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736 Grasshoppers and their Relatives Figure 11 Tetrigoidea: Pygmy grasshopper Afrolarcus aequalis from Guinea Figure 12 Tridactyloidea: False mole cricket Ripipteryx sp from Guyana leaves Desert wingless grasshoppers are found in desert habitats, and they differ from other grasshoppers in the unique structure of the male copulatory organs (cerci), which resemble enlarged, multibranched antlers Tridactyloidea (False Mole Crickets and Sandgropers) Tetrigoidea (Pygmy Grasshoppers or Grouse Locusts) This interesting lineage of the Orthoptera includes approximately 1660 species in nearly 260 genera, placed in one family, Tetrigidae (some authors divide this superorder into two families: Tetrigidae and Batrachideidae) (Figure 11) Most species of pygmy grasshoppers are tropical but a few occur in temperate zones, often at very high elevations Their body size is generally small, seldom exceeding 20 mm The pronotum is always greatly enlarged, covering the entire body and often extending far beyond the end of the abdomen Sometimes the pronotum is vertically expanded, forming a large crest or a leaf-like lobe A few species display a pronounced polymorphism in the development of the pronotum and wings Wings are usually present but may be reduced or absent in some forms The tegmina are always reduced to small, oval lobes, with greatly reduced venation The hindwings are well developed, fanlike, and usually completely concealed under the pronotum The hind femora are very stout and all tarsi lack the arolium between claws Members of Tetrigoidea have neither stridulatory organs nor the abdominal auditory tympana Most species are associated with moist or semiaquatic habitats Many can swim very well and dive when threatened Some species are arboreal and many live on bark of trees in tropical forests Pygmy grasshoppers feed on a variety of small plants, such as mosses, as well as on lichens and algae They have little economic importance, although some may cause some damage in rice plantations This superfamily includes approximately 230 species in 17 genera divided among three families (Figure 12) Most species are small, 4–15 mm in length, although some sandgropers (Cylindrachetidae) can reach the length of approximately 40 mm Families Tridactylidae and Ripipterigidae have characteristically modified hind tibiae, which bear a pair of long, apical flaps, whereas the tarsi are strongly reduced Their tegmina, if present, are short and leathery and sometimes have a row of stridulatory pegs The Tridactylidae are distributed worldwide, whereas the Ripipterigidae are restricted to Central and South America They inhabit wet and semiaquatic habitats and some of them make dense networks of shallow burrows in the mud The Cylindrachetidae are restricted to Australia and New Guinea, and one species is known from Patagonia The body is strongly elongated and completely wingless The pronotum is greatly elongated and cylindrical, with its lateral edges strongly curved downward, nearly meeting on the underside of the thorax The front legs are modified for digging, and the second and third pairs are shortened Sandgropers spend their entire lives underground in sandy soils They are omnivorous, feeding on plants as well as insects and their larvae Sandgropers produce odorous defensive secretion from a pair of abdominal glands See also: Insects, Overview References Eades DC, Otte D, Cigliano MM, and Braun H Orthoptera Species File Online Version 2.0/4.0 October 2011 http://Orthoptera.SpeciesFile.org
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