Philodina megalotrocha were grown in isolation culture in Knop's solution or variations thereof, buffered at pH 8.4, at a constant temperature of 30° C. Temperature toleration ranged from 5° C. to 35°C. Upper and lower limits of pH tolerance were pH 10.2 and pH 4.0. Longevity in low salt concentrations (0.02 percent) was increased over that of high concentrations; egg production was not altered except at high concentrations (0.06 percent), at which point it was very low. The effects were tested, one at a time, of high and low concentrations of calcium, magnesium, and potassium. In low calcium solutions longevity was increased, but when magnesium was used as a variable and calcium and potassium held constant, the pattern for calcium did not occur. The results with potassium were similar to those obtained with calcium. Also, potassium, under the conditions of this experiment, appeared to affect longevity. In low potassium concentrations fertility was approximately doubled.
Proceedings of the Iowa Academy of Science
©1959 Iowa Academy of Science, Inc.
Pray, Francis A.
"Experimental Studies on the Effects of Certain Environmental Factors on Fecundity and Longevity of the Rotifer,"
Proceedings of the Iowa Academy of Science, 66(1), 432-442.
Available at: https://scholarworks.uni.edu/pias/vol66/iss1/60