Usefulness of the lipid index for biouptake studies with Daphnia magna

Adult Daphnia magna were starved and monitored for lipid content and brood production. Mean lipid index values declined for 72 hours to less than 50% of 24 hour values. Number of hatched young was inversely related to lipid storage and ovary production. Uptake kinetics of 14C-labelled quinoline was compared between two daphnid test groups with mean lipid scores of 5.4 and 2.8, respectively. Total 14C counts were significantly higher for the high lipid group at 8 hour. Our studies indicated that lipid reserves of daphnid test populations can be routinely monitored as an indicator of environmental stress