The influence of temperature upon the duration of embryonic development of tropical Brachionus species ( Rotifera).

Abstract

The duration of embryonic development of Brachionus caudatus from the tropical reservoir, Parakrama Samudra, was determined at several constant temperatures and compared with data on B. calyciflorus from a neighbouring water body. Duration-temperature regressions differed in elevation, but not in slope for 28oC. They predict a duration of embryonic development 5.67 ha for B. caudatus and 10.51 for B. calyciflorus. The difference lay not in their responses to temperature, since the Q10 values are similar, but in the leftward shift of the development rate-temperature curve for B. caudatus with respect to that for B. calyciflorus. The experimental B. caudatus were smaller (97-127 mu m in length) than B. calyciflorus (295 mu m) and were carrying small eggs (0.079-0.148 X 106 mu m3 compared with 0.641 X 106 mu m3 for B. calyciflorus). The shorter durations of B. caudatus are possibly due to the smallness of the eggs produced by the small adult females which were characteristic of the planktonic populations inhabiting the lake.-from Author