EDUCATION: Codependent Creatures

Science  06 Sep 2002:
Vol. 297, Issue 5587, pp. 1615
DOI: 10.1126/science.297.5587.1615c

When it emerges from hiding, the bobtailed squid will quickly become fish food without help from some bright bugs. Luminous bacteria, cousins of the gut-wrenching microbe that causes cholera, bed down inside the mollusk's body. On moonlit nights, their glow helps obscure the squid's silhouette as it swims near the surface.

Close associations, or symbioses, between animals and bacteria are common, and this site by microbiologist Joerg Graf of the University of Connecticut, Storrs, explores four examples, including the bacterial denizens of the leech's gut and the bugs that feed aphids their essential amino acids. The descriptions are full of fascinating details about these relationships. A hatchling squid, for example, nets its stock of bacteria from seawater using mucuslike goop. This partnership also has its tensions: The squid feeds its tenants lavishly while trying to slay them with corrosive chemicals, which the bugs counter with neutralizing compounds. Each account features a bibliography and links to labs studying the symbiosis.

www.sp.uconn.edu/∼mcbstaff/graf/Sym.html

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