Temporal range: Moscovian–Recent
|Acanthosoma haemorrhoidale, a shield bug|
The Hemiptera // or true bugs are an order of insects comprising around 50,000–80,000 species of groups such as the cicadas, aphids, planthoppers, leafhoppers and shield bugs. They range in size from 1 mm (0.04 in) to around 15 cm (6 in), and share a common arrangement of sucking mouthparts. The name true bugs is sometimes limited to the suborder Heteroptera. Many insects commonly known as "bugs" belong to other orders; for example, the lovebug is a fly, while the May bug is a beetle.
Humans have interacted with the Hemiptera for millennia. Some species are important agricultural pests, damaging crops by the direct action of sucking sap, but also harming them indirectly by being the vectors of serious viral diseases. Other species have been used for biological control of insect pests. Hemipterans have been collected for the dyestuffs cochineal and carmine, and for shellac. The bed bug is a persistent parasite of man. Cicadas have been used as food, and have appeared in literature from the Iliad in Ancient Greece.
- 1 Characteristics
- 2 Taxonomy and phylogeny
- 3 Life cycle and ecology
- 4 Interaction with humans
- 5 References
- 6 External links
Hemiptera is the largest order of non-holometabolous insects (insects that do not undergo complete metamorphosis) containing over 75,000 named species. The defining feature of hemipterans is their possession of a "beak" in which the modified mandibles and maxillae form a "stylet" which is sheathed within a modified labium. The stylet is capable of piercing tissues and sucking liquids while the labium supports it. The stylet contains a channel for the outward movement of saliva and another for the inward movement of liquid food. The beak is usually kept folded under the body when not in use. The diet is typically plant sap but some hemipterans, such as assassin bugs, are blood-suckers and a few are predators. The group is very diverse. The majority of species are terrestrial, including a number of important agricultural pests, but some are found in freshwater habitats. These include the water boatmen, pond skaters and giant water bugs.
The forewings of Hemiptera are either entirely membranous, as in the Sternorrhyncha and Auchenorrhyncha, or partially hardened, as in most Heteroptera. The name "Hemiptera" is from the Greek ἡμι- (hemi; "half") and πτερόν (pteron; "wing"), referring to the forewings of many heteropterans which are hardened near the base, but membranous at the ends. Wings modified in this manner are termed hemelytra (singular: hemelytron), by analogy with the completely hardened elytra of beetles, and occur only in the suborder Heteroptera. In all suborders, the hindwings – if present at all – are entirely membranous and usually shorter than the forewings. The forewings may be held "roofwise" over the body (typical of Sternorrhyncha and Auchenorrhyncha), or held flat on the back, with the ends overlapping (typical of Heteroptera). The antennae in Hemiptera typically consist of four or five segments, although they can still be quite long, and the tarsi of the legs have two or three segments.
Although hemipterans vary widely in their overall form, their mouthparts (formed into a "rostrum") are quite distinctive; the only other insect orders with mouthparts modified in a similar manner are the Thysanoptera and some Phthiraptera, and these are generally easy to recognize as non-hemipteran for other reasons. Aside from the mouthparts, various insects can be confused with hemipterans, including cockroaches and psocids, both of which have longer many-segmented antennae, and some beetles, but these have fully hardened forewings which do not overlap.
Taxonomy and phylogeny
The present members of the order Hemiptera were historically placed into two orders, Homoptera and Heteroptera/Hemiptera, based on differences in wing structure and the position of the rostrum. The order is now more often divided into four or more suborders, after it was established that the "Homoptera" were paraphyletic. Molecular phylogenetics analysis by Song et al (2012) supports the following cladogram:
|Suborder||No. of Species||Examples||Characteristics||Image|
|Auchenorrhyncha||over 42,000||cicadas, leafhoppers, treehoppers, planthoppers, froghoppers||plant-sucking bugs; many can jump; many make calls, some loud|
|Sternorrhyncha||12,500||aphids, whiteflies, scale insects||plant-sucking bugs, some major horticultural pests|
|Coleorrhyncha||fewer than 30||moss bugs (Peloridiidae )||evolved in the southern palaeo-continent of Gondwana|
|Heteroptera||25,000||shield bugs, seed bugs, assassin bugs, flower bugs, sweetpotato bugs, water bugs||larger bugs, often predatory|
Life cycle and ecology
Hemipterans are hemimetabolous, meaning that they do not undergo metamorphosis, the complete change of form between a larval phase and an adult phase. Instead, their young are called nymphs, and resemble the adults to a greater or less degree. The nymphs moult several times as they grow, and each instar resembles the adult more than the previous one. Wing buds grow in later stage nymphs and the final transformation involving little more than the development of functional wings (if they are present at all) and functioning sexual organs, with no intervening pupal stage as in holometabolous insects. With around 75,000 described species, Hemiptera is the largest insect order that is hemimetabolous; the orders with more species all have a pupal stage, Coleoptera (370,000 described species), Lepidoptera (160,000), Diptera (100,000) and Hymenoptera (100,000).
Parthenogenesis and vivipary
Many aphids are parthenogenetic during part of the life cycle, such that females can produce unfertilized eggs, which are clones of their mother. All such young are female (thelytoky), so 100% of the population at these times can produce more offspring. Many species of aphid are also viviparous: the young are born live rather than laid as eggs. These adaptations enable aphids to reproduce extremely rapidly when conditions are suitable.
Some species of ant protect and farm aphids (Sternorrhyncha) and other sap-sucking hemipterans, gathering and eating the honeydew that these hemipterans secrete. The relationship is symbiotic, as both ant and aphid benefit. Ants such as the yellow anthill ant, Lasius flavus, breed aphids of at least four species, Geoica utricularia, Tetraneura ulmi, Forda marginata and Forda formicaria, taking eggs with them when they found a new colony; in return, these aphids are obligately associated with the ant, breeding mainly or wholly asexually inside anthills.
Some leafhoppers (Auchenorrhyncha) are similarly "milked" by ants. In the Corcovado rain forest of Costa Rica, wasps compete with ants to protect and milk leafhoppers; the leafhoppers preferentially gave more honeydew, more often, to the wasps, which were larger and may have offered better protection.
Most other hemipterans are predatory, feeding on other insects, or even small vertebrates. The predatory shield bug for example stabs caterpillars with its beak and sucks out the body fluids. The nymph of Reduvius personatus, the masked hunter bug, camouflages itself with layers of particles on its body; it can give a painful bite.
A few hemipterans are parasitic, feeding on the blood of larger animals. These include bedbugs and the triatomine kissing bugs of the assassin bug family Reduviidae, which can transmit the dangerous Chagas disease.
The first known hemipteran parasite of vertebrates was the extinct assassin bug Triatoma dominicana found fossilized in amber and dating back about twenty million years. Faecal pellets fossilised beside it show that it transmitted a disease-causing Trypanosoma and the amber included hairs of the likely host, a bat.
Several families of Hemiptera are water bugs, adapted to an aquatic lifestyle, such as the water boatmen and water scorpions. They are mostly predatory, and have legs adapted as paddles to help the animal move through the water. The "pondskaters" or "water striders" of the family Gerridae are also associated with water, but use the surface tension of standing water to keep them above the surface; they include the sea skaters in the genus Halobates, the only truly marine group of insects.
Interaction with humans
Although many species of Hemiptera are significant pests of crops and garden plants, including many species of aphid and scale insects, other species are harmless. The damage done is often not so much the deprivation of the plant of its sap, but the fact that they transmit serious viral diseases between plants. They often produce copious amounts of honeydew which encourages the growth of sooty mould. Significant pests include the cottony cushion scale, a pest of citrus fruit trees, the green peach aphid and other aphids which attack crops worldwide and transmit diseases, and jumping plant lice which are often host plant-specific and transmit diseases.
For pest control
Members of the familes Reduviidae, Phymatidae and Nabidae are obligate predators. Some predatory species are used in biological pest control; these include various nabids, and even some members of families that are primarily phytophagous, such as the genus Geocoris in the family Lygaeidae. Other hemipterans are omnivores, alternating between a plant-based and an animal-based diet. Dicyphus hesperus for example is used to control whitefly on tomatoes, but also sucks sap, and if deprived of plant tissues will die, even in the presence of whiteflies.
Other hemipterans have positive uses for humans, such as in the production of the dyestuffs cochineal and carmine. The scale insect Dactylopius coccus produces the brilliant red-coloured carminic acid to deter predators. Up to 100,000 scale insects need to be collected and processed to make a kilogram (2.2 lbs) of cochineal dye. A similar number of lac bugs are needed to make a kilogram of shellac, a brush-on colourant and wood finish. Additional uses of this traditional product include the waxing of citrus fruits to extend their shelf-life, and the coating of pills to moisture-proof them, provide slow-release or mask the taste of bitter ingredients.
As human parasites and disease vectors
The bed bug, Cimex lectularius, is an external parasite of humans. It lives in bedding and is mainly active at night, feeding on human blood, generally without being noticed. Bed bugs mate by traumatic insemination; the male pierces the female's abdomen and injects his sperm into a secondary genital structure, the spermalege. The sperm travel in the female's blood (haemolymph) to sperm storage structures (seminal conceptacles); they are released from there to fertilise her eggs inside her ovaries.
Some larger hemipterans such as cicadas are used as food in Asian countries such as China, and they are much esteemed in Malawi and other African countries. Insects have a high protein content and good food conversion ratios, but most hemipterans are too small to be a useful component of the human diet.
In art and literature
Cicadas have featured in literature since the time of Homer's Iliad, and as motifs in decorative art from the Chinese Shang dynasty (1766-1122 B.C.). They are described by Aristotle in his History of Animals and by Pliny the Elder in his Natural History; their mechanism of sound production is mentioned by Hesiod in his poem Works and Days "when the Skolymus flowers, and the tuneful Tettix sitting on his tree in the weary summer season pours forth from under his wings his shrill song".
In mythology and folklore
Among the bugs, cicadas in particular have been used as money, in folk medicine, to forecast the weather, to provide song (in China), and in folklore and myths around the world.
- "Hemiptera". Integrated Taxonomic Information System.
- Jon Martin & Mick Webb. "Hemiptera...It's a Bug's Life" (PDF). Natural History Museum. Retrieved July 26, 2010.
- "Hemiptera: bugs, aphids and cicadas". Commonwealth Scientific and Industrial Research Organisation. Retrieved May 8, 2007.
- "Suborder Heteroptera - True Bugs". Bug guide. Iowa State University Entomology. n.d.
- Denmark, Harold; Mead, Frank; Fasulo, Thomas (April 2010). "Lovebug, Plecia nearctica Hardy". Featured Creatures. University of Florida/IFAS. Retrieved 22 September 2010.
- "Melolontha melolontha (cockchafer or May bug)". Natural History Museum. Retrieved 12 July 2015.
- Ruppert, Edward E.; Fox, Richard, S.; Barnes, Robert D. (2004). Invertebrate Zoology, 7th edition. Cengage Learning. pp. 728, 748. ISBN 978-81-315-0104-7.
- Coulson, Robert N.; Witter, John A. (1984). Forest Entomology: Ecology and Management. John Wiley & Sons. pp. 71–72. ISBN 978-0-471-02573-3.
- Alford, David V. (2012). Pests of Ornamental Trees, Shrubs and Flowers: A Color Handbook. Academic Press. p. 12. ISBN 978-0-12-398515-6.
- "Hemiptera". Discover Life. Retrieved 13 July 2015.
- Chinery, Michael (1993). Insects of Britain and Northern Europe (3rd ed.). Collins. ISBN 0-00-219918-1.
- Song, Nan; Liang, Ai-Ping; Bu, Cui-Ping (2012). "A Molecular Phylogeny of Hemiptera Inferred from Mitochondrial Genome Sequences". PLOSone 7 (11): e48778. doi:10.1371/journal.pone.0048778.
- "Suborder Auchenorrhyncha". NCSU. Retrieved 12 July 2015.
- "Sternorrhyncha". Amateur Entomologists' Society. Retrieved 13 July 2015.
- "Hemipteroid Assemblage". Tree of Life Web Project. 1995.
- André Nel, Patrick Roques, Patricia Nel, Alexander A. Prokin, Thierry Bourgoin, Jakub Prokop, Jacek Szwedo, Dany Azar, Laure Desutter-Grandcolas, Torsten Wappler, Romain Garrouste, David Coty, Diying Huang, Michael S. Engel and Alexander G. Kirejtshuk (2013). "The earliest known holometabolous insects". Nature 503 (7475): 257–261. doi:10.1038/nature12629.
- Shcherbakov, D. E. (2000). "Permian faunas of Homoptera (Hemiptera) in relation to phytogeography and the Permo-Triassic crisis" (PDF). Paleontological Journal 34 (3): S251–S267.
- Britton, David (9 July 2009). "Metamorphosis: a remarkable change". Australian Museum. Retrieved 13 July 2015.
- "Insect groups (Orders)". Amateur Entomologists' Society. Retrieved 16 July 2015.
- Mackean, D.G. "Aphids, an Introduction". Biology Teaching Resources. Retrieved 13 July 2015.
- "Glossy Shield Bug: Cermatulus nasalis". Brisbane Insects and Spiders. 1 August 2010. Retrieved 16 July 2015.
- Ivens, A. B. F.; Kronauer, D. J. C.; Pen, I.; Weissing, F. J.; Boomsma, J. J. (2012). "Reproduction and dispersal in an ant-associated root aphid community". Molecular Ecology: 1–13. doi:10.1111/j.1365-294X.2012.05701.x.
- Choe, Jae (14 February 2012). Secret Lives of Ants. JHU Press. pp. 62–64. ISBN 978-1-4214-0521-6.
- Wierauch, C. (2006). "Anatomy of Disguise: Camouflaging Structures in Nymphs of Some Reduviidae (Heteroptera)". Am. Mus. Novit. 3542: 1–18.
- Poinar, G. (2005). "Triatoma dominicana sp. n. (Hemiptera: Reduviidae: Triatominae), and Trypanosoma antiquus sp. n. (Stercoraria: Trypanosomatidae), the First Fossil Evidence of a Triatomine-Trypanosomatid Vector Association". Vector-Borne and Zoonotic Diseases 5 (1): 72–81. doi:10.1089/vbz.2005.5.72. PMID 15815152.
- "Sooty moulds". Royal Horticultural Society. Retrieved 16 July 2015.
- David L. Green (10 August 2003). "Cottony cushion scale: The pest that launched a revolution in pest control methods". Retrieved 16 July 2015.
- Capinera, John L. (October 2005). "Featured creatures". University of Florida website - Department of Entomology and Nematology. University of Florida. Retrieved 16 July 2015.
- de Queiroz, Dalva Luiz; Burckhardt, Daniel; Majer, Jonathan (2012). "17: Integrated Pest Management of Eucalypt Psyllids (Insecta, Hemiptera, Psylloidea)". In Larramendy, Marcelo L.; Soloneski, Sonia. Integrated Pest Management and Pest Control: Current and Future Tactics. pp. 385–386. ISBN 978-953-51-0050-8.
- Mahr, Susan (1997). "Know Your Friends: Damsel Bugs". Biological Control News (University of Wisconsin–Madison) IV (2). Retrieved 16 July 2015.
- James Hagler. Weeden, Catherine R.; Shelton, Anthony M.; Hoffman, Michael P., ed. "Geocoris spp. (Heteroptera: Lygaeidae): Bigeyed Bug". Biological Control: A Guide to Natural Enemies in North America. Cornell University. Retrieved 16 July 2015.
- Torres, Jorge Braz; Boyd, David W. (2009). "Zoophytophagy in predatory Hemiptera". Brazilian Archives of Biology and Technology 52 (5). doi:10.1590/S1516-89132009000500018.
- "Cochineal and Carmine". Major colourants and dyestuffs, mainly produced in horticultural systems. FAO. Retrieved June 16, 2015.
- "How Shellac Is Manufactured". The Mail (Adelaide, SA : 1912 - 1954). 18 Dec 1937. Retrieved 17 July 2015.
- Pearnchob, N.; Siepmann, J.; Bodmeier, R. (2003). "Pharmaceutical applications of shellac: moisture-protective and taste-masking coatings and extended-release matrix tablets". Drug Development and Industrial Pharmacy 29 (8): 925–938. PMID 14570313.
- "American Trypanosomiasis". Centers for Disease Control (CDC). Retrieved 17 July 2015.
- Goddard, J; deShazo, R (1 April 2009). "Bed bugs (Cimex lectularius) and clinical consequences of their bites". JAMA: the Journal of the American Medical Association 301 (13): 1358–66. doi:10.1001/jama.2009.405. PMID 19336711.
- Reinhardt, Klaus; Siva-Jothy, Michael T. (Jan 2007). "Biology of the Bed Bugs (Cimicidae)" (PDF). Annual Review of Entomology 52: 351–374. doi:10.1146/annurev.ento.52.040306.133913. PMID 16968204. Archived from the original (PDF) on 5 July 2010. Retrieved 26 May 2010.
- Carayon, J. 1959 Insémination par "spermalège" et cordon conducteur de spermatozoids chez Stricticimex brevispinosus Usinger (Heteroptera, Cimicidae). Rev. Zool. Bot. Afr. 60, 81–104.
- Greenaway, Twilight. "The Best Way to Handle the Coming Cicada Invasion? Heat Up the Deep Fryer". Smithsonian.
- Anthes, Emily (14 October 2014). "Could insects be the wonder food of the future?". BBC. Retrieved 17 July 2015.
- Myers, J. G. (1929). Insect Singers (PDF). G. Routledge and Sons.
- "Cicada". Britannica. Retrieved 12 July 2015.
- Cladogram of Hemiptera at Tree of Life Project
- Media related to Hemiptera at Wikimedia Commons
- Data related to Hemiptera at Wikispecies