Experimental Studies on Temperature-Dependent Embryonic and Postembryonic Developmental Rates of Bosmina Longispina Maritima (Cladocera) in the Baltic

Abstract

For postembryonic studies, a laboratory culture apparatus was constructed, where the risk of animals being trapped in the air/water interface was eliminated. The embryonic development (in days) both for resting eggs and parthenogenic eggs could be predicted between 1.5-15'C by the equation log, De = 3.346 0.165 -1 + 0.003T2 which below 10'C is considerably different from predictions by other equations found in literature of which most are based on experiments made at higher temperatures. It was possible to predict the duration of the embryonic development in the field by this equation, obtained at constant temperatures, by using the weighted mean temperatures for the field periods. These experiments indicated that the postembryonic development cannot be predicted by a temperature-dependent relationship only since food conditions have an effect on the duration of the pre-adult period. Laboratory culture experiments where natural water is used as the culture medium are preferable since non-controllable food conditions occur in longterm field experiments.