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Amitermitinae constitute a subfamily of harvester termites and allies (family Termitidae) in the Isoptera infraorder. They have been merged with the Termitinae subfamily and are considered by ITIS as an invalid taxon. 〔 (ITIS ) 〕 However, a case could be made to keep them in their own subfamily because they have some important attributes that affect soil. Amitermitinae consists of 18 genera and 296 species. They have as typical characteristics a usually rounded head and a bilobed clypeus. The mandibles of their soldiers have usually a single median tooth. They have evolved the ability to have many reproductives in their colony, up to a hundred, which allows very large colonies. As with other members of their Termitidae family, they have lost most of their cellulose digesting protozoa. Instead they digest fungi, which fungi digest the cellulose and other organic matter. As a result the Termitidae can make use of a wide variety of food. Not only rotten wood, but also grass, seeds, dung, soil, and detritus 〔MacKay WP (1991) The role of ants and termites in desert communities. p113-150 in; Polis GA ed. The Ecology of Desert Communities. University of Arizona Press, Tucson.〕 〔Hill GF (1942) Termites (Isoptera) from the Australian Region. HE Daw, Govt. printer, Melbourne, Australia.〕 are all used by one species or another. In addition some species can synthesize nitrogen compounds 〔Schaefer DA Whitford WG (1981) Nutrient cycling by the subterranean termite Gnathitermes tubiformans in a Chihuahuan desert ecosystem. Oecologia 48; 277-283.〕 Many members of the Amitermitinae have evolved a very effective way of securing food. The Amitermes genera especially build a shell of earth by cementing the earth with their saliva and use it to cover vegetation. This smothers the plant and they can then eat the fungi that grows in the safety of the covering. They probably evolved in savanna regions. They probably evolved in monsoon and desert regions because their runways are not very resistant to rain erosion〔Weber CE (1993) Cretaceous termites and soil phosphorus. J. Soil Biol. Ecol. 13; 108-121.〕 They use saliva to build runways, and this is an adaptation of an earlier use of saliva to entangle enemies 〔Noirot CH (1969) Glands and secretions of termites p89-119 in; Biology of Termites. Krishnar K Weesner M, ed. Vol I, Academic Press NY.〕 The cemented soil is richer in phosphorus than the soil it is derived from 〔 Weber CE (1993) Cretaceous termites and soil phosphorus. J. Soil Biol. Ecol. 13; page 111.〕 This causes an increased loss of phosphorus from sheet erosion. It is probably a major part of the reason why tropical savanna soils are depleted in phosphorus, especially in Australia. The Termes genus branch probably arose in Africa 〔Emerson AE (1955) Geographical origin and dispersions of termite genera. FieldianaZool. 37; 465-521; p. 478 〕 Amitermitinae are thought to have arisen in southeast Asia 〔 probably from primitive Oriental Termitinae 〔 Krishna K (1970) Taxonomy, phylogeny, and distribution of termites p127-150 in: Biology of Termites, Vol II Krishna K & Weesner FM, eds. Academic Press NY.〕 in early Cretaceous 〔 Bouillon A (1970) Termites of the Ethiopian region, in; Biology of Termites. Krishna A Weesner FM eds. Academic Press, NY.; p. 162〕 but it may be even more likely in Australia, since that is where phosphate deposits were clustered in late Jurassic and early Cretaceous 〔 Cook PJ (1984) Spatial and temporal controls on the formation of phosphate deposits- a review P242-274; page = 251; map in; Phosphate Minerals. Nriagu JO Moore PB eds Springer Verlag Berlin NY. 〕 The primitive Amitermitinae species are most numerous in those regions at present. The development of at least 25 fundamentally different sesquiterpenes and several unique cyclic ethers for termite defense in Amitermitinae 〔 Prestwick GD (1983) The chemical defenses of termites. Sci. American 249; pp. 78-87.〕 hint at considerable success and large numbers in the early years for such systems must be elaborate to evolve. == References == 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Amitermitinae」の詳細全文を読む スポンサード リンク
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