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Index of flora
Index of fauna
SYMBIOSIS: Living Together—Commensalism
Barnacles on Crabs

Barnacles like Balanus (Family Balanidae) commonly grow on the shells of crabs (here the flower crab, Portunus pelagicus), but are quite harmless, and are lost when the crab moults.

Stalked barnacles, mainly of the genus Octolasmis (Family Lepidae) also appear to favour animal hosts, and often grow on the shells and gills of crabs, as well as skins of sea snakes. Octolasmis is not strictly a.parasite since they only use the gills as a base, and take advantage of the respiratory currents to bring in planktonic food (they are also filter feeders). They are lost each time the host moults.

Barnacles on Portunus

Photo by Tan Bee Hong
Octolasmis on gills of Scylla
Shore environment
From A Guide to Seashore Life by Dr Leo W H Tan and Peter K L Ng
Published by the Singapore Science Centre and sponsored by BP

@Raffles Museum of Biodiversity Research and Singapore Science Centre