Species of carnivorous plant
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The Venus flytrap (Dionaea muscipula) is a carnivorous plant native to the temperate and subtropical wetlands of North Carolina and South Carolina, on the East Coast of the United States. Although various modern hybrids have been created in cultivation, "D. muscipula" is the only species of the monotypic genus Dionaea. It is closely related to the waterwheel plant ("Aldrovanda vesiculosa") and the cosmopolitan sundews ("Drosera"), all of which belong to the family Droseraceae. "Dionaea" catches its prey—chiefly insects and arachnids—with a "jaw"-like clamping structure, which is formed by the terminal portion of each of the plant's leaves; when an insect makes contact with the open leaves, vibrations from the prey's movements ultimately trigger the "jaws" to shut via tiny hairs (called "trigger hairs" or "sensitive hairs") on their inner surfaces. Additionally, when an insect or spider touches one of these hairs, the trap prepares to close, only fully enclosing the prey if a second hair is contacted within (approximately) twenty seconds of the first contact. Triggers may occur as quickly as ;templatestyles src="Fraction/styles.css" / ;1⁄10 of a second from initial contact.
The requirement of repeated, seemingly redundant triggering in this mechanism serves as a safeguard against energy loss and to avoid trapping objects with no nutritional value; the plant will only begin digestion after five more stimuli are activated, ensuring that it has caught a live prey animal worthy of consumption. These hairs also possess a heat sensor. A forest fire, for example, causes them to snap shut, making the plant more resilient to periods of summer fires.
Although widely cultivated for sale, the population of the Venus flytrap has been rapidly declining in its native range. As of 2017, the species was under Endangered Species Act review by the U.S. Fish &amp; Wildlife Service.
Etymology.
The plant's common name (originally "Venus's flytrap") refers to Venus, the Roman goddess of love. The genus name, "Dionaea" ("daughter of Dione"), refers to the Greek goddess Aphrodite, while the species name, "muscipula", is Latin for both "mousetrap" and "flytrap". The Latin word ("mousetrap") is derived from "mus" ("mouse") and ("trap"), while the homonym word ("flytrap") is derived from ("fly") and .
Historically, the plant was also known by the slang term "tipitiwitchet" or "tippity twitchet", possibly an oblique reference to the plant's resemblance to human female genitalia. The term is similar to the term tippet-de-witchet which derives from tippet and witchet (archaic term for vagina). In contrast, the English botanist John Ellis, who gave the plant its scientific name in 1768, wrote that the plant name tippitywichit was an indigenous word from either Cherokee or Catawba. The plant name according to the "Handbook of American Indians" derives from the Renape word "titipiwitshik" ("they (leaves) which wind around (or involve)").
Discovery by Europeans.
On 2 April 1759, the North Carolina colonial governor, Arthur Dobbs, penned the first written description of the plant in a letter to English botanist Peter Collinson. In the letter he wrote: "We have a kind of Catch Fly Sensitive which closes upon anything that touches it. It grows in Latitude 34 but not in 35. I will try to save the seed here." A year later, Dobbs went into greater detail about the plant in a letter to Collinson dated Brunswick, 24 January 1760.
 ;templatestyles src="Template:Blockquote/styles.css" / ;The great wonder of the vegetable kingdom is a very curious unknown species of Sensitive. It is a dwarf plant. The leaves are like a narrow segment of a sphere, consisting of two parts, like the cap of a spring purse, the concave part outwards, each of which falls back with indented edges (like an iron spring fox-trap); upon anything touching the leaves, or falling between them, they instantly close like a spring trap, and confine any insect or anything that falls between them. It bears a white flower. To this surprising plant I have given the name of Fly trap Sensitive.
This was the first detailed recorded notice of the plant by Europeans. The description was before John Ellis' letter to "The London Magazine" on 1 September 1768, and his letter to Carl Linnaeus on 23 September 1768, in which he described the plant and proposed its English name "Venus's Flytrap" and scientific name "Dionaea muscipula".
Description.
The Venus flytrap is a small plant whose structure can be described as a rosette of four to seven leaves, which arise from a short subterranean stem that is actually a bulb-like object. Each stem reaches a maximum size of about three to ten centimeters, depending on the time of year; longer leaves with robust traps are usually formed after flowering. Flytraps that have more than seven leaves are colonies formed by rosettes that have divided beneath the ground.
Fly trap leaves.
The leaf blade is divided into two regions: a flat, heart-shaped photosynthesis-capable petiole, and a pair of terminal lobes hinged at the midrib, forming the trap which is the true leaf. The upper surface of these lobes contains red anthocyanin pigments and its edges secrete mucilage. The lobes exhibit rapid plant movements, snapping shut when stimulated by prey. The trapping mechanism is tripped when prey contacts one of the three hair-like trichomes that are found on the upper surface of each of the lobes. The mechanism is so highly specialized that it can distinguish between living prey and non-prey stimuli, such as falling raindrops; two trigger hairs must be touched in succession within 20 seconds of each other or one hair touched twice in rapid succession, whereupon the lobes of the trap will snap shut, typically in about one-tenth of a second. The edges of the lobes are fringed by stiff hair-like protrusions or cilia, which mesh together and prevent large prey from escaping. These protrusions, and the trigger hairs (also known as sensitive hairs) are likely homologous with the tentacles found in this plant's close relatives, the sundews. Scientists have concluded that the snap trap evolved from a fly-paper trap similar to that of "Drosera".
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 usually reopen within 12 hours. If the prey moves around in the trap, it tightens and digestion begins more quickly.
Speed of closing can vary depending on the amount of humidity, light, size of prey, and general growing conditions. The speed with which traps close can be used as an indicator of a plant's general health. Venus flytraps are not as humidity-dependent as are some other carnivorous plants, such as "Nepenthes", "Cephalotus", most "Heliamphora", and some "Drosera".
The Venus flytrap exhibits variations in petiole shape and length and whether the leaf lies flat on the ground or extends up at an angle of about 40–60 degrees. The four major forms are: 'typica', the most common, with broad decumbent petioles; 'erecta', with leaves at a 45-degree angle; 'linearis', with narrow petioles and leaves at 45 degrees; and 'filiformis', with extremely narrow or linear petioles. Except for 'filiformis', all of these can be stages in leaf production of any plant depending on season (decumbent in summer versus short versus semi-erect in spring), length of photoperiod (long petioles in spring versus short in summer), and intensity of light (wide petioles in low light intensity versus narrow in brighter light).
Other parts.
The plant also has a flower on top of a long stem, about long. The flower is pollinated from various flying insects such as sweat bees, longhorn beetles and checkered beetles.
Habitat and distribution.
Habitat.
The Venus flytrap is found in nitrogen- and phosphorus-poor environments, such as bogs, wet savannahs, and canebrakes. Small in stature and slow-growing, the Venus flytrap tolerates fire well and depends on periodic burning to suppress its competition. Fire suppression threatens its future in the wild. It survives in wet sandy and peaty soils. Although it has been successfully transplanted and grown in many locales around the world, it is native only to the coastal bogs of North and South Carolina in the United States, specifically within a 100-kilometer (60 mi) radius of Wilmington, North Carolina. One such place is North Carolina's Green Swamp. There also appears to be a naturalized population of Venus flytraps in northern Florida as well as an introduced population in western Washington. The nutritional poverty of the soil is the reason it relies on such elaborate traps: insect prey provide the nitrogen for protein formation that the soil cannot. They tolerate mild winters, and require a period of winter dormancy to survive freezing temperatures and low photoperiods. It is a common misconception that Venus flytraps require dormancy if kept indoors under sufficient artificial light. However, most professional carnivorous plant growers recommend dormancy, and Venus fly traps grown without dormancy may require more light, water, and food to remain healthy.
They are full sun plants, usually found only in areas with less than 10% canopy cover. The habitats where it thrives are typically either too nutrient-poor for many noncarnivorous plants to survive, or frequently disturbed by fires which regularly clear vegetation and prevent a shady overstory from developing. It can be found living alongside herbaceous plants, grasses, sphagnum, and fire-dependent Arundinaria bamboos. Regular fire disturbance is an important part of its habitat, required every 3–5 years in most places for "D. muscipula" to thrive. After fire, "D. muscipula" seeds germinate well in ash and sandy soil, with seedlings growing well in the open post-fire conditions. The seeds germinate immediately without a dormant period.
Distribution.
"Dionaea muscipula" occurs naturally only along the coastal plain of North and South Carolina in the U.S., with all known current sites within of Wilmington, North Carolina. A 1958 survey of herbaria specimens and old documents found 259 sites where the historical record documented the presence of "D. muscipula", within 21 counties in North and South Carolina. As of 2019, it was considered extirpated in North Carolina in the inland counties of Moore, Robeson, and Lenoir, as well as the South Carolina coastal counties of Charleston and Georgetown. Remaining extant populations exist in North Carolina in Beaufort, Craven, Pamlico, Carteret, Jones, Onslow, Duplin, Pender, New Hanover, Brunswick, Columbus, Bladen, Sampson, Cumberland, and Hoke counties, and in South Carolina in Horry county.
Population.
A large-scale survey in 2019, conducted by the North Carolina Natural Heritage Program, counted a total of 163,951 individual Venus flytraps in North Carolina and 4,876 in South Carolina, estimating a total of 302,000 individuals remaining in the wild in its native range. This represents a reduction of more than 93% from a 1979 estimate of approximately 4,500,000 individuals. A 1958 study found 259 confirmed extant or historic sites. As of 2016, there were 71 known sites where the plant could be found in the wild. Of these 71 sites, only 20 were classified as having excellent or good long-term viability.
Carnivory.
Prey selectivity.
Most carnivorous plants selectively feed on specific prey. This selection is due to the available prey and the type of trap used by the organism. With the Venus flytrap, prey is limited to beetles, spiders and other crawling arthropods. The "Dionaea" diet is 33% ants, 30% spiders, 10% beetles, and 10% grasshoppers, with fewer than 5% flying insects.
Given that "Dionaea" evolved from an ancestral form of "Drosera" (carnivorous plants that use a sticky trap instead of a snap trap) the reason for this evolutionary branching becomes clear. "Drosera" consume smaller, aerial insects, whereas "Dionaea" consume larger terrestrial bugs. "Dionaea" are able to extract more nutrients from these larger bugs. This gives "Dionaea" an evolutionary advantage over their ancestral sticky trap form.
Mechanism of trapping.
The Venus flytrap is one of a very small group of plants capable of rapid movement, such as "Mimosa pudica", the telegraph plant, starfruit, sundews and bladderworts.
The mechanism by which the trap snaps shut involves a complex interaction between elasticity, turgor and growth. The trap only shuts when there have been two stimulations of the trigger hairs; this is to avoid inadvertent triggering of the mechanism by dust and other wind-borne debris. 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 trap, but the mechanism by which this occurs is still poorly understood. When the trigger hairs are stimulated, an action potential (mostly involving calcium ions—see