The visual pigments of crabs - I. Spectral characteristics

1. The visual pigments of 27 species of crabs from a variety of habitats were investigated by microspectrophotometry of the isolated rhabdomeric photoreceptors. The rhodopsins ranged in λmax from 473 to 515 nm (Tables 1 and 2). No evidence was found for the presence of more than a single rhodopsin in retinular cells 1-7. 2. All rhodopsins produced thermally stable metarhodopsins on irradiation with long-wavelength light. The metarhodopsins of hermit crabs (Anomura: section Paguridea) all absorbed hypsochromically to their rhodopsins. Brachyuran metarhodopsins. with the exception of that of Cancer irroratus, absorbed at the same spectral position as the rhodopsin or bathochromically to it. 3. The absorption spectra of all rhodopsins but one could be fit closely by the Dartnall nomogram. Since prior studies have located only retinal in the eyes of crabs, retinal may serve universally as a chromophore in crab visual pigments © 1988 Springer-Verlag.

Duke Scholars

Author Richard B. Forward Marine Science and Conservation