Fig. 1

Sampling sites in the three crater lakes fields in Uganda and at the supra-regional scale. a Ndali-Kasenda crater lakes. b Bunyaruguru crater lakes. c Populations from East Africa. d Fort Portal crater lakes. Snail symbols indicate localities of Bulinus populations studied, whereas a star indicates when sampling did not yield a Bulinus population in the respective crater lake. Note that data for some populations used were retrieved from GenBank (see Table 1)