Chromatophore Activity in relation to Temperature and Eyestalk Extract Concentration.



  • 1The rate of contraction of the red chromatophore of the shrimp is influenced by temperature and by the concentration of eyestalk extract.
  • 2The initiation of chromatophore activity requires a definite minimum concentration of eyestalk extract; the concentration necessary varies with temperature. Above this threshold concentration, the response of chromatophore cells at a given temperature is the same for different concentrations of extract.
  • 3When the conditions necessary for the initiation of the chromatophore activity are fulfilled, an increase in temperature from 15.6° to 20.7°C. results in a linear increase in the rate of chromatophore contraction. Above this temperature the rate of contraction is constant and independent of temperature up to 30°C.
  • 4Chromatophore cells in extracts of a concentration lower than the threshold value behave like controls in pure Ringer. They remain in the wholly dispersed state for a considerable length of time, without showing any sign of pigment concentration.