalink

    My gawd there are so many horrible ways to die in Nature….

  15. Posted October 2, 2017 at 12:22 pm | Permalink

    “It’s a complex ability, and we’re still trying to understand the algorithms, the calculations, that our own brains use to do it,” Dr. Read said.

    I don’t think that “calculation” is the appropriate mechanism. If you look at machine learning applications and how neural networks function, it’s much more likely that this is a pattern matching operation based on visual inputs that connect to kinesthetic outputs. Like pulling on a string to ring a bell does not require a differential equation for the entire length of the string to perform the action while it may require one to describe the action mechanically. A dynamically configured series of learned or pre-wired patterns would be much more energy efficient than individual calculations, hence why brains can do all these wonderful things without hundreds of watts of energy and running at temperatures much higher than 98.6 degrees.

  16. Thanny
    Posted October 2, 2017 at 5:05 pm | Permalink

    I’ve always thought mantids were the most terrifying possible giant insect scenario, because they don’t kill their prey – they just grab it and start eating.


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