Black Stink Bug
One of the most attractive of the true bugs, the black stink bug (Proxys punctulatus) is only an occasional visitor to our yard. It is a member of the family Pentatomidae, which includes many flat, triangular-shaped bugs generally called stink or shield bugs. Although a few of these insects are predators, the majority, including the black stink bug, feed by sucking out plant juices. I only occasionally see these bugs feeding, and they always seem to occur singly. I usually find black stink bugs walking on leaves or stems of various plants, perhaps because they are easily disturbed. Their unusual black and white coloration stands out, perhaps signaling that they are distasteful (not to mention spiny) and would not make a good meal for a bird. Some predatory stink bugs are also black, and they are capable of stabbing with a strong proboscis, so the dark color may provide that deterrent as well.
Stink bugs produce their scent through glands on the sides of their bodies. Other true bugs, including those in the family Coreidae, also have strong odors. In fact, I find some of these bugs "stinkier" than the stink bugs. While the predatory stink bugs are beneficial, those that feed on plants sometimes cause considerable damage, mostly to ornamentals and fruits. Cactus plants are another favorite target. The feeding of stink bugs usually produces disfigured leaves and discolored areas on plant stems. Because the black stink bugs are never numerous, any damage they cause to our plants is insignificant. Its strikingly elegant colors are a delightful surprise whenever this uncommon bug is encountered.