Fig. 12. Navigational and mechanical behaviors decoupled. Evolutionary trajectory of the population mean in [NP, k] behavior space, from generation 1 to 10 (italic numbers). Arrowheads indicate the presence of selection. Note that while selection always acts to increase NP, two selection events increase and two decrease k. Moreover, large changes in NP, from generation 2 to 4, driven by chance, occur with little or no change in k. The points are the mean values for the population (N=3), and the ellipses represent the population's footprint in behavior space (axes ± 1 s.e.m.).