Flea is a non-flying insect that forms an Siphonaptera order. As an external parasite of mammals and birds, they live by consuming blood from their host. Adults have a length of about 3 mm (0.12 inches) and are usually brown. The flattened bodies to the side allow them to move through their feathers or fur; strong claws prevent them from dislodging. They have no wings, and have mouths adjusted to pierce the skin and suck blood and back legs adjusted for jumping. The latter allows them to jump about 50 times their body length, a second achievement after the jump made by froghoppers. The worm larva is like without limbs; they have chewing mouths and eat organic impurities.
More than 2,500 species of ticks have been described worldwide. Siphonaptera is most closely related to snow scorpionflies (Boreidae), placing them in the order of Mecoptera endopterygote insects.
Lice appear at the beginning of Cretaceous, most likely as mammalian ectoparasites, before moving on to other groups including birds. Each species of tick is more or less specialized in its host species: many species never breed on other hosts, although some are less selective. Some exclusive louse families belong to one host group: for example, Malacopsyllidae is found only in armadillos, Ischnopsyllidae only in bats, and Chimaeropsyllidae only in elephant mice. The oriental rat tick, Xenopsylla cheopis , is a vector of Yersinia pestis , a bacterium that causes plague. The disease is spread by rodents such as black rats, bitten by ticks that then infect humans. Major epidemics include the Justinian Plague and Black Death, both of which kill most of the world's population.
Lice appear in human culture in various forms such as flea circus, erotic poems like John Donne The Flea , musical works such as by Simple Mussorgsky, and films by Charlie Chaplin.
Video Flea
Morphology and behavior
The lice are wingless insects, 1/16 to 1/8 inches long (1.5 to 3.3 mm), are lively, usually dark in color (eg, reddish brown on cat lice), with trunk, or stylet, adapted to eat with piercing skin and suck their host's blood through their epipharynx. The tick's leg ends with a powerful claw designed to capture the host.
Unlike other insects, ticks do not have compound eyes but only have simple eyespots with single bikonveks lenses; some species have no eyes at all. Their bodies are compressed laterally, allowing easy movement through the feathers or feathers on the host's body (or in the case of humans, under clothing). The body of the lice is covered with a hard slab called sclerites. These sclerites are covered with lots of hair and short spikes directed backwards, which also helps his movements on the host. The resilient body is able to withstand enormous pressure, the possibility of adaptation to survive an attempt to eliminate them by scratching.
Fleas spawn small, white, oval eggs. The larvae are small and pale, have feathers covering their worm-like bodies, lacking eyes, and having a mouth piece adapted for chewing. The larvae feed on organic matter, especially mite feces, which contain dried blood. Adults only feed on fresh blood.
Jump
Their legs are long, the rear couple adapts well to jump; a tick can jump vertically up to 7 inches (18 cm) and horizontally up to 13 inches (33 cm), making the ticks one of the best jumper of all known animals (relative to body size), second only to froghopper. The flea jump is so fast and powerful that it exceeds the muscle's ability, and instead of relying on direct muscle strength, the lice store muscle energy in elastic protein pads called resilin before releasing them rapidly (like humans using bows and arrows). Immediately before the jump, the muscle contracts and destroys the resilin pad, slowly deposits the energy which can then be released very quickly into the power leg extension for propulsion. To prevent the release of energy or foot movements that are not fast, lice use "capture mechanisms". At the beginning of the jump, the tendons of the primary jump muscle pass slightly behind the coxa-trochanter joint, producing a torque that holds the closed joint with the legs close to the body. To trigger a leap, another muscle pulls the tendon forward until it passes the axis of the joint, producing an opposing torque to extend the leg and push the jump by releasing the stored energy. Takeoff has actually been shown by high-speed video of the tibiae and tarsi rather than from the trochantera (knee).
Maps Flea
Life cycle and development
Flea is a holometabolous insect, through four stages of the egg, larva, pupa, and imago (adult) life cycle. In most species, female or male lice are not fully mature when they first appear but must eat blood before they are able to reproduce. The first blood meal triggers ovarian maturation in women and the dissolution of the testes in men, and copulation soon follows. Some species multiply throughout the year while others synchronize their activities with their host life cycle or with local environmental factors and climatic conditions. The Flea population consists of about 50% eggs, 35% larvae, 10% pupae, and 5% adult.
Egg
The number of eggs placed depends on the species, with batch sizes ranging from two to several dozen. The total number of eggs produced in a woman's lifetime (fecundity) varies from about one hundred to several thousand. In some species, lice live in nests or holes and eggs are deposited on the substrate, but on the other, the eggs are placed on its own host and can easily fall to the ground. Therefore, the area where the parent rests and sleeps becomes one of the main habitats of the egg and develops the larvae. Eggs take about two days to two weeks to hatch. Experiments have shown that lice put more eggs on hosts that have limited food intake, and that eggs and larvae survive better under these conditions, possibly because the host's immune system is compromised.
Larva
Flea larvae arise from eggs to eat available organic materials such as dead insects, faeces, special eggs, and vegetables. In laboratory studies, some dietary diversity seems to be necessary for the development of appropriate larvae. The only blood diet allows only 12% of the larvae to mature, while the blood and yeast or dog chow diet allows almost any mature larvae. Other studies have also shown that 90% of mature larvae become mature when diet includes eggs that can not be eaten. They are blind and avoid the sun, keeping the dark, damp places like sand or dirt, cracks and crevices, under the carpet and in bed.
Pupa
Considering a sufficient food supply, the pupate larvae and weave a razor cocoon after three stages of the larvae. In cocoons, larvae moults for the last time and undergoes metamorphosis into adult form. This can take only four days, but it may take longer in bad conditions, and there follows a long-variable stage in which pre-emergent adults wait for a suitable opportunity to emerge. The trigger factors of emergence include vibrations (including sound), heat (in warm-blooded hosts), and increased levels of carbon dioxide, all of which stimulate the presence of a suitable host. A large number of pre-existing bugs may exist in an environment that is not tick-free, and appropriate host introductions can trigger bulk appearance.
Adult
Once the louse reaches adulthood, its main purpose is to find blood and then reproduce. Female lice can put 5000 or more eggs throughout their lives, allowing a rapid increase in numbers. In general, an adult louse only lives for 2 or 3 months. Without a host to provide blood food, lice life can be as short as a few days. Under ideal conditions of temperature, food supply, and humidity, adult lice can live up to one and a half years. Adult cats that actually develop can live for several months without eating, as long as they do not arise from their puparia. The optimum temperature for the flea life cycle is 21 ° C to 30 ° C, (70 ° F to 85 ° F) and optimum humidity is 70%.
Adult female rabbit fossils, Spilopsyllus cuniculi , can detect changes in the hormone levels of cortisol and corticosterone in rabbit blood that indicate getting closer to childbirth. This triggers sexual maturity in the lice and they begin to produce eggs. As soon as the baby rabbits are born, the lice go to them and once they rise, they start feeding, mating, and laying. After 12 days, adult lice go back to his mother. They complete this mini migration every time she gives birth.
Taxonomy and phylogeny
Between 1735 and 1758, Swedish naturalist Carl Linnaeus classified the first insects, doing so on the basis of their wing structure. One of the seven commandments in which he divides them is "Aptera", which means no wings, groups where as well as ticks, it includes spiders, woodworms and myriapods. It was not until 1810 that the French zoologist Pierre Andrà ©  © Latreille reclassified the insects on the basis of their mouths and their wings, splitting Aptera to Thysanura (gegatung), Anoplura (sucking lice) and Siphonaptera (lice), at the same time separating arachnids and crustaceans into their own subphyla. The group name, Siphonaptera, is the Latin zoology of the Greek siphon (a tube) and aptera (without wings).
Lice are associated with Diptera (true fly) and Mecoptera (scorpion fly) as shown in the cladogram, based on a 2008 analysis of four locus (18S and 28S DNA ribosomes, cytochrome oxidase II, and factor alpha-1 alpha) for 128 flea taxa of all world. The Boreidae (snow scorpionflies) is a fake sister to Siphonaptera.
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- Amfies. = Amphiesmenoptera
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Fossils of "pre-fleas" without wings with siphonate mouths (sucking) from the middle of the Jurassic to early Cretaceous have been found in northeastern China. These include three extinct families, Pseudopulicidae, Saurophthiridae, and Tarwiniidae. The last common ancestor of modern Siphonaptera is separated from Mecoptera at the beginning of Cretaceous. Most of the flea families formed after the end of the Cretaceous (at Paleogen and beyond). Ticks may appear in the southern continent region of Gondwana, and migrate rapidly north from there. They are most likely to evolve with mammals, then move on to birds.
Siphonaptera is a relatively small insect order: members of the order have complete and secondary metamorphosis without wings (their ancestors have wings whose modern forms have been lost). In 2005, Medvedev enrolled 2005 species in 242 genera, and although the description of the new species, carries a total of up to about 2500 species, this is the most complete database available. Orders are divided into four infraorders and eighteen families. Some families are exclusive to one host group; These include Malacopsyllidae (armadillo), Ischnopsyllidae (bats) and Chimaeropsyllidae (elephant shrews).
Many species are known to be little studied. About 600 species (one quarter of the total) are known from a single note from a single parent. More than 94% of the species are associated with mammal hosts, and only about 3% of species can be considered bird-specific parasites. Bird ticks are thought to come from mammalian lice; at least sixteen separate lice groups have switched to poultry hosts during Siphonaptera's evolutionary history. The appearance of ticks on reptiles is not intentional, and lice are known to eat body fluids (blood-like fluids) from lice.
Flea phylogeny has long been neglected, homologous discoveries with other insect parts are complicated by their extreme specialization. Whiting and colleagues prepared detailed molecular phylogeny in 2008, with the basic structure shown on the cladogram. Tungidae, including a dangerous chigoe or jigger, is the brother of the remaining Siphonaptera.
Host relationship
Fleas eat a variety of hot-blooded vertebrates including humans, dogs, cats, rabbits, squirrels, weasels, rats, mice and birds. Lice typically specialize in one species of host or group of species, but can often feed but not reproduce in other species. Ceratophyllus gallinae affects birds and wild birds. As well as the degree of association of potential hosts to the native host, it has been shown that bird ticks exploit hosts, only species parasitise with low immune responses. In general, the specificity of the host decreases as the size of the host species decreases. Another factor is the opportunities available for ticks to alter the host species; this is smaller in colonial nesting birds, where lice can never meet other species, rather than solitary nesting birds. The large, long-lived host provides a stable environment that supports host-specific parasites.
One theory of fragility in humans is that loss of hair helps humans to reduce the burden of ticks and other ectoparasites.
The immediate effect of the bite
In many species, lice are essentially a nuisance to their host, causing an itching sensation which in turn causes the host to try to remove the pest by biting, pecking or scratching. However, lice are not just a source of distraction. Flea bites cause slightly elevated spots and swelling to form; It has a single puncture point in the center, like a mosquito bite. In addition, itchy itchy skin allergies allergic dermatitis common in many host species, including dogs and cats. Bites often appear in clusters or lines of two bites, and may remain itchy and inflamed for several weeks afterwards. Fleas can cause hair loss due to frequent scratching and biting by animals, and can cause anemia in extreme cases.
As a vector
Flea is a vector for viral, bacterial, and rickettsia diseases in humans and other animals, as well as protozoa parasites and worms. Bacterial diseases carried by lice include murine or typhoid endemic and plague disease. Ticks can transmit Rickettsia typhi , Rickettsia felis , Bartonella henselae , and myxomatosis virus. They can bring Hymenolepiasis tapeworm and Trypanosome protozoa. Chigoe flea or jigger ( Tunga penetrans ) causes tungiasis disease, a major public health problem worldwide. Ticks that specialize as parasites in certain mammals may use other mammals as hosts; thus, humans can be bitten by cat and dog fleas.
Relationships with humans
In literature and art
Lice have appeared in poetry, literature, music, and art; this includes Robert Hooke's flea images under a microscope in his pioneering book Micrographia published in 1665, a poem by Donne and Jonathan Swift, a musical by Giorgio Federico Ghedini and Modest Mussorgsky, a play by Georges Feydeau, a film works by Charlie Chaplin, and paintings by artists such as Giuseppe Crespi, Giovanni Battista Piazzetta, and Georges de La Tour.
Erotic metaphysical poet John Donne "The Flea", published in 1633 after his death, used the arrogance of a louse, which had sucked blood from the male speaker and his girlfriend, as an extended metaphor for their sexual relationship. The speaker tries to convince a woman to sleep with him, arguing that if their blood mixing in the lice is innocent, then sex will also occur.
Circus Flea
Circus Flea provides entertainment for the nineteenth-century audience. These circuses, which were very popular in Europe from 1830 onwards, featured ticks dressed as humans or pulled on miniature carts, horse-drawn carriages, rollers or cannons. These devices were originally created by watchmakers or jewelers to show off their skills in miniaturization. A call leader called a "professor" accompanied their performance with a fast-paced circus.
Plague operators
An oriental rat tick, Xenopsylla cheopis , can bring coccobacillus Yersinia pestis. Infected lice feed on these mouse vectors of bacteria, such as black rats,
Since fleas carry outbreaks, they have seen service as a biological weapon. During World War II, Japanese soldiers dropped fleas filled with Y. pestis in China. Outbreaks of bubonic and septicemia are the most likely outbreaks that will spread as a result of bioterrorism attacks that use ticks as vectors.
Rothschild Collection
Banker Charles Rothschild devoted much of his time to entomology, creating a vast collection of ticks now in the Rothschild Collection at the Natural History Museum, London. He invented and named the vector of the plague epidemic, the Xenopsylla cheopis, also known as the oriental rat flea, in 1903. Using what may be the world's most complete tick collection of about 260,000 specimens (representing about 73% of 2,587 species and subspecies so far described), it describes about 500 species and subspecies of Siphonaptera. He was followed in this interest by his daughter, Miriam Rothschild, who helped catalog a large collection of insects in seven volumes.
Nursing care
Flea has a significant economic impact. In America alone, about $ 2.8 billion is spent annually on vetinal bills related to fleas and $ 1.6 billion annually for nursing care with pet care nurses. Four billion dollars is spent annually for prescription flea treatment and $ 348 million for flea pest control.
See also
- Louse
- Check
- Chigger
References
External links
- Flea at Curlie (based on DMOZ)
- Insects Parasites, Mites and Lice: Genera Importance of Medicine and Animals
Source of the article : Wikipedia
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