Fig. 2

Phototaxy plastic chamber used to determine effects of light on cercarial behavior, comprising two zones each with a length of 20 cm. One zone was dark (covered with black plastic) and the other was uncovered and exposed to light. Illumination (cold light from a Leica microscope) was placed in the light end. Cercariae were placed by pipette on the border between zones (dark spot). The location of 60 cercariae was determined after 60 min incubation