Polarization
Vision in Wolf Spiders
1.3 Mb download, requires the Quicktime plugin, available free
from Apple.
This movie shows a wolf spider (Pardosa tristis)
running on a ball that is suspended on a frictionless air cushion.
The spider is stimulated to run by a light touch from a probe
applied to its rear legs. Once it commences running, its motion
is tracked by optical sensors, which can be seen to illuminate
at the rear of the ball. The motion is analysed before and after
rotation of a polarized light source (out of view at the top of
the image) in order to establish the spiders response to rotation
of the e-vector of polarized light. Towards the end of this sequence,
the spider is seen to turn the ball.