Venus Flytrap

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{{Taxobox | color = lightgreen | name = Venus Flytrap | image = Dionaea muscipula01.jpg | image_width = 250px | regnum = Plantae | divisio = Magnoliophyta | classis = Magnoliopsida | ordo = Caryophyllales | familia = Droseraceae | genus = Dionaea | species = D. muscipula | binomial = Dionaea muscipula | binomial_authority = Soland. ex Ellis }}

The Venus Flytrap (Dionaea muscipula) is a carnivorous plant that catches and digests animal prey (mostly insects and arachnids). The trapping structure is formed by the terminal portion of each of the plant's leaves. The plant's name refers to Venus, the goddess of love and plant life.

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Description

The plant is a small herb, forming a rosette of 4 to 7 leaves, which arise from a short subterranean stem. Each leaf reaches a maximum size of about 3 to 7 cm, depending on the time of yearTemplate:Ref; longer leaves are generally formed after flowering. Flytraps that appear to have more leaves are generally colonies, formed by rosettes that have divided beneath the ground.

Image:VenusFlytrapRedLeaf.wmg.jpg Image:Venus.gif The leaf blade is divided into two regions: a flat photosynthetic blade, and a pair of terminal lobes hinged at the midrib, which form the trap itself. The upper surface of these lobes contains red anthocyanin pigments and its edges secrete mucilage: these lures serve to attract insect prey. The lobes exhibit rapid plant movements, snapping shut when stimulated by prey. The trapping mechanism is tripped when prey items stumble against one of the three hair-like trichomes that are found on the upper surface of each of the lobes. The trigger hairs must be touched twice in quick succession (which prevents non-prey stimuli such as raindrops from triggering the trap), whereupon the lobes snap shut in c. 100 ms. The edges of the lobes are fringed by stiff hair-like protrusions, which mesh together and prevent large prey items from escaping. (These protrusions, and the trigger hairs, are probably homologous with the tentacles found in this plants close relatives, the sundews). The holes in the meshwork allow small prey to escape, presumably because the benefit that would be obtained from them would be less than the cost of digesting them. If the prey is too small and escapes, the trap will re-open within a few hours.

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Mechanism of trapping

The Venus flytrap is one of a very small group of plants that are capable of rapid movement, such as Mimosa, the Telegraph plant, sundews and bladderworts.

Image:Venus fly trap macro.jpg

The mechanism by which the trap snaps shut involves a complex interaction between elasticity, turgor and growth. In the open, untripped state, the lobes are convex (bent outwards), but in the closed state, the lobes are concave (forming a cavity). It is the rapid flipping of this bistable state that closes the trapTemplate:Ref, but the mechanism by which this occurs is still poorly understood. When the trigger hairs are stimulated, an action potential (mostly involving calcium ions) is generated, which propagates across the lobes and stimulates cells in the lobes and in the midrib between themTemplate:Ref. Exactly what this stimulation does is still debated: cells in the outer layers of the lobes and midrib may rapidly secrete protons into their cell walls, loosening them and allowing them to swell rapidly by osmosis and acid growth; alternatively, cells in the inner layers of the lobes and midrib may rapidly secrete other ions, allowing water to follow by osmosis, and the cells to collapse. Both, either or neither of these mechanisms may play a roleTemplate:Ref.

If the prey is unable to escape, it will continue to stimulate the inner surface of the lobes, and this causes a further growth response that forces the edges of the lobes together, eventually sealing the trap hermetically and forming a 'stomach' in which digestion occurs. Digestion is catalysed by enzymes secereted by glands in the lobes. Digestion takes about 10 days, after which the prey is reduced to husk of chitin. The trap then re-opens, and is ready for re-use; however, it is rare for a single trap to catch even three insects in its lifetime.

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Habitat

The Venus flytrap is found in nitrogen-poor bogs in the southeastern United States, mainly within a 100-mile radius of Wilmington, North Carolina. Collecting wild plants is severely restricted by federal and state laws due to its limited range. The nutritional poverty of the soil is the reason that the plant has evolved to have such elaborate traps: insect prey provide the nitrogen for protein formation that the soil cannot. The venus fly trap is not tropical plant and can tolerate mild winters.

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Cultivation

Venus flytraps are popular as cultivated plants, although they have a reputation for being 'difficult'. Much of this reputation is due to inappropriate treatment of the plants by retailers, and their consequent ill-health on purchase.

Image:Drawing of Venus Flytrap.jpg

Although terraria are an ideal growing environment, Venus flytraps can also be grown on a windowsill if a few requirements are respected.

The ideal soil is a mix of sand and sphagnum moss, or sphagnum alone. Soil pH should be in the range of 4.0 to 4.5.

They thrive with at least a few hours of direct sunlight daily. However, hot sun combined with low humidity can kill for a weak Venus flytrap fresh out of tissue culture. Insufficient light can lead to long, thin leaves that lack red coloring in the traps.

Venus flytraps must not be watered with tap water; accumulated salts cause most carnivorous plants — including Venus flytraps — to die. Distilled water, clean rain water, or water that has been artificially acidified with sulfuric acid should be used instead. The soil should be kept constantly moist (and the humidity high) by placing the pot in a tray full of water. There is no danger of over-watering. Venus flytraps have been known to live underwater for weeks at a time.

Some horticulturists have experimented with giving small amounts of fertilizer to Venus flytraps, usually applying diluted solutions of products formulated for epiphytes, using cotton swabs, to the plant's foliage. Beginners, however, and those without expendable plants, would be wise to avoid fertilizer in favor of insects.

Image:Venus Fly Trap.jpg

Growers should resist the temptation to trigger the traps manually, whether by poking them or by feeding them food such as hamburger, which will rot traps due to high fat content. Venus flytraps are entirely capable of catching their own food; thus, feeding them manually is not necessary. The plants do not require insects and can thrive without eating at all. If for some reason a grower wishes to feed a flytrap, live insects no larger than 1/3 of the size of the trap may be used. Algal growth near the plant is an indicator of over-feeding.

Healthy Venus flytraps will produce scapes of white flowers in spring; however, growers may wish to pinch these out, as flowering consumes some of the plant's energy, and reduces the rate of trap production.

In winter, wild Venus flytraps will become dormant. If one lives in an area with chilly, but not freezing, winters (similar to the plant's natural habitat in North Carolina), they can be placed outside in a cool area protected from frost. The soil should be kept slightly moist and the area well ventilated to prevent the growth of grey mould. Those who live in areas with extremely cold winters might consider placing plants in a plastic bag in the refrigerator for two to three months, starting in autumn.

Plants can be propagated by seed, although seedlings will take several years to mature. More commonly, they may be propagated by division in spring.

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Popular culture

Image:TV MMPR invenusable flytrap.jpg

Venus flytrap-like plants are common in fictional works, usually in a much larger form capable of digesting a human. Probably the most famous is Audrey II in Little Shop of Horrors, a plant that needs to eat people to live. Other fictional outings include the Philippine comic Darna, where the villain Flaviana turns Venus flytraps into monsters as a defense. A one-time villain on Mighty Morphin Power Rangers was the Invenusable Flytrap, a humanoid plant creature. There was also a character by this name on the television sitcom WKRP in Cincinnati.

Cartoons frequently make use of monstrous plants; examples include, but are certainly not limited to Inspector Gadget, Darkwing Duck, The Simpsons and Zetsu, a villain character in the manga series, Naruto. Video games such as Super Mario Bros. use similar creatures as (usually immobile) enemies; and in a video game called Venus the Flytrap, a robotic fly tries to destroy other robotic insects. The Infocom text adventure game Leather Goddesses of Phobos features a giant (mobile) flytrap which attempts to eat the player's character.

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References

| url = http://www.sarracenia.com/faq/faq2000.html
| work = The Carnivorous Plant FAQ
| title = Venus Flytraps
| accessdate= 2005-06-13
}}

| author=Forterre Y, Skotheim JM, Dumais J, Mahadevan L
| title=How the Venus flytrap snaps
| journal=Nature
| volume=433 | issue=7024 | year=2005 | pages=421-5
| url = http://www.nature.com/nature/journal/v433/n7024/abs/nature03185.html
| id = Template:Doi
}}

| author=Hodick D, Sievers, A
| title=On the mechanism of closure of Venus flytrap (Dionaea muscipula Ellis)
| journal=Planta
| volume=179 | year=1988 | pages=32-42
| url = http://www.springerlink.com/index/QPK061437U675H10.pdf
| id = Template:Doi
}}

| author=Hodick D, Sievers A
| title=The action potential of Dionaea muscipula Ellis
| journal=Planta
| volume=174 | year=1989 | pages=8-18
| url = http://www.springerlink.com/index/KL80VV1327508844.pdf
| id = Template:Doi
}}
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Further reading

als:Venusfliegenfalle da:Fluefanger de:Venusfliegenfalle es:Dionaea muscipula eo:Muŝkaptilo de Venuso fr:Dionée attrape-mouche he:דיוניאה it:Dionaea muscipula nl:Venusvliegenvanger ja:ハエトリグサ pt:Dionaea simple:Venus fly-trap

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