726 Grasshoppers and their Relatives mountain tops Most species are nocturnal or crepuscular, although several major groups consist almost exclusively of diurnal species Major Lineages Tettigoniidae (Katydids or Bush Crickets) Katydids are a large and diverse group of orthopterans, elevated by some authors to the rank of a superfamily with numerous families More than 6900 species have been described, placed in nearly 1200 genera and 20 subfamilies Most katydids are medium- or large-sized insects The largest katydid, Siliquofera grandis, from New Guinea, has a wingspan of more than 250 mm On the other hand, members of the Australian subfamily Microtettigoniinae have a wingspan of less than 10 mm Males of almost all species have a well-developed stridulatory apparatus at the base of the tegmina The exceptions are the subfamilies Phyllophorinae, Phasmodinae, and some members of Meconematinae and Mecopodinae Males of the Australasian subfamily Phyllophorinae, despite having fully developed wings, lack the stridulatory apparatus and instead produce sound by rubbing their hind coxa against specially modified thoracic sterna Australian Phasmodinae lack wings altogether and are presumably totally silent This is also the only subfamily of katydids having greatly reduced tympanal tibial structures (‘‘the ear’’) and lacking the thoracic auditory spiracle All katydids have long, thin antennae, often longer than the body, in extreme cases exceeding its length three to four times The head of katydids is hypognathous (mouth directed down), rarely prognathous (mouth directed forward) (Phasmodinae and Zaprochilinae); and sometimes bears distinct, cuticular, horn-like processes between the antennae Their function is uncertain, but is likely related to the fact that many predators (especially bats and birds) tend to seize their katydid victims by the head The pronotum is enlarged, saddle shaped, and in some forms greatly expanded, covering part of the wings and the abdomen In the male, the enlarged pronotum often acts as a call amplifier Curiously, the group with a particularly enormous, box-like pronotum, the Phyllophorinae, lacks the ability to produce sounds with their wings The pronotum is also sometimes armed with sharp spines and processes The wings of katydids can be fully developed or reduced to a varying extent, in some lineages (Tettigoniinae) showing significant intraspecific polymorphism in the degree of their development The tegmina are sometimes reduced to scale-like structures, the only function of which is sound production Hind wings in such taxa are either totally missing or are greatly reduced Many katydids use their wings to enhance their remarkable mimicry of leaves, twigs, or bark to a degree that can fool professional biologists Members of the neotropical tribe Pterochrozini are particularly convincing mimics of both live and dead leaves, perfectly imitating the look and feel of leaves, including simulated traces of herbivory, with fake lichens and mosses ‘‘growing’’ on them A few katydids are Batesian mimics of wasps The legs of katydids are usually long and slender Predaceous species frequently have rows of long spines along the ventral edges of the front and middle legs, using them for grasping and holding prey In some Listroscelidinae, the spines are particularly long, forming a kind of net, used for scooping small flies and other insect prey The hind legs are saltatorial, except for the members of some groups living in burrows or under rocks (Hetrodinae and Bradyporinae) The abdomen of males has a pair of cerci, in some groups modified to grasp the end of female’s abdomen during mating The ovipositor of females is usually long and sickle or sable shaped The reduction of the ovipositor to short processes appears independently in ground-dwelling forms (Hetrodinae) and some arboreal ones (Phaneropterinae), apparently related to the fact that the eggs are laid on the surface of the soil or leaves, rather than inserted into them, as most katydids The significant male investment in offspring is one of the characteristics of katydids that attracts many researchers to study their behavior and evolution During copulation, males of many katydids produce a large, protein-rich spermatophylax, which is eaten by the female after copulation The size of the spermatophylax can approach 60% of the male’s body mass, making it an extremely costly and significant contribution to egg production This causes the males of many species to be quite choosy in selecting their mating partners; and under certain circumstances, the females may compete for males, a role reversal remarkably rare in the animal world The geographic distribution of katydids reveals several large centers of endemism, the largest being Australia, where of the 13 subfamilies known from the continent are unique to it The neotropics have the highest number of described species (approximately 1800) but no endemic subfamilies, followed by Eurasia (approximately 1350 species), the IndoMalaysian region (approximately 1150), and Africa (approximately 850 species and endemic subfamilies) However, these numbers are very likely to be multiplied in the future if taxonomic work in these regions is intensified Major Subfamilies Bradyporinae This is likely the most basal subfamily of katydids and is characterized by having a large, stout body, greatly reduced wings, and the tarsus with a metatarsal pulvillus Members of this family are restricted in their distribution to southwestern Palearctic Often grouped with several other subfamilies (Hetrodinae and Ephippigerinae), they nonetheless appear to be a separate clade of their own Approximately, only 50 species have been described All species of the subfamily are dark colored, often black, and resemble giant crickets rather than typical, graceful katydids Most live on the ground or low vegetation Some species are known to produce defensive autohemorrhage and squirt their hemolymph from orifices on their body if the insect is seized by a predator Phaneropterinae This is the largest subfamily of Tettigoniidae, with more than 2200 species described from all continents of the world (other than the polar regions) Members of this subfamily are medium- to large-sized insects, usually green and leaf-like katydids, characterized by a lack of lateral grooves on the tarsi, and rather primitive venation of the wings Wing reduction is widespread in several lineages of the subfamily but the stridulatory apparatus is always present Female stridulation is known in a few genera Virtually