Meeting Abstract

P1.173  Wednesday, Jan. 4  Chromatophore control mechanisms underlying crypsis in the European cuttlefish, Sepia officinalis. HADJISOLOMOU, S.P.*; GRASSO, F.W.; The Graduate Center of the City University of New York; The Graduate Center of the City University of New York

Cephalopods control light reflected off their skin for crypsis and communication. Muscle-effected dilation and contraction of chromatophores allow for sub-second changes in skin reflectance to match benthic substrata or for signaling to conspecifics or predators. These behaviors are modulated by visual input from the optic lobes. From the optic lobes, the bilateral, interconnected lateral basal lobe and anterior and posterior chromatophore lobe networks contribute to motor programs that control the state of chromatophores. While the anatomical arrangement of the neuro-muscular components and the sensory contributions of the visual system have been documented, the organizing mechanisms that control body patterns have received less attention. We recorded high speed (100 Hz) video of changes in skin reflectance from a European cuttlefish, Sepia officinalis (Linnaeus, 1758) following brief (100 microsecond duration) intense light flashes presented to the eyes. This stimulus was adequate to trigger chromatophore responses, producing spatial gradients of contrast across the mantle. These responses were slow to be triggered, initiating with a delay of 130 milliseconds. Time-spectral analyses of the responses from individual mantle regions of skin (< 0.25 mm2) provide evidence for several processes, which involved brief dilation followed by gradual contraction of the chromatophores. These processes resulted in differential intensities of reflected light off the skin. The responses could be long, lasting up to 4 seconds. The long duration of these responses may reflect the persistence of a sensory trace of our intense flash input. The responses also suggest potential opponent processes at work, consistent with a system that adapts to ambient light level, which changes in the natural environment.