A laboratory examination of light as a proximate cue for Chaoborus flavicans vertical migration.

Abstract

Very few manipulative studies have been performed to elucidate the cues for vertical migration in zooplankton. In our study we attempted to test the hypothesis that light is the proximate cue for vertical migration in Chaoborus flavicans. We expected that light would cue C. flavicans to vertically migrate toward the bottom of a water column. However, we found positive phototaxis as well as indications that endogenous rhythms play a role in regulation of vertical migration. Despite the simplicity of our study, which limited its interpretive abilities, we were still able to come up with some very important information. C. flavicans responds to light, but other factors such as prey, endogenous rhythms and temperature probably also play a role in regulating vertical migration in C. flavicans.