Today we’re talking about terrarium bugs. The good, the bad and the ugly.
Love them or hate them, insects and bugs can make a valuable addition to a terrarium ecosystem.
Provided you get the right ones.
Some insects can keep your terrarium clean, rich in nutrients and free of pests, whereas others simply are the pests…
In this article we’re going to identify which bugs and insects are terrarium friendly (which are not) and where to find some really cool varieties.
Ready to unearth some gems? Let’s go.
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Bioactive Terrarium Bugs
Part of building a functioning terrarium ecosystem is replicating the natural processes and cycles that keeps our woodlands and rainforests alive.
Creating a mini water cycle for example, is pretty straightforward. A sealed container should do most of the work itself.
Harnessing the power of life and death, however. It’s a little more complicated.
Being able to decompose dead organic matter – and processing it to become available nutrients for your live plants – is part of being a truly self-sustaining terrarium.
The term for such a thing is a bioactive terrarium.
What makes this possible is the microorganisms (bacteria and fungi) and the microfauna (insects and bugs) that are able to help the decomposition process along.
Leaf litter bugs do this naturally in the wild, and they can do it in your terrarium too.
Springtails (Collembola sp)
Springtails are the perfect compromise for someone who wants the mould-fighting, terrarium cleaning dream team – without giant bugs crawling all over the place.
These tiny critters are only 1/16″ at full size, and they’re really more jumpers than they are crawlers (hence the name).
Springtails are detritivores, which means they love to feed on dead organic matter. This makes them perfect for processing any dead leaves or roots that you’ve missed, before they rot and start causing a problem.
Their second favourite food is fungi. So in the absence of any mushrooms in your terrarium, they’re going to feed on the most abundant source – mould (or mold if you’re american).
That’s right, you can say goodbye to those awful mould blooms with a colony of springtails.
In my Essential Guide to Tropical Terrariums, I recommend springtails across the board for anyone looking for a healthy terrarium.
Springtails are typically cultured amongst chunks of charcoal. Mostly because the porosity of charcoal lends itself to be a breeding ground for bacteria and fungi, which the springtails can feed on.
It’s also a nice easy (non-messy) way to keep and/or transfer them.
Or, substrate works well too. Then you can just mix it right in without any extra fuss.
So, when you order a springtail culture it’ll normally be a small pot of material with enough springtails to seed a new terrarium.
Different varieties can be found to best match your terrarium conditions (or colour preferences). Though people report that temperate springtails tend to adapt to tropical terrarium conditions just fine too so I don’t think it matters too much which you get.
Isopods go by many names, but you may know them as pill bugs, roly polies, doodle bugs or just good old fashioned woodlice here in the UK.
They’re much larger than springtails, so I guess they’re more for the bug enthusiasts out there.
Just like springtails, isopods will readily feed on decaying organic matter and help keep your terrarium clean and fertile. Though, they are known to feed on plants in the absence of decaying matter – so keep an eye out for that.
One important thing to note with isopods is that they need a high humidity to survive. They don’t have lungs per-se, and they instead breathe through gill-like structures beneath their armour.
> See my guide, 12+ Funky Types of Isopods to Collect (Species + Photos) for isopod inspiration.
Almost all of the isopod species for sale are dwarf varieties so that they’re small enough to fit in our terrariums.
They come in an extensive variety of colours and patterns – see the range on Etsy!
In practice they’re not all that different to those found in our gardens, but the different varieties will have different nuances in their reproductive rate and environmental favourability. Plus I’m told some varieties are less likely to eat plants than others.
If you like to make small terrariums, I’d opt for varieties with a relatively slow reproduction rate. Otherwise you can very quickly have a colony that’s growing faster than your terrarium can handle.
Bioactive Clean up Crew for Sale
Finding appropriate springtail and isopod cultures online is super easy these days. Many online companies stock a variety of microfauna for the terrarium and herpetoculture communities.
Springtails for Sale
Isopods for Sale
Non-Desirable Terrarium Insects
As much as I Iove to recreate natural worlds in my terrariums, some little critters just aren’t so suited to terrarium life.
Worms are fantastic at aerating soil and reaching areas that other insects won’t. The only real issue is their size (and maybe a little bit of mess on the glass). For larger terrariums, there’s potentially some value in adding one or two earthworms.
Much like pill bugs, millipedes are effective decay-munching machines… that also run the risk of feeding on your plants. They get some use in larger vivariums, but I see people talking about feeding them apple slices and such so personally, I’d worry they would run out of food and turn to my plants.
The likes of snails, slugs and beetles will probably love being in a terrarium… but they’ll probably eat all your plants too. Not ideal.
Whereas spiders, ants and ladybugs will eat all of your beneficial terrarium bugs, or they’ll die. Either way, not ideal.
Finally we come to the true terrarium pests.
Gnats, mites and mealybugs are all known plant parasites that can hitch a ride into terrariums via plants and substrate. These have different negative effects on plants ranging from generally harmless (just unsightly and annoying) to vitality-sapping swarms.
Solving terrarium pest problems can be a challenging task and often involves significant interventions, from quarantining plants to swapping out substrates. But those are stories for another time…
Terrarium Insect FAQ
Springtails are detritivores, so they love to eat dead organic matter along with fungi, mould, pollen, bacteria, and algae. Everything that can cause a problem in terrariums. Though, you can also buy specific springtail food to get them started in new colonies.
Springtails don’t eat living plant matter, so your healthy plants are completely safe.
Springtails look like tiny fleas and often come in a variety of shapes and colours. Terrarium springtails are typically bright white or other vivid colours.
Springtails are completely harmless to plants, people and animals. They don’t bite or sting, and nor do they carry disease.
The amount of springtails you’ll need depends on the size of your terrarium, but even just a small colony can be hugely beneficial.
Springtails are incredibly easy to culture. They tend to culture best on moist natural wood charcoal in a sterile container, and fed with a simple food source like uncooked rice or brewers yeast.
Different varieties of springtails reproduce at different rates, but generally as a species springtails reproduce easily and rapidly under the right conditions.
Isopods are easy to culture in an appropriate substrate, housed in a moist, dark environment. They’ll happily feed on fruit and vegetables.
Now it’s Your Turn
Which of these beneficial terrarium critters will you be adding to your terrarium first?
The pink springtails don’t look natural at all but I can’t help but want them. Let us know in the comments!