Will Isopods Overpopulate a Terrarium/Vivarium?

You've set up your vivarium or terrarium and added some isopods, now you're wondering, can they take over the whole place? Will there become too many?

 Given that isopods won’t eat any plants, unless they are starving, and even then it’s unlikely as most species need the leaves to have broken down before they can be digested. Most species are not going to bite, or even disturb a healthy reptile or other inhabitant, and I’ve never felt the need to complain that too much waste is being cleaned up. Then there’s no real concern that you’ll get too many.

 The only danger is if you have other similar inhabitants, such as springtails or snails. Even then it's unlikely to cause any harm, but they might out-complete them for resources.

Isopods as decomposers.

 Isopods are a crucial part of the food web being decomposers. Their role in nature is to break down waste from other living things, mostly tree leaves. Having said that they struggle to break down and eat leaves until they have started to break down on their own.

What this means is that they’re not evolved to eat plants that aren’t already starting to decompose, although some species will enjoy other foods such as fish food, or in the wild even enjoy some meat in their diet from a dead animal.

 

Understanding Isopod Reproduction and Growth

Isopods will reproduce in the vivarium or terrarium, but they reproduce slowly when compared to other creepy crawlies. Females carry their young for the first stage of their life, and so are limited in terms of numbers that they can bring on at any one time.

 Some species will breed more rapidly than others, such as Dairy Cow Isopods (Porcellio Laevis), Porcellionides pruinosus (Powder Blue, Powder Orange, etc.), and Armadillidium Granulatum. But even these will only increase their population in line with available resources.

 If food and other resources are abundant, and the environmental conditions are correct, the population will grow, and you might get to the point where you feel that there are too many isopods. But never fear there are things you can do.

Isopods swaps

Why not consider swapping some isopods for another species? Keep an eye out for invertebrate shows, and have a chat with people attending these shows. It’s a great chance to get your hands on a slightly more difficult species. I mean if you are doing this well then it’s worth going for something more challenging.

Talk to other keepers as well, not just isopod keepers, but also reptile keepers. There may be someone out there who will happily take some off your hands.  

Balancing your ecosystem

 If the isopods are just a part of the ecosystem have a look at what’s allowing them to have a population boom. You could consider adding a predator or just removing excess population yourself.

Lack of food

 Whilst isopods will help decompose the waste in an enclosure they also need other things as food, including leaf litter and similar. Some species also need protein, including the ever-popular Dairy Cow Isopods. If you have an ever-growing colony there is the chance that they will run out of food, including protein. That leads to a risk of cannibalising themselves or possibly trying to have a nibble on any other inhabitants. For most species of reptile, this isn't a real concern, but it might become a nuisance and stressful.

Is overpopulation a real concern

No, I’m literally only writing this article as it’s a question people have been asking. There is no real risk of isopods taking over the vivarium in a negative way.  Some species are territorial, and you may have to keep an eye on that. But it’s not a huge concern. There are plenty of outlets for excess isopods that you might have.

 If you worry about things like this consider getting a harder-to-breed species. That way you don't have to worry about having excess animals.

In general over overpopulation isn't going to be an issue for an isopod keeper. If you get too many for the space then there is always another keeper that will take them off your hands.