Wild things: Tiger beetles (Cicindela sp.)
This group of beetles has a world-wide distribution and is ancient; fossil records date back about 125 million years. Of some 2,600 species currently known, about 100 occur in the North America. They are related to ground beetles, but differ in that the head of the tiger beetle is wider than the thorax. They favor dry, sandy soil and are often seen along forest paths. I normally encounter them along trails in the National Forest, where they run along the dirt path in front of me or fly ahead about 5 yards, stopping, then flying farther ahead as I approach.
Tiger beetles are an inch or less in length and have long, thin legs and large eyes. Though some species are dull and well camouflaged, many others are beautifully colored in various iridescent shades of brown, orange, turquoise, or red patches in artistic looking patterns. They are predaceous both as larvae and adults. Larvae have hooks at the rear of the abdomen that anchor the body in the soil. They wait at the entrance to the burrow and grab passing invertebrates and drag them into the burrow. Adults may wait and pounce on a passing prey animal or run after prey, such as other beetles, larvae, spiders, ants, grasshoppers, and other invertebrates. As such they are welcome garden guests, ridding the beds of destructive pests. They may run as fast as 5 mph and often stop in their pursuit of a prey. It is thought that they may run faster than they are able to visually process their environment and they have to take a moment to reorient themselves before continuing a chase.
In turn, tiger beetles are preyed upon by a variety of insects and vertebrates, such as robber flies, dragonflies, other tiger beetles, frogs, birds, small mammals, and they are even parasitized by mites.
The female lays a single egg in moist soil and the Tiger beetle larvae digs a cylindrical burrow in the soil where it lives during its growth phase. Development proceeds through several “instars,” or growth stages, sometimes lasting several years before the larva finally pupates and transitions into the adult stage. Adults engage in mating after emerging in the summer and live only one season, less than two months.