...Squeamish to Insects

The trick is to get the trap closed and well-sealed before the egg is put in. Possible feeding technique: load up a diabetic syringe with about 1 mL of egg, and lay its needle across the edge of the trap towards the centre. Tickle the trap with a firm-but-flexible filament, e.g. a broom bristle, until the trap is fairly well sealed around the needle and bristle. (The tickling might be done with the needle itself, but it would be trickier to do that, especially with a fairly serious risk of scratching up the inside of the trap.) Then inject the egg. If you want to be extra careful, dull the needle first using a grinding tool, fine file, or other abrasive. Another possibility would be to get the trap closed around some small solid non-digestible object such as a plastic bead, again with the syringe in place before the trap closes.

I've read papers about analyzing the fluid inside a trap, mid-digestion, but I don't recall the details of how the liquid was extracted.
 
The trap with textured vegetable protein, wrapped in onion membrane, started opening a couple of days ago, and was almost completely open today. The remains of the membrane were brown and had the usual look of dead onion skin. I spent a little while keeping it wet with a mister before peeling the membrane off the trap; it came off with no difficulty. The trap appears to be completely normal. I'll leave it for another few days, then feed it again with the same material. The other two traps, with bits of dried earthworm and tofu, are still closed.
 
Lloyd Gordon said:
I just fill the trap with dried ones until the trap closes. Opens a few days later, ready for another meal. I don't add water, the trap supplies some moisture.
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What is left behind after a VFT finishes with a FDBW? Does the jar contain small bloodworms, or pieces of large ones?
 
Some science!

Things my slow VFT is *still* eating, for a while (I guess 3+ weeks now on this same meal):

* A single pea. Sort-of. Half of this trap is dead, and half is apparently still trying to digest the pea.

* A single (raw, unsalted, shelled) sunflower seed. I see that I said "sesame seed" above, which is a mistake. (For some explanation: I had *intended* to try a sesame seed on a smaller trap, but then found that I actually didn't have any raw sesame seeds in the pantry. I did, however, have raw sunflower seeds. I guess my brain got confused. Poor brain.) This trap looks perfectly healthy, but it's been stuck in "digestive pouch mode" for a while now. The sunflower seed still feels solid within the trap if I squeeze it gently.

Things my slow VFT has completely digested during this same time period:

* a complete medium-sized fly that it caught on its own.

--
So, okay, it clearly likes sunflower seeds a lot! It remains to be tested whether or not this is actually a healthy, balanced diet for a VFT. At the moment I don't really have the duplicate VFT plants to do this test.

--
As for my color-changing drosera: feeding it a fish food pellet *does* change it (or at least its new leaves) back from unhealthy-looking red to happy-looking green. I haven't re-tried the cricket powder.
 
spiffyzha said:
So, okay, it clearly likes sunflower seeds a lot! It remains to be tested whether or not this is actually a healthy, balanced diet for a VFT. At the moment I don't really have the duplicate VFT plants to do this test.
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I'm not confident in that conclusion. Often enough, I've given my VFTs "strange" food, and the traps remain closed for a long time and eventually die. It's possible that the digestion process has done something that damaged the trap enough that it can't open again. Or that the seed releases digestion products very slowly, enough to trigger the "stay closed" response, but that staying in digestive mode for a long time eventually harms the trap. My understanding is that a trap is usually good for three or four digestions and then stops working; it may be that something that keeps it digesting for as long as three or four normal digestions is enough to do it in.
 
BunsenH said:
I'm not confident in that conclusion. Often enough, I've given my VFTs "strange" food, and the traps remain closed for a long time and eventually die. It's possible that the digestion process has done something that damaged the trap enough that it can't open again. Or that the seed releases digestion products very slowly, enough to trigger the "stay closed" response, but that staying in digestive mode for a long time eventually harms the trap. My understanding is that a trap is usually good for three or four digestions and then stops working; it may be that something that keeps it digesting for as long as three or four normal digestions is enough to do it in.
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Hm. That's an interesting take, that the trap might be damaged somehow. It doesn't *look* damaged -- it just looks like it's digesting. And I can't easily imagine a mechanism to damage it in a way that reproduces this behavior. But, obviously, my lack of imagination certainly doesn't mean that this isn't what's happening!

If it's not damaged, I would naively expect that if the object inside is still releasing enough of whatever it is to signal the trap to stay closed, then the plant is almost certainly still absorbing nutrients from it. That seems like a good thing! If it can get several bugs' worth of food out of a single feeding, then that's about as efficient a food source as I could ever hope for.

I'll probably try feeding sunflower seeds to a few different traps soon, just to see if this result is repeatable. Though, if it is repeatable, that still doesn't really distinguish between the two hypotheses, I think. Only if the results vary hugely between different traps/feedings would it be possible to conclude that the trap not re-opening must be due to damage.
 
spiffyzha said:
If it's not damaged, I would naively expect that if the object inside is still releasing enough of whatever it is to signal the trap to stay closed, then the plant is almost certainly still absorbing nutrients from it. That seems like a good thing! If it can get several bugs' worth of food out of a single feeding, then that's about as efficient a food source as I could ever hope for.
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That's been my assumption when I've fed them with things like tofu and textured vegetable protein — if nothing else, these should be very nutritious protein sources, and have some potassium and phosphorus as well. And if the plant is getting enough nutrition from one trap to grow several more, and is getting lots of light energy, that's to the good. I'm just not sure about how well the trap is able to digest something like a solid sunflower seed... notwithstanding the slow extraction of nutrients, enough to keep the trap closed, if the total benefit from that seed is enough to counter the loss of the trap. The seed's nutrients are locked up in the tissue in a cellulose structure with rather a lot of oil. I'm curious about how much of those nutrients get into the plant, and am looking forward to hearing about what's left behind when the trap has finished its work.
 
The trap that I fed with tofu wrapped in onion membrane (raw, dried and rehydrated) has a brown spot and presumably is dying, on the second feeding. Perhaps if the membrane was either boiled or frozen, to disrupt the cell walls...

I'm still wondering what the difference is between an insect and the alternate foods, in terms of nutritional composition and structure. For an insect, after the chitinase weakens the exoskeleton and the enzymes get in, they're immediately in contact with the insect's "blood" / circulatory fluid / hemolymph. They get right to work on the proteins in the fluid and on the muscle tissue. The muscle is porous, for the fluid to flow through; it may even be that the fluid pumps enzymes into the muscles before the insect dies. For dried-out dead insects (or FDBW), the food absorbs the digestive fluid to at least partially rehydrate it, which again would distribute enzymes through it.

The alternate foods that I've been trying have been much more solid, less porous. Even the bits of sun-dried earthworm have flattened out and compacted. Perhaps I need to try finely-powdered protein sources which are made to stick together just well enough to let the trap seal around them. Perhaps moistened with a bit of alcohol to make pellets, then the alcohol allowed to evaporate. Or water, if it can be evaporated away quickly enough that the pellet doesn't get affected by bacteria.
 
Finely-powdered textured vegetable protein, wet with rubbing alcohol, and allowed to dry, adheres poorly. Little pellets disintegrate when touched gently. After several tries, I was able to transfer a dry pellet to a VFT trap, but it started crumbling as I got the trap closing. By the time the trap was fully closed after the requisite multiple touches and massaging, the TVP powder had spread out a bit from where the pellet was initially placed. "Candling" the trap let me see how much.

After being moistened with water and dried, the TVP powder formed a fairly sturdy pellet. I fed another trap with a small amount of TVP powder moistened with just enough water to get it to hold together, and "candling" the trap showed that the TVP was still close together after the manipulations needed to close the trap. Those traps went quickly into their "digesting" configurations, so I seem to have the plants' attention, so to speak.

My tofu-fed plant has been putting out quite small traps since I repotted it, but it's beginning to get a few slightly-larger ones. I've been feeding it with bits of pest insects that I've stored in my freezer, but soon I'll try it on powdered dried tofu.
 
I am interested in trying osmocote for my pitcher plants. Do you use just the regular or the plus for feeding?
 
So this is super embarrassing to admit: I was looking over the outer package thingy again to check on the type of osmocote pellet ... and apparently I've been using nutricote all along.

I am not quite sure how my brain did this thing. I remember reading this article at some point, so I probably chose this intentionally. I apparently got the 180 day release 16-10-10 version from here.

Now that I've had my nepenthes eating it for a few months, I can assert that it works fairly well. It doesn't burn most pitchers, even the tiny ones -- with the one exception I've found being N. mikei -- and I can also see the improved growth (in comparison with making them catch their own food) in a few of my plants that must have just been very hungry before. It does seem to turn some of the pitchers more green than I'd aesthetically prefer them to be though, so if I ever manage to use these pellets up I might try some with a lower 'N' content next.
 
I've been thinking some more about what's different between a VFT's normal food (i.e. live bugs) and anything else.

Ordinarily, a bug is trapped, then immersed in the digestive fluid, which contains a bunch of enzymes. The chitinase starts making the bug's exoskeleton porous, to let other enzymes in and to let the digested products out. Enzymes might also enter the bug's body via its respiratory system (via the spiracles), or other gaps or pores. The bug is still alive for a while. It seems to me that some of the enzymes would be carried around the bug's body, circulating in its "blood" (hemolymph) throughout the tissues, until the circulatory system shuts down. This would mean that all of the bug's tissues would be exposed to the enzymes rather quickly, right from the start, through whatever pores or channels usually let the cells have access to oxygen and nutrients.

Contrast with putting a lump of non-living food into a trap. The enzymes would only be in contact with the surface of the food. It would take a lot longer for the enzymes to work their way through the food, perhaps through cracks or pores. Finishing the job will take a lot longer, and the trap will be in contact with the food all that time. In the case of the bug, of course, all of the digestion is separated from the trap's surface by the exoskeleton.

In the case of a dead bug, that circulation of the enzymes wouldn't happen, of course. But if the bug is dried out, then the tissues would be rehydrated by the digestive fluid, with the enzymes again soaking in through the pores.

If this is all true, then there are a few things I can try to do to enhance the digestion of non-bug food. First, I should be avoiding solid lumps. Fine powder or paste would be better. Second, dried food would be better, so that the enzyme-containing liquid would soak in. Semi-liquids would also be possible, if the enzymes are able to diffuse into them.

I've started experimenting with finely-powdered textured vegetable protein, with just enough moisture added to stick together as porous lumps. And with silken tofu forced through a series of needles to give a fairly homogeneous paste. So far, the results are fairly promising, but with less light, it's not a good time of year to be expecting a lot of growth.
 
spiffyzha said:
So this is super embarrassing to admit: I was looking over the outer package thingy again to check on the type of osmocote pellet ... and apparently I've been using nutricote all along.

I am not quite sure how my brain did this thing. I remember reading this article at some point, so I probably chose this intentionally. I apparently got the 180 day release 16-10-10 version from here.

Now that I've had my nepenthes eating it for a few months, I can assert that it works fairly well. It doesn't burn most pitchers, even the tiny ones -- with the one exception I've found being N. mikei -- and I can also see the improved growth (in comparison with making them catch their own food) in a few of my plants that must have just been very hungry before. It does seem to turn some of the pitchers more green than I'd aesthetically prefer them to be though, so if I ever manage to use these pellets up I might try some with a lower 'N' content next.
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A slight update, for science! I've found more tiny Nepenthes pitchers that can be burned with nutricote. In addition to N. mikei, tiny pitchers (think: mildly challenging to fit the pellet in) on N. tobaica and N. adrianii will also immediately shrivel up and die when given a nutricote pellet. These plants will eventually make much bigger pitchers, so I suppose I can try again at that point. I know N. mikei and N. tobaica (not sure about N. adrianii) are known for putting out a lot of pitchers, so maybe it makes sense that each individual pitcher wouldn't be able to "eat" as much food.

Similarly sized super tiny pitchers on N. glabrata, N. hamata, N. murudensis/tentaculata, N. spectabilis x aristolochioides, N. vieillardii, and N. 'St Gaya' all do just fine when forced to eat a whole nutricote pellet.
 
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