FlytrapCare Carnivorous Plant Forums

Before I get to the article-stuff, a quick intro - all plants need nitrogen in order to make amino acids and proteins so that they can survive and grow. Flytraps evolved to feed on insects because, in nature, they live in nitrogen-poor soil. Since they require nitrogen in order to thrive, they either needed to evolve in a way to obtain this nitrogen, or perish. Insects contain moderate levels of nitrogen, which fills this need. This is a primary reason that carnivorous plants like the flytrap exist today.

It's known that flytraps evolved from carnivorous sundews; sundews (and I think this part is still theory) may have evolved from non-carnivorous sundew-like plants prior to the depletion of nitrogen in their environment's soil. The Venus Flytrap's evolution was the product of a "Hobson's choice" in which plants that did not evolve nutrient-capturing abilities in nitrogen and phosphorus-poor environments would not have survived. (citation).


I. Flytrap size and Nitrogen-feeding

In their native habitat, the flytrap diet is 33% ants, 30% spiders, 10% beetles, and 10% grasshoppers, with fewer than 5% flying insects (citation). All of these insects contain various amounts of nitrogen in their bodies, which the flytrap consumes in order to generate amino acids, proteins, and DNA (all of which affect plant mass). According to this paper, feeding on insects' nitrogen content does result in larger traps, as would be expected; 20% to 54% of a flytrap's total internal nitrogen levels come from insects. Therefore, a group of flytraps that never feed on insects will be smaller than a group of flytraps that feed on insects.


II. Insects and Nitrogen

Insects with higher nitrogen content are theoretically the "best" to manually feed an indoor flytrap. According to this paper, predaceous (predatory/carnivorous) insects have an average of 15% more nitrogen content than herbivorous insects. Spiders, predatory beetles (e.g. ladybugs), wasps, and other carnivorous flying insects have the highest nitrogen values of all insects, while insects like moths and butterflies have the lowest nitrogen value. The paper also suggested that although no data exists, there is reason to believe that collembola (springtails) may also have high nitrogen content. Since they are readily available in pet stores, I'll also note that insects such as crickets have a moderate nitrogen content as well. While not among the highest in nitrogen content, they fall well above that of moths and butterflies.


III. Adverse affect of flowering

You may have heard us mention on the forum that flytraps are "set back" from flowering because it takes a lot of energy to do so. If you've ever seen a flytrap flower stalk in comparison with the size of the plant, you can plainly see why it costs them so much energy; the thing is often as massive as the rest of the plant! In a reference to the Roberts and Oosting 1958 flytrap study, the Duke article above mentioned that the reason this setback occurs is because when producing a flower stalk, most of the nitrogen found in the plant's leaves (obtained partially from insect consumption) is removed to support the flower, which adversely affects the overall health of the plant's leaves. This is why traps often look poor during/after flowering, and why flowering often results in a higher level of dying traps. The flytrap is shedding them intentionally; they were "sacrificed" so the plant could pool together the energy required to make the healthiest flower stalk possible.

It follows that the more nitrogen (and other nutrients, including quantity/quality of light it receives daily - it's not all about the nitrogen here) a flytrap has at its disposal, the less of a setback it will suffer when flowering, and the more seed it will be able to produce.

Flowering late in the season or during dormancy can also pose a higher risk - if it's cold enough, the flytrap's flower will all but stop growing, but the process was interrupted and may not complete properly, wasting a lot of energy in the process. Flytraps evolved to flower in Spring because that's when the sun is strong enough and temps are warm enough to support it properly, and because the earlier it sets seed, the better chance the seedlings have of developing enough to survive their first winter.

An unhealthy flytrap (not enough light, or other inadequate conditions) will not only sacrifice its leaves to transfer nitrogen to produce a flower stalk, but it may do so to the point of being unable to recover from the flowering, and could die after setting seed. At the very least, it will not grow as well afterward, usually very noticeably so, for months or an entire season.

This is why there are so many flytrap care sheets out there that instruct novice growers to cut off the flower stalks - it decreases the likelihood of death resulting from flowering because 1) novices often grow flytraps in far-less-than-ideal conditions, and 2) flytraps in cultivation often have internal clocks that are "off" due to shipping/sitting on shelves that they flower at inopportune times, like during the end of the season (e.g. late October/early November) or during dormancy.


IV. Best insects to feed your flytrap due to their higher nitrogen content:
per scientific studies conducted primarily at Arizona State University
Spiders
Wasps (have been known to occasionally damage traps)
Any other predaceous insect (insects that eat other insects)
Mealworms
Crickets


V. Insects to not feed your flytrap

Known to blacken or kill individual traps:
Ants *
Hard-shelled super-chitinous beetles (e.g. pill bugs, stink bugs; and snapper bugs, which are the black beetles that "snap/click" their neck to flip over if stuck upside down) *
Lightning bugs

* Ants and other chitinous bugs may only be intermittently problematic, or are only problematic for some flytraps and not others. Chitinous insects should not automatically be discounted as good food source, as chitin contains nitrogen (mealworms are a good example of this; they are chitinous but make a good food source). Your mileage may vary.

Can, and often do, chew their way out of a trap:
Caterpillars
Earwigs
Snails/slugs
Wasps (in my experience wasps usually don't escape)

"Worst" insects to feed due to low nitrogen content - doesn't give the plants much in the way of nutrients compared to other bugs, but still provide the plant with some nitrogen; also, the ones listed below often kill traps due to allowing bacteria to enter the trap because the large wings generally protrude from the trap, preventing the trap from sealing properly:
Moths
Butterflies

Very interesting! I learned something new about venus flytraps just about now




Thanks for sharing!

niice thanks for the info what about when the stock grows traps off it?

Thanks for the write-up about the interesting research you came across!

This is why there are so many flytrap care sheets out there that instruct novice growers to cut off the flower stalks - it decreases the likelihood of death resulting from flowering because novices often grow flytraps in far-less-than-ideal conditions.

I'm lucky, then, that for the five years I had my flytraps outside in a pot on my porch and didn't cut their flower stalks, that they thrived.

(Of course, bugs were plentiful, so it's fortunate...)

I also wonder about crustaceans. Roly-polies (isopods) are crustaceans, probably one of the only terrestrial crustaceans. And they're easy to find under pots. What about their nitrogen content?

Edit: Reading the article, realized it was from Duke! Haha! That's awesome.

Can't believe I miss this......very well written!

Thanks Veronis.

Wow, great info! Thanks for posting it, Veronis. So how about daddy-long-legs? (Not a true spider, but also an arachnid.) When I checked on my plants this morning, one of the traps on my Jaws plant had gone shut overnight, but there were several long spindly legs sticking out of it everywhere! I wish they would eat *all* of them. I know it's totally irrational, but those things have always given me the creeps. Probably from when I was about three years old and my sister made me watch Jonny Quest cartoons with her. There was one episode where the villain's robot was shaped like a big black ball and it would sprout multiple legs and walk around at night just like a daddy-long-legs with one big red blinking eye. Funny how childhood fears like that can stick with you your entire life!

ambkosh8465 wrote:Wow, great info! Thanks for posting it, Veronis. So how about daddy-long-legs? (Not a true spider, but also an arachnid.) When I checked on my plants this morning, one of the traps on my Jaws plant had gone shut overnight, but there were several long spindly legs sticking out of it everywhere! I wish they would eat *all* of them. I know it's totally irrational, but those things have always given me the creeps. Probably from when I was about three years old and my sister made me watch Jonny Quest cartoons with her. There was one episode where the villain's robot was shaped like a big black ball and it would sprout multiple legs and walk around at night just like a daddy-long-legs with one big red blinking eye. Funny how childhood fears like that can stick with you your entire life!

I'm guessing that since they make webs and catch bugs, presumably for eating, they'll have similarly higher levels than non-predacious insects.

Although they're so tiny, most of their size seems to come from their legs and not their actual body. I personally stick with spiders I find building webs across my plants.

And whatever you do, don't go for wolf spiders. I've seen some of them grow up to be three inches long, and fit neatly into my palm. They go after lots of pests without building webs over your traps, and it's not worth the shock of going after a tiny one only to see that it's running from a much larger one. Not to mention that they're actually quite friendly-- or at least chill-- with regards to people, so they don't induce that spazz reaction in me that I get when I see a black widow. You can usually scoop them up carefully in your hands, and they'll just sit on your arm like it's nothing.

Wow, you're nuts, Jackal! Catching spiders with your bare hands?! Braver than me, bud!

The kind of daddy-long-legs I see most often don't ever spin webs. They just creep around all over plants, usually hanging on or underneath the leaves, I guess waiting for something smaller to crawl by that they can eat. I googled it just now and found there are some *true* spiders that also have the common name daddy-long-legs because they have really long legs too, but all the pictures showed those poised in webs. I doubt that kind would ever leave home looking for food like my creepers do.

In any case, I had to water my VFTs this afternoon because it's been so sunny and windy here today, and I was horrified when I saw that the long spindly legs that are sticking out of the trap on my Jaws plant are *still* twitching! It must have caught it sometime last night so it's been in there for several hours, but it's still not dead yet. That's a pretty horrible, long, slow way to die! I know it's just part of the food chain, so maybe I'm just too much of a wimp to be growing these monsters... Nah, it's just revenge for what Jonny Quest did to me as a kid!

Veronis wrote:In their native habitat, the flytrap diet is 33% ants, 30% spiders, 10% beetles, and 10% grasshoppers, with fewer than 5% flying insects (citation).

That's really surprising to hear, especially since most of the care sheets usually tell you that feeding them ants is a waste of time because of their hard exoskeleton that can't be digested. So how did they ever come up with the name Venus FLY trap, if they hardly ever eat any bugs that fly?! Hmm, maybe we should start calling them VATs - Venus Ant Traps!

ambkosh8465 wrote:Wow, you're nuts, Jackal! Catching spiders with your bare hands?! Braver than me, bud!

The kind of daddy-long-legs I see most often don't ever spin webs. They just creep around all over plants, usually hanging on or underneath the leaves, I guess waiting for something smaller to crawl by that they can eat. I googled it just now and found there are some *true* spiders that also have the common name daddy-long-legs because they have really long legs too, but all the pictures showed those poised in webs. I doubt that kind would ever leave home looking for food like my creepers do.

In any case, I had to water my VFTs this afternoon because it's been so sunny and windy here today, and I was horrified when I saw that the long spindly legs that are sticking out of the trap on my Jaws plant are *still* twitching! It must have caught it sometime last night so it's been in there for several hours, but it's still not dead yet. That's a pretty horrible, long, slow way to die! I know it's just part of the food chain, so maybe I'm just too much of a wimp to be growing these monsters... Nah, it's just revenge for what Jonny Quest did to me as a kid!

I grew up in a really rural area with farms every couple miles away from each other, dealing with snakes and spiders there was a kind of ordinary thing. The farm I hung out at taught a lot about "being like a tree"-- if you act like a tree, animals will treat you like one. Let a wild snake chill on your arm, and it's happy with the body heat and lack of threat. Let a wolf spider chill on your arm, and it'll act as though it's just on a tree limb-- no reason to bite you. Of course, if you grabbed it by the leg, it'd bite-- but if you kind of sort of just scoop it up, it won't mind too much. I've only ever done this with wolf spiders, though, and only the big ones have painful bites (but they're not venomous.) It is kind of scary, though, because spiders are scary-looking, but that's why I do it-- because if I continue to fear them, that just means I continue to misunderstand them, even when I know intellectually that they're not out to get me. I consider it a valuable lesson to myself.

The daddy long-legs I'm familiar with ARE venomous, but they're not strong enough to break human skin to inject it. So they have venom, but they're harmless to humans because our skin's too tough for them to handle But it's good for catching insects. They tend to hang out in my garage.

It might not actually be alive. Some bugs still twitch long after being squashed.

And LOL! Johnny Quest vengeance! Personally, the spider in The Grim Adventures of Billy and Mandy freaked me out more.

GothicJackalPaws wrote:I grew up in a really rural area with farms every couple miles away from each other, dealing with snakes and spiders there was a kind of ordinary thing.

"I don't like spiders and snakes
And that ain't what it takes to love me"
-- Jim Stafford, 1974

GothicJackalPaws wrote:And LOL! Johnny Quest vengeance! Personally, the spider in The Grim Adventures of Billy and Mandy freaked me out more.

Never heard of that one, but I'll be sure to stay away now that you mention it!

ambkosh8465 wrote:So how did they ever come up with the name Venus FLY trap

Here's a page explaining how flytraps got their name


http://www.flytrapcare.com/venus-fly-tr ... ml?start=3

Thanks for the link, pieguy. I hadn't seen that page yet.

Dobbs describes a `Venus's flytrap` as "a kind of Catch Fly sensitive which closes upon anything that touches it.".

Sounds like they were comparing it to another plant I have, Silene regia, or more commonly, Royal Catchfly. There are lots of species of Silene and their common name Catchfly comes from the way the leaves and stems are so sticky that bugs often get stuck to them, kinda like a sundew but without the visible droplets and they don't curl up around the bugs to digest them. I always hate trimming them because I have to wear gloves and even then, everything I cut off always sticks to my gloves just like velcro!

Just a little update - my Jaws plant has just caught *another* daddy-long-legs! It's got two traps with those long spindly legs sticking out everywhere now! Maybe it heard me saying I wished they'd eat *all* of them! Unfortunately, there are still hundreds of those creepy-crawlies all over my entire deck. I probably have enough of them to feed a couple *acres* of flytraps!