Some info about carnivorous plants

December 22, 2012 2:35 PM

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 (9 answers total)

Response by poster: 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

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 [4 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