Phylum Arthropoda (Arthropods)
Subphylum Hexapoda (Hexapods)
Class Insecta (Insects)
Order Coleoptera (Beetles)
Suborder Polyphaga (Water, Rove, Scarab, Long-horned, Leaf and Snout Beetles)
Superfamily Elateroidea (Click, Firefly and Soldier Beetles)
Family Elateridae (Click Beetles)
Click Beetles are the adults of wireworms and with about 1,000 species in NA are often quite common. The adults have a unique behaviour which, when first seen, borders on the unbelievable. When placed on their backs they are able to launch themselves into somersaults with (I’m guessing) a 50:50 probability of landing on their feet where they can run away. I am not knowledged enough to explain how they accomplish such a jump; this article tries to explain the mechanics:
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3116849/
The ability to somersault-jump depends on some unique (?) morphology. In most (?) beetles the 3-segmented thorax consists of one inflexible 2nd & 3rd unit connected by a moveable joint to the 1st segment. In Click Beetles there is a far more flexible membrane (fm) between the 1st and 2nd thoracic segments. Ventrally there is a spine (sp) on the 1st thoracic segment that fits into a deep groove (gv) on the 2nd thoracic segment between the leg bases. The flexible membrane and the peg-and-socket joint are intimately involved in the jumping mechanism.
Top: ventral view of 1st and 2nd thoracic segments of a Melanotus sp.; note the almost complete separation between the two segments (joined and far less flexible in other beetles)
Bottom: side view
Both images with Apo Componon lenses; ZS PMax
