Ref ID : 1698
Maria Dolores Galindo, Castor Guisande, and Julia Toja; Reproductive investment of several rotifer species. Hydrobiologia 255/256:317-324, 1993
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A comparative study was carried out on the seasonal variation in egg and body volumes of four species of rotifers, Brachionus calyciflorus, Brachionus angularis, Keratella quadrata and Anuraeopsis fissa, from ponds near Sevilla and in Donana National Park. Temperature and food concentration significantly affected egg volume in all four species; clutch size significantly affected egg volume in A. fissa, B. calyciflorus and B. angularis but not in K. quadrata. As temperature increased, egg and body volumes declined in A. fissa and B. angularis but increased in K. quadrata and B. calyciflorus due, perhaps, to complex interactions between temperature, food level and clutch size. All four rotifer species responded similarly to changes in food concentration: below a certain food level, egg and body volumes were small but increased to a maximal size, which differed in the four species, as the food concentration was raised. At higher food levels, there was a reduction in egg and body volumes. The food levels for maximum egg and body volumes are interpreted as optimal ones; below these, food limitation reduces the size of the reproducing adult and, consequently, the size of eggs. Above this optimal level, higher food levels accelerated the rotifer life cycles, resulting in adults maturing at smaller sizes with a larger number of smaller eggs.