Minnesota Profile: Six-Spotted Tiger Beetle
Six-Spotted Tiger Beetle (Cicindela sexguttata)
Appearance: Despite its name, the six-spotted tiger beetle in Minnesota might have no spots-or as many as four white spots along the posterior edge of each wing cover. This half-inch-long, iridescent green or blue-green insect has conspicuous sickle-shaped mandibles (jaws) and large, bulging eyes on the side of its head.
Range: Common in the southern two-thirds of Minnesota and the eastern United States, it ranges from New England and southern Canada south to Florida and as far west as North Dakota and central Texas.
Habitat: This beetle is found primarily in deciduous forests and adjacent open areas. Watch for it on sunny trails, logs, and stones. Sometimes it turns up in urban yards and gardens.
Biology: Very active during the day, it moves rapidly in short bursts. Tiger beetles are among the fastest runners in the insect world.
The six-spotted tiger beetle needs two years to complete its life cycle. In spring the adults emerge and mate. The females lay eggs, which hatch into larvae in June or July. The grublike larva burrows into the ground, living in its vertical tunnel. The following summer it pupates. Though it changes to an adult in August or September, it doesn't come out of its burrow until the next spring.
Food: This beetle feeds on many kinds of insects, especially ants, as well as spiders and other small invertebrates. It moves quickly in search of prey. Encountering its quarry, the beetle turns toward it and waits for it to move. The instant the quarry moves, the beetle pounces, attempting to capture it with powerful mandibles. The larva is also predaceous. It waits in its burrow until an unsuspecting insect passes by, then it springs out like a jack-in-the-box to capture it.
Natural Enemies: Dragonflies and robber flies can capture beetles in flight. Birds, frogs, and other animals eat beetles they find on the ground. To avoid predators, the six-spotted tiger beetle relies on its speed, agility, and ability to secrete a noxious chemical.
Observation: Look for this beetle in May and June. Because tiger beetles have excellent vision, you might have trouble getting close to one. Move slowly to try to see this magnificent insect close up.
Jeff Hahn, entomologist
University of Minnesota Extension Service
The tiger beetle's eye-catching brilliance and fascinating predatory behavior have made it a longtime favorite with researchers and collectors. It is a good bioindicator species with a wealth of data on range and population. Adults have powerful, saw-toothed, overlapping mandibles. Larvae ambush prey from vertical burrows, braced at the opening by a large, plated head and abdomen with hooked spines.