Potential new carnivorous species...


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Hi Dave,

My understanding is that the following have been clearly demonstrated (as a quick online literature search will reveal):

  1. Roridula does possess clear adaptions to carnivory (highly absorptive leaf surfaces and the production of phosphatases, for example, as well as the obvious ability to capture significant quantities of animals which, although not an feature exclusive to carnivorous plants, is obviously a necessary attribute for a plant to be considered carnivorous)
  2. Roridula (when Pameridea are present) is able to obtain very significant quantities of nitrogen from captured insects- in fact Roridula may sequester higher proportions of nitrogen from its prey than many other carnivorous species
  3. Both species of Roridula grow in habitats with very low nutrient levels in the substrate, similar to other CPs.
  4. There are numerous examples of CPs which do not protect their prey from kelpto-parasites (or mutualistic partners, depending on your point of view) which are similar to Pameridea, at least not with any obvious degree of success- for example, many Drosera and Byblis species in Australia.

In other words, the evidence overwhelmingly suggests that Roridula, like other genera of CPs, has evolved carnivory in order to obtain, from prey, certain nutrients which are wholly or partly lacking in the nutrient-deficient substrates of its natural habitat. The evolutionary path that Roridula has taken in order to achive carnivory, similar to many other carnivorous species, has resulted in dependence on organisms of separate species for successful nutrient sequestration. Whilst some of your speculations are interesting, you have not, as far as I can see, produced any compelling evidence to support them. Until you do so, it will be difficult for you to convince people that the scientific consensus is wrong.

Additionally, several other questions arise from some of your statements

  1. What does the apparent regression from carnivory of some Nepenthes species have to do with the status of Roridula as a carnivorous genus?
  2. Is there any evidence that the ancestors of Roridula were carnivorous?
  3. Are there any field studies which indicate that, in the absence of Pameridea, naturally occurring Roridula become ‘sick’ as a result of capturing excessive numbers of insects?
  4. Even if this is the case, how does it logically follow that Roridula is not a carnivorous genus?
  5. Have you never seen mouldy prey on CPs in your collection? I have seen this in several species of Drosera and Byblis, as well as in Drosophyllum, for example. Sometimes, this mould has also had a detrimental effect on the health of the plants concerned.
  6. How is the fact that some individuals of some plant species may occasionally benefit from the chance deposit of animal droppings of relevance to the discussion of carnivory in a genus which possesses features which facilitate the capture of animals, particularly as those features are atypical in the plant kingdom?
  7. How is it ‘broken logic’ to compare organisms which utilise the activities of other species in order to obtain nutrients?
  8. Is there any evidence that all CPs possess adaptions in order to ‘manage’ the micro-organisms which are present in/on their traps? For example, has this been proven in Heliamphora or Brocchinia?

Cheers,

Greg

Edited by Greg Allan
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There's recently been a lot of talk about many 'new' species of carnivorous plant, including the humble potato and the tomato, and when you look closely at the leaves you can see why, in that they are

My recollection from plant biochemistry is that the resin is produced as a sunscreen to protect plants against UV. Would be happy to carry out some cultivation trials though... ;)

Dave. You need to go smoke some more pot and chill out.

Man, I do have answers for most of those questions, but come on. The Pameridea are the carnivores in the Pameridea/Roridula relationship. It is rather difficult for me to understand how knowing the nutrients pass from prey through Pameridea and into Roridula is proof of carnivory by the plant. It is proof the carnivorous activities of the Pameridea feeds Roridula.

The reason I think proto-Roridula was probably a carnivore, it would be in a good position to develop exactly this kind of relationship with an insect partner. Then, with its new source of nutrients, it no longer has to stick low to the ground in humid pockets in wetter areas. Free of the expenses of carnivory, it can now grow into rather large bushes. The only carnivorous trait it has retained is the absorptive lamina that has taken the place of carnivorous leaves.

What sense does it make to say a insect eating plant can be considered as moving away from carnivory as a portion of its diet being supplied by animals different from the targeted prey in the form of feces, but then say a plant wholly dependent on feces is a carnivore. That is very broken logic to me. If Nepenthes lowii is less carnivorous because it lures tree shrews and consumes their feces, how does the same logic not apply to Roridula?

BTW, you've also hinted it isn't a carnivore. Think about this: it is better at getting nitrogen this way than are real carnivorous plants; probably because the carnivory is so biologically expensive.

Edited by Dave Evans
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Now lets consider Brocchinia. It doesn't have digestive enzymes. But it does have a place for digestion to take place. Same for all Pitchers Plants. The pitchers provide prey protection and a place for digestion and nutrient absorption. Roridula provides food to Pameridea in an exchange for nutrient. This association is more similar to that of mycrohizzal associations between fungus and plant roots. The plants provide nutrients to the associate it cannot get on its own and the associates provide nutrients to the plant it cannot digest from the soil. Roridula lets the Pameridea do most of the work of carnivory and in exchange doing this work of digestion and thus some cleaning the bugs receive habitat and a steady flow of prey items.

Is there any evidence that all CPs possess adaptions in order to ‘manage’ the micro-organisms which are present in/on their traps? For example, has this been proven in Heliamphora or Brocchinia?

Yes, if they weren't producing these biologically expensis molecules to control the rot in/on the leaves, they would rot all the time, not just when they become "overwhelmed" with food.

Also, in the case of heli's and brocchi's they are also general detrivores getting a fair amount of their nutrients from dust. Perhaps making enzymes is just too expensive for the benefit received thanks to the overall lower rates of insects where they grow?

Edited by Dave Evans
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Greg, well put and much more eloquent than my tired brain ramblings (and teasings) :)

Dave. I am quite surprised that as someone who advocates field observations as critical to for example Sarracenia purpurea relationships that you put a lot of store into other people's observations of cultivated plants! I have grown Roridula gorgonias with and without bugs and never had an issue with mould. I have also been to their natural habitat several times and certainly think that the dry and almost always windy conditions are not conducive to mould on plants.

Certainly Roridula have a strong symbiotic relationship with their bugs, but think you are in the minority in suggesting that this plant/symbiosis does not fit within the definition of carnivory.

Edited by gardenofeden
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Are Roridula carnivorous without their helpers? If the answer is "no", they aren't carnivorous plants. The carnivores in the relationship grew from eggs, not seeds. Or am I missing something?

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In 1998 I wrote an article for CPN to show that most CP have animal partners regarding the digestion of prey. This list has meanwhile grown and microbes are even not mentioned, however, even the 15 years old original (see below) tells a story, ranging from simple clepto-parasitism over mutualism to true symbiosis. The borders are - like always in nature - ambigous and floating and the term "carnivorous" is just a question of definition ... and such definitions change the more we know about the complexity of the phenomenon.

But one question @Dave: If Roridula would have been truly carnivorous in a former state of evolution, what kind of traps should that have been?? With resinous glue it would never be able to digest prey without the "little help of its friends", no matter if bacteria, bugs or other organisms with polar aquious acid conditions in their stomache.

EXAMPLES OF PLANT-ANIMAL MUTUALISM ON CP (CERTAINLY NOT COMPLETE)

Byblis gigantea / Setocornis bybliphilus

Byblis liniflora / Setocornis species

Darlingtonia californica / Metriocnemus edwardsi

Drosera erythrorhiza / Cyrtopeltis droserae

Drosera pallida

Drosera stolonifera / Cyrtopeltis russelli

Drosera indica (different variations) / Setocornis and/or Cyrtopeltis species

Drosera ordensis / The smallest Miridae species the author knows, very good adapted in color and size. Still not described and named.

Heliamphora species / Several mosquito larvae

Nepenthes bicalcarata / Camponotus schmitzii

Several Nepenthes species / Misumenops nepenthicola & Thomisus nepenthiphilus

& different Mosquito larvae and mites (name = ?)

Roridula dentata / Pameridea marlothii

Roridula gorgonias / Pameridea roridulae

Sarracenia flava / Sarcophaga species

Sarracenia purpurea / Wyeomyia smithii and other larvae

Remark: Darlingtonia, some Heliamphora and Roridula do not produce own digesting enzymes. Are they not carnivores anymore? What "finally true" definition fits them all?

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It is the way the various plants achieve their nutrients. Roridula splits the costs of carnivory with insects that were pre-adapted to carnivory, assassin bugs. All Roridula does is catch prey via filtering the air of flying insects, not sure it even attracts them. The Pameridea do all the work; and Roridula had to make modifications since they weren't leaving it alone. If Roridula used to be a carnivore; the traps certainly worked differently at that point and this point in time would also be previous to its current association with Pameridea.

I do not believe the association between Pameridea and Roridula can be say to be of equal important as for bacteria which colonize the whole planet and dozens of random species will "volunteer" to help your carnivores digest their food. This association is too specific between them. Pameridea does not "ecologically replace" bacteria. This is a food web, if a short one. I know Roridula get its food by providing Pameridea with prey which they then process for the plants and thought it was true long before the tests were done to "prove" it. This is not a model of carnivorous behavior on the part of Roridula, at least not currently. If Pameridea were to go extinct, Roridula would have to wait until other species evolved to take over Pameridea's niche to be considered a carnivorous plant again. So no, bacteria and Pameridea are not ecological analogs.

In all other examples given thus far, the CP's do not rely on their partnered species' carnivorous nature to replace their own; Drosera, Nepenthes, Cephalotus, Heliamphora, ect are carnivores without or with animal associates. They will continue catching and eating their own prey in the absence of their commusals.

Edited by Dave Evans
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Hey Dave, even if you call me an inch pincher, first just a general remark on systematics: The term "Assassin bug" should not be used for the mutualistic Capsid bugs (Miridae) which live on Roridula, Byblis, Drosera, Tobacco and many other plants world-wide. Assasin bugs are predatory true bugs belonging to the suborder Heteroptera family Reduviidae. I know the name is often used for the discussed Miridae, however, as I always state in such discussions, that is scientifical simply incorrect and does not become true, only because many people use it that way.

Many species of the world-wide Miridae live on plants with sticky emergences, and there are surprisingly many different genera world-wide which use that strategy for protection, and some are specialized to a certain host plant. I think we are at one, that most of those plants are certainly no carnivores only because they have mutualistic bugs "cleaning" their sticky zones from sticking insects, however, even these plants benefit certainly from the bug droppings through leaf fertilisation. I think your above comment is mainly correct in these cases.

For more than 10 years I grew both Roridula species hosting up to several hundred bugs on our balcony and during winter inside our living-room, enough time to examine their behavior very detailed. As a result I state, Roridula and Pameridea have actually a true symbiosis because the winged bugs live and stay their whole life on "their host plant" and they die without a Roridula. When I lost the plants some bugs tried to survive on Pinguicula, however, died also after several weeks. So they are no opportunistic predators, which only visit Roridula for its rich nutrient supply. They also developed a sophisticated "cleaning mechanism" to get rid of the sticky resin when they get in contact with the tentacles, which happens very often when they are fighting on the leaves. A very sophisticated adaptation which surely avoids that they become prey of their host.

In return Roridula adapted the normal ability of nutrient absorbance through plant leaves effectively, the plants simply grow much better and get older if bugs are present. For a comparable healthy and fast growth you need to fertilize the plants if no bugs are present, or they grow very slowly. Of course, mould is in both cases no problem if enough ventilation and a not too high humidity is provided.

Yes, everything is a question of definition, but Roridula is one of the most successful insect catchers, and in the presence of bugs it needs only a day or two until the prey protein is detectable inside the plant tissue, as experiments with radioactive marked prey showed without doubt. Therefore the plant clearly benefits from its prey, yes indirect, but very effectively and that is clear carnivory in my understanding. And yes, all carnivores are indirect digesting, because without the microbes inside their stomaches they would simply die of starvation. If those little helpers consist of only one or a few cells or if they have a multi-cellular organism has in my opinion only a secondary meaning in this concern, as far as their action is essential.

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Thank-you Siggi, I will try and delete that word in reference to Capsid insects from now on. I was unaware of the incorrect usage. So we all agree on what is happening, I'm pretty sure though this relationship which is like you say wholly symbiotic, then it is more specialized than our average bacteria/Host CP interaction. I think we've settled for calling it a carnivorous plant because there isn't really a named category that accurately fits it. "Arthropod induced carnivorous symbiosis"? That is quite a mouthful…

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Getting back to the point of "possible carnivory in plants" has anyone done any research,or are aware of any proof that Schizolobium Parahyba may be carnivorous?

I have grown this species (known as a Brazilian tree fern) and the "leading" stem of this plant is Very sticky and "trapped" many small flies!! There must be some reason for this, but im no scientist, i just like weird plants!!! ;)

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Cannabis is a kind of mint. I call it Indian Mint. Anyone who thinks it is illegal or should be illegal has got a screw loose in their head. Your Rights as Humans already guarantee your safe access to marijuana or Cannabis for whatever use you deem fit. Only through the application of libel and outright lies does marijuana somehow become associated with crime. The War on Drugs, the heights of a liberal madness--yet so tantalizing of a power trip (with those gorgeous mountains of wasted money, time and lives) not even conservatives can say "no" to it.

It used to be black cats and their "evil" people , now its pot plants and their "evil" people. Have we really gotten any smarter?

Cannabis is not part of the mint family, as far as I know it's closely related to hops.

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Thats is so weird, hops? Nothing in that family is even similar...

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Thats is so weird, hops? Nothing in that family is even similar...

Yes I know, weird. Here's a bit of info I lifted from the Web. The hops plant is a member of the Cannabaceae plant family and part of the Humulus genera. Hops are another extremely important commercial plant used in beer making. They are non-woody, perennial vines native to temperate climates around the world. The flower clusters of the hops plant are used in beer brewing. They contain bitter resins and essential oils that create the flavour of beer.

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Thats is so weird, hops? Nothing in that family is even similar...

Yes I know, weird. Here's a bit of info I lifted from the Web. The hops plant is a member of the Cannabaceae plant family and part of the Humulus genera. Hops are another extremely important commercial plant used in beer making. They are non-woody, perennial vines native to temperate climates around the world. The flower clusters of the hops plant are used in beer brewing. They contain bitter resins and essential oils that create the flavour of beer.

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It is illegal to grow female plants, you can grow as many male plants as you like they would be simply decorative. Its the flowers that make the difference!

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Dear Adam,

My comments are mostly directed at crazy people in the USA. We've spend billions of dollar going into other countries, telling them to make Cannabis illegal. It isn't our business. And we should be growing hemp here too. Not wasting money and other counties' respect for us on our leadership's insane notions.

The reason Cannabis is so smelly is because it is a kind of mint. Mints are known from ancient times as healing plants. They are also generally fully of volatile, aromatic chemicals which are often the source of the healing properties.

You human rights include being able to grow and use a Cannabis plant to drive away pest insects in liu of using some kind of dangerous material that can damage your tissues. It really is a human rights problem.

Well Cannabis is not related to mint, the genus Mentha. Mentha is a member of the Lamiaceae and Cannabis of the Cannabaceae.

Alexander

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Never heard that before, so that's why, whenever I get drunk I'll eat anything even a kebab.

I was just about to post the same thing! :laugh2:

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It is illegal to grow female plants, you can grow as many male plants as you like they would be simply decorative. Its the flowers that make the difference!

Hi is very illegal to grow male and female plants in the UK (unless you have a home office licence to grow it).

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OMG, you fellows across the pond, why do you have so many bans? You can't grow hops? Really? Someone actually cares that much, there is a law about it?

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OMG, you fellows across the pond, why do you have so many bans? You can't grow hops? Really? Someone actually cares that much, there is a law about it?

I'd be intersted in it [cannabis] from a horticultural point of view but the penalties for being caught are so not worth it just for satisfying curiosity.

edit: and I'm pretty sure the US FDA doesn't approve of people growing weed either

Edited by 19Silverman93
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