As carnivorous plants , including carnivorous or insectivorous plants are referred to plants that means converted leaves mostly unicellular or arthropods through catch and digest, but also larger prey to frogs and so its supply of minerals, especially nitrogen , at extreme locations like moors or improve bare rocks.
Usually the prey consists of small insects such as mosquitoes , ants and flies ; larger pitcher plants ( Nepenthes ) can also digest small mammals (e.g. small rodents ). Traps and mosses specialize in protozoa (unicellular organisms). In the case of the water hoses ( Utricularia ), in addition to insects, planktonic algae form a considerable part (up to 50%) of the prey, and in the case of the fatty herbs even pollen (up to 70%).
The formation of traps is very time-consuming for a plant, since trapping leaves are much less suitable for photosynthesis than normal leaves. Carnivorous plants therefore usually grow quite slowly. In nutrient-rich locations, where many other plant species are also able to thrive, they are often displaced by the faster growth of competitors. They are therefore only competitive where other plants cannot or can hardly grow due to a lack of nutrients. Such nutrient-poor locations are, for example, bogs, tropical rainforests, tropical table mountains, sand or rocks.
Furthermore, a sufficient supply of light and water must be guaranteed so that the trapping leaves can carry out sufficient photosynthesis to generate energy for the plant. Carnivorous plants are therefore found almost without exception in full sun or at least very bright locations. Most species also like to grow on moist soils, but some can also cover their water needs with fog or dew. The majority of the species also require a high humidity of over 70%.
Since carnivorous plants cover a large part of their nutrient requirements through the catch leaves and not through the roots, these are often sparsely developed and very resistant to unfavorable soil conditions. For example, some species tolerate a lack of oxygen ( sundew ( Drosera ), fatty herbs ( pinguicula ) and many other species on peatland), heavy metal pollution ( Darlingtonia in California, Sarracenia on Newfoundland, several types of Nepenthes ), extremely acidic or basic soils (sundew, pinguicula , Sarracenia ), Nepenthes at coastal locations, radioactive pollution (water hoses in the cooling basin of a decommissioned nuclear power plant) and much more.
Carnivorous plants can be found on all continents with the exception of Antarctica . Due to their special location requirements, however, they are particularly species-rich in bogs in the warm temperate zone ( Sarracenia , Dionaea , Darlingtonia ) as well as in tropical high mountains ( Heliamphora , Nepenthes , Brocchinia etc.). Only a few species can be found in the tropical rainforest, as it is usually too dark there. Dry areas are generally avoided, with the exception of Drosophyllum lusitanicum and those that survive dry periods underground, such as the Australian tuberous drosera. In Central and Northern Europe, i.e. in the cool and cold temperate climate, relatively few species are represented in comparison. There are around 16 species in German-speaking countries.
There are five different types of trap in carnivorous plants. Depending on their ability to actively move in connection with catching or digesting the prey, the species can also be characterized as active or passive.
Adhesive traps work via a sticky secretion , which emerges via glands on the leaves themselves or at the tips of small tentacles with which the leaves are occupied. Plant species that use this method of fishing, are sundew ( Drosera ), fat herb ( Pinguicula ), byblis ( Byblis ) roridula ( Roridula ) that drosophyllum ( Drosophyllum ) and Liane hook blade ( Triphyophyllum ) and the largest genus of carnivorous plants that stylidium ( Stylidium ). Each of these genera developed the carnivory independently of the others.
The insect is attracted by the fragrant secretion and sticks to it. Through its attempts to free itself, more and more body parts get stuck to the sticky secretion; In the case of the active sticky traps of the genera Drosera and Pinguicula , this is also supported by additional movements of the catch leaves. The majority of all sticky-trapped species then release enzymes which then perform digestion, but some rely on commensals (especially bed bugs) to decompose , which suck the prey. The nutrients of the trapped animals are finally absorbed by the plant through the excrement of the bedbugs.
The catching technique of the folding trap is probably the best-known, albeit rarest, method of catching carnivores. This is the rapid closing movement of two halves of the leaf, which is triggered by small feeler hairs on the inside of the leaf. Each of the two halves of the leaf has three to nine of these hairs. If one person is touched several times or different hairs are touched twice within approx. 20 seconds, the two halves of the leaf close within two seconds. The stimulus control prevents closing due to rain or drafts. After sealing, a cavity forms between the leaf halves in which the insect is digested by secretions. The valves open again after about eight days, releasing the indigestible remains of their victim. The only plants with this trapping principle are the two species Venus flytrap ( Dionaea muscipula ) and water trap ( Aldrovanda vesiculosa ).
The principle of suction traps only works under water or underground. The plant that catches with this trapping method builds up a negative pressure in the trap, which is equalized suddenly when touched and sucks water and prey into itself. The only genus that applies this principle is that of water hoses .
With pitfall traps , the leaves form a cavity into which the insect falls and due to the smooth inner walls and small space it is difficult or impossible to get out. There are two sub-groups, namely on the one hand the pitcher plants such as the dwarf pitcher (Cephalotus) , the heliamphora (Heliamphora) and the pitcher plants (Nepenthes) and the hose plants (Sarracenia) and on the other hand their close relatives, the monotypic genus Kobralilie (Darlingtonia) .
Much more complicated are the trap traps , whose occurrence is named to the genus of trap traps ( Genlisea ) with its 21 species and - in very different ways - the parrot pitcher plant (Sarracenia psittacina) . However, adult Nepenthes aristolochioides pitchers also seem to show signs of trap formation. Their victims - at Genlisea only single-cell organisms - are guided into the inside of the trap by attractants. A reversal is made impossible for the organisms by locking hairs. Eventually they end up in a kind of stomach where they are digested by enzymes. The S. psittacina fish trap, on the other hand, does not digest the trapped animals in a stomach device, but, like the other Sarracenia, directly through enzymes inside the tube. The two moss genera Colura and Pleurozia , classified as either carnivorous or precarnivorous, also use this trapping principle.
In roridula ( Roridula ), the Gemsenhorngewächsart ibicella and bromeliads the genera Brocchinia and Catopsis one speaks of the so-called Präkarnivoren (except Brocchinia reducta , a carnivorous plant in the narrower sense). These are plants that do not meet all of the requirements to be recognized as carnivorous, which usually means that they catch insects but have no digestive devices . An interesting intermediate stage can be found in the bedbug plants, which use their catch indirectly through a symbiosis , in that they absorb the excretions of the bedbugs Pameridea marlothii , Pameridea roridulae and spiders ( Synaema marlothii ), which live symbiotically with them and feed on their catch, as foliar fertilizers.
Genera and species of carnivorous and precarnivorous plants
Over 1000 different species are known, only around 15 of them are native to German-speaking countries. They are divided into nine families and 17 genera, with over 300 species the weft plants and with over 200 the water tubes the largest genera, five genera are monotypical . Other species are still being discovered, especially pitcher plants, water hoses, fatty herbs and sundew.
Although not all carnivorous plants are directly related to one another, almost all species (with the exception of the dwarf jug, the bromeliads Catopsis berteroniana and Brocchinia reducta as well as the shot plants) belong either to the carnation-like (6 genera), the mint-like (4 genera) or the heather-like (4 genera).
Research on mosses is still relatively early, only for two species ( Colura zoophaga and Pleurozia purpurea , both from the order of the Jungermanniales ) at least zoophagy (the catch) has been documented, but evidence of digestion and nutrient absorption is still pending .
In the case of some field herbs, such as shepherd's purse , it has been found that the seeds become sticky during germination, which means that microorganisms are held in place in order to probably use the nutrients of the dead animals.
- Brocchinia reducta
- Catopsis berteroniana
- Butterwort ( Pinguicula )
- Yellow unicorn flower ( Ibicella lutea )
- Hook leaf ( Triphyophyllum peltatum )
- Pitcher plants ( Nepenthes )
- Cobra Lily ( Darlingtonia californica )
- Rainbow plants ( Byblis )
- Traps ( Genlisea )
- Pitcher plants ( Sarracenia )
- Shot plants ( Stylidium )
- Sundew ( Drosera )
- Swamp Jugs ( Heliamphora )
- Pigeon leaf ( Drosophyllum lusitanicum )
- Venus Flytrap ( Dionaea muscipula )
- Bug Plants ( Roridula )
- Water trap ( Aldrovanda vesiculosa )
- Water hoses ( Utricularia )
- Dwarf jug ( Cephalotus follicularis )
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- The pigeon leaf. Exchange and news organ of the Society for Carnivorous Plants. since 1984 – running, (trade journal of the Society for Carnivorous Plants).
- Carnivorous Plants Society
- Large picture gallery with high-resolution images - from seeds to plants
- Website about carnivorous plants
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