National Geographic : 1998 Mar
LONG-HORNED BEETLE The antennae of many long-horned beetles, like this Asian species, approach or exceed body length. Recyclers of dead plants, some also have a taste for live vegetation. LEAF BEETLE Plant material, preferably living, is the diet of this family. Though some are destructive pests, others are used to biologically control noxious weeds. Many are important pol linators of flowers. A profusion of forms and functions Small and mostly inconspicuous, beetles can nevertheless be viewed as evolution's biggest success story. About one-fourth of all animal species on Earth are beetles, an order that encompasses the bizarre, the destruc tive, the attractive, and the beneficial. The eight groups shown here account for two-thirds of all known beetles. A key to the insect's adaptability is its elytra, a "shell" that is actually a pair of hardened wings. It protects and also serves as custom equipment, per mitting some species to live in the des ert by sealing in moisture and others to move underwater by trapping air. Beetles fill critical ecological niches; their scavenging helps remove animal wastes, carcasses, and plant matter. As pollinators they aided the great explosion of flora in the Mesozoic era.