Effects of copepod foraging behavior on predation risk: An experimental study of the predatory copepod Pareuchaeta norvegica feeding on Acartia clausi and A. tonsa (Copepoda)

Tiselius, Peter; Jonsson, Per R.; Kuurtvedt, Stein; Olsen, Esben Moland; Jørstud, Tom

doi:10.4319/lo.1997.42.1.0164

Cited by 81 publications

(75 citation statements)

References 16 publications

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“…Swimming behavior-Elevated rates of predation mortality may be associated with feeding (Tiselius et al 1997) and mating activities in copepods (Maier et al 2000). Such behaviors may therefore reflect conflicts between different objectives.…”

Section: Discussionmentioning

confidence: 99%

Motility patterns and mate encounter rates in planktonic copepods

Kiørboe

Bagøien

2005

Limnol. Oceanogr.

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Mate encounter rates in pelagic copepods depend on the characteristics of the mate detection mechanism as well as on the motility patterns and concentrations of males and females. We describe male and female motility patterns in two species (Centropages typicus and Pseudocalanus elongatus) in which the females excrete male-attracting pheromones and in one species (Acartia tonsa) in which the mates are detected by hydromechanical signals. For both pheromone-producing species, male and female motilities differ strongly; males are more directionally persistent and swim as fast as or faster than the females, and only at scales exceeding several centimeters do the male motilities resemble random walk. This prevents resampling of the same volume at the scale of encounter and maximizes the rate at which males encounter female signals. In contrast, female motility patterns are more similar to random walk, even at small scales. For the species depending on hydrodynamic cues and in which detection is practically symmetrical between the mates, male and female motilities are similar and can both be described as random walk, also at small scales. We develop simple encounter models and utilize information on motility patterns and mate signaling from our own observations and the literature to estimate search volume rates for pelagic copepods ranging between 0.6-3.0 mm in length. We show that pelagic copepods are capable of searching tens to thousands of liters of ambient water for mates daily, that search capacity increases approximately with the cube of copepod length for both chemical and hydrodynamic signalers, and that these impressive mate search volume rates are sufficient to sustain populations at typical adult densities.

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Section: Discussionmentioning

confidence: 99%

Motility patterns and mate encounter rates in planktonic copepods

Kiørboe

Bagøien

2005

Limnol. Oceanogr.

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“…(b) Predation risk and optimal foraging behaviour Feeding exposes a zooplankton to predation risk (Tiselius et al 1997), and the magnitude of the risk depends on the feeding behaviour. We can now use the model and our description of the imposed flow field to estimate the distance at which a mechanoreceptory predator may detect an ambush-feeding copepod, and compare that with estimates for the two other feeding modes (cruising and feeding-current feeding).…”

Section: Discussionmentioning

confidence: 99%

“…Thus, ambush feeders typically reposition by jumping upwards every 1 -10 s Titelman & Kiørboe 2003). As a result, the frequent weak repositioning jumps may create a hydrodynamic signal that may expose ambush feeders to a significant predation risk (Tiselius et al 1997).…”

Section: Introductionmentioning

confidence: 99%

Danger of zooplankton feeding: the fluid signal generated by ambush-feeding copepods

2010

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Zooplankton feed in any of three ways: they generate a feeding current while hovering, cruise through the water or are ambush feeders. Each mode generates different hydrodynamic disturbances and hence exposes the grazers differently to mechanosensory predators. Ambush feeders sink slowly and therefore perform occasional upward repositioning jumps. We quantified the fluid disturbance generated by repositioning jumps in a millimetre-sized copepod (Re $ 40). The kick of the swimming legs generates a viscous vortex ring in the wake; another ring of similar intensity but opposite rotation is formed around the decelerating copepod. A simple analytical model, that of an impulsive point force, properly describes the observed flow field as a function of the momentum of the copepod, including the translation of the vortex and its spatial extension and temporal decay. We show that the time-averaged fluid signal and the consequent predation risk is much less for an ambush-feeding than a cruising or hovering copepod for small individuals, while the reverse is true for individuals larger than about 1 mm. This makes inefficient ambush feeding feasible in small copepods, and is consistent with the observation that ambush-feeding copepods in the ocean are all small, while larger species invariably use hovering or cruising feeding strategies.

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“…The swimming behavior of Acartia tonsa in filtered water has been described as monotonic jumping (Tiselius & Jonsson 1997 ) for 1.9 ± 0.1 2.0 ± 0.1 2.0 ± 0.0 2.0 ± 0.0 2.1 ± 0.0 4 treatments 2.9 ± 0.1 2.9 ± 0.1 2.9 ± 0.0 3.0 ± 0.0 3.1 ± 0.0 7.0 ± 0.0 7.2 ± 0.1 6.7 ± 0.0 7.7 ± 0.1 7.6 ± 0.2…”

Section: Methodsmentioning

confidence: 99%