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Vol. 40 No. 1, 2001
Can Copepods Differentiate Prey from Predator
Hydromechanically?
Jiang-Shiou
Hwang1,* and Rudi Strickler2
1Institute
of Marine Biology, National Taiwan Ocean University, Keelung, Taiwan 202
2Great Lakes WATER Institute, 600 E. Greenfield
Avenue, University of Wisconsin-Milwaukee, Milwaukee, WI 53204-2944, USA
Jiang-Shiou
Hwang and Rudi Strickler (2001) Copepods use hydromechanical signals to
detect prey and predators. However, little is known about their
ability to differentiate prey from predators, neither from random water
flow. We used laser- and video-optical equipment with a modified
Schlieren optical pathway to observe a tethered copepod under variable
hydrodynamic conditions. The results suggest that the copepod can
distinguish between hydromechanical signals generated by an external
source and those created by its own feeding current, even when these
disturbances are within a similar speed range, as defined by
measurements of spatial displace-ment of suspended particles. The
data suggests that planktonic copepods may use a simple form of pattern
recognition to distinguish between sources of signals: predators, prey,
or random flow.
Key words: Calanoids,
Centropages hamatus, Random flow, Escape reactions, Pattern recognition.
*Correspondence: Tel: 886-2-24622192 ext. 5304. Fax:
886-2-24629464. E-mail: Jshwang@mail.ntou.edu.tw
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