(^) Copepods probably have several mechanisms for particle feeding. That of
Eucalanus pileatus is well documented. Rudi Strickler and colleagues used high-
frequency movies (to 2000 frames sā1) to capture the movement patterns of feeding
limbs cycling at 50 Hz and higher. Elaborate measures were needed to obtain such
movies, including laser illumination of animals held in position before a microscope
objective by hairs glued to their backs and special mechanisms to move film and
shutters at such high frame frequencies. Strickler developed and applied all that. One
problem was that only a few seconds of filming at 2000 frames sā1 required whole
reels of movie film, which then were evaluated frame-by-frame to determine the
sequence of limb movements. Work along these lines was popular in the 1980s, and
lately more is being done with similarly high-frequency video. Video has also been
used for studies of swimming mechanics. In the form of particle-image velocimetry
(PIV), it has allowed definition of the flow field around feeding copepods, both
tethered and free swimming.
(^) The work on Eucalanus is likely the least affected by tethering (see below) before a
microscope objective, since feeding movements of its mouthparts generate only very
slow motion of the whole body. Koehl and Strickler (1981) described the basic
feeding mechanism. They emphasized that all water movement at the scale of the
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