Mantis on Coleus Leaf (D. Rhodes)
I am not an entomologist, but I believe that this insect observed on my backyard Coleus plant is a mantis, most likely a female Mantis religiosa which is renowned for practicing sexual cannibalism -- namely eating the male. Apparently, the female may first bite off the male's head, which increases copulatory movement and delivery of sperm: Mantis.
The female may begin feeding by biting off the male's head (as they do with regular prey), and if mating has begun, the male's movements may become even more vigorous in its delivery of sperm. Early researchers thought that because copulatory movement is controlled by a ganglion in the abdomen, not the head, removal of the male's head was a reproductive strategy by females to enhance fertilization while obtaining sustenance.
The Coleus genus has now been renamed Plectranthus, a member of the Lamiaceae family of angiosperms: Coleus. It is mostly grown as an ornamental for its colorful leaves. Certain species accumulate a compound called forskolin (coleonol), a compound that is used in biochemical research to raise levels of cyclic AMP (cAMP). Forskolin is an activator of the enzyme adenylyl cyclase.