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Some info about carnivorous plants
December 22, 2012 2:35 PM   Subscribe

I am a creative writer (NOT a gardener or botanist) and have some questions about carnivorous plants. I'm wondering what some of the more "out-there" examples of carnivorous plants are and how they work. I was also wondering how a person could modify a carnivorous plant so it doesn't eat insects (it doesn't matter if this would kill the plant; just need to know how to do it.) Have read wiki page and some other basic info.

Again, please keep in mind that I'm just using this info for creative writing projects, not as practical gardening advice. Also, since I'm not a gardener, my plant vocabulary isn't all that advanced.
posted by mermaidcafe to Science & Nature (10 answers total) 1 user marked this as a favorite
 
One more thing: I know there are different kinds of trapping mechanisms, so there may not be only one way to disable one, but any way that works would be fine. Again, it doesn't matter if this would kill the carnivorous plant or not--this part is just a metaphor.
posted by mermaidcafe at 2:38 PM on December 22, 2012


This video has a plant that's big enough to catch rats. No modification necessary, other than growing large enough.
posted by Solomon at 2:39 PM on December 22, 2012 [1 favorite]


Venus fly traps, pitcher plants, sundews -killing methods respectively are hair-trigger traps, slippery slopes, glues. They rely on insects/etc. because they grow in soil that doesn't have nutrients - swampy soil (in full sun). You could try to have them not eat insects by providing more nutrients via the root system, though in reality you'd probably just chemically burn the roots. You could try to evolve them into better soil conditions to make their roots able to process nutrients.
posted by vegartanipla at 2:46 PM on December 22, 2012


The only way to make them unable to catch insects is to cut off the trapping mechanisms. In the case of a sundew that would probably kill the plant, because it's nearly all the leaves. For a venus flytrap, they appear on the ends of leaf branches and could be cut off very easily. For a pitcher plant, you'd have to remove the pitchers, which would be very easy because they're on the ends of stems.
posted by Chocolate Pickle at 3:34 PM on December 22, 2012


I grow carnivorous plants (CPs) as a hobby, I have ~800 plants, representing each genus and a little over 350 species--there's many more species then that but I only have so much growing space.

Some of my favorite CPs are in the Utricularia genus. Commonly known as bladderworts, they have little pouches with trap doors they compress in order to vacuum in prey in at high speed, so quickly actually that the aquatic type are among the fastest movers in the plant kingdom. What's extra cool is the clear traps on this tiny plant are large enough so you can see the prey vanish within: the prey is outside and nearby and then seemingly without any visible movement, the prey is struggling inside. Sarracenia are also fascinating: they are pitfall traps, at the top of the trap the plant exudes a sweet scented nectar which attracts insects. The nectar also contains a narcotic (to insects, not to people unfortunately not for lack of licking on my part). Stiff hairs point down the throat of the trap and once the insect climbs down those, the inside of the tube is lined with waxy scales which cling to the bottom of the insect's feet but pop right off the surface of the plant. It's just amazing watching an insect pratfall its way into a sarr: the climbing bugs can't crawl out because of the waxy scales and the ones with wings are too stoned to fly.

One could easily disable the insect-eating abilities of Dionaea (Venus Flytraps), Nepenthes and some of the Utricularia by snipping off their traps as their traps are at the end of the plant's leaves rather than being wholly made up of the entire leaf structure such as with any of the Sarraceniacea. It's also possible to disable or severely compromise new trap growth by any number of cultivation errors, such as letting the plants dry out, watering with mineralized water, and poor pest/disease control (sucking insects such as scale will, for example, cause a Sarracenia to produce deformed leaves which never open up as traps). One can also temporarily disable the insect catching ability of Drosera (sundews) and Pinguicula (butterworts) by covering their sticky surfaces with misted water or a good coating of dust but these plants' glands tend to drool their way out of that predicament within a day. None of these modifications will kill the plant outright as it still is able to gather energy via photosynthesis but the nutrients are essential for new growth, especially for trap and flower formation.

OK, once again I've been sucked into nattering on about CPs too long. Let me know if you need more.
posted by jamaro at 3:40 PM on December 22, 2012 [40 favorites]


My favorite CP story that isn't about the usual bug eaters is about figs and wasps. Figs are pollinated by a special kind of wasp which crawls inside them and then dies. Then the fig digests the wasp. Some figs are also full of wasp-laid eggs which then hatch and the wasps eat the figs on their way out. It's all really interesting and while not the active sort of carnivorousness of the other plants, it's pretty interesting and weird. And you can read about what the fig farmers to to try to keep this sort of thing to a minimum to keep their fig yields high. More than you care to know about this on FigWeb.
posted by jessamyn at 7:48 PM on December 22, 2012 [5 favorites]


You must watch this clip from Planet Earth about spiders that live inside pitcher plants.
posted by silvergoat at 8:56 PM on December 22, 2012 [1 favorite]


The action potential of Dionaea muscipula Ellis

"The intention of this investigation was to acquire more concise information about the nature of the action potential of Dionaea muscipula Ellis... The action potentials are strictly dependent on Ca2+... Perfusions with 1 mM ethylene glycol-bis(β-aminoethyl ether)-N,N,N′,N′-tetraacetic acid (EGTA) or 1 mM LaCl3 completely inhibit excitability... Sodium azide and 2,4-dinitrophenol also abolish excitation, probably by reducing the intracellular ATP concentration."
The basic translation is that there are specific mechanisms involved in triggering leaf closure in Venus Flytraps, and these can be disrupted by certain chemicals. I know practically nothing about plant biology, but I'd imagine the mechanism is similar in most plants that utilize some form of stimulus-triggered movement. Indeed, the general scheme of action potentials triggering calcium influx is common to excitable cells (e.g., muscles, nerves, and glands) in animals too.

Also, jamaro, your comment was awesome and informative. Please feel free to natter on about carnivorous plants anytime, but maybe avoid licking them in the future! Coniine is a neuromuscular blocker, so I'd wager its primary effect on insects is paralysis rather than a pleasantly sedating high.
posted by dephlogisticated at 11:36 PM on December 22, 2012


To slightly extend what dephlogisticated said:
Leaf movement is due to the movement of potassium and chloride ions into specialised cells, followed by water movement (due to osmosis), and a change in cell shape. Calcium ions are involved in various signalling pathways that can trigger this; EGTA chelates the calcium ions and so interferes with the process.

However, the same mechanism acts in guard cells to open and close stomata. These are small pores on the underside of leaves which open in a regulated way to allow the carbon dioxide needed for photosynthesis to enter, whilst limiting water loss. Trying to chemically/pharmacologically prevent leaf closure would probably also disrupt stomata function, which would be a problem.
posted by James Scott-Brown at 5:29 AM on December 24, 2012


jessamyn: My favorite CP story that isn't about the usual bug eaters is about figs and wasps. Figs are pollinated by a special kind of wasp which crawls inside them and then dies. Then the fig digests the wasp. Some figs are also full of wasp-laid eggs which then hatch and the wasps eat the figs on their way out. It's all really interesting and while not the active sort of carnivorousness of the other plants, it's pretty interesting and weird. And you can read about what the fig farmers to to try to keep this sort of thing to a minimum to keep their fig yields high. More than you care to know about this on FigWeb.
Have there been any chemical studies done to prove the fig actually digests the wasp, as suggested? There are several plants that actively kill or trap (and kill passively) insects without actually absorbing significant nutrients. Typically radioactive markers are used to verify if the nutrients travel to the plant tissues.

If it truly is insectivorous behavior, it's huge news to me - but my CP info is about 10 years old.
posted by IAmBroom at 11:32 PM on December 24, 2012


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