Regeneration

Definition

The biological process by which an organism restores lost, damaged, or amputated tissues, organs, or appendages through cell proliferation, dedifferentiation, and redifferentiation. In arthropods, regeneration typically occurs during molting cycles, when epidermal cells proliferate beneath the wound site and secrete a new cuticle that expands and hardens after ecdysis. Capacity varies widely: some insects regenerate legs, antennae, or cerci only as nymphs or larvae, losing this ability in adults, while certain arachnids and crustaceans retain regenerative capacity throughout life. Regeneration may restore original form (epimorphosis) or reorganize remaining tissues without cell proliferation (morphallaxis).

Etymology

Latin regenerare, from re- 'again' + generare 'to produce, beget'

Example

A juvenile stick insect (Phasmatodea) that autotomizes a leg to escape a predator can regenerate a functional limb over successive molts; the new leg emerges as a small bud after the next molt, gradually attaining normal size and segmentation through several instars.

Synonyms

• restoration
• Epimorphosis

Related Terms

• Autotomy
• molting
• Ecdysis
• dedifferentiation
• blastema
• wound healing
• compensatory growth

Usage Notes

Distinguish from simple wound healing (repair of tissue without restoration of lost structure) and from asexual reproduction by fission or budding. In entomology, 'regeneration' is sometimes used loosely for any regrowth, but specialists reserve it for true restorative processes involving cell proliferation. Note that adult holometabolous insects generally lack regenerative capacity for appendages, while hemimetabolous nymphs and many arachnids retain it longer. The term 'autotomy' describes the preceding self-amputation behavior, not the regrowth itself.