Fig. 1.

Generation of starvation-resistant flies. (A) Three outbred fed control (F) populations and three starvation-selected (S) populations were used in these experiments. S populations were maintained on agar until only 15% of the population survived, then were transferred to food to lay eggs. F populations were maintained on food throughout this process. These steps were repeated for >60 generations. (B) All three F populations (top) are visibly smaller than S groups (bottom). (C) Survival of individual flies was measured following transfer of flies onto agar. All S populations survived significantly longer on agar compared with F flies (Kaplan–Meier analysis: χ²=155.5, d.f.=1, P<0.001 between S and F populations).