What Time is it in Nature: Six-spotted Tiger Beetle
The recent warm weather has brought the insects out in droves! You’ll be able to see one charismatic insect species over the next few months, the Six-spotted Tiger Beetle, Cicindela sexguttata.
The Six-spotted Tiger Beetle belongs to the tiger beetle group within the ground beetle family Carabidae. Like other ground beetles, you will typically spot tiger beetles running along the ground, but their distinctive shape can help you tell them apart from their close relatives. Their half-inch long bodies sit atop long, slender legs and the pronotum (the section that sits between the wing covers and the head) is narrower than the rest of the body. Tiger beetles also have large eyes and long, sickle-shaped mouthparts. Six-spotted Tiger Beetles are bright, iridescent green and typically have six white spots arranged as you see in the image above, though the exact number of spots is variable.
Six-spotted Tiger Beetles are usually found in forests in sandy, exposed areas or on fallen logs. Adult beetles spend their days hunting for prey, eating small insects, spiders, and isopods (the small land crustaceans commonly known as rolly polies or pill bugs). These beetle are especially quick, both while running and flying, and are able to capture fast-moving prey. On especially hot days, you may see these brilliantly green beetles walking with their legs stretched out as far as possible. This behavior, called stilting, keeps their bodies far from the hot sand and helps the beetles stay cool.
You will see Six-spotted Tiger Beetle adults from spring through mid-summer, though these are long-lived insects. Females lay their eggs in sandy soils, digging a small hole, depositing a single egg, and covering it with soil. Once the larva hatches, it will dig itself a cylindrical burrow that it enlarges as it develops. The duration of the larval stage depends on the weather and prey availability, but it typically lasts 2-3 years. Most larvae pupate in the summer with adult beetles emerging in the fall. Adults will then hibernate through the winter before reproducing the following spring. The entire life cycle takes 2-4 years or more, a long life for an insect! Thier long lives make these beetles valuable for assessing the environmental quality of an area. Because the adults and larvae live in the same habitats for multiple years, they are very susceptible to environmental changes or stresses. The presence of tiger beetles, especially the larvae, in an area is often a sign of good, stable habitat.
You are most likely to see Six-spotted Tiger Beetles along the sandy banks of the Prairie Ridge stream. Next time you visit, look for bright flashes of iridescent green in sunny areas near the steep banks of the stream. Once you spot one, you’ll start to see more of these wonderful, speedy beetles, a welcome sight for many visitors to Prairie Ridge!
What Time is it in Nature is a weekly feature highlighting the current plants, animals, and other wildlife at the Musuem’s public outdoor facility, Prairie Ridge Ecostation. Find out more about the natural happenings at Prairie Ridge at our What Time is it in Nature Archive!
(Photo by Greg Bryant, used with permission)