A child’s first encounter with a mystery of nature makes an indelible memory:
“‘Doodlebug, doodlebug, your house is on fire! Come out! Come out! Wherever you are!’ Those were the words my sisters and cousins and I used to say as we took a small, thin stick and barely made a circle in the upside-down cone of soft, very fine dust, called the ‘doodlebug hole.’ We were rewarded by a soft, gentle, little bug coming to the surface where we could pick him up and put him in the palms of our hands. The doodlebugs were so small and gentle and soft they were wonderful to hold. We would carefully put them back and dust would fly as they dug back into their little home and remained unseen.”
E.C. Morris Chinetti, Wimberley, Texas
Sound familiar? How many generations of children have lain near a doodlebug hole chanting a similar rhyme to tempt an afternoon’s entertainment?
So, what we’re talking about here is an antlion, one of about 2,000 species of Myrmeleon immaculatus, family Myrmeleontidae—you know, the feisty little architect of those funnel-shaped holes you find in the sand? Fascination with antlions is a world-wide phenomenon, almost a childhood rite of passage. Why doodlebug? Because the odd winding, spiraling trails it leaves behind when it moves looks as if some budding artist has been “doodling” in the sand. What Americans call a “doodlebug” is known as a “torito” (little bull) in Mexico. And for good reason!
You see, despite the cuteness described in the opening quote, the antlion is as dangerous as a wolf in a cage—if you’re an ant. Unsuspecting ants (or other small insects) that stumble into the antlion’s trap are doomed. The ground beneath them collapses and they plunge to the bottom where ‘el torito’ awaits, buried in the sand. He rushes out of his blind and grabs the ant with his fearsome jaws. His bite is like a vise, and he injects a deadly venom into the victim, rendering it immobile. Enzymes soon liquify the internal organs of the ant, and the antlion sucks out the goodies, tosses the carcass away, tidies up his trap, and once again buries himself in the sand for the next meal. It’s like Jurassic Park. In fact, a remarkably similar large-scale model of the antlion was used in the Star Trek II film, The Wrath of Khan!
As it turns out, the antlion (or doodlebug) very often could benefit from food stamps. Catching prey is risky business because food arrives unpredictably, and maintaining the trap is a time consuming, tiring endeavor. This is why the antlion has a low metabolic rate and can survive for long periods without food. In colder climates they dig their way deeper and remain inactive during the winter. When food is plentiful, they grow faster, take larger prey, and demonstrate their good health by making larger traps.
As you can see from the photo, antlions are butt-ugly and built like a tiny steam shovel. Given his size, this little bug is strong as an ox, and can comparatively move mountains. He’s got a spindle-shaped body, a very plump abdomen, and a thorax bearing three pairs of walking legs. The prothorax gives him a slender “neck” which carries the large, square, flattened head with a face that looks carved from stone with a dull blade. Part of the head bears an enormous pair of sickle-like jaws with several sharp, hollow projections. His body is clad in forward-pointing bristles which helps anchor him to take down prey many times his size. He’s a perfectly built assassin!
The engineering that goes into making the trap is a thing of genius. First a general outline of the pit is marked out in the sand. The antlion executes a type of dance, crawling backwards, around and around the circle, using its abdomen to push up the soil. By digging in a spiral when constructing its pit, the antlion minimizes the time needed to complete the job. With one front leg, tiny sand particles are loaded on top of its head and, with a smart jerk, are heaved up out of the hole to form the walls of the trap. He gradually works his way backwards around the circle toward the center. As he moves around, the pit gradually gets deeper and deeper, until the slope reaches the critical angle of repose. This angle defines when the sand is near the “avalanche” stage. Any small disturbance will cause the walls to come tumbling down.
At this point everything’s a question of patience. With tufts of hair on the sides of his two hindmost thoracic segments, he can pick up minute vibrations of prey moving toward the pit. Buried and out of sight, he readies himself with only jaws exposed at the bottom. Wait for it. . . wait for it. . .BINGO! the walls disintegrate like the tail of a comet and down comes lunch. As the prey scrambles to escape, the antlion adds insult to injury by hurling a hail of sand at it, further undermining the sides of the pit. All the king’s horses and all the king’s men can’t save humpty-dumpty at this point. Want to see this in real time? Take a look: https://www.youtube.com/watch?v=CWkfAyfBDHE
As ferocious as they are, antlions have enemies too. To their own predators, antlions are simply little snacks. A large expanse of dirt or sand dented and dimpled with numerous funnels is a dead giveaway. These are like a flashing McDonalds drive-through sign for birds, scorpions, carabid beetles and wolf spiders on the hunt. If lucky enough to escape immediate demise, antlions have taken a move right out of the opossum playbook. Rather than put up an active defense, they lie totally still for unpredictable intervals of time. This confuses some marauders. In 2016 Nigel Franks and Ana Sendova-Franks (married biologists at the University of Bristol in England) decided to see how much antlions weighed. “I thought it was going to be a nightmare of impatient bugs,” Dr. Franks said. Instead, when tipped onto the scale, the antlions quickly froze. The researchers took out their stopwatches. Under their gaze, one antlion remained motionless for 61 minutes. “Watching paint dry would have been fun by comparison,” Dr. Franks said.
“Doodlebug, doodlebug, come out of your house. Your house is on fire, your children are all gone. Doodlebug, doodlebug, come out of your house.”
There must be hundreds of heirloom rhymes passed down to coax antlions from their holes. This one, however, mistakenly assumes the antlion is a parent. In fact, it’s only a mere child itself. These brutal little carnivores are really just larvae. The entire time from egg to adult may take 2-3 years. Like a number of other insects, the larval stage is the longest part of the life cycle in the antlion’s life. Researchers speculate this may be because of the uncertainty and irregular nature of the antlion’s food supply. When the larva reaches maximum size, it pupates and undergoes metamorphosis. It constructs a cocoon of sand grains cemented together with silk spun from a slender spinneret from its bottom. In Texas, the cocoon is about the size and shape of large rabbit droppings and is buried an inch or so beneath the sand. How to do this under the sand without getting sand in the cocoon, no one knows.
The antlion remains a little mummy anywhere from several weeks to several months (time seems unimportant). When the pupa finally breaks through the wall of the sand cocoon, it pushes up to the surface. What emerges is so very unlike the larva. The adult is winged, flimsy, and much more delicate than the larva. Sometimes known as antlion lacewings, the adult’s wings are fully opened in 20 minutes, and then it flies off. People often mistake the adult antlion for dragonflies or damselflies, but the prominent clubbed antennae give it away. Compared to damselflies, adult antlions are very feeble flyers and are normally found fluttering around at night looking for a mate. The adult typically lives about 25 days (it does not feed). As is the case in so many species, sex is an end-of-life event, the capstone to having fulfilled one’s ultimate purpose in life.
It’s not easy being an antlion. As they fight their way through a demanding and hard-scrabble life cycle, antlions have captured the imagination of children worldwide.
Doodlebug, doodlebug come to supper, I’ll give you some bread and butter.
There is such a promise of light in this tentative act of trust. It seems we only get moments as children. We should treasure the delight in our first discoveries of nature’s miracles. Where else but in the mind of a child could we find joy by enticing doodlebugs from their holes with nursery rhymes? Only, perhaps, on the far side of the moon. . .which until recently only a cow had seen, just before the dish ran away with the spoon.
By Larry Gfeller