Fall Composition of Storage Lipids is Associated with the Overwintering Strategy of Daphnia

This study was aimed at evaluating whether the composition of storage lipids in the fall differs between diapausing and active overwinteringDaphnia. We assessed the quantity of storage lipids and fatty acid (FA) composition ofDaphnia species, along with FA content of seston, in six boreal, alpine and subarctic lakes at the onset of winter, and evaluated the association between storage lipids andDaphnia overwintering strategy. We found that active overwinteringDaphnia had>55% body fat and the highest FA concentrations. Polyunsaturated FA, especially stearidonic acid (18:4n-3; SDA) and high ratios of n-3:n-6, were preferentially retained to a greater extent in active overwinteringDaphnia than in those that entered diapause.Daphnia FA composition was independent of that of the seston diet, indicating thatDaphnia adjusted their storage lipids according to the physiological requirements of a given overwintering strategy. The occurrence of an active overwintering strategy has consequences for zooplankton community structure, and can have important implications for the transfer of high-quality energy at higher trophic levels.

Source: Lipids - December 14, 2016 Category: Lipidology Source Type: research