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Pit Monsters – The Immature Antlion

27 Aug
Antlion Larvae (Myrmeleontidae)

An antlion larvae removed from its pit.

An antlion larvae, viewed up close, is a truly creepy little critter.   It is one of those horror movie-esque predators that makes me very glad I am not insect-sized.  If you remember the pit monster from the original Star Wars movies you have some idea what these guys are all about.  Antlion larvae are famous for the conical pit traps they build to catch their prey.  The antlion larvae finds a fine, sandy soil and moves in backwards circles, burrowing down and flicking sand up to create a funnel above it.  (In fact, pit-building antlions have adapted to a point where they can no longer move forwards.)  The antlion larvae lurks at the base of the pit, ready to grab any small critters that fall down the slippery sides of the pit and become entrapped.  The antlion will also use its head to toss sand at any escaping prey, further collapsing the walls of the pit, and bringing the prey sliding down.

An antlion larvae (Myrmeleontidae) in sand pit.

The head and jaws of an antlion larvae lurking in its sand pit.

Like other members of the order Neuroptera (such as lacewings), antlion larvae have large, distinctive jaws for hooking their prey.  The moving parts of their jaws form two straw-like tubes through which they can inject digestive chemicals and drink their liquefied prey.  Antlions belong to the family Myrmeleontidae (from the Greek words for “ant” and “lion”).  They take their common (and family) name from the large portion of their diet comprised of ants, but they will prey on anything of an appropriate size which stumbles into their grasp.  Although pit building antlion larvae are the best known (and the most easily spotted) only about 40% of antlion larvae actually build pits.  Other antlion larvae employ a wide variety of hunting strategies.  Some lurk just under the soil and rear up to grab unwary passersby.  Other will even emerge and chase down prey above ground.  (And that is not a creature I would want to see running after me.)

Antlion larvae (Myrmeleontidae) with fire ant (Solenopsis invicta).

An antlion larvae catching a fire ant in its pit.

Come back next week to see the adult antlion!