Ant Lion, from larva to adult

2012 November 28

On May 19, 2012, Sandy found this antlion larva for me in a little pit it had dug in the sand floor of one of our outbuildings.

I put it in a small ceramic dish filled with dry sand, and it promptly stuck its abdomen into the sand and wiggled its way underground in the time it took me to snap four pictures (about fifteen seconds).
Going . . .

Going . . .

Going . . .

And gone! Well, almost.

It then proceeded to dig a conical pit about an inch in diameter, which was surprisingly hard to photograph. I marked the rim with an oval drawn on the photo:

The pit actually shows up better in a blurry photo (taken without a flash) than in the focused one (taken with a flash).

So, anyway, I think you can see that an insect like an ant could easily miss seeing this pit, and fall in. Right into the waiting jaws of the inhabitant at the bottom.

We fed this one ant grubs from a nest of pavement ants that was living under a paver stone in our yard (the ants were raising new queens at the time, so we were able to get very fat grubs). The ant lion ate these voraciously for a few weeks, and then abruptly stopped eating. So on June 6, we carefully excavated the pit and found this spherical cocoon that looked like a ball of sand about a quarter-inch in diameter.

It stayed in the cocoon for quite a long time, finally emerging on July 2, 2012. The insect that came out was much bigger than the cocoon, well over an inch long, and it is kind of astounding that it was able to fit. It also left its pupal skin outside of the cocoon.

Unfortunately, it got itself wedged under the bowl of sand when it emerged, and its wings didn’t unfurl properly. I felt terrible about that, because if I’d put the sand bowl in a larger container, it would have been OK.[1]

The jaws are a lot different from the larva, although they do still look like they are capable of eating something.

At any rate, this is definitely one of the antlions in the genus Myrmeleon, as they are the only ones that dig the conical pits as larvae. Looking at the adult, the pattern of banding on its abdomen looks like Myrmeleon immaculatus.

As it happened, a few weeks later (July 22), I found another adult ant lion that looked to be the same species, hanging out on the siding of our house.

I’m not sure what its little companion is here, it looks like some sort of bug nymph. At any rate, it looks surprised. Or maybe worshipful.

It was actually pretty unexcitable, so here it is sitting on the tip of my finger, for scale:

Eventually, it did decide to fly, landing on our doormat with its wings spread. You can see here how, when it is ready to fly, all four wings flap independently.

The best places to find antlion larvae are patches of dry sand, particularly those that are mostly protected from rain by trees or buildings. The conical pits are pretty distinctive, and to a human eye looking down from above they stick out like a sore thumb. They can be pretty numerous, too. Once when I was in Florida, I saw patches where there were dozens of ant-lion pits so close together that there was no flat sand between the pits. I kind of suspect that, in those conditions, the antlions might turn a bit cannibalistic.

[1] Actually, it might have done all right even with the deformed wings. I let it go on the sandy soil just inside our carriage house on July 2, and noticed on August 14 that there were about 30 new ant-lion pits within a couple of feet of where I let it go. If it was a female, then it is quite likely that a male found her and she just went ahead and laid all her eggs on the spot.

9 Responses
  1. JRR permalink
    November 28, 2012

    Cool! I like ant lions (I like getting pine needles and teasing them) but I didn’t know the life cycle or what the adults looked like.

  2. November 28, 2012

    Huh – another critter I didn’t know we had this far north. I’ve never found an antlion pit here, although I saw them all the time in Georgia (

  3. November 28, 2012

    oh, PHEW. I really appreciate that epilogue, ’cause I assumed from the upside down photo that the animal had died. Glad to hear she got to fulfill her destiny (presumably). =) Such interesting creatures that, now that I see your shots of the larva, that is CLEARLY what they used in the Wrath of Kahn to terrify/control foes. =)

  4. November 28, 2012

    I love the photo with the worshipful “friend”. All hail the ant-lion! Great discovery of the metamorphosis though.

  5. Carole permalink
    November 28, 2012

    We are blessed with lots of doodlebugs, as we call them, here in Florida. Ants moved in to my greenhouse over the summer leaving sand on top of the brick floor. When I started my seedlings in the fall I was having a terrible time avoiding them. I finally used a whisk broom and dust pan to relocate them under the eaves of the house.
    Great article.

  6. December 1, 2012

    I am having a hard time reconciling the photograph of grubby (no doubt pestilence carrying) creature (the larva) in the first photographs with the exotic tail-end photographs (the adult).

    It seems a shame that they spend their time scurrying under sand waiting for sun dazed ants to fall into artful conical pits which can’t be seen unless you draw a circle on a photograph. If we can’t see it in a photograph then does it really exist or are you trying to flummox us?

    Who can provide geometric dimensions in a scientific study of the antlion’s work? That blurry picture looks like a piece of Kleenex with a wet spot. I find it hard to believe that it is a death trap for foolish ants.

    The voluptuous ooze of the creature in the first few photographs as it entered its bog is quite neat. I often want to do this (disappear fast) when the boys are bugging me for meals (I am a bad cook but what do you care about my troubles?)

    The picture of the spherical cocoon looked edible.

    It looks like a round Rice Krispie treat (I know they are traditionally squares but if you go to this site you can find a round Rice Krispie treat with a Christmas motif:

    The later pictures of the adult antlions as I have already told you —were disorienting.
    I do not think that the bug nymph was worshiping anything.
    She looks dazed and bug eyed.
    How you can put these bugs on parts of your body is really beyond my comprehension.
    They look as if they could feel icky.

    That last picture on the mat (which by the way is a lot cleaner than our front door mat) is very pretty and it seems a shame the bug has to start life in such a fugitive fashion as a larval from that has to hide under sand in order to eat. But there you go.
    I have to hide in a cell to eat words like this poor creature (and so what if I am whining?)

  7. Arjit Jere permalink
    February 1, 2017

    Hey cool story . I am from india and have been studying antlion pits myself.I want to identify species of the specimen for publication purposes. but havent found much relevant literature on antlion taxonomy from here.I sent a photo to a russian guy who thinks it might be myrmeleon genus.I wanted to ask can i put a photo of the adult here so you can take a look at it,and try for ID.Appreciate if some one from here could help

    @ Julie The pits are clearly visible to the naked eye but maybe in the photo they arent much clear.I have done some study on geometry of antlion pits so more than happy to share info with you about it.I measured pit diameters and depths.I can send you relevant papers on pit geometryYou can mail me any questions at arjitkjere The antlion larvae are adults look way different ,not only morphologically but also behaviorally.that makes their metamorphosis interesting.

  8. Ron Harrison permalink
    July 22, 2017

    I think pit geometry is dependent on the slump slope of the soil.

  9. Cynthia permalink
    July 24, 2017

    I live in Las Vegas NV, a few years ago I randomly noticed cone shaped holes in the soft sand in my backyard, curious with smart phone in hand I found interesting info. Great article, and I didn’t realize the round clumps of dirt I had seen when (we dug around an abandoned nest) were leave. So, thank you for great pix. I’ve watched them come and go the past two yrs. Last week I was happy to see they’re back, more than twice as many as their last appearance. This time the location is directly under the ants main route-I’d like to believe they did this intentionally, but that IDK. Who would have known I’d get enjoyment watching these little (Sand Vampires) When I read your article just wanted to Thank you and share my recent interest, amatuer observation and experience with such a tiny, un-overlooked interesting part of this universe.

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