Another wonderful creature: the cicada-killing wasp

July 12, 2013 • 10:33 am

I’ve been a professional biologist for decades, but I’m still learning stuff that just floors me. Reader Gregory called my attention to a piece in the Atlantic about the wasp Sphecius speciosus: “The cicada killers are coming.” The whole short piece is worth reading, but I wanted to highlight one bit that stupefied me (it’s in bold):

Cicada killer females construct burrows that are small wonders of engineering and effort. Several feet long, and featuring numerous individual brood chambers at their far end, they require the excavation of hundreds of times the insects’ own weight in soil. The female killers manage the feat in just a few hours, using only their jaws and hind legs.

After that they hunt, for the so-called dog-day cicadas of genus Tibicen. A killer paralyzes a cicada with a single sting, but getting it back to the burrow can be an all-day affair. It may be three times the killer’s own weight–too heavy to properly fly with. Instead she drags it up the nearest tree, then launches herself, prey in claw, and glides as far as possible toward her burrow. She may have to repeat the process half a dozen times.

Back at the burrow, she deposits the paralyzed cicada in a brood chamber. Then she lays an egg and carefully tucks it beneath the cicada’s foreleg, beside the puncture wound from her sting. (The doomed creature looks, creepily, like a wizened old man with a baguette tucked under his arm.) The female then seals the chamber with dirt, the cicada still living and immobilized within it. A few days later the egg hatches and grub begins to eat the cicada alive, using the puncture wood as an entry point. Later, the grub spins a cocoon, in which it metamorphoses into an adult wasp, emerging the following year. (Footage of these behaviors has been kindly posted online by filmmaker Sam Orr, who is working on a documentary about the 17-year cicadas.)

(I haven’t found Orr’s videos, though I’ve found his Kickstarter page with a 3.5 minute clip about cicadas, so if you find his other videos, feel free to embed them in the comments.)

I’m astounded, and still find it hard to believe, that the wasps actually glide to their nests from a tree rather than fly. Verification by insect-savvy readers is welcome, but the video below suggests that it would be very hard for a wasp to fly while carrying a cicada.

The ability to glide toward her burrow after climbing several trees in succession suggests that these wasps have an exquisite sense of direction. And what tenacity!

It’s this kind of eating-the-prey alive behavior that helped convince Darwin that if there was a god, it wasn’t a kindly one.

Here are several of these fearsome insects:

cicadakillers
Photo by Chuck Holliday
 
h/t: Gregory

62 thoughts on “Another wonderful creature: the cicada-killing wasp”

  2. Just think, before the Fall of Man, this wasp was eating vegetable matter. Since then, it and its larva have become carnivores, so it must have……………evolved?

  5. Seems to me that it’d be more energy to climb the tree with the load and glide than it would be to just drag it. Any physicists care to chime in?

    If so, then one would assume that there’s some other force more important than efficiency at work.

    b&

    1. I guess it depends on the terrain. In the video it appears that the wasp has a difficult time clambering through the vegetation.

      1. Saw one at a country yard sale. Just swooped in and effortless grabbed the cicada- at least 50% bigger than itself. It didn’t have a chance. Most efficient.

    2. At a very rough estimate, let’s suppose that a wasp crawling across irregular ground encounters on the order of 100 centimeter-scale obstacles per meter of forward travel. Climbing over 100 centimeter-high bumps is (roughly) as much work as climbing a meter up a tree. If your glide angle is better than 45 degrees, then the tree wins because you can skip over more than 100 bumps per meter of height on your way back to the ground.

      1. They navigate by vision; which is obviously better from the air than when crawling through obstacles on the ground.

    3. Based on what I see in the above video, it seems entirely plausible to me that battling gravity takes less energy than battling grass and friction. I’d like to know what kind of glide angle they can get, but ultimately, if climbing and gliding is what they actually do, it’s a fool’s bet against that being the most efficient option.

    4. As elsewhere in evolution, a trait (or even a learned behavior) doesn’t need to mean “most efficient”. Merely “survivable”.

      And that is my physicist take. =D

    5. They should be mostly capturing their cicada prey from up the trees anyway, so they wouldn’t need to drag them up to glide down. I’ve never seen the cicada-killers in my backyard climbing up with a cicada, but I haven not been looking for this behavior in particular. I have seen them carrying cicadas in flight, but since they’re mostly coming from high to their holes in the ground, I didn’t realize they were gliding. They were just going in the natural flight path to their destination.

    7. Cicada killers are pretty common in East Texas. We had several burrows in the sandy soil in our side yard when I was a kid. I think they do the climb and flutter move because they need to get over the fences and hedges that might be between them and their burrows.

      Also, flying is not that big a deal for an insect. At their scale they get a boost from the viscosity of air, which we humans don’t really feel. Honey bees seem to think that a short distance walking is as much effort as a muck linger flight when they are forced to walk to find food.

      Climb and glide is more efficient over all for them and also helps them avoid obstacles.

    8. An important variable would be the distance to the nearest tree, but since cicadas are dependent on trees it would be likely to be quite close.

    1. Except when a giant Japanese hornet invades a hive of Japanese honey bees, per WEIT.

      1. The honey bees have a defense that sometimes saves them from the hornets. Dozens of bees mob the hornet and form a ball around it. Then they start vibrating their wing muscles and drive the temperature of the ball up to around 40C, killing the hornet. It was described in a Nture article in the 28Sept1995 issue. I think there are some videos online documenting the bahavior. Pretty cool.

    1. You need to come to Arizona, and see some tarantula hawks, Diana. They’ll blow your mind!

          3. This is *so* going to all my anti-spider friends, relatives, and colleagues. Hilarious!

            By the way, I love spiders.

          4. My dad feels this way about scorpions. I’m not as creeped out by scorpions for some reason.

      2. Thank you, I really didn’t need to know how big they are!

        Or how painful their sting: “Just how painful is the sting? Well, on the Schmidt Sting Pain Index, Pepsis wasps (and Bullet Ants) register a 4.”

        [The good news is that a) the insect is not aggressive, as opposed to the ant AFAIK, b) the pain only lasts for 3 minutes, as opposed to what the “24 (hour) ant” can deliver.]

        That’s it, no more Pepsis. I’ll stick to Cokes.

        1. I think I’ll stick to Cokes too! It is a nice looking giant thing though. I bet many a pet gets stung!

      3. For what it’s worth, I’ve lived in Arizona since the tail end of the Reagan administration, and I’ve yet to see one. Not that I’ve gone looking….

        b&

        1. Well, if you ever decide to go looking, Ben, the Boyce-Thompson Arboretum up near Superior is a primo spot. They’re pretty common along the Rio Salado at places like Granite Reef picnic area and Phon D Sutton rec area too.

          1. Thanks for the tip — and for reminding me that I need to make a pilgrimage to the Arboretum. Still haven’t managed to make it out there. No, I don’t have a good excuse.

            b&

          2. It’s a great place, well worth a visit. My SO and I have volunteered there for years, leading birdwalks and dragonfly field trips, and the Arb is usually one of the four fieldtrips she schedules for her beginning birders’ classes. Be sure to take your camera–there’s always something interesting to shoot.

  8. A reading recommendation: “Wasp Farm” by Howard Ensign Evans. It’s a popularization, but since JAC isn’t an entomologist, he should find it interesting.

    Cicada killers are among the many species discussed

    1. Anything by Evans is worth reading. His “Life on a Little-Known Planet” is life-changing.

    2. I saw one of these wasps in action yesterday while walking home. The cicada was lying on its back on the sidewalk and the wasp appeared to be repeatedly stinging the lower end of the cicada’s abdomen while eating the head. It looked very gruesome, and I wish I’d had a camera with me. Also in TX north of Dallas!

      I couldn’t help wondering at the time how an IDer would explain this…

  10. “A few days later the egg hatches and grub begins to eat the cicada alive, using the puncture wood as an entry point.”

    Cicada: “Well srew you too, nature.”

  11. Not exactly clear from that piece – are these wasps on 17yr cycles too, or do they have alternate prey in all those off-years?

    2. I think the hypothesis for the long period cicadas is that they evolved to throw off any specialized predators such as this one. (But I’m too lazy to check now.)

      Finding a specialized predator that can tie over with other prey would shoot down that hypothesis.

    3. I think cicada killers live mostly in the warmer parts of the US where the annual cicada is more common than periodic cicadas.

      Anywhere it is wet enough and the ground never freezes, huge annual cicadas dominate and you can find cicada killers.

      1. Cicada killer wasps are pretty common in the Midwest, despite our cold winters (I’ve seen them just about every year in central Indiana and earlier in eastern Iowa when I lived there).

        I had a friend back in the early 70s who was stung on the hand by a c.k. wasp as I watched. He said the pain was tansitory, quickly replaced with a numb sensation.

  12. I have these wasps currently infesting my backyard patio for 2 summers now! They appeared last year leaving lots of holes in the sand between the stone slates of my patio. The critters are slow flying and they don’t sting. They are quite amazing in the way they carry the cicadas which are bigger than them. But I can’t live with them because they’re destroying my patio, digging up all the gravel from under the slabs, I’m afraid one of these days I’m gonna step into a slab and it will cave in. Last year I used the brute force method of trying to exterminate them – by swatting them with a badminton racket. I probably killed a hundred, but I dealt with them too late in the season, when they have evidently mostly laid their eggs already. So this year they’re back – or stricly speaking, their progeny. They started coming out a couple of days ago. I’m trying chemical warfare this time. Waiting until after sundown when they have returned to their burrows, then pouring ammonia in each hole and covering it and marking it (so I know I’ve already dealt with that hole). The next day a few more new holes appear and I repeat the chemical attack. Fourth day now and it seems to be working as fewer and fewer new holes are appearing. Also I see fewer and fewer wasps during the day.

  13. Have seen them here in Iowa climbing trees with cicadas in tow. Have also seen them in tall grass trying to get airborne and going ass over teakettle repeatedly.

    And they are completely oblivious to everything else around them. One can be two feet away without disrupting them.

  14. i have a garden in southeast PA which cicada killers love because the soil is really easy to dig into. I’ve see them flying with the cicada in tow plenty of times. They even bang into the fence around the garden before finding an opening to get through. I’ve never seen them gliding.

  15. Responding to a couple of questions that have come up:
    – Yes they definitely have to glide with the prey, and shorter distances and more iterations with the heavier female cicadas.
    – The cicada in the video is a Tibicen.

  17. As a former lawn-owner in Nebraska I have had many chances to observe digger wasps (which are either the same as cicada killers or closely related) making holes in the yard, and have seen them dragging paralyzed insects (one was a katydid, I think). I didn’t kill them even though the holes weren’t pretty. I was amazed at how something so small could move so much dirt! And they don’t bother humans unless greatly provoked.

  19. I’m astounded, and still find it hard to believe, that the wasps actually glide to their nests from a tree rather than fly.

    Many years ago, while eating lunch on the National Mall behind the National Museum of Natural History, one of the other entomologists called attention to a cicada killer gliding with its prey from a tree.

  20. I have these amazing critters year after year. (150 miles due east of Chicago…if you fly a crow) They make their “nests” by excavating in the cracks of my large cement driveway. I have a 5 acre woods about 100 meters behind the driveway which I assume makes this prime territory.
    Although the CK’s appear meanacing, they have never stung anyone and make a mess my wife doesn’t appreciate, it is a great source of entertainment and education for my 6 yo grandson and 3 grade twins that live next door.I’ve been hearing the cicadas the last few days so expect activity to begin soon. Very cool!

  21. I have watched a number of these at work. The ‘glide’ is more like a powered glide, in that they are beating their wings. This greatly extends the length of their descending glide. I do not recall clearly how far they travel horizontally, but my recollection is at least 25 yards.
    The tree climbing also probably helps them to orient to their burrows.
    As a grad student at Urbana-Champaign one treat was in the late spring when the male wasps emerge first from their burrows from flower beds near our building. They would fly back and forth over the flower beds, waiting for the females to emerge later. This would be alarming for the passing students (big scary wasps, swooping about), but of course they are harmless b/c the males lack stingers. As soon as any female starts to emerge several males would dive in, pile on, and, compete to mate with her.

  22. A friend of mine, aware of this tree climbing behavior, allowed one to climb to the top of his head. It glided from there. No need to mention that my friend is quite tall.

  23. You called this wasp “fearsome”. I will agree that it is certainly fearsome looking. They are fairly common here in Oklahoma. I have never known anyone to have been stung by one.

    Despite that, I was terrified of them as a child.

  25. Several years ago, while taking a break from mowing my mom’s lawn, I heard a cicada “scream” bloody murder from a tree top, followed by a very noticeable thud on my mom’s front deck. I went around to investigate. There was a hornet, the same size as the cicada, embracing a cicada and stinging it over and over in one spot. It almost looked like it was having sex with it, in an unconventional fashion and spot. I came within inches of them and it never stopped or acted as if it noticed me at all. I backed away and just watched. Eventually, after a couple of minutes, with the cicada in its jaws, it waddled over to the tree only 10-15 feet from the deck. It stopped for a breather once or twice, before taking its prize up the tree. Its wings were beating furiously to help with the transport. I wanted to kill it, but the size of them both together would almost completely fill the palm of my hand; Nasty mess on the shoes. Plus, I wasn’t sure that if I was unsuccessful that I wouldn’t become target #2. So, in the words of Gollum “up, up, up it goes” and never saw anything like it, before or since.

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