Phototaxis and geotaxis of light-adapted zoeae of the golden king crab Lithodes aequispinus (Anomura: Lithodidae) in the laboratory

Phototaxis and geotaxis of light-adapted zoeae of the golden king crab Lithodes aequispinus Benedict were investigated in the laboratory. Stages I, II, and III zoeae were positively phototactic to white-light intensities of 1.5 x 10(15) q s(-1) cm(-2) and 3.1 x 10(13) q s (1) cm( 2). No significant response was observed in zoeae of any stage to 7.3 x 10(11) q s(-1) cm(-2). Negative geotaxis was observed in all three stages, although this response was significantly diminished in stages II and III. These behaviors are similar to those seen in stage I larvae of the red king crab Paralithodes camtschaticus, as well as in later zoeal stages of several brachyuran crabs.