Fig. 3
On left: adult females of the benthic (upper) and limnetic (lower) species from Paxton Lake, British Columbia. The abdomen of the limnetic female is likely swollen because of an infection by the parasitic cestode, Schistocephalus solidus (photo by T. Hatfield). On right: seining for stickleback in one of the experimental ponds (photo by A. Paccard)