THE study of mechanisms affecting the rate of ageing can be facilitated by naturally occurring phenomena, innate to some organisms, that enable the species to retard its ageing rate and extend its life span1. Such a phenomenon exists in certain species of nematode. Larval forms of the free-living soil nema-tode, Caenorhabditis elegans, possess the ability to enter a semi-dormant, quiescent state referred to as the dauer larval stage (German, “enduring” larva). Newly hatched larvae of C. elegans undergo four larval stages (L1–L4) punctuated by moulting. If larvae are starved, they will enter the dauer state during the second larval moult. At this time, the old cuticle is replaced by a special, relatively impermeable cuticle unique to dauer larvae2.
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