Fig. 1.

Survival (in percentage) of S. exigua larvae from three strains (with control, cadmium or zinc pretreatment through ten generations) divided into experimental groups accordingly to exposure to control diet or contaminated by cadmium or zinc. Symbols stand for the experimental groups according to metal exposure of 11th generation larvae to control diet: control (originated from control strain), Cd–C (originated from cadmium strain), Zn–C (originated from zinc strain); cadmium-contaminated diet: C–Cd (originated from control strain), Cd–Cd (originated from cadmium strain), Zn–Cd (originated from zinc strain); zinc: C–Zn (originated from control strain), Cd–Zn (originated from cadmium strain), Zn–Zn (originated from zinc strain). Mean value ± SD. Different letters denote significant difference among experimental groups (Kruskal–Wallis test, P < 0.05)