Last week we returned from several weeks of tropical adventures to the DMV and visited delightful ground-nesting plasterer bees. This week let’s meet the tiger king of the insect world, a beautiful tiny terror, the six-spotted green tiger beetle. Recently, I received an inquiry from a neighbor who discovered a stunning emerald green creature entangled in a sheet of plastic covering a backyard water garden. My hopes for capturing a leprechaun and its attendant pot of gold were dashed when the accompanying image revealed a lovely six-spotted green tiger beetle that had somehow become trapped in the translucent plastic jungle. Tiger beetles are well-adapted to hunt. Exceptionally long legs provide lots of ground clearance and enable bursts of speed as they dash across the forest floor. Large eyes enable them to peruse their surroundings for signs of movement and potential meals. Unlike praying mantids that are “sit and wait” predators, tiger beetles actively stalk, pursue, and capture their victims. As I have observed tiger beetles, I’ve found that tossing a small twig in the vicinity of a hunter often triggered an inquisitive charge as the beetle scrambled to see if a potential meal had entered its ambit.
Six-spotted green tiger beetles prowl in a terrarium while keeping an eye out for a meal. It looks like this tiger beetle has no intention of sharing its dinner with a nosy cricket.
Like its feline namesake, the tiger beetle has powerful jaws used to subdue its victim. Each jaw is armed with several stout teeth. The jaws grasp, pierce, and crush. Tiger beetles are carnivores as both adults and juveniles. The female tiger beetle lays her eggs singly on the ground. Upon hatching, the immature stage, the larva, constructs an underground burrow. From this lair, the larva stealthily awaits dinner. As a hapless insect or spider strolls by, the larva springs from the hole like a jack-in-the-box and impales its victim with impressive jaws. The prey is then drawn into the burrow and eaten. Strange hook-like structures found on the abdomen of the tiger beetle larva help anchor it in its burrow. As generalist predators and members of Mother Nature’s hit squad, tiger beetles consume pests in our gardens and landscapes and provide the important ecological service of biological control.
Tiger beetles are tough to capture without a net, but if you catch one, be careful; they have powerful jaws and can give you a little nip. On a recent trip to the Western Maryland Rail Trail near Hancock, Maryland legions of six-spotted green tiger beetles capered and dodged bicycles and walkers along the asphalt surface. As I slithered on the ground to photograph tigers, one inquisitive hiker shared his observations of the beetles as he encountered them along the sun-dappled trail. He said “When you get too close, those critters fly up and settle down a little way down the path, then they turn around and look at you. When you get close again, they do the same thing.” Good observations. As I watched the lethal power and speed of tiger beetles, I was glad to be five feet something tall rather than five millimeters in height. This diminutive tiger will be common along sunny bike trails and paths in the forest over the next month or so. A quest for six-spotted green tiger beetles at an appropriate social distance is a tonic on these days of sequestration, and well worth a walk in the forest on a fine spring day.
Sunny bike trails and paths through the forest are great places to watch six-spotted tiger beetles, but alas, fast wheels and speedy feet may spell danger for inattentive tigers.
“An Introduction to the Study of Insects” by Borrer, De Long , and Tripplehorn was used as a reference for this Bug of the Week. Thanks to Anne Marie for providing the inspiration for this week’s episode and for releasing her tiger beetle back into the wild.