No, sadly this post is not about terrifying ant/lion hybrid creatures roaming the beaches of Jekyll Island. It’s about an insect. But a very cool insect.
Ever since I moved here I’ve been wondering about these odd trails in the sand.
The photo doesn’t give a great sense of scale, but they’re too small, narrow and non-winding to look like snake tracks to me. Over the weekend the mystery was finally solved – I walked down toward the beach to talk on the phone (better reception) and noticed movement in the sand at the end of one such trail. When I brushed my hand lightly across it, I unearthed an antlion! Apparently this is where the colloquial name “doodlebug” comes from: they leave what look like doodles in the sand.
If you’re wondering why the heck this guy is on a pink background, he’s on my flip flop. I uncovered this one this afternoon and had to scoop him up onto something to keep him from burrowing back down into the sand faster than I could photograph him. Though I’d never made the connection before between the trails and antlions, it makes sense that they would travel just under the sand’s surface instead of over it, because these creatures are known for creating pitfall traps in the sand to catch the ants they eat – hence the name.
The antlions lurks at the bottom, just out of sight under a thin layer of sand. When a hapless ant stumbles into the pit, it generally has a hard time climbing out again – it seems to me that natural selection has perfected the pits so they’re constructed with their sides at just the right slant so that the slightest movement sends more sand cascading down inward, making it difficult for small insects to clamber out. It doesn’t help, of course, that the antlion is flicking even more sand at its struggling victim, until finally it grasps it in those massive pincers and drags it under the surface to devour. It took me a while to get a video clip showing this behavior, so I hope you appreciate it; I had to catch an ant and injure it slightly to prevent its escape, then toss it into one antlion trap after another until I found one that was active and hungry. The beginning of the clip shows the ant trying to escape while the antlion flicks sand on it, and at the end you can see the ant get dragged down out of sight.
The antlions we’re familiar with are actually the larvae of insects in the family Myrmeleontidae. As adults, they’re flying nocturnal insects that bear a certain resemblance to dragonflies, albeit with long antennae that dragonflies and damselflies lack. I think it’s clear, though, that the carnivorous subterranean larvae have inspired some classic sci-fi monsters over the years…