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Amazing results: Pygmy sundews capture minute prey like springtails with rapid catapult action. Our experiments for this film (English subtitles) show that Drosera glanduligera is not longer the only sundew with a catapult-flypaper trapping mechanism. Also the snap-tentacles of several pygmy Drosera act with the speed of a closing Venus flytrap and fling walking prey from the periphery of the plant onto its sticky leaf. Therefore they turn out to be actually comparable with the amazing Drosera glanduligera, however, their catapults are multifunctional and possess a mechanism to avoid unessential movement: Like Venus's Flytrap. Under our microscope we examined 22 Drosera and received surprising results. Furthermore we were able to film many pygmy Drosera in situ on field trips with Allen Lowrie, Greg Bourke and Kirstie Wulf (1991 & 2001), providing these shots now for the first time on YouTube.

 

We are happy to introduce Gideon Lim from Malaysia, who showed the first video of the rapid snap-tentacles of D. pygmaea "New Zealand, all green" on the internet even in 2014. In addition, we recommend a visit at "Andy Landgraf Makrofotografie" on Flickr and on Facebook. Andy kindly provided some of his impressive macro-shots for our film, to feature some more minute prey and predators in "Pygmyland".

 


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Hello Siggi, very nice video. I have been aware of these tentacles for many years. I'm not sure, isn't any person that grows Drosera and also looks at them generally aware? How can you miss the visible movement? Ten years ago I was showing people these traps on D. scorpioides and D. burmannii. Most were extremely un-impressed. Not me though, I agree with Darwin, Drosera is one of the most amazing of plants; master chemists and structural engineers.

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You are right Dave. 10 years ago we published our film "Snap-tentacles and Runway Lights" and found D. ericksoniae (renamed D. omissa) to possess - after the annual D. glanduligera - the fastest movement with about four seconds. The film contains also my first footage on tentacle-movement from 1994: D. burmannii. We did the experiments mostly on hot summer days, however, I meanwhile know that the temperature for pygmies, especially cool nights and moderate during day, plays an essential role to observe the speed. If it is too hot, the snap-tenacles curl and become inactivated. Another reason to find that not interesting is probably the size. With a leaf-diameter of one millimeter one has problems to see what happens with the minute tentacles without a magnifier. One more reason is probably a conservative view on the plants, which means: All sundews move their tentacles more or less and have different tentacle structures in different states of evolution. Therefore it is not of interest how single species act. I read this argument by a prominent person even this year. I don't think so and prefere the view of functional morphology, which needs much more experiments on functionality and much more time to examine single plants. Actually more time and more work, but the results are much more meaningful. Haha, and the story goes on ....

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Pygmy Drosera are widespread in CP-collections, however, I don't know who offers them in the UK. The fastest species (fraction of a second) are the small ones, from which I found D. occidentalis and D. pygmaea are relatively easy to grow. But they need a lot of light and a cool winter.

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Hi Siggi/Dan,

I recall looking into this a while back with my own plants. I think that I observed this effect in

, amongst others, D callistos and, surprisingly, D pulchella, as well as D scorpiodes. Many species are available in the UK, especially in gemmae season in the autumn. Also, lots of gemmae will be available from foreign growers in the autumn.

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" One more reason is probably a conservative view on the plants, which means: All sundews move their tentacles more or less and have different tentacle structures in different states of evolution. Therefore it is not of interest how single species act. I read this argument by a prominent person even this year."

I know, I am becoming convinced certain types of schooling actually encourage the students to develop OCPD (Obsessive Compulsive Personality Disorder) which then hinders their ability to actually do science. Yes, you do have to be Obsessive Compulsive in order to keep doing the same testing over and over while making sure everything is working right. It is a part of the process of getting good data, but one cannot be in that same mind set when one thinks about the results.

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Pygmy Drosera are widespread in CP-collections, however, I don't know who offers them in the UK. The fastest species (fraction of a second) are the small ones, from which I found D. occidentalis and D. pygmaea are relatively easy to grow. But they need a lot of light and a cool winter.

This is going to my next plant, i find a Drosera pygmaea -Eastern States on triffid nurseries, is this the correct species

Thanks

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Hi Siggi/Dan,

I recall looking into this a while back with my own plants. I think that I observed this effect in

, amongst others, D callistos and, surprisingly, D pulchella, as well as D scorpiodes. Many species are available in the UK, especially in gemmae season in the autumn. Also, lots of gemmae will be available from foreign growers in the autumn.

Hi greg, do you know of any sellers in the uk that have any of the above plants that you said. Thanks

Dan

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  • 3 weeks later...

I think that sticky-leaved CPs are grossly under-studied as a whole. I noticed a few years ago that Drosera latifolia (formerly ascendens) has tentacles which move rapidly enough for the movement to be perceived with the naked eye. I suspect a lot of species have tentacles which move far more rapidly than is commonly appreciated.

 

I am also beginning to have serious doubts as to whether all Byblis can properly be described as wholly passive carnivores. Byblis gigantea seems to me to possess some kind of ability to draw prey to its epidermis (although I have not observed the method). Byblis guehoi has similar abilities. The other day, I noticed a small flying insect (some sort of fly, I think) which was adhered to the outer tentacles of the underside of a semi-erect leaf a B guehoi plant in my greenhouse. It was most certainly dead. The following morning, it was in contact with the epidermis and enveloped in fluid. It is now dry, but still in contact with the epidermis. Cindy on ICPS forum is the first person whom I know to have suggested that Byblis may have this ability, and I have observed it many times on my plants since reading her comments. I wonder whether Byblis tentacles remain erect owing to fluid pressure within the cells; if the plant has the ability to reduce the turgidity in the cells, it may be able to cause individual tentacles to collapse, this bringing ensnared prey into contact with the sessile glands. Byblis gigantea cells are undoubtedly able to communicate with one another, and seem to possess a sense of 'taste'. I have demonstrated this by placing small pieces of cheese on the epidermis of a leaf and observing glands above the cheese (presumably, the sessile glands) literally oozing fluid.

 

Lots of work for potential PhD students, I think!

 

Greg

 

 

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Yeah and since the ID's of some species aren't nailed down, folks with OCPD don't feel comfortable working with them. These are some of the most intricately designed plants and some scientists find them "too troubling" to work with. That just sounds crazy to me.

The traps in Drosophyllum and Byblis are passive, but the digestion is active. I've never understood why publications continue to describe Drosera as being "passive fly paper traps". Even that guy, "Sundew Matt" describes Drosera this way, and I've argued that Drosera traps are active and thus he should call them "active fly paper traps" but he refuses to as someone else has already published them as "passive". And I'm like, "but you grow sundews and can personally see those traps are active." And he's like, "But I'm not an expert enough to make that distinction". And I'm like, "WTF?".

Edited by Dave Evans
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@Greg and Dave: Yes, also Byblis is able to move its leaves by the pulvini at the leaf-base. It was ignored (not metioned in publications) until Brian Barnes wrote about it. Until now I never read something about the similar pulvini in Drosera section Arachnopus (D. indica, etc.), did you? These Drosera are able to move their leaves similar to Byblis. For demonstration (in Byblis):

 

 

 

Regarding the catapult-flypaper traps of sundews which fling prey in parts of a second, I recently received comments of persons who really tried to tell me that such movement is irrelevant and not of interest. It looks like, that the amazing results of such examinations disturb some persons in their conservative ideology. On the other side I receive a great feedback by well known scientists and technology writers who enthusiastic ask for such footage to show it on TV. However, it's a pleasure to continue our research under such circumstances. I am still convinced, that all rapid moving carnivores tell us a great story about nature and especially the catapulting sundews illuminate how evolution could jump from a former passive glue-trap to the "most wonderful plant of the world" (Ch. Darwin): Dionaea (and Aldrovanda).

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