How long does a starter culture of ten isopods actually take to begin multiplying?

HOW LONG DOES IT TAKE A STARTER CULTURE OF 10 ISOPODS TO START MULTIPLYING?

When you put in a starter population of ten isopods in a new plastic storage bin, you can usually expect to see the first generation of young ones within four to eight weeks, the exact time depending on the species you have selected. But it is much longer before you can actually see a visible explosion of numbers with the bin seeming crowded—this usually happens after four to six months.
At the beginning, it seems to move extremely slowly if you start with a small number such as ten individuals, but if you understand the biological timetable of how an isopod matures and reproduces, you will never worry that your culture has come to a standstill.

THE LIFECYCLE TIMELINE FROM DELIVERY TO BROOD

When the ten that your culture produces arrive by post, they are seldom all mature, breeding-ready adults; good breeders generally provide a mixture of juveniles and subadults. Younger isopods are able to travel much better than fully grown adults, who are more fragile and susceptible to shipping stress.
As a result, during your first few weeks it's just a question of waiting while your subadults reach sexual maturity; when they have reached breeding age, the mating process starts, but you will not be able to see it. The female isopods keep their eggs inside their bodies, where they then develop into a specialised fluid-filled brood pouch on the underside of their bodies known as a marsupium. She carries these developing young inside the pouch for about 3 to 4 weeks before finally releasing them into the substrate.

THE NEWBORN PHASE: THE INVISIBLE MANCAE

Even when the babies are finally released, you will not be able to see them. The newborn isopods are known as mancae. They are entirely white and translucent, have only six pairs of legs as opposed to the seven that adults have, and are about the size of a grain of sugar.

Since they are extremely fragile and do not have a hard, calcified shell, their first reaction is to dig down deeply into the dampest, lowest layers of your substrate mixture. For the first 4 to 6 weeks of their lives, they will remain entirely underground, feeding on thin films of soil, on slightly rotten wood, and on the decaying undersides of the leaf litter. Even if your ten original isopods manage to produce a large number of mancae, ranging from 30 to 50, the enclosure will appear just as empty on day 60 as it did on day 

FAST BREEDERS AS OPPOSED TO SLOW BREEDERS

The particular week during which you realize that your population is increasing will entirely depend on the specific genetics of the species you have kept.
Examples of fast multipliers (such as Porcellio scaber and Porcellio laevis 'Dairy Cow') are species that have a high metabolism and move about quickly; they attain maturity rapidly, have a large number of offspring, and can make a plastic tub seem overcrowded within three to four months. 

The Moderate Breeders (for example, Armadillidium vulgare and Armadillidium klugii 'Clown'): These typical 'roly-poly' pillbugs take a longer time to mature and put in more energy into forming thick, calcified shells. It may be before the 5 to 6month period that you notice a substantial increase in their numbers. 
The specialist species that are slow-growing (for example, the High-end Cubaris types such as 'Rubber Duckies') need extremely stable microclimates since they are moisture-loving cave dwellers; their brood sizes are very small and their gestation periods are long, it taking from six to nine months just to see a few juveniles moving about on the surface.

HOW TO SAFELY CONFIRM YOUR CULTURE IS MULTIPLYING

The most undesirable thing you can do is, every weekend, to vigorously dig through the soil in search of babies; constantly turning over the substrate damages the micro-burrows that the mancae depend on for humidity control and can easily crush them.
Rather, hold a torch up to the clear bottom or sides of your plastic container at night and look in particular around the edges of your damp sphagnum moss area. When your culture has reproduced successfully, you will eventually spot small, pale insects, similar in size to ants, attached to the clear plastic below the soil level or positioned on the lower surface of the lowest leaf layer.

FAQ

Will a starter culture consisting of ten members ensure that both males and females are included?
Yes, that's true from a statistical point of view; if you take ten people at random from a healthy breeding colony, you can be more than 95% certain of getting an equal number of males and females. In order to make sure that your culture has the right genetic variety to begin a new population, breeders deliberately choose a diverse group.

Can one female isopod produce several batches of offspring as a result of a single mating?
Right, females in many common species of isopod can keep the sperm obtained during one mating. As a result, they can give birth to two or even three successive broods of mancae over a period of several months without having to mate with a male once more.

What caused my isopods to produce a batch of young and then suddenly to stop breeding?
This is generally a sign of a shortage of essential nutrients or of limited space. When your colony shows an initial period of rapid growth followed by a halt in development, verify that your substrate hasn't become dry and compacted, make sure that you are continually adding fresh crushed leaf litter, and ensure that you are providing consistent protein and calcium supplements.

Should I put my first wave of babies into a separate bin in order to protect them?
Not at all; isopods are highly social and communal creatures and will not eat their own healthy young provided that they are given a proper diet. In fact, the young gain considerable benefits from remaining in the adult container since they eat the droppings of the adult isopods (frass), this feeding introducing essential beneficial bacteria into the juveniles' digestive tracts.