The Life Cycle of the Antarctic Nematode Plectus murrayi Under Laboratory Conditions

Cecilia Milano de Tomasel, Byron J. Adams, Fernando G. Tomasel, Diana H. Wall


We study and describe the life cycle of Plectus murrayi, a free-living, bacterivorous soil nematode endemic to terrestrial Antarctica. The study was performed at 158C, a temperature identified as optimal for growth rate studies in the laboratory. Under these conditions, we observed that the first molt occurs in the egg, and second-stage juveniles hatch 12 to 14 d after egg laying. Individuals undergo three subsequent molts to become adults 23 to 26 d after hatching with a final average length of 950 mm. Egglaying begins 41 to 43 d after hatching, resulting in an egg-to-egg life cycle ranging from 53 to 57 d under our experimental conditions. Considering that the average soil temperature during austral summers in the McMurdo Dry Valleys is only a few degrees above freezing, it is highly likely that many, if not most of these animals, require more than 1 yr to complete their entire life cycle. Our study supports other research that establishes P. murrayi as an important model organism for studying adaptation to extreme environmental stress.

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