Effects of temperature on the rate of development of eggs of a planktonic water mite, Piona exigua

1. The eggs of a planktonic, predatory water mile Piona exigua Viets were reared in the laboratory at constant temperatures ranging from 10°C to 280C. Egg development rates increased with increase in temperature. 2. Five models describing the effect of temperature on egg development times were fitted to the data. 3. The variances of the egg hatching times at each temperature differed widely, but these variances were not made more equal by In‐transformation. 4. A simple power curve, fitted to the raw data, accounted for ≥.97% of the variation in the data. Two further models, both of which included a third parameter, provided a better fit at the temperature extremes. 5. Close examination of the patterns of variance at difference temperatures may provide information relating to the pattern of emergence of aquatic poikilotherms. 6. At temperatures below 230C. eggs of Piona exigua developed more rapidly than eggs of Piona constricta, from Heney Lake. Quebec (Riessen, 1982)