Antlion Timelapse

Three years ago, I wrote a blog post on antlions, fantastic little creatures that live along the base of my house (and elsewhere in the world, I’m sure).  I moved to a new house last year, and was happy to find antlion larvae living along its foundation too.  I dug a few up the other day and brought them indoors for our family to watch (we have a praying mantis nymph in the house at the moment too).  I’ll put them back outside soon.

An antlion larva, a compact and efficient killer, with a muscular
An antlion larva, a compact and efficient killer, with venomous mandibles for subduing prey and a muscular “neck” for tossing sand (and insect carcasses) out of its pit.

It’s been fun to feed ants and other small insects to the larvae, and we’ve been able to watch them construct their cone-shaped hunting pits, but the construction is slow enough that it’s hard to see much progress over the course of a few minutes.  To help us get a better feel for how that construction process works, I set up my camera…

My Nikon D300s camera can be set to take a photo at regular intervals and make timelapse videos.  I set mine for a one minute frequency and let it run for about three and half hours.  During that time, the three antlion larvae moved around the bowl a lot more than I’d expected.  You can see for yourself in this 17 second video…

In the video, you can see that one larva constructs a pit near the bottom left corner of the frame. Another larva makes a larger pit near the center.  Near the bottom of the frame, a third antlion seems to start a pit, give up, wander over (and maybe through?) the smaller pit and then strike off toward the top of the frame and beyond.  The larva in the small pit then begins repairs.  I checked in on these larvae now and then while the camera was running, but never would have guessed there was that much action going on because it happened so gradually.  Compressing time with the timelapse process was invaluable.  It was also interesting how sporadically the action happened – as opposed to a fairly continuous excavation process.

Timelapse is a fairly simple, but very powerful, way to see the world.  You can see some earlier timelapse posts here:

Bison in a blowout

The formation of a cattle trail

A wetland “breathing” through evapotranspiration

Photo of the Week – September 13, 2012

Antlion!  One of the most nightmarish creatures most people have never seen…

When dislodged from its trap, an antlion might sit still just long enough for a photo before backing down into the loose soil again.  You can click on the photo to see a sharper image.

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The antlion digs a cone-shaped hole in the soil and then buries itself beneath the point of the cone with only its fearsome mandibles showing.  When an unwary creature ventures too near the edge of the pit, it slips in the loose soil and falls down the slope toward the antlion.  The antlion gives the poor creature a paralyzing bite and then sucks the juices out of it.  If the antlion misses with its first bite or the creature manages to stop its slide down the slope, the antlion throws soil at it and knocks it back down toward its doom. 

Fortunately for us, antlions (actually the larvae of antlions) are only 1/2 inch long, and eat small invertebrates.  They tend to make their pits in loose dry soil – often around foundations of houses or other buildings these days.  Antlion adults look very different from their larvae, and resemble damselflies with clubbed antennae.

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Antlion pits around the base of our house.

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My son, Daniel, and I saw an adult antlion on our window screen the other day, so we decided to go hunting for the larvae.  It didn’t take long to find some pits along the foundation of our house, safely positioned in the dry rain shadow of the eaves.  We dropped a cucumber beetle into one and watched as it slid down to the bottom of the slop and then jerked violently as the antlion grabbed it. 

Later, we dug the antlion out of the ground and brought it inside so we could watch it more carefully for a few days.  (My wife doesn’t like to admit this, but she’s mellowed considerably over the years about keeping temporary “pets” in the house…)  We filled a bucket with loose dirt and put the antlion in to see if it would make itself at home.  By the next morning, there was a nice conical pit along the edge of the bucket.  So far, the antlion has eaten a pillbug (roly poly) and a millipede, though it took several tries before it was able to catch the millipede.

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Here’s a clearer look at the antlion – photographed in my homemade photo studio.

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It’s not hard to find information on anlions online, but one of the most comprehensive sites is Mark Swanson’s “The Antlion Pit“.  You can learn all about antlions, why they’re also called doodlebugs, and watch videos of many different behaviors.