Ashy Gray Tortoise Beetle
Cassida lacrymosa (?)
On Morning Glory, Ipomoea sp., Kerio Valley, Kenya. December 2015.
Tortoise Beetles are amazing to look at, and there are hundreds of known species. The adult beetles often are so metalic that one could believe they are items of jewelry. Like a reptilian tortoise, their shell offers considerable protection against predators. When threatened the beetle's feet cling to a smooth leaf surface with powerful forces and pull the shell down all around leaving just a slick impenetrable surface exposed.
Both the larvae (grubs) and adults feed on leaves of various plants. This group has preferences for plants in the morning glory family (Convolvulaceae) including cultivated sweet potatoes. The larvae have barbed spines on their dorsum and posterior that can hold fecal material and cast exoskeletons. This pile of trash is designed to deter or hide the beetle from would-be predators.