Faculty & Staff Profiles

Antlion

The Antlion


The Antlion is a most peculiar, yet fascinating insect.  It is the larva stage of a dragonfly and lives in the larva stage for about 2 to 3 years.  While the adult dragonfly lives for only about 35 days.  The most interesting aspect of this larva insect is the way in which it catches prey.  It is genetically driven to create a pit in the sand that acts as an insect trap

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The pit that is created is at the maximum angle of repose.  Such that, if the angle of the pit walls were any steeper the sand grains would spontaneously fall deeper into the pit.  This is an insect that has evolved an instinctual sense of slope stability!  In fact, when a prey insect, such as an ant, wonders into the pit, the extra weight causes the sand to collapse.  The ant moves toward the bottom of the pit where the antlion is waiting.  The antlion has also been seen to throw or kick sand out of the bottom of the pit to destabilize the walls of the pit when an insect is in it.  This forces the sand to collapse, along with the insect, for easy capture.

Movie of an antlion digging a pit.  

Some popular folklore surrounds this insect.  It is sometimes called a Doodlebug because of the doodling like pattern it makes in the sand while searching for a suitable location for a pit.  It has been said that saying "doodlebug, doodlebug, come out into view" close to a pit will cause the insect to respond to the command and show itself.  The insect does respond but not to the word commands.  It responds to the sound generate during the statement which may cause sand grains to tumble or vibrations felt within the sand.  Thus, fooling the insect into thinking it caught an insect.  Ironically, this is one of the few species in which the adults often need to avoid coming near the kids.  Such that, if an adult dragonfly gets too close to a pit, it may become a meal for the younger larvae.  In much of nature, it is the other way around.  The kids usually have to avoid adults whose behavior is not in the best interest of the kids.  

This insect even came up in conversation between Apollo 16 astronauts walking around on the Moon.  [source: Apollo 16, Lunar Surface Journal]  While discussing the formation of a crater-like hole, the astronauts stated:

Looks like a sink hole; a big doodlebug hole.

What, pray tell, is a 'Doodlebug Hole?'

You've never seen a doodlebug?

I've never seen a doodlebug hole.  Sorry

Well, in the South, when I was a little kid, my Grandmamma had a house that was up on posts - pillars.  And so, as kids, you could crawl underneath.  On hands and knees you could crawl under the ouse; and it was sandy under there.  And there was these little bugs - we called 'em Doodlebugs, but I don't know what they were.  It wasn't like they dug a hole like this (throwing the dirt out in a pile around the hole), it was like they just drilled down and everything fell into it.  So it was a level surface (around the lip of the hole); you'd come up and there was no rim to this hole, it was just sink in.  So, what I'm saying is, this hole that we're describing here was like that: it just came, and it didn't have any rim around the hole - which indicates ejecta.  It was like everything just sunk out the bottom.  So it looked like doodlebug holes.

It is thought that Hollywood has used this insect to build some of it's fictional creatures.  In Star Trek: The Wrath of Khan (1982) an insect that looked strikingly like a large Antlion as used as a creature of a distant, desert-like planet.  The creature was named a "Ceti eel."  This creature was used as a torture device because the audience was told it would crawl into a victims ear and attach to their brain.  This would cause suggestibility, extreme pain, madness, and possibly death.

In 1983 the movie Return of the Jeti came out.  This Star Wars movie depicted a creature called the "Sarlacc."  It was an enormous beast that lived at the bottom of a giant sand hole called the Great Pit of Carkoon.  This creature waited at the bottom of the sand pit for it's prey.  The antlion could have formed the basis for this fictional creature.

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Good Web Pages About The Antlion

AntLionFarms.com

http://waynesword.palomar.edu/pljuly97.htm
http://www.antlionpit.com/