COMPARISON OF THE PIGMENTARY EFFECTOR TROPINS IN THE EYESTALKS AND ABDOMINAL NERVE CORD OF THE PRAWN PALAEMONETES VULGARIS

¹ Department of Biology, Tulane University, New Orleans, Louisiana 70118, Department of Biology, Louisiana State University in New Orleans, New Orleans, Louisiana 70122 and Marine Biological Laboratory, Woods Hole, Massachusetts 02543

1. Extracts of the eyestalks and abdominal nerve cords of the prawn Palaemonetes vulgaris were chromatographed on Bio-Gel P-6. The fractions of both extracts revealed melanin-dispersing activity in the fiddler crab Uca pugilator and red and white pigment-dispersing activities and distal retinal pigment light-adapting activity in the prawn. In addition, the eyestalk fractions contained red and white pigment-concentrating activities whereas only the red pigment-concentrating activity was found in the fractions of the abdominal nerve cords.

2. The pigment-dispersing and distal retinal pigment light-adapting activities were eluted from the column ahead of the pigment-concentrating activities and were consequently separated from them. However, the pigment-dispersing and distal retinal pigment light-adapting activities did not separate from each other. The pigment-concentrating activities likewise did not separate from each other.

3. The substance from the prawn which evokes melanin dispersion in the fiddler crab is not the substance that causes red pigment dispersion and perhaps white pigment dispersion as well in the prawn itself.

4. Furthermore, dispersion of the red and white chromatophoric pigments in the prawn is not caused by the substance that evokes light adaptation of its distal retinal pigment.

5. Evidence is presented to support the hypothesis that light-adaptation of the distal retinal pigment in Palaemonetes is caused by the substance found in the prawn that causes melanin dispersion in the fiddler crab. Palaemonetes itself lacks melanophores.