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The blowholes of a gray whale, with barnacle epibionts
The tabulate coral Aulopora attached to the brachiopod Strophodonta, from the Middle Devonian of Wisconsin

An epibiont (from the Ancient Greek meaning "living on top of") is an organism that lives on the surface of another living organism, called the basibiont ("living underneath").[1][2] The interaction between the two organisms is called epibiosis. An epibiont is, by definition, harmless to its host. In this sense, the interaction between the two organisms can be considered neutralistic or commensalistic; as opposed to being, for example, parasitic, in which case one organism benefits at the expense of the other, or mutualistic, in which both organisms obtain some explicit benefit from their coexistence. These organisms have evolved various adaptations to exploit their hosts for protection, transportation, or access to resources. Examples of common epibionts are bacteria,[3] barnacles, remoras, and algae, many of which live on the surfaces of larger marine organisms such as whales, sharks, sea turtles, and mangrove trees.

Although there is no direct effect of the epibiont to the host, there are often indirect effects resulting from this interaction and change in the surface of the host. This has been found to be especially important to marine organisms and aquatic ecosystems, as surface qualities do impact necessary ecological functions such as drag, radiation absorption, nutrient uptake, etc.[4]


  • Epiphytes are plants that grow on the surface of other plants.
  • Epizoic organisms are those that live on the surface of animals.

Adaptations and Mechanisms

  • Barnacles attach via a secreted polyprotein complex that can bind to underwater surfaces.[5]
  • Remoras attach to their basibionts using a suction disk with parallel pectinated lamellae[6]

Epibionts and their basibiont

Further examples

Pagurus bernhardus and its epibionts

Pagurus bernhardus foraging at night.

P. bernhardus, or hermit crabs, acts as basibionts to many species of varying protozoa, hydrozoa, entoprocts, cirripeds, and polychaetes. The different types of epibionts are found on either the crab, the shell, or both the crab and the shell. In a study done over the course of two years, densities and diversity of epibionts were measured and considered. Multiple studies have found that P. bernardus in shells colonized with epibionts were likely to survive longer in laboratory settings when attacked by predators. [9]

See also


  1. ^ Lescinsky, H. L. (2001). "Epibionts". In Derek Briggs and Peter Crowther (ed.). Palaeobiology II. Wiley-Blackwell. pp. 460–63. doi:10.1002/9780470999295.ch112. ISBN 978-0-632-05149-6.
  2. ^ Gregorio Fernandez-Leborans; Yukio Hanamura; Ryon Siow; Phaik-Ean Chee (2009). "Intersite epibiosis characterization on dominant mangrove crustacean species from Malaysia". Contributions to Zoology. 78 (1): 9–23. doi:10.1163/18759866-07801002. S2CID 58942621. Archived from the original on 2013-06-16.
  3. ^ Jiang, Lijing (2020). ""Candidatus Desulfobulbus rimicarensis," an Uncultivated Deltaproteobacterial Epibiont from the Deep-Sea Hydrothermal Vent Shrimp Rimicaris exoculata". Applied and Environmental Microbiology. 86 (8): 02549–19. Bibcode:2020ApEnM..86E2549J. doi:10.1128/AEM.02549-19. PMC 7117923. PMID 32060020.
  4. ^ Martin Wahl (2008). "Ecological lever and interface ecology: epibiosis modulates the interactions between host and environment". The Journal of Bioadhesion and Biofilm Research. 24 (6): 427–38. Bibcode:2008Biofo..24..427W. doi:10.1080/08927010802339772. PMID 18686057. S2CID 27804881.
  5. ^ de Almeida Alves-Júnior, Flavio; Martins, Déborah Elena Galvão; de Araújo Silva, Kátia Cristina; de Macedo Klautau, Alex Garcia Cavalleiro; Cintra, Israel Hidenburgo Aniceto (2022-10-03). "Barnacles as Epibionts in Crustaceans from the Great Amazon Reef System (GARS) Northern of Brazil: New Records and New Host Associations". Thalassas: An International Journal of Marine Sciences. 38 (2): 1371–1378. Bibcode:2022TIJMS..38.1371D. doi:10.1007/s41208-022-00480-y. ISSN 0212-5919. S2CID 251556347.
  6. ^ Xu, Yunxin; Shi, Weichao; Arredondo-Galeana, Abel; Mei, Lei; Demirel, Yigit Kemal (2021-07-21). "Understanding of remora's "hitchhiking" behaviour from a hydrodynamic point of view". Scientific Reports. 11 (1): 14837. Bibcode:2021NatSR..1114837X. doi:10.1038/s41598-021-94342-x. ISSN 2045-2322. PMC 8295263. PMID 34290347.
  7. ^ Barea-Arco, J. (2001). "Evidence of a mutualistic relationship between an algal epibiont and its host, Daphnia pulicaria". Limnology and Oceanography. 46 (4): 871–81. Bibcode:2001LimOc..46..871B. doi:10.4319/lo.2001.46.4.0871. S2CID 85419053.
  8. ^ Fernandez-Leborans, Gregorio (January 2006). "Inter-annual variability of the epibiotic community on Pagurus bernhardus from Scotland". Estuarine, Coastal and Shelf Science. 66 (1–2): 35–54. Bibcode:2006ECSS...66...35F. doi:10.1016/j.ecss.2005.07.016.
  9. ^ Brooks, William (1985-04-18). "Protection of the hermit crab Pagurus pollicaris say from predators by hydroid-colonized shells". Journal of Experimental Marine Biology and Ecology. 87 (2): 111–118. doi:10.1016/0022-0981(85)90084-X.

External links