Abstract
Earthworms (Annelida: Oligochaeta) exhibit robust regenerative abilities that vary across species, body regions, and evolutionary lineages. This manuscript synthesizes classical and contemporary research on annelid regeneration—including wound closure, immune activation, blastema formation, segment reconstruction, and ventral nerve cord regrowth—and integrates these mechanisms with ecological observations from Prince Edward Island (PEI) earthworm communities. Drawing from cellular, molecular, and transcriptomic studies, we outline the processes that enable successful regeneration and contrast them with taxa that have lost regenerative capacity. We also contextualize regeneration within earthworm immunity, extracellular matrix (ECM) remodelling, and segmental patterning. Figures illustrate the regeneration sequence, coelomocyte dynamics, molecular pathways, and comparative outcomes. This synthesis provides a mechanistic foundation for interpreting regeneration in PEI earthworm species and supports future ecological and applied research.
Keywords: earthworm regeneration; blastema; neuroregeneration; fibrosis; tissue engineering
References
- Bely AE. “Evolutionary loss of animal regeneration: Pattern and process”. Integrative and Comparative Biology 50.4 (2010): 515-527.
- Bely AE. “Early events in annelid regeneration: A comparative perspective”. Journal of Experimental Zoology (B), 322.7 (2014): 633-645.
- Bely AE, JM Sikes and D Futuyma. “Latent regeneration abilities persist following recent evolutionary loss in asexual annelids”. Proceedings of the National Academy of Sciences 107.4 (2010): 1464-1469.
- Chih-Han Chang and Jiun-Hong Chen. “Axonomic status and intraspecific phylogeography of two sibling species of Metaphire (Oligochaeta: Megascolecidae) in Taiwan”. Pedobiologia 49.6 (2005): 591-600.
- Cooper EL and P Roch. “Earthworm immunity: A model of immune competence”. Pedobiologia 47.5-6 (2003): 676-688.
- Ebrahimi Fana S., et al. “Earthworm as a peripheral nerve regeneration biomaterial: a comprehensive review”. Traditional and Integrative Medicine 8.1 (2023): 77-85.
- Gurtner G., et al. “Wound repair and regeneration”. Nature 453 (2008): 314-321.
- Kinberg JG. Newly cancelled. Translated from the proceedings of the Royal Academy of Sciences, Stockholm 23 (1867): 97-103, 356-357.
- Linnaeus C. “The system of nature through the three kingdoms of nature, according to classes, orders, genera, and species, with characters, differences, and synonyms., locis, Edition tenth, reformatted”. Tom I. Laurentius Salvius, of Holm, (1758): 824.
- Müller MCM and AE Bely. “Regeneration in annelids: A comparative overview of developmental processes and molecular mechanisms”. Development Genes and Evolution 229.1 (2019): 1-18.
- Myohara M. “Differential tissue regeneration in Eisenia fetida”. Developmental Dynamics 231.3 (2004): 396-403.
- Perrier E. “Research Contributing to the History of Terrestrial Earthworms”. New Archives of the Natural History Museum, Paris 8 (1872): 5-198.
- Reynolds JW. “Earthworm community structure and species co-occurrence patterns across Prince Edward Island, Canada”. Megadrilogica 30.2 (2026): 13-31.
- Rosa D. “The exotic terrestrial animals of the Imperial-Royal Natural History Court Museum”. Annals of the Imperial-Royal Natural History Court Museum, Vienna 6 (1891): 399-406.
- Rossan Mathews MG., et al. “De novo transcriptome of anterior epimorphic regeneration in Perionyx excavates”. Scientific Data 11 (2024): 1093.
- Savigny JC. “Analyses of the work of the Royal Academy of Sciences during the year 1821, physics section”. Baron G. Cuvier (ed.), Memoirs of the Royal Academy of Sciences of the Imperial Institute of France 5 (1826): 176-184.
- Shi G., et al. “Isolation and characterization of earthworm peptides with neuroprotective effects in Parkinson's disease models”. Molecules 30.9 (2025): 1952.
- Wu L., et al. “Piezoelectric materials for neuroregeneration: a review”. Biomaterials Science 11 (2023): 7296-7310.