Friday, February 25, 2005

It's not easying seeing green

As I mentioned before, the current big project that we're working on right now deals with whether or not cuttlefish are colorblind. The current data supports that they have only one visual pigment that allows them to see in shades of green. In order to test this, Lydia constructed 18 checkerboard substrates in which a green checker remained constant and the intensity of the other checker varied from white to black. At some point, the intensity of the gray match that of the green. It is believed that the cuttlefish would not be able to distinguish this substrate from the others. And so far, that's what the data appears to indicate. The way we tell this is by lots and lots of video data :P It is already known that cuttlefish put on a disruptive pattern on a high contrast substrate.

If the substrate is uniform, or they perceive it to be, then the pattern will be as well.

Here is a sample of what we have been seeing which seems to indicate that cuttlefish are indeed colorblind.

At Substrate 1, white and green, which is a high contrast substrate, a disruptive pattern is shown.

At Substrate 8, in which the intensity of the gray and green are match, a uniform pattern is shown.

At Substrate 16, black and green which also happens to be the highest contrast substrate besides black and white, a strong disruptive is shown.

This study also gave insight onto the contrast detection of Sepia officinalis. It would be expected that since they appear to be colorblind, they would have very good contrast detection to enable such remarkable camouflage abilities. However, it appears to be only around 20%.


Post a Comment

<< Home