This week while meandering along a pathway in a forest, Bug of the Week happened upon a most remarkable beetle, the eyed click beetle. One look at this beauty provides instant understanding of how “eyed” became part of its name. As you stare at the beetle, two large and impressive eyes stare back at you. These are not true eyes. The real eyes are on the head of the click beetle near the base of the antennae. The markings on the back of the beetle are false eyespots the ilk we have seen on other guests of Bug of the Week like the Polyphemus moth (NEED LINK TO JULY 14, 2008) Antheraea polyphemus, swallowtail larvae (NEED LINK FOR OCT 1, 2007), Papilio sp., and Owl butterflies (NEED LINK TO MARCH 2, 2009), Caligo sp.
The spine and notch are part of the engineering that give this beetle it's click.
The eyespots are thought to startle or confuse predators such as birds or reptiles that might want to make a meal of a tasty beetle. Ok, that explains the business about the “eyed”, but what about the click? To understand the click, you must be lucky enough to find and capture a click beetle. When grasped by a predator like a bird or a geeky entomologist, the eyed click beetle produces an unnerving snap of its body so forceful that it can escape the grasp of its tormentor. Click beetles have a remarkable spine on the under surface of the first segment of the thorax.
False eyespots may help the eyed click beetle look scary to predators.
This spine fits into a notch on the second thoracic body segment between the legs. The beetle flexes its body in such a way that the spine quickly releases with a click. When placed on its back, this snap can catapult the beetle in the air. The beetle often lands right side up. If the beetle lands on its back, the process may be repeated until the beetle rights itself.
Smaller, less dramatic click beetles are frequent visitors to our porch lamps in spring and summer. Larvae of several species of click beetles are plant eaters and when they feed on subterranean parts of crops such as wheat, corn, or potatoes, they can be noxious pests. Many click beetle larvae including the eyed click beetle are meat eaters rather than plant eaters. The fierce larva of the eyed click beetle has powerful jaws used to disable and dismember victims. Prey commonly includes other insects such as larvae of flies, caterpillars, and other beetles such as bess beetles. Click beetles are great fun to capture and most entertaining, but please put them back unharmed when you are done.
References
Bug of the Week thanks eagle-eyed Paula for spotting the eyed click beetle. For more information of click beetles and their kin, please visit the following web sites.
http://insects.tamu.edu/fieldguide/bimg151.html
http://www.umassturf.org/mangement_updates/2005_archive/05sep16.html