Fig. 1.

Diagram of experimental design. Note that F₆ is not shown in the figure because it was not reared to the adult stage after eggs were collected. High and low density refer to larval rearing density and are described in the Methods. An arrow represents the end of a generation, with each generation ending at the adult stage and the subsequent generation beginning with eggs. Rectangles with an alphanumeric code represent rearing of strains from egg to adulthood (i.e., one generation).