Truly self-sustaining systems are definitely possible. Those little glass globes I mentioned are truly self-sustaining. The question is how complicated a system is feasible, and how many variables I can toss into the equation. Probably, it's not really possible at the level of complexity I'm interested in (at least, not for someone like me; rocket-scientist-types might be able to pull it off), but it's still fun to experiment with.

With the plant/aphid/ladybird mini-system, what would regulate the ladybirds is the same thing that regulates them in the real world ... starvation. The question is whether I can set up a large enough, complex enough system where most of the ladybirds starve periodically, allowing the aphid population to rebound, but still supporting enough ladybirds that their population would also eventually rebound, etc. I have considered introducing a certain species of jumping spider, or some sundews, or something along those lines, which would help control the population of both the ladybirds and the aphids, but then, that's added complexity which must also be considered ... can you see why this idea fascinates me?

For the record, any experiments I would try that involved any reptiles or other vertebrates (and I think reptiles are the only group that's even remotely feasible), are a long way down the line, after I have a lot of hands-on experience with this concept ... and I may figure out long before then that it just isn't feasible.

The biggest problem with any animal life -- vertebrate or invert -- is actually oxygen. This is the problem they ran into in the original Biosphere 2 experiment. Even on a very large scale, oxygen levels (and more significantly, CO2 levels) tend to fluctuate too much over the short term to support any animal life dependably. Insects are much more tolerant of such fluctuations; and among vertebrates, reptiles are the most tolerant of this problem (which is why I still consider one of them a possibility), but it's iffy.

I suppose it's not theoretically impossible, but I wouldn't bet on it in practical application. One of the things that helps critters balance out in nature, is having somewhere else to go. When the population of aphids (and other prey food) drops, ladybird beetles fly off to some other location with better prospects before they've munched down every aphid in their old territory. With a limited area in which to hunt and survive, I think your beetles would eat every single aphid before they themselves starved.
Being the soft-hearted sort, I'd release the beetles rather than let that happen...but experimenting is a great way to learn. It's surely worth a try!

Hi Rainbird,

In my view, the globes are not truly self sustaining -- but I think that is a matter of my personal view of "self sustaining". To be so would require that the shrimp enclosed therein would replace themselves [reproduce] and stable populations [shrimp and plant life] would exist and remain in balance. This does not happen within the globes though true, if properly situated, they will go on for some time.

I also must concur with Jen about what would likely be the outcome the ladybugs and aphids. It is unlikely, I think, that you would get a simple decrease in the ladybugs by starvation. Instead, a population crash in which all the ladybugs die out is more likely. Btw while starvation is a control in nature -- it is only one of the controls. Predation, disease, and -- as Jen mentioned -- the ability to relocate to find new habitats are all parts of the picture.

Finding a plant that the aphids will feed on and which will go the distance in an enclose viv could be a bit of a challenge. I don't know if aphids will feed on ferns -- don't recall ever finding any on them. If they will, then at least you know from experience that ferns will last a while. Did you just use window lighting to grow the fern? Lighting could well be the other big challenge for you. The only plants that come to mind as "aphid food" to me [like radishes] all require quite a bit more light than ferns. But in an enclosed viv that much light could cause overheating. You'll also need to consider doing something for air circulation, I imagine. Many plants don't seem to do very well in highly stagnant enviroments. [Molds tend to run rampant.]

: )

What you may consider doing, is using several spheres. I know this isnt what you had in mind, but if it were me, and I were trying this, if I were to fail 4 or 5 times, I would probably just say "forget it" and I would put it on the shelf.

But if you were to set up a sphere that had a good plant population for oxygen, you could then use a small computer fan to help cirulate that air to a different chamber, where you may have something else, which leads to a different chamber with yet sometime else. Basically setting up 3 biospheres, all connected, but still seperated so that it makes it easier (at least at first) to figure out where problems on a bigger bioshpere may come up.

It sounds like a very interestiing project you are thinking about. I am sure a lot of people would enjoy hearing any progress you make on it.

I think your idea is very much possible, it's just a matter of finding the right balance of microfauna. Have you though about insects such as millipedes and centipedes. No I'm not talking about the big ugly ones people keep as pets, I'm talk about small native millipedes and centipedes which will reproduce in the tank. I'm not sure what you would use to control their population. But if you want to keep reptiles or amphibians you will need ventilation.

I hope to start keeping PDFs these summer in a 90 gal viv. The viv (which houses a mountain horned lizard right now) has been setup for two years and is filled with mircofauna. springtail, sowbugs, worms, fungi, and bacteria brake down waste which feed the plants. If I get the frogs in there (the lizard will be move to a new home) they will feed off the springtail and sowbugs. The only maintenance I would do is misting and keeping the glass clean. I believe a setup of this sort, with the exception of a vent or two, could be closed.

Chris

Chris- I'm working towards setting up for PDFs this summer also. There are a few invertebrates in my tank, but I'm planning to offer supplemental food.
A couple questions: Presumably you have a water feature of some sort. How will you keep the water clean without interfering? Will you have filtering waterplants? I'd be interested to hear anything you have to offer about it.
Second Q is a little off topic, but I'll squeeze it in. Where do you think you'll be getting your frogs? I know people have had good luck with plants from Black Jungle, and that's primarily where I've been looking at frogs. Since I've never ordered live animals I'm pretty ignorant about which options are good ones. Any advice?
Rainbird- I hope you'll keep us posted on your project when you get going. (Pictures are great, too!) -- Jen

Yes, I currently do and will continue to use water plants as a filter, there is a small pump in the water for the falls but no filter. The water section is 1/3 of the tank 8" deep, the original plan was to keep fish in there, after two years I still don't have any fish LOL. I have recently noticed a small snail population in the water, and I plan on adding something like crayfish or freshwater crabs, (or maybe I'll get those fish I wanted, something that eats snails would be nice).

I have not decided on a source for the frogs yet, I've order plants from Black Jungle with great results, but have heard mixed opinion about the frogs they sell. I'm trying to find the closes source possible so I can see the frogs before I buy them, possibly travailing out of state this summer.

Chris

Thanks for the information. I hope you don't mind one more question about the substrate for the your water plants. With no fish to offer fert, do you have soil held down by gravel, or what?

Interesting thread!
btw Paul, I have definitely found aphids on ferns before. I just scraped some off one this afternoon, actually!
catalina

Hi catalina -- really? on ferns? Well if that proves to be sufficient then at least that may make the selection of plants easier for Rainbird. I just remember ... once upon a time in a galaxy far, far away ... when my dad had a garden that the radish plants were always heavily aphid infested. Generally the other veggies were fine.

Ah Jen and Chris -- you're making me envious with your talk of PDF's!!! Definitely on my "someday" list!

Btw Chris, are there any particular plants that you have found to be more effective water filterers?

: )

Hi
This is a most interesting thread to me as I've been experimenting along these lines for most of my life. All have ended in intervention on my part.From adding water to reduction of species to feeding.
The most successful have been aquatic with algae and protozoans. Not much to look at lol.
I think the error in logic of the microsm is that it doesn't exist.No matter how large or small it is still
attached to and interacting with the macrosm. It is impossible to stop outside influences on your tiny planet.
Here is a way to think about it.
What temps can I easily maintain.?
Constant or seasonal?
Light and water,humidity gas exchange.
How large will it be?
What things do I absolutly want?
What are complimentary to these needs?
Naturally the higher the life forms the more complex the system becomes.
You have some interesting ideas.Start simple and expand
on the principle.Naturally,systems of either plant or animal are much easier.But rather dull.
Hope you have half as much fun with it as I have.
Gary

Yep, Paul! Aphids all right.
I don't know if this is normal, though. These seem to be oddly persistent critters. They love the new fiddleheads and have been munching on them before they can unfurl all the way. I douse the plant in dish soap mixture every couple of days but they always come back. One day though, I'll win the battle!
dumb question: what's a PDF?
catalina

I just use gravel (and whatever soil Monty has kicked into the water). Sense I don't keep any aquatic animals I don't worry about the water quality too much, as long as it is safe for Monty to drink. Right now the only plants I have in the water are some java fern and a philodendron vine growing into the water. I will be putting more thought in to the setup when it gets a make over this summer, but for now it works.

PDF's = poison dart frogs

Chris

Wow. A lot of interesting responses, both pro and con. It seems I'm not the only person intrigued with this idea -- at least in theory.

Paul -- I didn't realize the shrimp in the water globes didn't reproduce. I think we do have the same definition of 'self-sustaining' and I agree with you that, if everything in the globe eventually dies off, then it isn't a truly self-sustaining system.

Paul & Jen, good point about the ladybirds and 'starvation control', and I was just getting a bit discouraged, when I read RT's (in FL) posting. I don't think setting up multiple domes would help O2 & CO2 levels -- the problem is short-term spikes (of a few hours or days) in CO2 levels over the entire system, no matter how large it is. However, I do think the idea might help with the starvation problem. Having 3 domes connected with narrow, winding passages would tend (I think) to keep insects in their respective domes, at least as long as they're content. As populations are waning in one dome, they could be waxing in another. I don't know if it solves the starvation/extinction problem, but I'm going to give it some serious thought.

Yes, I'm definitely considering millipedes and many other non-insect arthropods, particularly those that would help with the breakdown of plant & animal waste matter. I've tentatively ruled out centipedes, though, as my understanding is they are voracious predators, and in a small closed system like this, I really need to limit the number of predators.

I had a small personal fan set up in my fern terrarium, set on a timer, to circulate air. I would have something similar in any future enclosed system I set up. The fern terrarium was lit with fairly strong fluorescent lighting, also on a timer.

Catalina, what kind of ferns do you have aphids on? more importantly, what kind of aphids? I've done a bit of research on aphids, and one of the problems I've run into is that there are actually hundreds or even thousands of different species, and most of them can only feed on a single plant species, or at most 3-4 species. So the challenge becomes not only to find a hardy plant species that will support aphids, but then to find the right kind of aphids to feed on the plant. It might sound silly, but is there any chance you could mail me a few of your fern aphids? -- actually, scratch that idea; I see you're in Canada, and there's probably all kinds of laws against intentionally sending insect pests across national boundaries. BTW Catalina, I'm glad you asked about PDFs; I didn't know either.

One plant I've been considering is marigold. While I'd prefer perennials, marigolds are dependable self-seeding annuals, and in my area, I've had success with getting them infested with aphids. Paul suggested radishes ... does anyone know offhand how large radishes get when they go to seed? and do they self-seed dependably? Actually, now that I'm thinking about it, there are probably several vegetable garden possibilities for this.

In my garden, in full sun, radishes get about 3'tall before they seed out. They set seed reliably, but there are many natural pollinators out there. I have no idea whether they're good at self-pollinating, or whether you'd need to include a critter to do the job.
It sounds like a very interesting project!

3 foot tall radish plants?! eek! [Course the fact that I never have liked the taste of radishes adds to the 'horror'.]

Rainbird, are marigolds selfpollinating? They do seem to be rather susceptible to fungal diseases so I imagine the air circulation would have to be REALLY good [so may require more than one fan].

AS far as decomposers go, I'd suggest earthworms but they'd never survive. [They require very cool soil temps to survive.]

: )

Paul, marigolds may not work. I didn't know they had fungal problems. But in general, this is the kind of information I need.

So now, it seems I need an aphid-susceptible, durable plant, either perennial or self-pollinating, self-seeding annual, that is fairly fungus-resistant. However, I did discover that many plants will get infected with fungus in a terrarium, but they won't die. They just look a bit unhappy.

As to earthworms, I am planning on using them in larger setting vivariums. I've already kept them succesfully for over a year in a 75-gallon terrarium that doubled last year as a vivarium for a pair of garter snakes I caught in the back yard. This wasn't a sealed environment, but I think the conditions would be similar for worms.

It was fun watching the snakes hunt earthworms. They actually "smell" the ground with their tongues, and when they find a likely spot, they burrow down into the ground, and occasionally come up with a worm. I let the snakes go in the fall, but the earthworms are still thriving.

First, what is PDF? This is a very interesting and ambitious thread. Living in New York, with the Natural History Museum which has that shrimp globe (can you also post a source please) I am aware of what your goal is. But the first thing to notice is that it is an organism that is low down on the scale. The shrimps that is. As some have suggested here, it gets more difficult as the level of complexity of organism rises. As for turtles, no way. I use to raise them along with fish as a kid, and they grow large need tons of space, eat more than you could provide, and dirty the water. My suggestion would be to find a local flora and the 'fauna' will come along, i.e., insects, snails, bugs, soil organisms, worms, ants, bugs, spiders, as I have had this happen with my terrariums. Seems eggs were in the soils and plants I picked. I use a magnifing glass and there are all sorts of things in my terrariums. They are grouped by like area (plants that naturally are grouped) and so far are self sustaining, except I feed the ants, which liked a scale bug that also arrived but it lived off my ferns and that I didn't like. I had to let go of a little spider because he crawled out of another terrarium, hid below the lid of my larger one, and picked off the ants as they came to feed. They are like dogs, they return to the same spot. Except for the scale bugs, there would be no food for them, so I give them yogurt and fresh meat, yes meat, they love chicken and shrimp. But the ants are several generations long now, have had queen ants fly off, (well I had to lift the lid and open the window for that) and they are doing well. As someone previously suggested, territory is a variable. In a larger space the ferns would spread and not be harmed as a species by the scale, the ants would be happy as they cultivate them for their 'juices' (waste products really), but the space was confined, so maintenance was required. I think you can pull it off, if you stick to a replica of one type of environment, where the plants and viable organisms go together and stay low on the scale of complexity with regard to living creatures. My undergraduate background was in biology and I feel that as some have suggested, nature is extremely complex and the best we can do is a pseudo replication with much maintenance. I always have regard for any living thing, plant insect or animal that I take responsibility for as well. But I think if you stay simple it might work. Best

PS I've had fungus, and it did kill my plants. That's why I keep the lid slightly ajar. But mold and fungus are problems in New York apartments, so maybe a 'killer' type. Best of luck, and again if you know of a source for larger globes, I'd really appreciate a source listing.

Sherry, PDF is Poison Dart Frog.

The place to get the enclosed shrimp spheres is ...

www.eco-sphere.com/

While they aren't eternally self-sustaining, apparently, the ecosystems generally survive for years, cycling through several generations of shrimp.

And the local, natural set-up idea is a good one. I've already been considering something similar, and now I think I'm definitely going to give it a try. In the next couple of weeks, I'm going to get my 75-gal tank set up to keep it outside through the summer. I'll try planting several local plants, throw in some flowerseeds (marigolds, for instance) and see what else moves in ...

Then towards the fall, depending on how it looks, I may try closing it up for the winter. If anyone's interested, I'll try posting some photos (although I actually don't know how to do that yet ... tips anyone?)

One thing I'd love to hear more about is how you got a complete ant colony going in a terrarium. I very much want to accomplish the same thing, but after a lot of ant research, I came to the conclusion that it's too hard to get a full colony--with queen--going like that. Any details you can offer would be appreciated.

I have two terrariums, no big deals and nothing challenging, but tons of experience with reptiles and amphibians...I can't think of a species that doesn't require daily care, and most require dietary supplementation, etc. and would make a self-sustaining system hard. Giant millipedes *might* be a better option, but I would think you'd still need to remove waste from the terrarium.

For all you PDF fans...Dendrobates azureus and D. reticulatus are nice, but I'm really a chameleon person.

HTH,

Celene

Auntie Celene

The millipedes sound like a good suggestion. I've already been considering "typical" millipedes. In a large enough system, waste should not be a problem, but I would have to learn more about giant millipedes before I knew whether the necessary size would be prohibitive (anything larger than a couple hundred gallons is outside my budget).

Plans for any vertebrates are definitely out of the question at this point. Currently, I'd be happy to set up a closed system with an intact, thriving insect community.

I'm still looking for--and open to--tips, thoughts and ideas on the whole closed-system subject.

Rainbird
Please give me some tips on how to keep ants OUT of my terrariums?? Every setup I've had in S.Florida had a thriving colony within months if not weeks. Even with hydroponics they would just build the nest higher. They even setup aphid farms.!! I figured it would be far too humid and wet. Just got a different type of ant lol
I keep my shadehouse on a 4 day rain cycle with a Jan Feb drought.Lowland raiforest cycle. I flood the main pool during this "season"while allowing the terrarium to gain
one third depth.for 3 weeks.I find many floating ants which are consumed by the birds but as soon as the water drops to
below main level.The ants move right back in.
I do believe that a slight benefit is gained from the ants by a sharp decrease in the slug population.Have found nothing reliable to eat slugs.
i suspect that i have some symbiotic ant-orchid relationships going on in the dry canopy.But don't want to
cut the pseudbulbs to find out naturally.
This system does completely eliminate Fire ants but do have them outside in the transition zone.
I do get to observe "farming" activities by the ants but it's far more interesting to watch geckoes root out cricket colonies. I figure I'm stuck with ants.
gary

I know this is a very old thread, but have you thought about using praying mantises to keep the ladybirds in check? They are cannibalistic, at least when young which should prevent overpopulation problems.

I've never seen this thread before! Very cool ideas and very interesting reading. How bout an update? Have you set anything up or made any discoveries?

praying mantises might work, the only problem would be what would control the praying mantises, anytime you have a food chain in nature the top preditor is controlled by starvation, its population is controlled by the populations it feeds on. i guess it would work if you dont mind having some of your animals starve to death, but on such a small scale, the praying mantises would probably eat all the lady bugs and then die off themselves with nothing to eat.

You would need atleast a 1,000 gallon forest (or rather dwarf tree) situation to provide the preying mantis with enought food (that might sustain 3 or 4 if the soil was fertile enought and they are cannibalistic) A while back someone talked about a water feature and snail control. Any fish that eats snails needs about 300 gallons (min) of convoluted vegitation covered terain for snails to hide in
(These fish have evolved for millions of years to find and at all sorts of snails and will redily eat themselves out of house and home) and feast off of and I'm talking about like a 1" dwarf puffer (one of these things can destroy a snail infestation in a normal 100 gallon tank in about a week) or a 3" bronze puffer mabey even a 4-6 inch loach. As for keeping the water clean I think the best way to do that is to pump water from the little "pond" at one end of your tank to the dirt t the other end all the water will run throught your substrate and fertilize your plants which then feed whatever it is that you want. If you were willing to give up the NATURAL EQUILIBRIUM aspect of the situation you could set up a 30 gallon tank with about 10 gallons of water in it (and either some floating hideing places or water plants) and then set up a shelf right above that with a small hydroponics system and grow aphids on those then have a small fan on a powerful motor that blows aphids and any other small insect thats not holding on tight into the water where you have guppies (get the red ones they eat there young the most) You would also need a heater (or you could use mosquitoe fish coldwatercolorless guppies). If you were to set up a system this small I would suggest that you set it up under flourescent lights on a timer and have an extremely short "day/night" schedual like 2 hours on 1.5 hours off this would interfere with many plants germanation cycles but it would prevent a CO2 spike that would kill off the fish.

As for the sunlightvs. cool temps issue you could set the tank in a deep tray of water (six or seven inches deep) and run it in a cyle with a bucket (I'd use a 60 gallon barrel) in the shade just cut an over4flow in the tray that leads to the water sorce and use a small pump to take the water up to the tray.

Just some ideas.

Hope they help someone

Brendan

I don't know if terrestrial verts would work in that sort of set-up. At least not for very long. Try checking out some killifish for the pond section. Many species of killies natural home are barely more then puddles and have an amzaingly high tolerance for confined spaces. Some will happily breed in liter sized fish globes. These fish also breed at slow rates pooping out a few eggs a day rather then big egg clutches. Some are pretty sensitive to water hardness though so you may need to start it out with RO, Distilled or rain water. heres a few species to check out;
Epiplatys annulatus
Aphyosemion australe
Aphyosemion striatum
Aphyosemion diapteron

add a net full of daphnia and a little algea and your set, with these fish at least.

In regards to the bio-globes, I've never seen them close up but I've had a semi sealed container, 3/4 of a gallon jar set up with daphnia, two kinds of ostrocots (SP?) and algea going for at least ten year with the only maintenance I've every needed to do was to add some distilled water every 2 or three years to make up for evaporation. I've never feed the jar and never change the water, just add at bit of water to it. Keep it in a bright light out of the sun. It ain't much to look at but you can easily see the critters swimming around. I've had a couple of die offs but sooner or later the resting eggs hatch out and it all starts over again.

Dan

Daphnia would be a bad idea for such a small system IMO. The fish would devour them right away but more importantly they fowl water quite quickly They are filter feeders but they produce huge amounts of waste.

Brendan

Greetings from Norway. ^_^

Interesting thread
I stumbled upon this one while searching for info on micro and macrofauna while writing a small article on naturalistic substrates for terrariums.

I think a self-contained system with small vertebrates that reproduce is theoretically possible at least for a period of several years.

I think the real challenge is not in the complexity of the setup but in the selecting of the species in it.
In order to support vertebrates you'd need a fairly large tank, or.. I think it would be easier to achieve with a larger tank, perhaps a 100 gallon tank.

I'm not experienced with Poison dart frogs (PDFs) but I've been reading up on various articles from PDF keepers in Europe since my hobby is geckoes.
I've noted that Europeans who concentrate on setting up naturalistic PDF tanks with vast amounts of vegetation have noted that air circulation is not very important once you get a certain amount of vegetation in the tank.

You would also need a misting system that circulates water through the tank.
In order to produce the necessary amount of vegetation you need to support a vertebrate it's probably harder to use a spherical tank. I think it would be easier to use a standard square tank.
First off you'll need a tank with a false bottom where water can accumulate. This water should be led thru a hose to a secondary tank connected to a misting system which can water the plants.

Secondly you'll need a living substrate. By that I mean a substrate with a micro and macrofauna. Since you want to close the system you need these to decompose feces and decaying plant matter. The micro and macro fauna regulate themselves but will never die out as long as there are living plants in the tank.
In order to set up a living substrate you need to build the substrate in several layers. A drainage layer in the bottom, then a fiber cloth, in order to separate the dirt and the drainage layer. on the fiber cloth you need to add at 3-4 inches of substrate (turf or some other airy substrate.
Start by wetting the substrate till you get a muddy consistence. Apply it to the walls (it will stick to them) then put some climbing plants on the substrate that's on the walls. As the plants grow roots they'll hold the substrate on the walls better together.
After you have added the plants add micro fauna, various decomposers.
Leave the tank like this for a couple of months for things to stabilise. After this add the macrofauna, woodlice, dirt mites, snails etc.
That roughly covers the first phase.
The tank needs about a year to stabilise.
During this period the plants will grow, the substrate fill stabilise and you'll see how things work out.
You may experience "up-blooms" of various "things" like mold and certain plants or fauna.
All the other factors except the plants stabilise themselves. Micro organisms will eat the fungus or mold etc.
As the plants reproduce themselves they will eventually be able to produce enough oxygen to support a small amount of vertebrates.

However, you need _vast_ amounts of lighting.
Since light is the only source of energy that is added to the system you basically need enough light to support the amount of vertebrates you want to maintain.
For a 100gal enclosure you'd probably need a HQL lighting system. Perhaps you can pull is off my using fluorescent lighting, in that case you'd probably need 2-3-4-5? Phillips PL-L or Osram Dulux 54W bulbs.

The lighting might create a heat problem since your preferred temperature range for this type of system should be somewhere around 25-29? Celsius (77-84F?).
At this temp you normally get a good reproduction frequency for insects and reptilians. So you may need to regulate the size of your water tank accordingly. Adjust the thermostat so that it produces a cool rainfall when the temp hits the high level of the range in the middle of the day.

When you have calibrated the lighting, temp, water cycle you may add the food source of the vertebrates and shortly after the vertebrates themselves.

This is where I fall short. I am certain the above can work in theory and I'm almost certain that it will work if properly set up in real life.
The food source is dependant of the vertebrate itself.
Since birds and mammals are "warmblooded" they can be excluded, they use too much energy and would need a larger tank.
Insectivorous insects could probably be set up easier than reptiles but they're not vertebrates. Still, if you want to test this with insects try some carnivorous beetle or some spider.
Reptiles are the best option if you want to go for a vertebrate.

When I thought of self containing systems I estimated parthenogenetic geckoes to be the best for me.
Poison dart frogs normally need water to reproduce and they produce a huge amounts of offspring per year.
Lepidodactylus lugubris (mourning geckoes) are a small parthenogenetic species, they were my theoretical choice.
You can start with only one hatchling, which would be around 1 inch and wouldn't require a lot of food. As the individual matures it can reproduce. This all female species is also social so there wouldn't be fighting as long as food is abundant.
Mourning geckoes produce one clutch of 2 eggs each 3-4 weeks during the breeding season, when there's enough food. I still think that this reproduction rate is too steep but I still found them to be the best compromise of various qualities. Females eat their eggshells after eggs hatch, so they can recycle lost calcium. I _think_ that in poor conditions with little food females will predate on hatchlings.

The important thing is that the females survive so that they can reproduce when the conditions are good enough.
I would think that a 100gal tank can support at least a few adult mourning geckoes (9cm - 3.5 inches total length) if one can find the appropriate food source.

Mourning geckoes are omnivorous; they eat both fruit and insects. I have maintained these periodically on either only fruit or insects and both work fine, ideally they need 50% of both but will prefer a 70%-30% of insects-fruit.
so unless one can find a small plant that bears fruit the geckoes will have to suffice on insects, which they will.

This is where I have met the wall. Which species of insects is small enough (I have normally fed mourning geckoes on fruit flies but these require fruit to reproduce. Mourning geckoes will feed on all appropriate sized insects.

In a closed system as the plants grow, they will stretch towards the light and shade for other plants. This will disrupt the lift cycle in the closed tank. Thus, the plants will also need a factor to keep them at bay.

My thought is that the insects who are the primary food source for the geckoes have to be able to eat the plants that are most prone to stretch up against the light but perhaps these plants shouldn't be the primary food source for the prey insects.

I have evaluated cockroaches as a possible food source for mourning geckoes. Midsized cockroach species will be too large for mourning geckoes to eat but the geckoes will be able to eat the nymphs. This ensures a staple source of cockroach nymphs as food for the geckoes while the parents of the nymphs are left alone.

I have looked into several cockroach species in connection to my gecko hobby. Some feed primarily on fruit, some primarily on fiber. all roaches are pretty hardy and opportunistic animals though. Fruit eating roaches are ideal as food for mourning geckoes but since we probably won't have fruit in the self sustaining tank they're probably not an option.. ?

If one can find a roach/(other insect) species that can feed both on macrofauna and on plants that would perhaps be the best bet.
I am not sure if roaches eat macrofauna (at least not the ones I've kept)
Crickets are omnivorous but they reproduce quite rapidly on the right diet. They are al teat in part omnivorous but I don't think that they'll survive for longer periods of time in this type of set up?

My conclusion.
The choice of plants and or insects, are the key to producing a small closed self-sustained environment. The system should contain as many different species as possible but a small amount of these have to be the dominant ones. A large amount of different decomposers (micro and macro fauna) are necessary in the substrate for the system to function. The choice flora influences in part which macrofauna will thrive. The choice of flora and macrofauna determines which type of prey items the system is able to sustain. The choice of vertebrate is determined by which type of prey can be found in the self-sustained system.

If toy can sustain an adult vertebrate (reptilian) for a period of 2 generations, in my opinion you have proved that the theory works. Parthenogenetic reptiles are not affected by inbreeding since offspring are genetic copies of the parents and if you can make them survive for a couple of generations you would have completed the reproductive cycle of adult individuals. This takes max 4-5 years from the time you introduce the geckoes. The mourning geckoes form a colony with a hierarchical ladder where the fittest female takes control of the best egg laying spot and lays most eggs.
Sorry for the long post, I guess I go carried away. ^_^

Regards
VÃ¥len GÃ¥nev (obeligz)

I came here with a similar interest, to discuss and try to build an entirely sealed terrarium that wouldn't ever be opened again. Not only would it be a cool experiment, but it has massive potential. I came up with the idea as it would be the perfect gift for friends that seem to kill all their house plants and don't have the time to look after them. I know many people who go on long holidays/business trips or allways forget to water their plants. The concept is fairly simple on the surface, a sealed glass bottle that will never have any watering, feeding or humidity concerns, it will simply sit on a surface in the correct sunlight and thrive. In theory, the only owner requirement is placing it in the right light and occasionally turning it to ensure even growth (under such slow growth conditions this would be very infrequent). I was hoping to find plants that naturally grow to a set size and stop, thus it wouldn't ever become overgrown.

I was just picturing plants (although I was looking in to the benificial bacteria that live in soil), but adding insects would make it a lot more exciting. They also make it a lot more complex. Still, before animals are even considered a working and entirely sealed terrarium design is needed on which to test the different insect combinations. It's important to take it one stage at a time, otherwise there will be too many new variables. A long lasting bottle garden that will remain sealed and alive for years is quite a complex task in itself, let alone such a small environment with insects as well.

Personally I was hoping to create something that would live in a bottle, nothing that seems complex or has electronic controls. While some people like the complex side, I find that making it work without anything extra is the exciting challenge. I want a miniture environment that self regulates, litterally living unsupported in a sealed container. I'm convinced I can do it with plants alone, and there's a possibly insects could be added as well...

Also, those biospheres look like they could be made at home. According to the sites I seen they contain filtered sea water (the filtration level isn't discussed, but I suspect that passing it through a home water filter jug would be sufficient), shrimps, some algae (some of the sites mentioned the exact type) and a dead structure that looks like a root for the algae to attach itself to. This could be made at home with a suitable glass container, and it looks fairly simple and affordable.

Anyway, I'd love to hear some more about your experiences with sealed terrariums, for example how the plants behaved and what problems you might have encountered? Also, you made it sound like some of them died? If they did, do you know why?

I've built a few closed system. the key is air movement.
it's easy to create air flow with a few hardware store items, like a small fan and wall hog but you need to also establish a nitrogen cycle, introduce a few pill bugs,
use distilled water, and slowly convert your plants over to this enclosure by weekly minimizing the open space at the top util its closed from a halfway point. if you have any specific questions let me know.

i only open mine to change out hte fruit fly culture, and that's once a month.

Wait a minute. . . are you saying that you culture your fruit flies directly in your vivarium, and it works? You don't get mites? The flies don't all die before the frogs can eat them? You only need to change it once a month?!? This is amazing. Please tell us more!

Several people have mentioned useing fans for circulation. Is it not possible to use heat, like the earth uses, to cause air movement. I know it has been a long time but I remember for elementry school if you heat one side of an aquarium and keep the other side shaded it creates wind curent.
That way you wouldn't be having to add electricity to the enclosed space only heat and light like the sun provides for us.

scottown2: you could use heat, but you'd need a fairly strong differential which means you'd need a fairly large amount of power to make it move. Much more efficient to use a computer fan; particularly as you would have a lot of trouble getting the heat through the glass.

Hi!
I had 2 ladybirds in my terrarium for nearly 4 months. They finally died about 2 months ago. I think they were just at the end of their cycle. They lived on the little bark bugs. Every two weeks I would crack the glass for a day with tooth picks because I didn't want to risk them dying from lack of air. It sounds like an interesting proposal to keep the terr. completely closed with sufficient food. I hope it works out and good luck!

I was looking to by a self contained plant terrarium and chanced upon this thread. It is very interesting! I think you should post more updates and progress. I am wondering if anyone has tried obeligz's idea and if so is it working so far? I have always been fascinated with miniature worlds and would love to try this.

Last post by the OP was 7 years ago. I doubt there will be any updates but I could be wrong.

I'm going to be looking for a big jar this weekend. The link below is my inspiration and the reason I searched and found this thread. Apparently it's possible to keep a sealed terrarium going for a very long time. I'm guessing the 'animals' involved are very small like bacteria, protozoa, and maybe mites. It would be hard to strike a balance with larger bugs or animals. Fruit flies are an interesting idea. Probably safe to try...the worst that would happen is they'd die off...without eating up all the plants first.

I realize the point of many of these systems is to have no outside energy other than sunlight but if airflow were important you could put a solar cell, fan and capacitor for periodic airflow inside. Or you could put a fan inside sealed glass with an induction coil and run power from the other side of the glass, with a solar cell or low voltage transformer. The cost could be under $100 USD.

Instead of the ladybugs and the aphids, try ants and aphids..Some ants will take care of the aphids, feed them..etc while the aphids give them honeydew, which they eat.It's an interesting relationship.

The subject of a self-sustaining bio-system is a very fascinating one as it begs us to consider these theoretical biological philosophies and musings.
All organisms must perform the essential Life Processes of Respiration, Nutrition, Reproduction, Irritability to environs,Excretion. These are catered to by various Levels of Organization viz Organelle; Cellular; Tissue; Organ systems;Social [think termite mounds or sanitation worker sub-serving "excretion"] Levels.This idea of Society being a huge animal probably drove anatomist Virchow into politics.
There is a natural force towards increased size and diverse biological niches. eg. Amoeba on the organelle scale carries out the processes by diffusion; the sponges increase size by syntactic bunching of cells etc... so on to complex Vertebrates, formed by keeping the evolutionary ball bouncing as it were.
Now to complicate matters, there are systems within systems eg every Renal cell sub-serving Excretion is like a organelle level protozoon performing the life processes, and is itself excreting by contractile vacuoles.
now having gone through this glorious celebration of the Creator's handiwork, if we are to recreate it on a small scale, it would I think, require choosing the complexity of organisms to match container size. plants eg might be best be limited to invertebrates, mosses, ferns and simple angiosperms, in table top systems. As the vivarium gets bigger, [a greenhouse or all purposes,] Nature gets into stride.

Well, it seems one guy nailed it. Just a plant in his case, but maybe introducing earthworms would have worked. He has it going for 40 years! A link is supplied below.

As for earlier posters - I see much enthusiasm, then silence. Not good, the most probable meaning is that their attempts failed.

Can't resist pointing out that this thread has been going for over 10 years, talking about a closed system vivarium/terrarium that could keep going for 10 years (and many more, if I understood Rainbird's intentions properly).

So I'd say Rainbird has succeeded, in some sense, by creating this thread.

More on topic, LSN8Veggies, how about some pictures? Your jugs sound really cool.

Hello I found this today, and I'm very interested in the same goal. Perhaps we could exchange ideas and even research work.i hope your still here and working on it!

I have found a queen ant and hope to introduce it to my vivarium soon. I will try to start a colony to feed my lizard.

LSN8Veggies, are you still doing these? If so, can you upload a picture?

What about putting worms in? The food would be constantly resupplied by their own waste and plant decay. Would they end up over-breeding? Or die out?

Wow this thread has been ages hahaha but anyway i just wanted to share cause i also want answers. Hopefully someone has a good theory about it. I have a closed terrarium/vivarium that i tried or shall i say experimented. It looks interesting cause I tried building it on a 3 liter glass container. I learned a little about creating it but i would say i dont have any background of biology or other sciences. So i piled the largest pebbles that could fit to the container's mouth that has a hole of an inch. The height of the pebbles from the very bottom is around an inch. Next to the pile is white sand that i dried up from a beach for half an inch, next to that are colorful beeds-mixed red and yellow to make it colorful if u look at it from the outside. Thats half an inch as well. Next is clay soil for half an inch, then pounded charcoal for half an inch. I heard that charcoal could clean the air or stabilize the atmosphere inside this but im not very sure of it. Hahaha Lastly, is a pile of loam soil which is ideal for the plants to grow. I planted moss which i got from the bark of a mango tree, a few fern, and few grass that only grow around 1/2 inch. Poured 5 tbsp of rainwater. Apparently its close and it can get enough sunlight to suntain its life. Its 11 months now and never been opened. It looks healthy cause the water does its cycle inside the bottle like the rain. And u know what? The interesting part is, i saw really tiny insect and a spider that came to life. BDW i didnt put anything in it. Do u think that was just normal or was it just part of the life cycle inside the bottle? Hahaha

Wow, I see this is 17 YEARS old, but I too share your interests. Did you everact on your ambitions? Tell us about it.