Testing the Optomotor Response in Sepia bandensis

Cephalopods (octopus, squid, and cuttlefish) have commonly been used as models to test visual function and camouflage due to their similarity in eye morphology with humans and because of their readily observable changes in body color in response to visual stimuli. Most studies have used a single species, Sepia officinalis, to make broad conclusions about camouflage and vision. However, these generalizations may not be applicable to all species. Here, I have examined visual function of the dwarf cuttlefish (Sepia bandensis), which differs from S. officinalis in habitat, geographic range, and size. Using the optomotor response, I quantified the minimum separable angle (MSA) of resolution, a behavioral measure of visual acuity, by recording cuttlefish movement in response to rotating black and white stripes of decreasing stripe width. The threshold of visual acuity for these experiments was a stripe width of 5mm and a MSA of 3.76°. These results indicate that S. bandensis has poorer visual acuity than S. officinalis (MSA 0.57°), and therefore, may be less able to resolve fine details in the environment. The ability to perceive these fine details enables animals to navigate, forage, and communicate with conspecifics. Future work should examine the behavioral ecology of S. bandensis to understand the biological and physical environmental context in which visual cues are used by this species