Grasshoppers and their Relatives all species are phytophagous, although opportunistic cannibalism has been observed in a few species Many species are exclusively arboreal Eggs are laid in the soil, plant tissues, or on the surfaces of leaves and bark Immature stages of many species mimic ants, tiger beetles, and even spiders, whereas adults of the same species usually mimic leaves or blades of grass Several South American genera are superb mimics of pompilid wasps Acridoxeninae This is a small, aberrant subfamily of large Central African katydids, with only one species, Acridoxena hewaniana Its relationship to other katydids is uncertain as it displays a mixture of very advanced and very primitive characteristics The most interesting feature of Acridoxena is its astonishing mimicry of a dried, spiny plant All parts of the body look like shriveled, twisted, dry leaves or twigs Nothing is known of its biology or behavior Ephippigerinae This is a small Palearctic subfamily, with approximately 140 described species All species have greatly reduced, scale-like wings, usually hidden under an enlarged, saddle-shaped pronotum Females of many species stridulate and certain species have long been model organisms for studies on acoustic communication and courtship in insects Some species occasionally cause minor agricultural damage Pseudophyllinae This is the second largest subfamily of Tettigoniidae, with approximately 1100 described species, distributed in tropical and subtropical regions of the globe A notable exception is the true katydid (Pterophylla camellifolia) of eastern USA, which is both the northermost member of the subfamily and the source of the name ‘‘katydid.’’ Its characteristic, loud call resembles (although some listeners disagree) the syllables ‘‘ka-ty-did.’’ Most pseudophyline katydids are found in the tropical areas of South America and Southeast Asia Many are spectacular mimics of leaves (tribes Pterochrozini and Pseudophyllini) and bark (tribes Pleminini and Cymatomerini) Secondary loss of stridulation and widespread presence of tremulation is characteristic of many neotropical members of the subfamily On the other hand, Old World members of the subfamily belong to the loudest night singers of tropical forests This disparity in their acoustic behavior has been explained by different hunting strategies of insectivorous bats in the New and the Old World, which in turn shaped different defensive strategies among acoustic insects Nearly all species of the Pseudophyllinae are arboreal or at least associated with tall vegetation A notable exception is the genus Callimenellus, which is known to inhabit marine littoral rock crevices in Hong Kong All species seem to be phytophagous although opportunistic insectivory has been observed in a few Central American species Virtually all species are nocturnal Tettigoniinae It is a large subfamily, with nearly 1000 described species Most of the species of this subfamily occur in the temperate regions of the world, and only a handful of species are present in the tropics Tettigoniinae achieved the greatest diversity in the regions of Europe, western North America, South Africa, and Australia characterized by the Mediterranean type of vegetation Many species have a large, 727 shield-like pronotum, hence the common name ‘‘shieldbacked katydids.’’ Females always have a long, sword-like ovipositor and lay eggs in soil or the stems of herbaceous plants Males stridulate loudly and many species are active during the day A few species of shield-backed katydids are agricultural pests, the best known being the Mormon cricket (Anabrus simplex) of western USA However, some species in China and Japan have been kept as pets for hundreds of years, and their pleasing calls have made a remarkable impact on the poetry and other arts of these countries Conocephalinae The conehead katydids are a large subfamily of Tettigoniidae, with more than 1100 described species worldwide Many are characterized by a prominent fastigium of the vertex, forming a characteristic ‘‘horn’’ on the head The diet of many of these katydids is restricted to grasses and their seeds, although quite a few species are predaceous The conehead katydids are quite common in temperate regions of North America and Europe, although they reach their greatest diversity in the tropical areas of South America Some species of Conocephalinae may become agricultural pests and a few have been known to form large, locust-like swarms (Ruspolia) Male investment in offspring can be significant in some neotropical conehead katydids, and an elaborate courtship behavior is common in such species Phasmodinae and Zaprochilinae These two, closely related subfamilies are restricted to Australia Phasmodinae contains only one genus, Phasmodes, with three species restricted in their distribution to Western Australia These insects are a good example of convergent evolution, resembling walking sticks (Phasmida) to an extraordinary degree Both sexes are completely wingless, and females lack tibial tympana as well as thoracic auditory spiracles The entire body is extremely elongate and thin, and the head is prognathous A simple way of telling these insects apart from walking sticks is looking at the proportions of thoracic segments In real walking sticks, the prothorax is extremely elongated, whereas in Phasmodes, it is the mesothorax that has such modification These interesting katydids feed on both leaves and flowers of the heath habitats Zaprochilinae They have similarly elongated bodies and prognathous head, but all species have wings They are strongly reduced in the genus Kawanaphila, but fully developed in the remaining three genera of the subfamily Males of all 28 described species produce short, ultrasonic calls Several species of the subfamily have been extensively studied with regard to the parental investment of males, which is significant and may lead to courtship role reversal All members of the subfamily feed primarily on pollen and nectar, and they play some role in pollination of the flowers on which they feed In addition to the above-described subfamilies, the family Tettigoniidae also includes the following subfamilies: Austrosaginae, Hetrodinae, Lipotactinae, Listroscelidinae, Meconematinae, Mecopodinae, Microtettigoniinae, Phyllophorinae, Saginae, Hexacentrinae, and Tympanophorinae