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Post by leilani on Mar 13, 2010 22:06:43 GMT -10
Hey Gus! Nice to hear from you. I appreciate your skepticism. I don't think this is a revolution, or anything like it, in the understanding of Nepenthes. It is interesting evidence of this phenomena ..... kudos to those who captured the video. Shrew Poo and Shrew Nepenthes pitchers catch shrew poo and shrew! Bat and bird and their poo too! Lizards that crawl and frogs that hop, As well as anything they may drop. No plan in advance before they begin. Blind to the world they catch what falls in! The more I learn about the working of the Nepenthes pitcher the more complex its processes seem to become. I think we search for plausible scenarios that will act, or pretend, as evidence for our theories. I expect that we will soon see this phenomena cited as evidence for a number of Nepenthes adaptations. If shrew poo could pull it all together then, that would be nice ..... it would fit nicely with, as dvg points out, our conception of a human "toilet". The trouble is that I'm not even sure what a "toilet" means outside of the human bath. I mean, sure, these pitcher 'collect' skat when birds, or shrews visit but so does my car. The same tweeting bird may even visit my car regularly. This does not make my car a "toilet". I am skeptical of any single or simple explanation of the "pitcher dynamic", or its evolution. I believe that any singular or simple, or in this case anthropomorphous, explanation offered will prove insufficient to the understanding of the complex dynamics involved.
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Post by agustinfranco on Mar 13, 2010 23:09:09 GMT -10
Hi Sam:
it's a pleasure to hear from you too!. I do believe that Nepenthes pitcher evolution is multifactorial. I am not trying to take away any merit from Dr. Clarke's findings. Perhaps there is some truth behind the shrew poo's theory, but a Nepenthes pitcher shape and size is multifactorial and not just restricted to shrews' poo as some may want us make us believe.
Rajah's pitchers may catch some poo I am amazed and you are sure too! There is more to be discovered so be ready and don't faint as you will soon have to be recovered These plants don't stop inspiring every time i see them, i'll start transpiring there is not end to this vicious circle to get over it, there must be a miracle
Not as good as your poem Sam, but your dedication and love for these plants are inspirations to anyone.
Kind Regards,
Gus
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amori
Urceolatae
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Post by amori on Mar 13, 2010 23:14:38 GMT -10
I'm probably just repeating a trite hypothesis/theory here: The pronounced constriction in the pitchers of lowii lead me to believe they're the most adapted for shrews, etc. to feed and defecate in. Maybe, should an animal lose its grip on the pitcher rim, it's saved from being digested, along with its faeces, by the constriction and general shallow gradient of the "bowl", thus allowing the animal to clamber out with ease (a flattened peristome with a distinct outer edge would be easier to grasp with fingers than, say, a rounded one with incurved teeth). This would clearly mostly or only apply to particularly large upper pitchers vs small/young animals. I think the shrews have simply learned that macrophylla and rajah are also suitable, although possibly slightly precarious due to those species' pitcher morphologies (broad, constriction-less body and wide, flaring persitome etc.) and lack of solid nectar bait. The way I see it, the shrew is just an opportunist.
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Post by sockhom on Mar 14, 2010 3:24:51 GMT -10
Hi Sam, Did you read the paper? If not, I can send it to you. Cheers, François. PS: Could you please answer to my PM request?
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Post by dvg on Mar 14, 2010 9:12:13 GMT -10
Poetry? Irreverent tongue in cheek humor? The all important anthropomorphic caveat? All before we even touch on the serious side of this issue. Gotta luv the Anarchist's Forum...I do. ;D
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Post by leilani on Mar 14, 2010 22:19:23 GMT -10
OK François! I'm busted. I have not read the full paper but only a couple of articles synopsizing it. I would be most grateful if you would pass it along. Did you see this one ...... Earthy News / March 4, 2010 / Pons Institute / Netherlands Nepenthes Use Insects to Bait for Bigger Prey Recent observation have revealed that a Nepenthes, large carnivorous plants from Asia, living in open environment in Hawaii attract and prey upon small birds known locally as Japanese white-eyes. These large plants attracts these birds by first luring and capturing insects. For years carnivorous plant enthusiasts believed this insect capture mechanism to be the primary function of the "Nepenthes Trap" or "pitcher". However, current studies now confirm that the insects captured supply only a tiny portion of the nitrogen these mysterious plants crave. The much greater reward for the plants comes after it has captured insects. It is believed that these amazing plants have evolved to use these captured insects not so much for the nutrition they provide but rather as a lure to attract even larger and more rewarding prey.
The mystery of these amazing "bird feeding" plants started to unwind when the authors of the study began recording their observations in the field. It seems that the devious Nepenthes, with its wickedly phallic pitcher appendage, captures small flying insects purposely in order to utilize them in an even more elaborate and diabolic scheme to capture the lovely little Japanese white-eye.
To quote one author ....
"It all became clear when I noticed that this particular species of bird was just the right size to perch on the rim of the pitcher, accommodated by a pitcher lid of just the right size and angle of reflex and a peristome that seem almost designed to the task. This "perch" gives the bird an advantageous position from which to view the pitcher contents. The opportunistic little insectivores are, of course, attracted to the small bounty of freshly captured insects floating on the surface of the pitcher fluid. Sooner or later the hungry bird can no longer resist the temptation of the free meal and will, head first, attempt to retrieve insects from the fluid."
This is where things get interesting.
"Once the bird enters the pitcher it is doomed". "Over millions of years of evolution the pitcher, or trap, of this amazing plant has evolved to become the perfect Japanese white-eye death trap. Once the bird enters it quickly finds that it can not back up. Inhibited by the slick walls of the pitcher and a formation known as the peristome the poor bird's fate is sealed and the diabolic Nepenthes will now slowly drown and consume its innocent victim."
The authors of these recent studies have backed their hypothesis on some very compelling numeric and nutritional studies.
"What struck me most was the coincidence of measurements." "The pitchers were exactly the right size to accommodate the birds both perched on the peristome and, more importantly, inside the pitcher." "Detailed measurement revealed that once the bird is inside the pitcher it just fits."
The fit is so exact that some have suggested a mutialistic evolution may be the only answer. The studies authors will not commit to that but do believe the two species are intimately connected.
"I mean .... what are the odds?" "You gotta bird AND you got a pitcher!" "AND, the bird fits perfectly inside the pitcher!"
Further studies clearly showed, by sophisticated analytical techniques, that those plants that captured birds derived a far greater amount of nutritional reward from their catch than those that did not.
The work of the author and his collaborators are expected to turn the world of carnivorous plants on its head. They conclude that as it is the nature of life to always maximize its rewards it is not surprising that the Nepenthes would adopt a scheme that reaches beyond the mere capture of insects and looks to the greater bounty to be found in feasting on our avian friends.
As one author says "It just makes sense!" "One bird is like a zillion mosquitoes!".
PS I will honor your request.
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Post by walterg on Mar 15, 2010 4:50:55 GMT -10
It is interesting that a conclusion about Nepenthes evolution ("Over millions of years") visa-vis a particular prey animal is based on observations of plants in Hawaii. All Nepenthes in Hawaii are either cultivated or escaped from cultivation. All bird species in Hawaii came from somewhere else. Were the scientists observing a naturally occuring Nepenthes species or hybrid that evolved without the assistance of Homo sapiens, and if so, does it naturally occur somewhere (in Asia) where that particular bird also naturally occurs?
Or, on the other hand, are these scientists full of, er, poo?
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Post by philgreen on Mar 15, 2010 8:41:08 GMT -10
Shawn - I would have to agree with you. On this particularly article - those 'scientists' are full of it. They might just as well say that Neps evolved their special traits just to lore humans to grow them and spread them around the world. I mean, what are the chances that it would have happened by chance Hey, maybe they are all actually one and the same. Neps evolved to be grown and spread by humans, so that they would be able to catch a bird that also didn't naturally belong in this new home ;D
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bobh
Insignes
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Post by bobh on Mar 15, 2010 9:28:53 GMT -10
"wickedly phallic pitcher appendage"
I couldn't have said it better myself.
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kain
Insignes
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Post by kain on Mar 15, 2010 16:40:04 GMT -10
Nepenthes feeding Who questions evolution Do shrews? Or do you?
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Post by agustinfranco on Mar 15, 2010 22:46:36 GMT -10
I am dying to open my mouth again, but before i do, i wanted to know whether the japanese white-eyes are endemic in the Hawaiian islands.
Gus
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Post by walterg on Mar 16, 2010 4:13:31 GMT -10
The Japanese White Eye ranges over a large area of East Asia, including Japan, Indochina, and the Philippines. So, no, it is not endemic to Hawaii, as "endemic" means "exclusively native to".
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bobh
Insignes
Posts: 52
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Post by bobh on Mar 16, 2010 4:23:13 GMT -10
Also, are there Nepenthes growing "wild" in Hawaii? If so, what kind(s)?
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Post by mikuláš on Mar 16, 2010 4:33:11 GMT -10
Beautiful satire, Sam. Swiftian, even.
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Post by dvg on Mar 16, 2010 4:40:27 GMT -10
Well with these plants now having a taste for larger prey, it is only a matter of time before they are laying elaborate traps for our little Muffy, Mitzi and Fluffles. Maybe a peristome that imitates kibble...
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