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Orthoptera

Orthoptera

Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Subclass: Pterygota
Infraclass: Neoptera
Superorder: Exopterygota
Order: Orthoptera
Latreille, 1793
Suborders
  • Suborder Ensifera – crickets, katydids, and allies
  • Suborder Caelifera – grasshoppers, locusts

Orthoptera (“straight wings”) is a w >

Orthopterans are associated in many people’s minds with the sounds they make. There are few places in the world where one cannot experience the “singing” of grasshoppers, katydids, and crickets during the warm seasons, with grasshoppers characteristically calling during the day, and katydids and crickets at night (Gwynne et al. 1996). While these qualities are used for the insects’ individual purpose of survival, maintenance, and reproduction (being used to find mates, warn of predators, and defend territory), they also enhance human enjoyment of nature. Orthopterans also are important to ecosystem food chains, converting plant biomass into a form usable by birds, mammals, and other animals.

Grasshoppers, katydids, and crickets also are known for their jumping ability.

Orthopterans are commonly divided into two suborders: Caelifera (short-horned grasshoppers, including true grasshoppers and locusts) and Ensifera (long-horned grasshoppers, including crickets and katydids). Traditionally, the order had also included cockroaches, praying mantids, and walking sticks. Among other distinctions, the two suborders are generally recognized by the size of their antennae, with Ensifera having longer antennae.

Description

Orthopterans are found in virtually all terrestrial habitats were plants can live and where one can find insects, being absent only in oceans, polar regions, and extreme alpine environments (Grizmek et al. 2004, Rowell and Flook 2001). They generally are large to medium in size as far as insects go, with body lengths of less than 10 millimeters (0.4 inches) uncommon, and some exceeding 100 millimeters (2 inches) in length with a wingspan of 200 millimeters or more. The smallest are below 2 millimeters.

All members of the suborder Caelifera are plant eaters, as are most members of Ensifera, but there are some carnivorous members of the long-horned grasshoppers.

Orthopterans have mandibulate mouthparts, large compound eyes, and antennae length that varies with species.

One of the characteristics most associated with orthopterans is the production of sound. Many, but not all, insects in this order produce sound, which is used for attraction of mates, defense of territory, and to warn of predators (Grizmek et al. 2004). The technique usually used is str >

This singing is typically a male phenomenon, as females are typically silent. The calls are generally species specific and the information can be a code in terms of the frequency modulation (pitch changes) or time modulation (pitch changes, but temporal pattern changes) (Grizmek et al. 2004).

Most orthopterans are solitary insects, but gregarious tendencies are common among many crickets, and swarming behavior is seen in locusts. Locusts are migratory short-horned grasshoppers of the family Acrididae. In response to certain cues, they shift in behavior from a solitary phase to a migratory phase. For example, the desert locust (Schistocerca gregaria) of Africa and Asia is normally solitary, but the spring rains trigger a behavior transformation that can result in single swarms larger than any other single congregation of organisms on Earth, ranging from 100,000 to 10 billion insects (Grzimek et al. 2004). One swarm in 1794 once spread over 5,000 square kilometers (almost 2,000 square miles) (Grzimek et al. 2004). Some members of the suborder Ensifera also produce huge swarms, such as the wingless katydid known as the North American Mormon cricket (Anabrus simplex), whose swams can be devastating to crops, and the Conehead kaytdids (Ruspolia spp.) of Africa (Grzimek et al. 2004).

Grasshoppers develop by incomplete metamorphosis, a process in which the larvae resembles the adults somewhat, as they have compound eyes, developed legs, and wing stubs visible on the outside, but the juvenile forms are smaller, lack fully developed reproductive organs, and, if the adult has wings, lack wings. In this mode of development, which involves gradual change, there are three distinct stages: The egg, nymph, and the adult stage, or imago. There is no pupal stage characteristic of complete metamorphosis. Through successive molts, the nymphs develop wing buds until their final molt into a mature adult with fully developed wings.

The number of molts varies between species; growth is also highly variable and may take a few weeks to some months depending on food availability and weather conditions.

The oldest opthopteran fossils trace to the Carboniferous period; most families of Ensifera appeared between the early Jurassic and early Triassic periods, while the oldest extant family of Caelifera appeared in middle Jurassic (Grizmek et al. 2004).

The suborder Caelifera (short-horned grasshoppers) consists of grasshoppers and locusts. All have jumping back legs, antenna composed of less than 30 segments, absence of auditory organs on the prothorax (hearing organs, if present, are abdominal), and an ovipositor in which there are four functional valves.

Members of Caelifera are classified into eight superfamilies, 22 families, about 2,400 genera, and about 11,000 described species, with many species undescribed (Grzimek et al. 2004, Rowell and Flook 2001). Five of these are major families:

The largest superfamily is Acridoidea with over 7,200 described species in 1,600 genera (Grzimek et al. 2004). The largest family is Acrididae, the “true grasshoppers.” The family is characterized by the short, thickened antennae and relatively unmodified anatomy. They are often visually more striking than other Caelifera, due to the adults’ wings and legs, which are well developed and may be brightly colored. The Acrididae includes the locusts, which can be serious agricultural pests.

The term grasshopper is an imprecisely defined common name. It generally is used in reference to members of both the orthopteran family Acrididae of the suborder Caelifera and to members of the family Tettigoniidae of the suborder Ensifera. It may also be used to refer only to the Acrididae or to the entire suborder Caelifera.

Locusts are grasshoppers that are characterized by behavior. They are defined as several species of short-horned grasshoppers of the family Acrididae that have solitary and gregarious (swarm) phases. They do not belong to a particular genus or subfamily, but are those species of grasshoppers that exhibit behavioral, morphological, and physiological changes from a solitary phase to a migratory phase (Grzimek et al. 2004).

Diurnal activity is common in Caelifera, with grasshoppers and locusts feeding and mating during the day, and molting and laying eggs at night, while the reverse is true for the Ensifera (katydids and crickets), who generally exhibit nocturnal activity (Grzimek et al. 2004). Grasshoppers sing typically during warm season days and katydids and crickets sing during warm season nights.

The suborder Ensifera (long-horned grasshoppers) consists of crickets and katyd >

The suborder is divided into six superfamilies, 21 families, 1,900 genera, and 11,000 described species (Grzimek et al. 2004). The largest superfamily is Tettigonioidea (katydids or bush-crickets) with over 1,000 genera and 7,000 known species (Grzimek et al. 2004). The superfamily Grylloidea (crickets) includes over 500 genera and 3,500 described species.

Members of the family Tettigoniidae are commonly known as bush crickets or katydids, and are closely related to the crickets.

Orthoptera as food

Orthoptera also are the only insects considered kosher in Judaism. As stated in Leviticus in the Bible: “All winged swarming things that walk on fours shall be an abomination for you. But these you may eat among all the winged swarming things that walk on fours—locusts of every variety; all varieties of bald locust; crickets of every variety; and all varieties of grasshopper.” However, different opinions exist on which exact species are considered kosher. The Jewish Torah states that the flying insects with four walking legs that are kosher are those whose knees extend above their feet to hop on the ground (Grzimek et al. 2004).

Although generally Orthoptera is divided into two suborders, Ensifera and Caelifera, there are classification schemes that consider only the short-horned orthopterans to be included in the order, and another order, Grylloptera, comprises the long-horned grasshoppers, such as crickets and katydids.

The following is one common classification scheme:

  • Suborder Ensifera – crickets, katydids, and allies
    • Superfamily Grylloidea
      • Gryllidae – true crickets
      • Gryllotalpidae – mole crickets
      • Mogoplistidae
      • Myrmecophilidae – ant crickets
    • Superfamily Hagloidea
      • Prophalangopsidae
    • Superfamily Rhaphidophoroidea
      • Rhaphidophoridae – camel crickets, cave crickets, cave wetas
    • Superfamily Schizodactyloidea
      • Schizodactylidae – dune crickets
    • Superfamily Stenopelmatoidea
      • Anostostomatidae – wetas, king crickets
      • Cooloolidae
      • Gryllacrididae – leaf-rolling crickets
      • Stenopelmatidae – Jerusalem crickets
    • Superfamily Tettigonioidea
      • Tettigoniidae – katydids / bush crickets
  • Suborder Caelifera – grasshoppers, locusts
    • Superfamily Acridoidea
      • Acrididae – grasshoppers, locusts
      • Arcypteridae
      • Catantopidae
      • Charilaidae
      • Chrotogonidae
      • Lathiceridae
      • Lentulidae
      • Pamphagidae – toad grasshoppers
      • Pneumoridae – bladder grasshoppers
      • Proscopiidae
      • Pyrgomorphidae – gaudy grasshoppers
    • Superfamily Eumastacoidea
      • Chorotypidae
      • Episactidae
      • Eumastacidae
      • Euschmidtiidae
      • Mastacideidae
      • Morabidae
      • Proscopiidae
      • Thericleidae
    • Superfamily Pneumoroidea
  • Pneumoridae
    • Superfamily Pyrgomorphoidea
  • Pyrgomorphidae
    • Superfamily Tanaoceroidea
  • Tanaoceridae
    • Superfamily Tetrigo >References
      • Grzimek, B., D. G. Kleiman, V. Geist, and M. C. McDade. 2004. Grzimek’s Animal Life Encyclopedia. Detroit: Thomson-Gale. ISBN 0787657883.
      • Gwynne, D. T., L. DeSutter, P. Flook, and H. Rowell. 1996. Orthoptera. Crickets, kaytd >

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      Grasshopper

      Scientific classification
      Kingdom: Animalia
      Phylum: Arthropoda
      Class: Insecta
      Order: Orthoptera
      Suborders, superfamilies, and families

      Suborder Caelifera (short-horned grasshoppers)

      • Superfamily: Acridoidea
        • Acrididae
        • Catantopidae
        • Charilaidae
        • Dericorythidae
        • Lathiceridae
        • Lentulidae
        • Lithidiidae
        • Ommexechidae
        • Pamphagidae—toad grasshoppers
        • Pyrgacrididae
        • Romaleidae
        • Tristiridae
      • Superfamily: Tridactyloidea
        • Cylindrachaetidae
        • Ripipterygidae
        • Tridactylidae
      • Superfamily: Tetrigoidea
        • Tetrigidae
      • Superfamily: Eumastacoidea
        • Chorotypidae
        • Episactidae
        • Eumastacidae
        • Euschmidtiidae
        • Mastacideidae
        • Morabidae
        • Proscopiidae
        • Thericleidae
      • Superfamily: Pneumoroidea
        • Pneumoridae—bladder grasshoppers
      • Superfamily: Pyrgomorphoidea
        • Pyrgomorphidae—gaudy grasshoppers
      • Superfamily: Tanaoceroidea
        • Tanaoceridae
      • Superfamily: Trigonopterygoidea
        • Trigonopterygidae
        • Xyronotidae

      Suborder Ensifera—crickets, katydids, and allies

      • Superfamily Tettigonioidea (long-horned grasshoppers)
        • Tettigoniidae—katydids/bush crickets

      Grasshoppers are long and slender insects belonging to the order Orthoptera, typically exhibiting long, strong hind limbs for leaping and powerful mouth-parts for chewing. The term grasshopper is an imprecisely defined name referring most commonly to members of two Orthopteran families: The family Acr >

      For the purposes of this article, “grasshopper” refers to all members of the suborder Caelifera and also to members of the family Tettigoniidae in the suborder Ensifera.

      Caelifera and Ensifera are the only two suborders in Orthoptera. Members of the family Tettigoniidae are commonly known as bush crickets or katydids, and are closely related to the crickets, which are also members of Ensifera, but are not included with the grasshoppers. Caelifera includes the locusts, which are the migratory members of the family Acrididae. Members of both Caelifera and Ensifera are primarily herbivorous species, but Ensifera includes a few carnivorous species.

      The Tettigoniidae (long-horned grasshoppers) are typified by antennae longer than the body, while the Acrididae (short-horned grasshoppers) have antennae shorter than the body.

      Grasshoppers are integral to natural food chains. Their destructive role as agricultural pests has been reduced in recent years through a better understanding of their population dynamics and development of chemical and biological control measures (Grzimek et al. 2004). The grasshoppers’ characteristic sound production, which can serve both to attract mates and to warn of predators, aids the grasshoppers’ survival and reproduction while it also adds to the diversity and richness of the human experience of nature.

      The suborder Caelifera is classified into 8 superfamilies, 22 families, about 2,400 genera, and over 10,400 described species (Grzimek et al. 2004). Five of these are major families:

      The largest superfamily is Acridoidea with over 7,200 described species in 1,600 genera. The largest family is Acrididae. The family is characterized by the short, thickened antennae and relatively unmodified anatomy. They are often visually more striking than other Caelifera, due to the adults’ wings and legs, which are well developed and may be brightly colored. Auditory organs are on the abdomen, unlike on the forelegs of the family Tettigoniidae. The true grasshoppers produce sounds by rubbing their legs against the abdomen, and there may also be a visual display. The Acrididae includes the locusts, which can be serious economic pests.

      Life cycle

      Grasshoppers develop by incomplete metamorphosis, a process in which the larvae resembles the adults somewhat, as they have compound eyes, developed legs and wing stubs visible on the outs >

      Most orthopterans lay their eggs in the ground or on vegetation. The eggs hatch and the young nymphs resemble adults but lack wings and at this stage are often called hoppers. Through successive molts, the nymphs develop wing buds, until their final molt into a mature adult with fully developed wings.

      The number of molts varies between species; growth is also very variable and may take a few weeks to some months depending on food availability and weather conditions.

      Eggs are commonly laid in the ground with a foamy substance around them to protect them during incubation; typically the number of eggs laid by a female is between 400 and 500.

      Diurnal activity is prevalent in the short-horned grasshoppers, when they feed and mate, with nighttime activities including molting and egg laying (Grizmek et al. 2004). This is in contrast to katydids and crickets, which tend to be nocturnal (Grzimek et al. 2004).

      Sound production is one of the main characteristics associated with grasshoppers; it is used to attract mates, defend territory, and warn about predators (Grizmek et al. 2004). The calls are generally species specific and the information can be be code in terms of the frequency modulation (pitch changes) or time modulation (pitch changes, but temporal pattern changes) (Grizmek et al. 2004).

      Digestion and excretion

      The digestive system of insects includes a foregut (stomodaeum, the mouth region), a hindgut (proctodaeum, the anal region), and a midgut (mesenteron). The mouth leads to the muscular pharynx, and through the esophagus to the crop. This discharges into the midgut, which leads to the malpighian tubules. These are the chief excretion organs. The hindgut includes intestine parts (including the ileum and rectum), and exits through the anus. Most food is handled in the midgut, but some food residue as well as waste products from the malpighian tubules are managed in the hindgut. These waste products consist mainly of uric acid, urea, and a bit of amino acids, and are normally converted into dry pellets before being disposed of.

      The salivary glands and midgut secrete digestive enzymes. The midgut secretes protease, lipase, amylase, and invertase, among other enzymes. The particular ones secreted vary with diet.

      Caelifera are herbivores, but under conditions such as overcrowding or dehydration, they can attack each other (Grzimek et al. 2004).

      Nervous system

      The grasshopper’s nervous system is controlled by ganglia, loose groups of nerve cells that are found in most species more advanced than cnidarians. In grasshoppers, there are ganglia in each segment as well as a larger set in the head, which are considered the brain. There is also a neuropile in the center, through which all ganglia channel signals. The sense organs (sensory neurons) are found near the exterior of the body and consist of tiny hairs (sensilla), which consist of one sense cell and one nerve fiber, which are each calibrated to respond to a certain stimulus.

      While the sensilla are found all over the body, they are most dense on the antennae, palps (part of the mouth), and cerci (near the posterior). Grasshoppers also have tympanal organs for sound reception. Both these and the sensilla are linked to the brain via the neuropile.

      Reproduction

      The grasshopper’s reproductive system consists of the gonads, the ducts which carry sexual products to the exterior, and accessory glands. In males, the testes consist of a number of follicles, which hold the spermatocytes as they mature and form packets of elongated spermatozoa. After they are liberated in bundles, these spermatozoa accumulate in the vesicula seminalis (vas deferens).

      In females, each ovary consists of ovarioles. These converge upon the two ov >

      During reproduction, the male grasshopper introduces sperm into the vagina through its aedeagus (reproductive organ), and inserts its spermatophore, a package containing the sperm, into the female’s ovipositor. The spermatophore, or sperm sack, can also include a large packet of nutritious proteins known as a spermatophylax (Grizmek et al. 2004). The sperm enters the eggs through fine canals called micropyles.

      The female then lays the fertilized egg pod, using her ovipositor and abdomen to insert the eggs about one to two inches underground, although they can also be laid in plant roots or even manure. The egg pod contains several dozens of tightly-packed eggs that look like thin rice grains. The eggs stay there through the winter, and hatch when the weather has warmed sufficiently. In temperate zones, many grasshoppers spend most of their life as eggs through the “cooler” months (up to nine months) and the active states (young and adult grasshoppers) live only up to three months. The first nymph to hatch tunnels up through the ground, and the rest follow. Grasshoppers develop through stages, progressively getting larger in body and wing size (incomplete metamorphosis). Grasshoppers can lay eggs underwater.

      The orthopteran courtship and mating behaviors are among some of the “most complex and fascinating spectacles in the insect world,” involving sound production and visual, tactile, and olfactory signals (Grzimek et al. 2004).

      Circulation and respiration

      Grasshoppers have open circulatory systems, with most of the body fluid (hemolymph) filling body cavities and appendages. The one closed organ, the dorsal vessel, extends from the head through the thorax to the hind end. It is a continuous tube with two regions—the heart, which is restricted to the abdomen, and the aorta, which extends from the heart to the head through the thorax. Hemolymph is pumped forward from the hind end and the sides of the body through a series of valved chambers, each of which contains a pair of lateral openings (ostia). The hemolymph continues to the aorta and is discharged through the front of the head. Accessory pumps carry hemolymph through the wing veins and along the legs and antennae before it flows back to the abdomen. This hemolymph circulates nutrients through the body and carries metabolic wastes to the malphighian tubes to be excreted. Because it does not carry oxygen, grasshopper “blood” is green.

      Respiration is performed using tracheae, air-filled tubes that open at the surfaces of the thorax and abdomen through pairs of spiracles. The spiracle valves only open to allow oxygen and carbon dioxide exchange. The tracheoles, found at the end of the tracheal tubes, are insinuated between cells and carry oxygen throughout the body.

      Locusts are grasshoppers that are characterized by behavior. They are defined as several species of short-horned grasshoppers of the family Acrididae that have solitary and gregarious (swarm) phases. They do not belong to a particular genus or subfamily, but are those species of grasshoppers that exhibit behavioral, morphological, and physiological changes from a solitary phase to a migratory phase (Grzimek et al. 2004). For example, the desert locust (Schistocerca gregaria) of Africa and Asia are normally solitary, but the spring rains trigger a behavior transformation that can result in single swarms larger than any other single congregation of organisms on Earth, ranging from 100,000 to 10 billion insects (Grzimek et al. 2004). One swarm in 1794 once spread over 5,000 square kilometers (almost 2,000 square miles) (Grzimek et al. 2004).

      Eastern Lubber Grasshopper, Romalea microptera

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