Nov 22, 2009

Carnivorous Plants - What, Where and How

“Looks pretty... smells sweet... let me get a closer look,” thinks the insect when WHAPP! The predator shuts its jaws to trap the prey.

Pop Quiz #1: Which animal is this?

Ans: What? This is no animal; it’s a plant — the Venus Flytrap! It certainly doesn’t seem or sound or behave like a plant, but nothing is what it seems. These carnivorous or insectivorous plants simply behave in a slightly different manner to replenish their nutritious needs — they gobble-up insects!
In an ordinary meal, all carnivorous plants use bait to attract insects into the trap and then kill them to decompose and absorb their nutrients. Now for the gory details...
          The Bait

You probably figured such plants need to be pretty well groomed to entice insects, so they usually are appealing and colourful. However, the bait may vary from plant to plant to make the kill more exciting! Some plants lay out a landing platform in the form of a brightly coloured petal or exude a sweet scent to lead the insect to the trap. Others still smear their plant parts with a sticky or slippery fluid that prevents the prey from escaping. The most welcoming plants prefer to drug the visitor with some narcotic mixture!
If you think that’s rather impolite of the plants, you had better read on!
When the hungry Venus Flytrap is intruded, the jaws protruding from the leaf edges snap shut and trap the foolish insect inside. The bug has only half-a-second to escape and even your reflexes aren’t that quick!
Once the spider or other crawling insect is ‘secure’ the glands on the leaf secrete a fluid that digests the insect’s delicious body. Ten days is all it takes for the insect to disappear off the face of the earth! Then the leaf opts for another helping...
As for the Pitcher plants, just as their name suggests, they have beautiful red tubular leaves that resemble a jug. A sweet tasting juice lures the bug into the pitcher. Upon realizing its stupidity, the bug desperately tries to crawl back up the smooth sides but all in vain. The insect eventually drowns in the pool of digestive fluids at the bottom of the pitcher and that’s the last anyone hears of it.
I admire the Sundews the most; the name sounds poetic, the flower looks exquisitely lovely so one could never guess the real nature of this deceptive plant. The tiny drops of clear fluid on its leaves resemble dewdrops glistening in the sun, hence the name. The ‘dewdrops’ are actually a sticky fluid at the tip of tentacles that attracts and traps insects. To ensure the guest is always ‘served’, the surrounding tentacles bend towards the centre of the leaf, forming a fist that holds on really tightly to the bug.
The digestive juices are excreted by the tentacles and two days later, NOTHING!
Not all carnivorous plants secrete enzymes themselves to digest the prey; they may rely on bacteria or assassin bugs. In the former case, the food just rots and decays to a state where the decomposed molecules can be easily absorbed. In the latter instance, the assassin bugs may live on the carnivorous plants (without being caught) and eat the captured insect. After digestion, the bugs excrete – the excretion is full of nutrients. And you’re lucky you don’t have to eat this way because the plant then absorbs the poop!
Certainly you think, these are one heck of a messed up creatures! But they are merely trying to attain mineral nutrients like nitrogen and phosphorus because they can’t draw them from the infertile soil around them. Carnivorous plants tend to adapt to the moist and nutrient-poor habitat this way, so it’s only survival of the fittest. And that, you cannot condemn!

Pop Quiz #2: Should we beware?

Ans: If you are about a centimetre long and fly about boggy marshes, then yes. On the other hand, if you’re larger than a small insect, you can intimidate these plants all you want without fear because their digestive enzymes are extremely weak. They prefer flies, moths, butterflies, water fleas and other tiny bugs instead of humans. However, frogs have been reported caught by some larger plants.
By the way, in the cartoon world carnivorous plants can do some pretty neat tricks. Morticia (The Adam’s Family) owns an admirable plant, Cleopatra, which often feeds on zebra burgers, yak meatballs and even Gomez’s photographs! Similarly, Homer Simpson (The Simpsons) once had a tête-à-tête with another such plant.
Meat-eating plants contribute more to our lives than cause wonder. Ancient Hindu doctors used Drosera Burmannii (better known as Sundews) to counter skin irritation and the juice obtained by squashing its leaves can remove warts and corns when applied to the skin…because it erodes skin!
In far off countries, physical properties are more efficiently used. For example, in Australia, the sweet syrupy bait is extracted to flavour food and in Portugal these plants are bought for the purpose of reducing fly population. I’m all for the second use; a summer spent in this country will keep the flytrap fully fed.

Pop Quiz #3: So, if they can move, these plants are pretty much like animals, right?

Ans: Not really, because the plants don’t really move about with their own effort. When a Flytrap snaps shut, it is the result of the insect triggering the sensory hairs on the leaf that changes the cells’ rigidity rapidly. The cells on the inside become limp by transferring water to the outer cells, hence the leaf folds.
At times, the size of some cells may change. Half the cells on the tentacles of the sundews outgrow the other half, thus the tentacles bend inward.
You have probably heard about the leaves that wilt as soon as they are touched; they are called Mimosa plants (translated to ‘shame’ in Hawaii and as children we wanted to be the first to enjoy the honour of disgracing them!) but since they move in a manner similar to the one described above, even they cannot be considered gifted.
And besides, plants cannot hear, smell, taste nor see. So any doubts must be banished.
Pop Quiz #4: How many species of carnivorous plants are there?

Ans: So far, about 600 species have been discovered, but they are quickly disappearing because humans have learnt well to destroy their habitats. These ingenious plants surely deserve more than that for they chose a resourceful evolutionary path that baffled humans for ages and suitably continues to deceive insects.
Unless protected, some species of the Pitcher plant will only take 20 years to be added to the ever increasing list of extinct plants.
Nevertheless, it’s a cruel world for an insect and you sure should be thankful to your parents that you’re not one. As for the carnivorous plants, I guess the main reason they chose to adapt this way is because they too got tired of being vegetarians!
Whatever the reason, I admire them. And one day I’d surely like to closely observe the vampire-like event; a forgettable fly and a cute plant share a moment that spelled food for the host and doom for the guest.
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