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Related to Hemiptera: Hymenoptera, Siphonaptera
(the true bugs), an order of insects most closely related to members of the order Homoptera (cicadas, leafhoppers, aphids, whiteflies, and scales). Sometimes Hemiptera are united with Homoptera (as a suborder) in the order Rhyncota.
Hemipterous insects measure 0.7–12 cm. The mouthpart is a jointed beak adapted to sucking; it consists of a labium, which is folded back into a tube, and two pairs of piercing organs (mandibular setae and maxillary setae). The beak is attached to the apex of the head and is divided from its base by the gula. The antennae are four- or five-jointed (sometimes they have one to three joints). There are two pairs of wings, which usually lie flat at rest; they cover the abdomen from above. The front wings consist of a leathery basal part (usually in two to four divisions) and a scarious distal part, or membrane. The front wings are rarely entirely leathery or alveolate. The membranes of opposite front wings usually overlap. In many hemipterans, such as the bedbug (Cimicidae), the wings are short or absent. Most hemipterous insects have scent glands; in adults the openings are on the underside of the thorax; in larvae, on the abdomen. The discharges have an unpleasant odor that frightens off enemies and attracts individuals of its own species. Metamorphosis from egg to adult is incomplete. The larvae are somewhat similar to adult hemipterans, and the pupal stage is absent.
Hemipterous insects are distributed throughout the world. There are approximately 25,000–30,000 known species, making up 50 families. In the USSR there are 2,000–2,500 species, belonging to 40 families. The principal families of Hemiptera are the aquatic families Corixidae (water boatmen), Notonectidae (backswimmers), and Nepidae (water scorpions) and the land-dwelling families Miridae (leaf bugs), Tingidae (lace bugs), Reduviidae (assassin bugs), and Pentatomidae (stinkbugs). The largest populations of hemipterans are found in the tropics; in the USSR these insects are concentrated in Middle Asia and Transcaucasia.
The habits of hemipterous insects are extremely varied. The overwhelming majority are terrestrial; however, some have transferred to life in the water or on its surface (Gerridae, or the water striders). Land-dwelling hemipterans usually live on vegetation; sometimes they are found on the surface of the soil or in its upper layer, in plant litter, along bodies of water, or under bark. Aquatic hemipterans swim or crawl along the benthos and on aquatic vegetation but breathe air from the atmosphere (only members of the family Aphelocheiridae get their oxygen from the water). Water striders skate on the surface of lakes and rivers; members of the genus Halobates are the only true marine insects (they are not found in the USSR).
The majority of terrestrial hemipterans feed on plant juices, primarily from the generative organs and seeds. Some terrestrial hemipterans, most aquatic hemipterans, and all water striders are predators; they suck the juices from various insects in the adult, larval, and egg stages (for example, mites and ticks). Some species have a mixed diet; for example, water boatmen feed on both small invertebrates and algae. Some aquatic hemipterous insects, including backswimmers and water boatmen, are harmful to the fishing industry because they prey on roe and fry. Bedbugs are parasites of man, bats, pigeons, swallows, and other birds. In the tropics, species of the family Polyctenidae parasitize bats. Some members of the family Reduviidae in Central and South America (for example, the genera Triatoma and Rhodnius) suck the blood of mammals, including man.
Many herbivorous hemipterans are agricultural and forest pests. The sucking of plant juices by hemipterans leads to incomplete seed development, a decrease in the germinating capacity, retardation of growth, leaf fall, and even the death of the plants (especially seedlings). The most harmful hemipterous insects in the USSR include those that damage grains (Eurygaster integriceps and species of Aelia, Notostira, and Trigonotylus), sugar beets (Poeciloscytus), vegetables (Eurydema), leguminous grasses (Adelphocoris lineolatus), fruit trees (Stephanitis pyri), and pine trees (Aradus cinnamomeus). The most harmful polyphagous hemipterans include species of the genera Lygus, Dolycoris, and Carpocoris. Some herbivorous hemipterans carry viral plant diseases.
Many insecticides are used in controlling hemipterous insects. Biological methods are also used against Eurygaster integriceps; egg parasites of the genus Telenomus are bred and released on fields infested with E. integriceps. The bedbug, which disturbs sleep, endangers human health. Members of the genus Triatoma are the carriers of Chagas’ disease, or American trypanosomiasis, which is a dangerous disease of humans.
Many predatory hemipterans, particularly those of the genera Orius and Nabis, are beneficial; they destroy aphids, mites, ticks, caterpillars, and beetle larvae that are agricultural and forest pests.
REFERENCESKirichenko, A. N. Nastoiashchie poluzhestkokrylye Evropeiskoi chasti SSSR: Opredelitel’ i bibliografiia. Moscow-Leningrad, 1951.
Kirichenko, A. N. “Poluzhestkokrylye.” In Zhivotnyi mir SSSR, vols. 1–5. Moscow-Leningrad, 1936–58.
Kirichenko, A. N. Metody sbora nastoiaschchikh poluzhestkokrylykh i izucheniia mestnykh faun. Moscow-Leningrad, 1957.
Vrednaia cherepashka: Sbornik, vols. 1–4. Moscow-Leningrad, 1947–60.
Kerzhner, I. M., and T. L. Iachevskii. “Otriad Hemiptera (Heteroptera) —poluzhestkokrylye, ili klopy.” In Opredelitel’ nasekomykh Evropeiskoi chasti SSSR, vol. 1. Moscow-Leningrad, 1964.
Zhizn’ zhivotnykh, vol 3. Edited by L. A. Zenkevich. Moscow, 1969.
Oshanin, B. Verzeichnis der palaeärktischen Hemipteren mit besonderer Berücksichtigung ihrer Verteilung im Russischen Reiche, vols. 1–3. St. Petersburg, 1906–10.
Weber, H. Biologie der Hemipteren. Berlin, 1930.
I. M. KERZHNER