Cactus Bug
Chelinidea vittiger
On blossom of Engelmann Prickly Pear, French Creek, Bradshaw Mts., Yavapai Co., Arizona, USA. May 2009.
Coreidae -- Leaf-footed Bug Family
Prickly Pear growing in the Sonoran Desert, will on close inspection, almost always bear the gray-brown, dime-sized scars on the pads caused by the feeding activity of the Cactus Bug (Cactus Coreid). Like all bugs, Cactus Bugs cannot chew their food - they are on a strict, liquid diet. Their mouthparts are formed into a kind of straw with which they pierce the plant tissue and suck up sap. At the same time they may inject digestive enzymes or even microbes. This frequently causes a necrotic blemish on the plant.
These nymphs are sticking together as they feed on joints of Buckhorn Cholla (Cylindropuntia acanthocarpa). Maricopa Co., Arizona, 13 August 2011.
We love our cacti, and some early explorers loved them too; and maybe some wanted profits such as commercial dye from Cochineal Scale). Prickly pears were transported from America and planted in Australia and Africa, for example; escaped from cultivation, the cacti ran rampant through the Outback until Cactus Bugs and other cactus-feeding insects were also brought there for control. Lesson learned: Transporting plants or animals around the world can have devastating, unintended consequences.