Although the Coccinellidae is generally thought of as a family of beneficial predators, it has its black sheep. Species in one little group of lady beetles (the subfamily Epilachninae) feed on plants, including plants we would rather they left alone. The leaf-eating lady beetles are less convex than most family members and they tend to be dirty yellow in colour rather than bright black and red of most of their more reputable relatives. Ontario has only one species of Epilachninae, the Mexican Bean Beetle (Epilachna varivestris), which feeds as adult and larva on the underside of leaves of beans and related plants. Both the spiny larvae and broad adults chew away on the lower surface of leaves, transform then into characteristic lacy networks. If you do encounter some of these distinctive pests, poke one of the adults with a pin or a small twig. It will respond by releasing toxic, sticky blood from its leg joints, an interesting phenomenon known as reflex bleeding. Other lady beetles also have toxic blood, a defensive weapon they are probably advertising with their generally bright colours.