Grasshopper
| Caelifera | ||||||||
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 Dissosteira carolina
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Suborder Caelifera - short-horned grasshoppers
Suborder Ensifera - crickets, katydids, and allies
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Grasshoppers are long and slender insects belonging to the order Orthoptera and typically with long, strong hind limbs for leaping and powerful mouthparts for chewing. The term grasshopper is an imprecisely defined common name. It generally is used in reference to members of both the orthopteran family Acrididae ("short-horned grasshoppers") of the suborder Caelifera and to members of the family Tettigoniidae ("long-horned grasshoppers") of the suborder Ensifera. It may also be used to refer only to the Acrididae ("true grasshoppers") or to the entire suborder Caelifera (Capinera et al. 2006). Members of Caelifera are also referred to as a group as short-horned grasshoppers, with members of Ensifera as long-horned grasshoppers (Grzimek 2004).
Orthoptera ("Straight Wings") is an order of insects with incomplete metamorphosis or hemimetabolism. They have two pairs of wings; the forewings are narrower than the hind wings and hardened at the base. They are held overlapping the abdomen at rest. The hind wing is membranous and held folded fan-like under the forewings when at rest. They have mandibulate mouthparts, large compound eyes, antennae length varies with species.
Caelifera and Ensifera are currently the only two suborders in Orthoptera. Traditionally, the order had also included cockroaches, preying mantis, and walking sticks. Members of Tettigoniidae are commonly known as bush crickets or katydids, and are closely related to the crickets, which are also members of Ensifera. Caelifera also includes the locusts, which is the name given to the migratory members of short-horned grasshoppers of the family Acrididae. Both Caelifera and Ensifera have mainly herbivorous insects, but there are a few carniverous species in Ensifera.
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.
Caelifera
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 outside, but the juvenile forms are smaller 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.
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 wings buds until their final moult 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.
Families
The suborder consists primarily of five major families:
- Acrididae (field grasshoppers and locusts)
- Eumastacidae (monkey grasshoppers)
- Tanaoceridae (tanaocerids)
- Tetrigidae (grouse locusts, pygmy grasshoppers, and pygmy locusts)
- Tridactylidae (pygmy mole crickets)
The most important family is Acrididae, consisting of about 10,000 species. The family is characterised 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.
Biology
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.
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 oviducts, which unite to create a common oviduct which carries ripe eggs. Each of the ovarioles consists of a germarium (a mass of cells that form oocytes, nurse cells, and follicular cells) and a series of follicles. The nurse cells nourish the oocytes during early growth stages, and the follicular cells provide materials for the yolk and make the eggshell (chorion).
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 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 9 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.
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.
Gallery
Eastern Lubber Grasshopper, Romalea microptera
Eastern Lubber grasshopper, Romalea guttata
Green Grasshopper
Grasshopper
Tropidacris violaceus, Bristol Zoo, England
Giant Green Slantface Grasshopper eating grass
Grasshopper, United Kingdom
Grasshopper, Hawaii
Grasshopper, Nova Scotia
Grasshopper on a bottle.
African Bushhopper Phymateus leprosus
Tettigoniidae
| Tettigoniidae | ||||||||||||||
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 Great green bush-cricket
(Tettigonia viridissima) | ||||||||||||||
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The family Tettigoniidae contains the more than 6,800 species known in American English as katydids and in British English as bush-crickets. It is part of the suborder Ensifera and the only family in the superfamily Tettigonoidea. Altough also known as long-horned grasshoppers, they are more closely related to crickets than to the true grasshoppers.
Tettigoniids may be distinguished from true grasshoppers by the length of their antennae, which may exceed their own body length, while in Acrididae are always relatively short.
The name "katydid" comes from the sound produced by species of the North American genus Pterophylla (literally "winged leaf"). The males of katydids have sound-producing organs (via stridulation) located on the hind angles of their front wings, which in some species produce a soundthought to resemble the words "Katy did, Katy didn't", hence the name. In some species, females are also capable of stridulation.
There are about 255 species in North America, but the majority of species live in the tropical regions of the world.
The diet of 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.
The spikeheaded katydid is somewhat notorious for its plantlike appearance, which allows it to blend in with the vegetation on which it lives, and the spikes discourage potential predators.
Tettigoniid on a rock
A long-horned grasshopper sitting on a leaf
Note the long antennae
Katydid
Katydid
Katydid
Tettigoniid
Katydid
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Grasshoppers and humans
In many places around the world, grasshoppers are eaten as a good source of protein. Some countries supposedly instruct military personnel to collect grasshoppers to eat as a food source.
kosher
Raw grasshoppers should be eaten with caution, as they can contain tapeworms.[1]
pests
Locusts are several species of short-horned grasshoppers of the family Acrididae that sometimes form very large groups (swarms); these can be highly destructive and migrate in a more or less coordinated way. Thus, these grasshoppers have solitary and gregarious (swarm) phases. Locust swarms can cause massive damage to crops. Important locust species include Schistocerca gregaria and Locusta migratoria in Africa and the Middle East, and Schistocerca piceifrons in tropical Mexico and Central America (Mesoamerica). Other grasshoppers important as pests (which, unlike "true" locusts, do not change color when they form swarms) include Melanoplus species (like M. bivittatus, M. femurrubrum and M. differentialis) and Camnula pellucida in North America; the lubber grasshopper Brachystola magna, and Sphenarium purpurascens in Northern and Central Mexico; and species of Rhammatocerus in South America.
The 1957 film Beginning of the End featured mutated giant grasshoppers attacking Chicago.
Kamen Rider, a live-action Japanese children's television show, often employs grasshopper-themed costumes. Notable examples are the First and Second Riders.
In the 1998 movie A Bug's Life, the lead villain and his henchmen are grasshoppers.
External links
- Tree of Life Web Project. Retrieved March 29, 2007.
ReferencesISBN links support NWE through referral fees
- Capinera, J. L., R. D. Scott, and T. J. Walker. 2006. Field Guide to Grasshoppers, Katydids, and Crickets of the United States. Cornell University Press. ISBN 0801489482.
- Grzimek, B., D. G. Kleiman, V. Geist, and M. C. McDade. 2004. Grzimek's Animal Life Encyclopedia. Detroit: Thomson-Gale. ISBN 0787657883.
- O'Toole, C. 2002. Firefly Encyclopedia of Insects and Spiders. Buffalo, N.Y.: Firefly Books. ISBN 1552976122.
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- ↑ Survivorman television show, Sonoran Desert episode, broadcasted on Science Channel 1 November 2006
