How do Madagascar Hissing Cockroaches Molt

5 min readApr 1, 2022

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Because of the tough, non-flexible properties of parts of the exoskeleton (“skin”), the nymphs (baby roaches) need to molt to grow. Before a molt, they begin to digest the softer parts of their exoskeleton inside. When this is complete, the nymphs shed the remaining exoskeleton.

Madagascar-Hissing-Cockroaches-Molting — Molted and adult Madagascar hissing cockroach

Once the molt is complete, they are soft and bright white. When they molt, they are completely white except for their eyes that stay black. Nymphs usually eat their own skin once it’s shed. They’ll expand, harden, and darken within a few hours to a day or two. As they mature and molt, their color can vary from dark brown or black to a golden brown depending on their diet.

A newborn nymph molts for the first time after 10–14 days. Some sources say that the number of days reaches 40. Among the many nymphs, there are several weak individuals who will not become adults and die. That’s true for every species.

They molt six or seven times before reaching maturity. It takes them from 3 months to 1 year and around 6 to 7 molts (shedding their skin) to grow into adults, depending on the climate and living conditions. In some resources, the number of molts reaches ten. Once they’ve grown up, they’ll start mating and produce more offspring. During this time, the nymphs increase in size 7–9 times.

How does the cockroach’s body continue to grow inside the exoskeleton?

The exoskeleton consists of sclerites — the chitinous plates constituting the hard surface of an insect. The creases between the scleritis are formed from a thinner and more elastic (bendable, but not stretchable) layer of chitin. This allows the cockroach to stretch a little to the next molt.

Unsuccessful molting

With insufficient humidity, a cockroach can get out with difficulty or even die. If you think that a cockroach will soon molt, you need to increase the humidity to 80–90% and offer more protein.

In some cases, the exoskeleton may deform.[Verification required]

deformed exoskeleton — Deformed exoskeleton

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FAQ

How can I understand that there will be a molt soon?

The day before molting, the cockroach hides in a shelter and will be inactive. His body stretches a little at the same time.

How can I help him?

If you think that a cockroach will soon molt, you need to increase the humidity to 80–90% and offer more protein. With insufficient humidity, a cockroach can get out with difficulty or even die.

Can I tear the exoskeleton myself?

No. Do not disturb the cockroach at this time and do not touch it.

Should I remove the exoskeleton after molting?

No. The cockroach will eat it to fill up the nutrients.

When my cockroach go black color again after mold?

They’ll expand, harden, and darken within a few hours to a day or two.

When will the first molt be?

A newborn nymph molts for the first time after 10–14 days. Some sources say that the number of days reaches 40.

When will the last molt be?

They molt six or seven times before reaching maturity.

My nymphs do not molt at the same time with other nymphs, despite the same environment and diet. Why?

Cockroaches have different food preferences. Molting depends on the growth rate of the cockroach. Some nymphs grow slower than others because they eat less protein.

One nymph died, although nothing has changed and all the other nymphs are fine. Why?

Some are just not meant to reach adulthood. That’s true for every species. Among the many nymphs, there are several weak individuals who will not become adults and die.

Can cockroaches regrow their antennae?

Since cockroaches have an impressive regeneration ability, antennae will grow back. Depending on its age, a cockroach can regrow up to 30% of its lost antennae during the next molt. It may take several molts to regenerate the lost appendage completely. Once it does, however, it will regain complete use of the antennae and return to normal.