Ref ID : 714
Terry W. Snell; Effect of temperature, salinity and food level on sexual and asexual reproduction in Brachionus plicatilis (Rotifera). Marine Biology 92:157-162, 1986
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The reproductive response of sexual and asexual female Brachionus plicatilis (Muller) was examined over temperatures ranging from 20 and 40 degrees C, salinities from 5 to 40 0/00S, and food levels from 0.25 to 20 ug Chlorella vulgaris dry-weight per ml. Reduced food levels, as well as temperature and salinity extremes, reduced reproduction of both sexual and asexual females, but did so differentially. Reproduction by sexual females was reduced to a greater extent at environmental extremes than asexual females. The broad, flat reproductive response curve of asexual females extended beyond the limits of the narrower, more sharply peaked curve of sexual females. Thus zones of exclusively asexual reproduction exist at environmental extremes where sexual reproduction is physiologically restricted. These results are corroborated by a comparison of the lifetime fecundity of individual sexual and asexual females over a 20 degrees C temperature range. No differences in lifetime fecundity reached its highest level, while sexual female fecundity declined 15%. The appearance of sexual females in rotifer populations is result of both inducible and repressible factors.