Ref ID : 3035
Roger Pourriot, Claude Rougier, and Daniellae Benest; [Role de la Lumiere et de la Temperature dans l'eclosion des oeufs de duree de Brachionus rubens Ehr. (Rotifere)]. Netherlands Journal of Zoology 31(4):637-649, 1981
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Two mechanisms induce B. rubens resting eggs to hatch. After a 2 week-minimum-threshold of obligatory dormancy has been passed, resting eggs hatch if they are exposed to light at temperatures of 10-22 degrees C. Under these conditions, the hatching rate can reach 80% in a short time, depending on the length of the dark period preceding exposure. Hatching rate is not influenced by the photoperiod to which the eggs are submitted following storage. In the absence of light, to hatching occurs at any temperature. However, after several months this block to hatching is removed even at low temperature. At 5 degrees C, in darkness, the first eggs hatch after 4 months and hatching continues at a steady, low rate. The ecological incidences of these mechanisms are discussed in conclusion. The hatching process in presence of light shows an adaptive convergence between the resting eggs of the rotifer (epizoic on Daphnia) and the hatching of its natural bearer.