St Albans, Hertfordshire
Although the long-lived mutant nematode strains created by Bernard Lakowski and Siegfried Hekimi smash the record for artificial life span (New Scientist, Science, 25 May, p 16), they are undoubtedly not the Methuselahs of the worm world.
Recent research increasingly suggests Caenorhabditis elegans and its closest relatives are highly specialised ecological r -strategists—that is, they have evolved highly compact reproductive and developmental cycles, allowing them to multiply very fast in conditions when food is very abundant. In contrast, most other nematodes—including some groups that may be ancestral to Caenorhabditis and relatives—reproduce and develop more slowly, having generation times in the order of weeks or months rather than days.
Life span has never been accurately determined for such species, but is presumably proportional to generation time. Some nematodes have only one generation per year, and obviously live much longer than the new mutants.
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