Contrast Orientation in Daphnia Magna and Its Significance for Vertical Plane Orientation in the Pelagic Biotope in General

Publisher Website
Google Scholar
Abstract
1. Optical orientation to light-dark boundaries in the cladoceran Daphnia is called contrast orientation. 2. It is suggested that vertical plane orientation in planktonic crustaceans in general is optical orientation and that contrast orientation is possible in the pelagic biotope. 3. Results of experiments clarifying the mechanism of contrast orientation in Daphnia magna are discussed. 4. These results lead to the proposition of an orientation area consisting of 3 median pairs of ommatidia and 2 lateral pairs situated dorsally from the eye axis. 5. Several modes of orientation can be distinguished and it is argued that in a particular case different pairs of ommatidia might have the orientation function. 6. A general model of the mechanism of contrast orientation in Daphnia magna is presented.

This publication has 0 references indexed in Scilit: