Temporal range: Jurassic–recent
|Stridulation of T. viridissima|
|Superfamily:|| Tettigonioidea |
|Family:|| Tettigoniidae |
Insects in the family Tettigoniidae are commonly called katydids (in Australia, South Africa, Canada, and the United States),or bush crickets. They have previously been known as long-horned grasshoppers. More than 6,400 species are known. Part of the suborder Ensifera, the Tettigoniidae are the only extant (living) family in the superfamily Tettigonioidea.
They are primarily nocturnal in habit with strident mating calls. Many katydids exhibit mimicry and camouflage, commonly with shapes and colors similar to leaves.
The family name Tettigoniidae is derived from the genus Tettigonia , first described by Carl Linnaeus in 1758. In Latin tettigonia means leafhopper; it is from the Greek tettigonion, the diminutive of the imitative (onomatopoeic) τέττιξ, tettix, cicada.All of these names such as tettix with repeated sounds are onomatopoeic, imitating the stridulation of these insects. The common name katydid is also onomatopoeic and comes from the particularly loud, three-pulsed song, often rendered "ka-ty-did", of the nominate subspecies of the North American Pterophylla camellifolia , whose most common English name is the common true katydid.
Tettigoniids range in size from as small as 5 mm (0.20 in) to as large as 130 mm (5.1 in). The smaller species typically live in drier or more stressful habitats which may lead to their small size. The small size is associated with greater agility, faster development, and lower nutritional needs. Tettigoniids are tree-living insects that are most commonly heard at night during summer and early fall. Tettigoniids may be distinguished from the grasshopper by the length of their filamentous antennae, which may exceed their own body length, while grasshoppers' antennae are always relatively short and thickened.
The lifespan of a katydid is about a year, with full adulthood usually developing very late. Females most typically lay their eggs at the end of summer beneath the soil or in plant stem holes. The eggs are typically oval and laid in rows on the host plant. The way their ovipositor is formed relates to its function where it lays eggs. The ovipositor is an organ used by insects for laying eggs. It consists of up to three pairs of appendages formed to transmit the egg, to make a place for it, and place it properly. Tettigoniids have either sickle-shaped ovipositors which typically lay eggs in dead or living plant matter, or uniform long ovipositors which lay eggs in grass stems. When tettigoniids hatch, the nymphs often look like smaller versions of the adults, but in some species, the nymphs look nothing at all like the adult and rather mimic other species such as spiders and assassin bugs, or flowers, to prevent predation. The nymphs remain in a mimic state only until they are large enough to escape predation. Once they complete their last molt, they are then prepared to mate.
Tettigoniids are found on every continent except Antarctica.The vast majority of katydid species live in the tropical regions of the world. For example, the Amazon basin rain forest is home to over 2000 species of katydids. However, katydids are found in the cool, dry temperate regions, as well, with about 255 species in North America.
The Tettigoniidae are a large family and have been divided into a number of species
The Copiphorinae were previously considered a subfamily, but are now placed as tribe Copiphorini in the subfamily Conocephalinae.The genus Acridoxena is now placed in the tribe Acridoxenini of the Mecopodinae (previously its own subfamily, Acridoxeninae). The genus Triassophyllum is extinct and may be placed in the Archaeorthoptera.
The diet of most tettigoniids includes leaves, flowers, bark, and seeds, but many species are exclusively predatory, feeding on other insects, snails, or even small vertebrates such as snakes and lizards. Some are also considered pests by commercial crop growers and are sprayed to limit growth, but population densities are usually low, so a large economic impact is rare.
Tettigoniids are serious insect pests of karuka (Pandanus julianettii).The species Segestes gracilis and Segestidea montana eat the leaves and can sometimes kill trees. Growers will stuff leaves and grass in between the leaves of the crown to keep insects out.
By observing the head and mouthparts, where differences can be seen in relation to function, it is possible to determine what type of food the tettigoniids consume. Large tettigoniids can inflict a painful bite or pinch if handled, but seldom break the skin.
Some species of bush crickets are consumed by people, such as the nsenene (Ruspolia baileyi) in Uganda and neighbouring areas.
The males of tettigoniids have sound-producing organs located on the hind angles of their front wings. In some species, females are also capable of stridulation. Females chirp in response to the shrill of the males. The males use this sound for courtship, which occurs late in the summer.The sound is produced by rubbing two parts of their bodies together, called stridulation. One is the file or comb that has tough ridges; the other is the plectrum is used to produce the vibration. For tettigoniids, the fore wings are used to sing. Tettigoniids produce continuous songs known as trills. The size of the insect, the spacing of the ridges, and the width of the scraper all influence what sound is made.
Many katydids stridulate at a tempo which is governed by ambient temperature, so that the number of chirps in a defined period of time can produce a fairly accurate temperature reading. For American katydids, the formula is generally given as the number of chirps in 15 seconds plus 37 to give the temperature in degrees Fahrenheit.
Some tettigoniids have spines on different parts of their bodies that work in different ways. The Listroscelinae have limb spines on the ventral surfaces of their bodies. This works in a way to confine their prey to make a temporary cage above their mouthparts. The spines are articulated and comparatively flexible, but relatively blunt. Due to this, they are used to cage and not penetrate the prey's body. Spines on the tibiae and the femora are usually more sharp and nonarticulated. They are designed more for penetration or help in the defensive mechanism they might have. This usually works with their diurnal roosting posture to maximize defense and prevent predators from going for their head.
When tettigoniids go to rest during the day, they enter a diurnal roosting posture to maximize their cryptic qualities. This position fools predators into thinking the katydid is either dead or just a leaf on the plant. Various tettigoniids have bright coloration and black apical spots on the inner surfaces of the tegmina, and brightly colored hind wings. By flicking their wings open when disturbed, they use the coloration to fool predators into thinking the spots are eyes. This, in combination with their coloration mimicking leaves, allows them to blend in with their surroundings, but also makes predators unsure which side is the front and which side is the back.
The males provide a nuptial gift for the females in the form of a spermatophylax, a body attached to the males' spermatophore and consumed by the female, to distract her from eating the male's spermatophore and thereby increase his paternity.
The Tettigoniidae have polygamous relationships. The first male to mate is guaranteed an extremely high confidence of paternity when a second male couples at the termination of female sexual refractoriness. These investment functions are a parental paternity. The nutrients that the offspring ultimately receive will increase their fitness. The second male to mate with the female at the termination of her refractory period is usually cuckolded.
The polygamous relationships of the Tettigoniidae lead to high levels of male-male competition. Male competition is caused by the decreased availability of males able to supply nutritious spermaphylanges to the females. Females produce more eggs on a high-quality diet; thus, the female looks for healthier males with a more nutritious spermatophylax. Females use the sound created by the male to judge his fitness. The louder and more fluent the trill, the higher the fitness of the male.
Oftentimes in species which produce larger food gifts, the female seeks out the males to copulate. This, however, is a cost to females as they risk predation while searching for males. Also, a cost-benefit tradeoff exists in the size of the spermatophore which the male tettigoniids produce. When males possess a large spermatophore, they benefit by being more highly selected for by females, but they are only able to mate one to two times during their lifetimes. Inversely, male Tettigoniidae with smaller spermatophores have the benefit of being able to mate two to three times per night, but have lower chances of being selected by females. Even in times of nutritional stress, male Tettigoniidae continue to invest nutrients within their spermatophores. In some species, the cost of creating the spermatophore is low, but even in those which it is not low, it is still not beneficial to reduce the quality of the spermatophore, as it would lead to lower reproductive selection and success. This low reproductive success is attributed to some Tettigoniidae species in which the spermatophylax that the female receives as a food gift from the male during copulation increases the reproductive output of the reproduction attempt. However, in other cases, the female receives few, if any, benefits.
The reproductive behavior of bush crickets has been studied in great depth. Studies found that the tuberous bush cricket ( Platycleis affinis) has the largest testes in proportion to body mass of any animal recorded. They account for 14% of the insect's body mass and are thought to enable a fast remating rate.
Orthoptera is an order of insects that comprises the grasshoppers, locusts and crickets, including closely related insects such as the katydids and wetas. The order is subdivided into two suborders: Caelifera – grasshoppers, locusts and close relatives; and Ensifera – crickets and close relatives.
A spermatophore or sperm ampulla is a capsule or mass containing spermatozoa created by males of various animal species, especially salamanders and arthropods, and transferred in entirety to the female's ovipore during reproduction. Spermatophores may additionally contain nourishment for the female, in which case it is called a nuptial gift, as in the instance of bush crickets. In the case of the toxic moth Utetheisa ornatrix, the spermatophore includes sperm, nutrients, and pyrrolizidine alkaloids which prevent predation because it is poisonous to most organisms. However, in some species such as the Edith's checkerspot butterfly, the "gift" provides little nutrient value. The spermatophore transferred at mating has little effect on female reproductive output. The alternative hypothesis of its usefulness is that the process of eating the spermatophore prevents the female from subsequent copulation, serving as a mating plug, thereby giving the male's sperm more time to fertilize. In some cephalopods, however, spermatophores from multiple males might be present inside the same female simultaneously.
Ensifera is a suborder of insects that includes the various types of crickets and their allies including: true crickets, camel crickets, bush crickets or katydids, grigs, wetas and Cooloola monsters. It and the suborder Caelifera make up the order Orthoptera. Ensifera is believed to be a more ancient group than Caelifera, with its origins in the Carboniferous period, the split having occurred at the end of the Permian period. Unlike the Caelifera, the Ensifera contain numerous members that are partially carnivorous, feeding on other insects as well as plants.
Roesel's bush-cricket is a European bush-cricket, named after August Johann Rösel von Rosenhof, a German entomologist.
Tettigonia viridissima, the great green bush-cricket, is a large species of katydid or bush-cricket belonging to the family Tettigoniidae, subfamily Tettigoniinae.
Gryllus veletis, commonly known as the spring field cricket, is abundant throughout eastern North America. G. veletis is a solitary, aggressive, omnivorous, burrow-inhabiting species of cricket. This species is commonly confused with Gryllus pennsylvanicus, as they inhabit the same geographical area. However, the two species are easily distinguished through examination of life history, ovipositor and behavioural differences. Predators of G. veletis, and most field crickets, include American toads, wild turkeys, red-tailed hawks, wolf spiders and red-backed salamanders.
Crickets, of the family Gryllidae, are insects related to bush crickets, and, more distantly, to grasshoppers. The Gryllidae have mainly cylindrical bodies, round heads, and long antennae. Behind the head is a smooth, robust pronotum. The abdomen ends in a pair of long cerci; females have a long, cylindrical ovipositor. The hind legs have enlarged femora, providing power for jumping. The front wings are adapted as tough, leathery elytra, and some crickets chirp by rubbing parts of these together. The hind wings are membranous and folded when not in use for flight; many species, however, are flightless. The largest members of the family are the bull crickets, Brachytrupes, which are up to 5 cm (2 in) long.
Acanthoplus discoidalis is a species in the Bradyporinae, a subfamily of the katydid family (Tettigoniidae). Like its closest relatives, Acanthoplus discoidalis variously bears common names such as armoured katydid, armoured ground cricket, armoured bush cricket, corn cricket, setotojane and koringkriek. The species is native to parts of Angola, Namibia, Botswana, Zimbabwe and South Africa.
Melanoplus bivittatus, the two-striped grasshopper, is a poikilothermic species of grasshopper belonging to the genus Melanoplus. It is commonly found in North America, with high quantities inhabiting Canadian prairies and farmland.
Eugaster spinulosa is a species of bush-cricket from Morocco.
Pterochroza ocellata, the peacock katydid, is an insect in the family Tettigoniidae. The species is a leaf-mimic katydid; when it is in repose its camouflage resembles a diseased or dead leaf. The katydid owes both its common name and its specific epithet to its startle display, in which it shows false eye spots on its normally hidden hind wings.
Tettigonia cantans is a species of bush crickets belonging to the family Tettigoniidae subfamily Tettigoniinae.
Tetrix ceperoi, Cepero's groundhopper, is a member of the family Tetrigidae and is very similar to common grasshoppers. Grasshopper is defined as a "plant eating insect with long hind legs that are used for jumping and for producing a chirping sound". However, unlike the common grasshopper, the wings of T. ceperoi extend beyond its pronotum. The front wings have evolved throughout history to be stumps, and the back wings are very well developed. Thanks to the front wings only, T. ceperoi is capable of flying. Furthermore, T. ceperoi sports wide shoulders while covering its narrow abdomen beneath the pronotum. T. ceperoi are classified as Orthoptera, which describes crickets, grasshoppers, and locusts. Furthermore, these Orthoptera have incomplete metamorphosis, which also affects sexual dimorphism later. T. ceperoi reach an average length of about 10 millimetres (0.39 in). T. ceperoi is a multi-coloured ground dweller with the ability to blend into its surroundings. The ability of T. ceperoi to be different colours makes it able to evolve colour schemes better adapted to specific habitats. This cryptic nature of their outer layer provides protection from predators as it is able to blend into its surroundings. T. ceperoi is diurnal, which means it is solely active in the daytime. However, although it is diurnal, it continues to hibernate during a late nymphal instar or later on in life as adults.
Conocephalus fuscus, the long-winged conehead, is a member of the family Tettigoniidae, the bush-crickets and is distributed through much of Europe and temperate Asia. This bush-cricket is native to the British Isles where it may confused with the short-winged conehead. These two species are phenotypically similar; however, the distinguishing factor between the two is the fully developed set of wings the long-winged conehead possesses that allows for flight. In the short-winged coneheads the hind wings are shorter than the abdomen, causing the wings to be vestigial and the species is incapable of flight. For this reason it is hard to discriminate between the two species during the early stages of their life cycle before the wings have fully developed. The colouration of the conehead is typically a grass green with a distinctive brown stripe down its back, though there are some brown phenotypes.
Oecanthus pellucens, common name Italian tree cricket, is a species of tree crickets belonging to the family Gryllidae, subfamily Oecanthinae.
Panoploscelis is a genus of very large insects belonging to the true katydid tribe Eucocconotini, which is a subfamily of the katydids. Like the other members of the suborder Ensifera, Panoploscelis are part of the insect order Orthoptera, which also contains crickets, grasshoppers and locusts. Members of this genus are among the largest katydids of the Neotropics.
The Copiphorini are a tribe of bush crickets or katydids in the family Tettigoniidae. Previously considered a subfamily, they are now placed in the subfamily Conocephalinae. Like some other members of Conocephalinae, they are known as coneheads, grasshopper-like insects with an extended, cone-shaped projection on their heads that juts forward in front of the base of the antennae.
Pterophylla camellifolia, the common true katydid, is a common North American insect in the family Tettigoniidae ("katydids"), in the order Orthoptera. Within the Tettigoniidae, it belongs to the subfamily Pseudophyllinae. Other common names include "northern true katydid" and "rough-winged katydid".
Caedicia simplex is a species of insect in the family Tettigoniidae.
Hemiandrus maculifrons is a species of ground weta endemic to New Zealand. They are nocturnal, carnivorous, and flightless orthopterans belonging to the family Anostostomatidae. Being a nocturnal species, individuals remain in tunnels (galleries) during the day and emerge from their burrows after sunset to forage and hunt for small invertebrates. H. maculifrons is one of the smallest New Zealand weta species, averaging 15 mm in length and weighing 1-3 g. Unlike the tree weta and tusked weta, where sexual dimorphism is found in the form of male weaponry, ground weta only exhibit sexual size dimorphism: the females are larger than the males.
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