VFT overfeeding experiment

[Veronis]

I've always heard it was possible to overfeed a VFT and that it could cause death of some or all traps, smaller traps, and slowed or halted growth; I decided to do a small experiment based on these claims out of curiosity.

The short result: Yes, the claims are true.

The long result:

I stopped feeding my VFT for almost three weeks and then stuffed small crickets in 5 of 7 traps on one, and 8 of 10 on the other (I didn't want to utterly kill my VFT's).

• It continued growing while it digested, and over the course of the next week instead of growing faster as would be expected after feeding, it grew slower.
• Two of the new traps are the same size as all the others; one of the traps is about 2/3 the size it should be. These VFT's have never made a "small" trap before.
• One trap died that really should not have. It was a new trap and no part of the insect was sticking out.
• All the traps are open now, and have been for about two weeks while I observed.
• Their growth WAS stunted, pretty badly. The VFT's are no longer growing quickly; they are growing slowly. If I see two flower stalks next week or something I'm going to laugh.
• After two weeks they still have not recovered - they are both growing much more slowly than they used to; no environmental changes (light, water, etc.) were made since before feeding.

I probably would have had different (worse) results if I'd have used bigger food (the crickets were small), or if I'd stuffed all the traps instead of leaving two open; additionally, my fly trap is under very strong lighting and was growing vigorously at the time so it was able to digest faster.

Attachments:
Top left - 3 days before overfeeding (the closed one was triggered by my finger while taking macros)
Top right and bottom left - today

 

[petmantis]

A sunny day of Summer `09, I woke up to find every single trap closed on an earwig. A few of the traps (the nicest-colored ones, ironically) had no earwig in them though, since the earwigs chewed little holes in the traps to escape.

The plant completely stopped growing for about a month, and had lost pretty much all its leaves except for little 'phyllodia' (short ugly leaf with tiny, undeveloped trap) that remained there, looking a sickly pale green.

That plant is no longer with me...spray grow area every week with insecticide, as carefully as possible (of course to make sure the plants don't get any on them)

 

[Lil Stinkpot]

I never knew that!


Come spring I intend to continue my earlier experiment with Boga Burgers, beans and nuts. It was a success last time, I wish to gather more data.

 

[Not a Number]

You should read Darwin's feeding experiments with Dionaea muscipula in his Insectivorous Plants (1875):

http://darwin-online.org.uk/content/frameset?viewtype=side&itemID=F1217&pageseq=309

The key is "nitrogenous organic bodies which are at all damp".

But don't let that stop your experiments. You also learn by doing.

 

[Alexis]

The thing is, your hypothesis is that feeding x number of insects to a VFT will result in faster growth and larger traps.

Your conclusion is that growth slows and newer traps are smaller.

But you need to look at other aspects - is the plant putting its energy into growing new roots? Is the rhizome enlarging out of view?

I suspect the plant will be growing roots and another growth point will appear in a few weeks. The rhizome is also an energy store especially useful for getting the plant through winter. Does a fed plant have less chance of running into problems in dormancy? Does it emerge from dormancy quicker? Does it flower more?

All I'm saying is that the plant will have benefited from the extra nitrogen, but because it hasn't been demonstrated visually in immediate growth doesn't mean there is such a thing as 'overfeeding'.

 

[Veronis]

The thing is, your hypothesis is that feeding x number of insects to a VFT will result in faster growth and larger traps.

Your conclusion is that growth slows and newer traps are smaller.

But you need to look at other aspects - is the plant putting its energy into growing new roots? Is the rhizome enlarging out of view?

I suspect the plant will be growing roots and another growth point will appear in a few weeks. The rhizome is also an energy store especially useful for getting the plant through winter. Does a fed plant have less chance of running into problems in dormancy? Does it emerge from dormancy quicker? Does it flower more?

All I'm saying is that the plant will have benefited from the extra nitrogen, but because it hasn't been demonstrated visually in immediate growth doesn't mean there is such a thing as 'overfeeding'.

My hypothesis was actually that it would slow down the growth, because these are the results that Barry Rice had - he stuffed every trap, and all of the traps died http://www.sarracenia.com/faq/faq2540.html. They changed color, grew poorly, and he didn't note that they did anything "noteworthy" afterward like divide - I think he would have said something.

Petmantis, above, also shared similar results. Maybe it's kind of like overfertilizing a nep, which can kill them.

I definitely hear you regarding the notion that it may be expanding roots/rhizome. It did slow down growth, but as to whether the VFT is "not feeling so good" or "working hard under the surface", I can't say. Based on the current information available and previous experiments, both on purpose and accidental, I think I probably just plain overfed it. It would be nice if overfeeding a flytrap often caused it to divide - I think people would use it as a means of propagation if that were the case.

I can't really do an experiment on such a scale that would show conclusively if they do better in dormancy or anything like that. I just don't have that many VFT's.

You should read Darwin's feeding experiments with Dionaea muscipula in his Insectivorous Plants (1875):

http://darwin-online.org.uk/content/frameset?viewtype=side&itemID=F1217&pageseq=309

The key is "nitrogenous organic bodies which are at all damp".

Thanks for the link NON - I didn't see anything on overfeeding though, and I went through several pages - maybe I skimmed past it? Or were you just talking about the fact that he did experiments in general?

 

[Lil Stinkpot]

You can die by drinking too much water.

 

[scottychaos]

If your plants have been outdoors all season, they are probably trying to go dormant now..(and for some reason you arent letting them)..that could account for slowed growth..
might have nothing to do with feeding..

Scot

 

[Veronis]

If your plants have been outdoors all season, they are probably trying to go dormant now..(and for some reason you arent letting them)..that could account for slowed growth..
might have nothing to do with feeding..

Scot

No, these are TC plants that have been under fluorescents for many many moons. They'll go outside next Spring and start their regular dormancy. They're definitely not trying to go dormant.

 

[Not a Number]

Thanks for the link NON - I didn't see anything on overfeeding though, and I went through several pages - maybe I skimmed past it? Or were you just talking about the fact that he did experiments in general?

That was aimed more towards Lil Stinkpot but yes, he conducted many feeding experiments on many species in general.

As far as nitrogen utilization goes:

Quantification of insect nitrogen utilization by the venus fly trap Dionaea muscipula catching prey with highly variable isotope signatures
W. Schulze, E.D. Schulze, I. Schulze and R. Oren
Journal of Experimental Botany, Volume 52, Number 358
http://jxb.oxfordjournals.org/cgi/content/full/52/358/1041

Using the slopes in Fig. 5 as an indication for the partitioning of nitrogen between source and sink organs, it was estimated that about 95% (slope in Fig. 5A) of the nitrogen in young leaves, 54% (Fig. 4B) of nitrogen in storage organs, 46% (Fig. 5C) of nitrogen in roots, and 76% (Fig. 5D, E) of the nitrogen in flowers originated from the trapping source leaf in plants growing at site I and site II. Following equation 1 and taking the differences in dry weight composition (Table 2) into account, up to 75% of the nitrogen in young seedlings originates from insects at sites I and II. In large capturing plants the proportion of insect nitrogen increases to about 80% due to the higher proportion of capturing leaf biomass and lower proportion of root biomass. In large flowering plants without leaves, the fraction of insect nitrogen decreases to 68%, due to an increased fraction of root biomass and decrease in that of capturing leaf biomass.

 

[Lil Stinkpot]

I should wait until I get home to try to read it all. I'm at work now; my mind's still all mush.

 

[scottychaos]

No, these are TC plants that have been under fluorescents for many many moons. They'll go outside next Spring and start their regular dormancy. They're definitely not trying to go dormant.

how many moons are we talking about?
if its more than 12 moons, they yes, they could be trying to go dormant..even though they have always lived under grow lights..
or if its too many moons, they might actually be starting to weaken and die from lack of rest..
which could also skew your test results..

im just saying..
these probably arent the best plants on which to conduct such an experiment..
because they have never experienced a "normal" growth cycle..and you have no way of knowing how they are *supposed* to be reacting right now..

and this is definitely the worst possible time of year to conduct such an experiement..you have too many variables..too many other things that could be causing your plants to slow down, apart from feeding..

you need healthy adult plants, that have been through at least 3 or 4 dormancy cycles..in July..when you know they will be only reacting to food and no other variables..

otherwise its just really not a valid test..sorry..

Scot