Shown are male mandible size (mm) (a), male abdomen size (mg) (b), male body size (mg) (c), female abdomen size (mg) (d) and female body size (mg) (e) (population means). Black circles are the control populations that were not subjected to selection by predation. Blue squares and red triangles, are the populations with male and female exposure to predators, respectively. Note we did not measure female fitness (lifetime reproductive success: LRS) at every generation as it was not logistically possible. Population means (estimated by measuring 50 male and females per generation), for each population/treatment are shown because only populations evolve and thus population is the biologically relevant unit of replication in an experimental evolution study. Source data are provided as a Source Data file.