ASU Research E-Magazine: Tiger Beetle Trivia

In the Sonoran Desert, some tigers hunt during the day. Others hunt only at night. All desert tigers use excellent eyesight to locate their prey, and then use amazing speed to run it down.

The hunted creature has little chance. Once caught, the tiger crushes it with huge, sickle-like jaws, and then tears it into pieces. The tiger pours powerful digestive juices from its mouth onto the bits and pieces. Once the pile of pieces is melted into a nice, gooey mush, the tiger rolls it all into a large meatball. Then it is time to chow down.

Tigers in the Arizona desert? No way, you say. Believe it. But these tigers are not giant cats. They are beetles. Their food of choice includes ants and termites and small insects of all kinds.

David Pearson studies these fierce desert hunters. Pearson is an ecologist and conservation biologist at Arizona State University. Tiger beetles, he says, are fascinating, colorful predators.

About 2,300 species of tiger beetles (family Cicindelidae) exist worldwide. They live everywhere there is land, with the exception of Antarctica, Tasmania, and some of the most remote oceanic islands.

Arizona is famous for its variety of tiger beetles. The state is home to 36 different species, which live everywhere from the Chiricahua Mountains in southern Arizona to the north rim of the Grand Canyon. The beetles are especially fond of the Sulphur Springs Valley in southeastern Arizona, where 18 different species live. That is one of the highest concentrations of species in all of North America.

Tiger beetles in Arizona grow from 10 to 25 millimeters long. Most are brown or green with stripes. Most are active during the day. Some are large and black and active only at night. The best time of year to see tiger beetles depends on where you look.

The insects are active from February to April in Sedona and along the Mogollon Rim near Payson. In July, they can be found in the White Mountains. In southern Arizona, tiger beetles are active at the start of the summer monsoons.

Tiger beetles vary in size. The smallest lives in Borneo and measures 6 millimeters, about the length of a housefly. The largest lives in southern Africa. It measures up to 45 millimeters, about the width of a tea bag.

Tiger beetles come in many colors. Some are plain black, but others are stunningly decorated in metallic green, brown, maroon, or purple, often with stripes or spots. All tiger beetles have long, thin mandibles shaped like sickles, which help them capture prey.

Tiger beetle larvae use their mandibles to dig tunnels in the ground, where they wait for small insects to pass close enough for capture. The larvae stay in their tunnels from one to three years before emerging as adult beetles.

An Australian tiger beetle takes the prize as the fastest runner of all the arthropods, a group that includes all insects, crustaceans, and arachnids. This beetle can move at 9 kilometers per hour (5.6 miles per hour), or 170 body lengths per second. If it were the size of a racehorse, the beetle would be running about 120 miles per hour.

Consider this: a human traveling 170 body lengths per second would have to run about 338 miles per hour, or 544 kilometers per hour!

The tiger beetle is a tough bug to catch, or to outrun.—Diane Boudreau