jeff
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Posts: 128
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Post by jeff on May 21, 2010 9:58:57 GMT
roridula , carnivorous or mutualist proto carnivorous ?
jeff
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Post by peterhewitt on May 21, 2010 14:11:11 GMT
In my opinion, plants that have adaptations to capture prey, and benefit from the nutrient provided by such, however processed are Carnivorous, much in the same way as Darlingtonia and S.Purpurea do not produce digestive enzymes, but are aided by mutualistic bacteria.
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Post by Dave Evans on May 21, 2010 17:02:19 GMT
Roridula is not capable of being a carnivorous plant. Its non-aqueous resin effectively prevents it from being able to become a carnivorous plant. I can't think of anyway for the plant to evolve into a carnivore from where it is now, and I wouldn't label it as a proto-carnivore since it isn't going to give rise to a carnivorous species either.
The 'problem' as I see it, is we don't actually have a word for the kind of plant Roridula is. We have strings of words like, "mutualist proto carnivorous" which is a definition looking for a word...
It is rather sinister, but I kind of like 'murderous plant' or 'assassin plant'. I think this would also cover that spiky-leaved desert plant that kills hover flies.
Carnivorous plants need to be able to eat the food they catch and Roridula doesn't. The insects are not analogs to the bacteria that Darlingtonia (and all other CP's and all animals) use to help breakdown their prey. The assassin insects in fact have their own bacteria that help breakdown their food. Meanwhile, Roridula is only absorbing the food produced by the assassin bugs; it is not eating insects. It is clear to me it is the insects living on Roridula which are carnivorous and not the plant.
Thinking about tomatoes as carnivorous plants might be useful educational tool for better understand of the life around us, but actually publishing tomatoes as and declaring them to be carnivores is just ridiculous. When they actually start eating insects, I'll be convinced.
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jeff
Full Member
Posts: 128
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Post by jeff on May 23, 2010 6:07:27 GMT
other opinion ?
jeff
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Post by peterhewitt on May 23, 2010 14:57:02 GMT
My opinion stands . since Pamiridea only occur on Roridula and cannot survive without the plant, they exist in a Mutualistic carnivorous Partnership. Both have evolved together.
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Post by Dave Evans on May 27, 2010 22:48:24 GMT
Right, the relationship is carnivorous in nature. The plant is just sticky and non-carnivorous by itself.
Pamiridea need more research.
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Post by Michael on May 30, 2010 3:24:58 GMT
I'm not sure if this is quite the research you were thinking about, but there is an interesting recent article on P. roridulae locomotion on Roridula.
Voigt & Gorb (2010). Locomotion in a sticky terrain. Arthropod-Plant Interactions, 4: 69-79.
Mike
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Post by mattopel on Jun 4, 2010 18:58:34 GMT
Like a lot of phenomena in the natural world, carnivory in plants exists as a spectrum of possibilities. There are unambiguously carnivorous plants, like VFTs, and unambiguously non-carnivorous plants, like lawn grass. And there are a bunch of plants with some, but not all, of the adaptations associated with fullmetal Dionaea-style carnivory; for example: Ibicella, Sarracenia, Byblis, Nepenthes and Roridula.
Where you draw the line between carnivorous and non-carnivorous is open to debate, but any definition of carnivory that included all of the New World pitcher plants (some of which apparently do not secrete digestive enzymes, and all of which rely at least in part on commensal microbes and insects to break down prey), would have to include Roridula, too. There has been a bunch of research recently on carnivory in Roridula, and the plants have an impressive range of specific adaptations to luring, trapping and absorbing nutrients from prey. Ecologically, Roridula turns out to be as dependent, or even more dependent on nutrients from prey animals, than traditionally recognized carnivores like Drosera.
I have no problem at all with calling Roridula carnivorous; classifying it as sub-carnivorous is mainly a holdover from the time when Roridula was poorly understood.
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