ABSTRACT
Animals typically search for food, hosts, and sexual partners and avoid predators in complex, spatially and temporally structured environments. The resulting movements have implications for the optimization of food search patterns, energy investment, habitat selection, and territorial and social behaviors (Morse, 1980; Pyke, 1984; Stevens and Krebs, 1986; Bell, 1991; Turchin, 1998; Boinski and Garber, 2000). In zooplankton ecology, examples come from the wide spectrum of swimming behaviors related to the species (Tiselius and Jonsson, 1990), the age (Coughlin et al.,
1992; van Duren and Videler, 1995; Fisher et al.,
2000; Titelman, 2001), the prey density (Tiselius, 1992; Bundy et al.,
1993; Dowling et al.,
2000), the presence of a predator or a conspeciÞc (van Duren and Videler, 1996; Tiselius et al.,
1997; Titelman, 2001), the sex of individuals (van Duren and Videler, 1995; Brewer, 1998; Strickler, 1998), the information imparted into the surrounding water by a swimming animal (Yen and Strickler, 1996; Gries et al., 1999), including both chemical (Yen et al.,
1998; Weissburg et al.,
1998) and hydromechanical (Costello et al.,
1990; Marrasé et al.,
1990; Hwang and Strickler, 1994; Hwang et al.,
1994; Brewer, 1998) stimuli. Moreover, considering that environmental complexity affects the movement patterns of animals (e.g
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