Fig. 2

Population means for paired and solitary threespine stickleback in small coastal lakes of British Columbia, Canada. Gill rakers are filaments on the internal gill arches and are involved in filtering prey from ingested water and directing it to the gut. Gill rakers are generally longer and more numerous in fish that consume zooplankton (such as the limnetic stickleback species) than in fish that consume larger invertebrates or fish. Symbols refer to the benthic (filled circle), limnetic (empty circle), and solitary species. Modified from Schluter (2000), after Schluter and McPhail (1992)