Ants molt. This biological process, technically known as ecdysis, is a necessary step in the ant’s life cycle as it moves through its developmental stages. Molting is the action of shedding the outer layer of the body, a requirement for any organism whose growth is restricted by a rigid external covering. This shedding process is an integral part of the complete metamorphosis all ants undergo.
Why Ants Must Shed Their Skin
The necessity for molting is rooted in the ant’s anatomy, which features a tough, external skeleton. This exoskeleton is primarily composed of chitin, forming a hard casing that provides structural support and protection for the soft internal tissues. However, this armor is non-living and cannot stretch or expand as the ant’s body grows. The rigid outer shell becomes a constraint that must be removed to allow for physical enlargement. Ecdysis is the mechanism that overcomes this structural limitation, permitting the organism to inflate its size before the new covering hardens.
Molting in the Larval Stage
Molting is a process that is exclusive to the ant’s larval stage, which is the organism’s primary phase of growth. The ant larva is a legless, grub-like creature that focuses almost entirely on consuming food to rapidly increase its size. To accommodate this rapid growth, the larva must shed its exoskeleton multiple times, with the periods between these molts referred to as instars. Ant larvae typically pass through three to five instars before they transition to the pupal stage.
The process begins when the larva secretes a new, soft cuticle underneath the old, outer layer, while also releasing enzymes that help dissolve the inner parts of the old shell. Once the old exoskeleton is separated, the larva physically pushes or wriggles out of it, leaving behind the shed skin, or exuvia. The new, pliable cuticle then rapidly expands before it hardens, allowing the larva to accommodate its larger size and continue its rapid development.
The Adult Ant and Growth
Once an ant emerges from the pupal stage, it has undergone its final molt and its size is permanently fixed. Adult ants, whether they are workers, males, or queens, do not grow larger, meaning they have no need for further molting. The size of an adult worker, for instance, is not an indication of its age, but rather a reflection of the amount of nutrition it received during the larval stage. The fully hardened exoskeleton of the adult provides the necessary leverage for muscle attachment, which is essential for movement, foraging, and performing colony duties. The adult stage is dedicated to reproduction and labor, not physical growth, so the rigid outer layer remains a permanent protective structure. Therefore, the smallest ant observed in a colony is not a juvenile that will later expand, but a full-sized adult whose development was completed during the molting-intensive larval phase.