Relationship between Water Temperature and Bisexual Reproduction Rate in the Rotifer Brachionus plicatilis

Abstract

Brachionus plicatilis was cultured individually and successively under four (15, 20,25 and 30°C) temperature conditions, and the frequency of mictic female production was examined. In order to avoid the density effect derived from accumulation of metabolites, culture medium was renewed at regular intervals proportionally to the metabolic rate which was specific to each temperature. The hereditary differences in bisexual reproductivity existing among strains could be negligible through experimenting on identical strain. A hundred substrains were made from the same stock, and cultured for 7–8 generations, picking up five offsprings in one generation-one strain. Data from the initial two generations were rejected, because a temporary lowering of mictic female production was observed just after the transference into new environmental condition. Bisexual reproduction rate increases in lower temperature below 25°C. There is no significant diferrence between 25 and 30oC groups. © 1984, The Japanese Society of Fisheries Science. All rights reserved.