How do you tell the difference between a dead isopod shell and a shed molt?

THE DIFFERENCE BETWEEN DEAD ISOPOD SHELLS AND SHED MOLTS

Most keepers have faced this situation before: they looked into their breeding plastic container and saw something similar to the ghost isopod lying on the substrate. The first instinct tells us that we lost one of our high-quality isopods. However, as crustaceans, isopods constantly get rid of their old hard exoskeletons as a part of a growing process. It is easy to distinguish a tragedy from a natural process with a couple of physical clues. Understanding these things will save your time and effort.

What Does a Shed Molt Look Like?

A molt is a perfect, fully formed white shell of the isopod without any tissue and color. Completely made of chitin and minerals of calcium, it reminds us of a glass shell. There is one rule here: isopods do not shed in one go, as snakes or spiders do. This process is biphasic and takes several days.

First, the rear half of the animal's shell sheds. As a result, you will see two "trousers" on the ground, the hollow white shells. Then, after some days, as the new rear shell hardens, the front half of the animal sheds. A perfectly white and completely hollow half-shell that easily collapses like tissue paper means that everything is fine. One more way to recognize a discarded molt is the color of the animal's antennae; they are completely white and empty hollow tubes that stay open.

THE SIGNS OF A DEAD ISOPOD

A dead isopod has a completely different appearance because the animal stays inside the shell. Even a pale or white morph of the isopod doesn't look like an empty shell. The internal tissue of a dead isopod starts breaking down. Thus, the shell of the isopod becomes dull, opaque, and turns grey, yellow, or chalky white.

Post-mortem muscle contractions are seen in dead isopods. The legs of the isopod are curled and turned towards the belly of the animal, or it lies on its back with rigid, straight legs. A dead isopod doesn't have splayed or flattened legs because it has no internal muscles to pull the legs in. If you pick up the shell with tweezers, it will be heavy and rigid. The isopod will produce a peculiar seafood smell or ammonia in 24 hours after it dies in a moist enclosure.

WHY DO MOLTS DISAPPEAR SO FAST?

This question arises quite often. However, the answer is simple: isopods start eating their shed as soon as they shed it. Discarded molts are a valuable source of pure minerals of calcium and structural chitin.

When an isopod sheds, its new shell becomes weak and delicate. To harden the new shell, the isopod consumes its own discarded half-shell. Other members of the colony also join this feast and eat the discarded skin. If you see a white half-shell of an isopod, most probably, it will be gone tomorrow.

FAQ
Is it okay to take away discarded molts from the enclosure?
No. You should always leave them there. Discarded skins are a valuable source of highly bioavailable calcium for your isopods. Taking them away deprives the isopod of its minerals.

Why is my isopod walking around with a two-colored body?
If you see an isopod whose rear half is pale and dull while the front half is bright and shiny, you will witness the molt. It can shed either the rear or the front half of its body. Leave the animal alone since manipulating it at this time can harm its delicate new skin.

What is the cause of a bad molt and how can I prevent it?
A bad molt occurs when the isopod gets stuck in the old shell, and it suffocates or crushes the animal. It is caused by an imbalance of the moisture gradient or a lack of calcium in the diet of the isopod. Make sure one corner of your plastic container has consistently moistened sphagnum moss and place a permanent piece of cuttlebone there.

Should I dig up the bin immediately if I think that there are new dead isopods in it?
No. If there are no bodies on the surface, don't dig. Digging will stress the surviving isopods who try to hide and recover. Just trust your setup conditions and make sure the moisture gradient is right, leave the lid closed, and watch for indirect signs of life during a week.