FIGURE 1.

Experimental design and study system. Populations separated in time of Daphnia magna were revived from dormant embryos resurrected from a sedimentary archive of Lake Ring (Denmark). From each population, 10 genotypes were used in the experiments presented here (N = 30). The three time periods are as follows: (1) eutrophication (EP)—1960–1970—high nutrients and low/no concentration of biocides, (2) pesticide (PP)—1980–1990—high concentration of nutrients and biocides, and (3) clear‐water (CWP) ‐ >1999—low concentration of nutrients and biocides. The 30 genotypes were kept in standard laboratory conditions for two generations (16:8‐h light: dark regime, 20°C and fed ad libitum with 0.8 mg carbon/L of Chlorella vulgaris daily) to control for maternal effect. Following the acclimation phase, clonal replicates of the 30 genotypes were used in multiple common garden experiments in which two algae levels (0.2 mg C/L and 2.4 mg C/L) and two insecticide Carbaryl concentrations (4 and 8 μg/L) were tested in isolation and factorial combinations on a suite of fitness‐linked life‐history traits. HA, high algae; HI, high insecticide; LA, low algae; LI, low insecticide