Coevolution of pierid butterflies and their cruciferous foodplants : I. The relative quality of available resources.

Two Colorado populations of Pieris butterflies show a spectrum of larval growth responses to potential foodplant crucifer species growing in montane habitats. Analysis of larval growth responses to this array suggests potential selection for differential utilization of these species: 1) available crucifers vary considerably in the rates of larval survival and growth they support; 2) climatological factors favor larvae which develop rapidly. Food-related larval mortality and climatological factors may provide selection for utilization of crucifer species on which larvae develop rapidly.