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Deutsch (EUR)Molting in Jumping Spiders: Why Did the Spider Hide in Its Nest and Stop Eating?
Jumping spiders, like all arthropods, have a rigid outer skeleton (exoskeleton or cuticle) that does not grow with them. In order for the spider to grow and advance to the next developmental stage (known as an instar), it must regularly shed its old skin. This complex, hormonally driven process costs the animal an enormous amount of energy. In slings, it happens relatively quickly and frequently (easily every 3 to 4 weeks); in sub-adults, the intervals are longer. It is also important to know that once a jumping spider reaches sexual maturity (becomes an imago), it never molts again.
1. How to Safely Identify Pre-Molt Preparation?
Many beginner keepers panic when their normally active hunter suddenly disappears from sight. However, the pre-molt phase has very typical signs:
- Building a thick hammock: The jumping spider spins a noticeably thicker and more opaque web nest in the terrarium (typically in the highest corner). It usually seals itself inside completely, closing off all entrances.
- Prolonged fasting: The spider naturally slows its metabolism and stops hunting even weeks before the actual molt. The body is entirely focused on internal processes.
- Lethargy and loss of color: The jumping spider does not leave the nest, and its otherwise bright colors may appear dull or grayish. Inside, a process called apolysis is occurring—the separation of the old exoskeleton from the new, currently soft tissue underneath.
2. Rules for Keepers: What (Not) to Do During a Molt
Once the spider retreats into its pre-molt nest, you must not interfere with the process. Your only role is to monitor the conditions.
- Maintain higher humidity: Proper ambient humidity prevents the spider from getting stuck in its old skin (dysecdysis). Mist the terrarium slightly more often than usual, but never spray water directly on the spider or its nest—large drops could suffocate it.
- Remove all live prey: An absolutely critical step. If even a single cricket or roach remains in the terrarium, it can attack, chew on, and kill the defenseless and soft jumping spider during molting.
- Absolute ban on disturbance and handling: Do not move the terrarium and under no circumstances tear the nest open to check if the spider is alive. If the spider gets startled and falls out of the hammock during the molting process, it faces fatal limb deformities or immediate death.
3. Hardening and First Feeding After a Molt
You will usually be informed of the process's successful completion by the presence of the old, translucent skin (exuvia), which the spider will eventually toss out of the nest. Despite this, you must not start feeding it immediately.
Right after molting, the new cuticle is extremely soft, including the spider's weapons—its fangs (chelicerae). The cuticle must first harden chemically (sclerotize). If you immediately offered the soft jumping spider harder prey, it could break its fangs, which means an irreversible death sentence by starvation.
Be patient and wait a few days (usually 2 to 7) until the spider has fully hardened and voluntarily leaves the nest to explore the terrarium. Only then should you offer it its first smaller, soft prey (ideally a fruit fly or a housefly).
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