By Jim Knox
They were curious looking. The diameter of a 50-cent piece and funnel shaped, the little depressions littered the ground in the dry soil at my feet. I tried to make them out. At first, I thought they may have been a result of water falling off the building’s eaves. Upon closer inspection, I realized they were within the band of dry soil tucked well under the building’s gutter drip line. Whatever they were, they weren’t the result of rain or dripping water. I looked closer still and studied them. I had a suspicion and decided to put it to the test. I took a nearby blade of grass and carefully flicked sandy soil from the rim of the funnel toward the center, filling the center of the inverted cone very slightly. I then did the same to two more alternating cones. I returned the next day, and my suspicions were confirmed. All three cones were restored to their perfect funnel shape, with the sandy soil removed. What I came to discover was that the cone-like depressions were not the result of wind, water, or chance. They were the calling card of a little-known predator.
The Eastern Spotted-winged Antlion, Dendroleon obsoletus, or Spotted-winged Lacewing is a Connecticut insect like no other. Also known as doodlebugs for the doodle-like scrawled trails of the juvenile insects in the dry sandy soil, they are members of an extraordinarily successful family of approximately 2,000 known species found throughout the globe. Preferring relatively warm climate and dry habitat such as dry forests, meadows, scrubby dunes, and soil beneath rocky outcroppings, these insects have colonized vast areas. Occupying a home range from Ontario and New Hampshire southward to Florida and westward to Kansas and New Mexico, Eastern Spotted-winged Antlions are quite adaptable to varying climatic conditions. Possessing four distinct life stages, with adults adopting a nocturnal lifestyle and larvae adopting a diurnal (daytime) lifestyle, it can be hard to tell which insect you’re seeing. The most recognizable stage is the adult form. Ranging from 1-1.5 inches in length, with a long slender dark gray dragonfly-like body with clear wings bearing back spots, the adults are fairly easy to identify. Delicate in appearance, the flighted adults are often attracted to artificial lights and are hard to miss. Chances are, if you have lights at your front door, or a back deck, you’ve even seen your fair share of these insects and haven’t even known it.
While these insects spend their brief adult lives of just 4-6 weeks feasting on plant juices and pollens, they are vastly different from the juveniles which are behavioral opposites. Antlion young, known as larvae, are strict predators. With a stocky oblong body equipped with ferocious looking spiked mandibles, the juvenile antlion is designed with one purpose—to catch and devour soft bodied insect prey. While the antlion is small, rarely topping half an inch in size, this micro beast more than compensates with trademark ferocity. When ants or other soft bodied insect prey crawl along the lip of the antlion’s funnel-shaped traps from 1-2 inches deep and 1-3 inches wide, the prey slides down the steep sides toward the waiting jaws of the predator. While the young are among the planet’s most patient ambush predators—often waiting months with open jaws for a passing meal—they have ways of enhancing their success.
When an ant or other insect stumbles upon the lip of the funnel trap and begins its slide toward the ambush below, the antlion flicks sand or bits of loose soil toward the prey, eroding its footing and collapsing the section of funnel below it—speeding its tumble to the hungry antlion below. Equipped with stiff, forward-facing bristles along its body to anchor itself firmly at the trap’s base, the antlion cannot only subdue small prey, but can successfully subdue prey far larger than itself.
Once within the spiked mandibles, prey rarely escapes. Possessing toxic capability, the antlion both impales the prey and simultaneously injects venom into the hapless quarry via grooves in its mandibles. The venom both paralyzes the prey and liquefies its insides, enabling the antlion to feast with little danger of injury or struggle. When finished, the antlion removes the prey’s husk from the trap and readies it for its next victim. In a most efficient conversion of energy, antlion larvae do not produce metabolic waste but produce silk for laying a cocoon and a single void at the end of this life stage.
With its varied habits and cryptic sign displayed quite literally beneath our feet; the antlion often flies under our collective radar. Yet frequently it is the hidden creatures that have the most to offer us. Boasting a veritable résumé for emulation, the antlion’s traits confer a keen competitive edge that yields consistent success. With hallmark patience, the antlion constructs—and maintains—a trap for opportunities, some far larger than itself. Once opportunity comes along, the antlion springs into action, reducing chance from its equation and hastening its moment to grasp its prize. Once opportunity is within its grasp the antlion employs its unique traits to ensure success.
By patiently funneling success toward our ready grasp, we too can spring into action—ambushing opportunities and employing our unique strengths to achieve our goals. While it is true we never know where success will come from, often, we simply must recognize what lies right at our feet.
Jim Knox serves as the Curator of Education for Connecticut’s Beardsley Zoo and as a Science Advisor for The Bruce Museum. A proud Member of The Explorers Club, Jim loves sharing his passion for the world’s wildlife with audiences near and far.
