Modes of cell capture in calanoid copepods1

Abstract

High-speed cinematography was used to observe adult female copepods feeding in pure cultures of roughly spherical algal cells ranging from 4.5 to 22.0 pm in diameter. Eucalanus pileatus and Puraculunus puruus detect and handle individual cells as small as 12 pm. Continuous low amplitude movement of the second maxillae and combing of the appendages is used by E. pileutus to capture cells smaller than the 12qm sensitivity threshold. Different energetic costs are probably associated with capturing small and large cells, and the probability of copepods encountering large cells should be greatly increased due to remote detection. The above suggests that descriptions of selective feeding in grazing trials using Coulter Counter data are influenced by the size above which the copepods can detect individual cells and by the proportions of the pregrazing particle spectrum larger and smaller than this threshold.

The feeding response of a marine planktonic copepod to quantity and quality of particles

“…During this acclimation period CIV moulted to CV within 24 to 48 h. Little mortality occurred during the experiments. All studies were run at 20 "C in a light-dark cycle of 14:10 h. High-speed movies were made with fertilized E. pileatus females, usually acclimated to experimental conditions for 48 h (Price et al 1983).…”

“…The method used to film copepod feeding behavior was similar to that employed by Price et al (1983). Hairs were glued onto Eucalanus pileatus females 18 to 24 h prior to filming.…”

Water flows produced by Daphnia and Diaptomus: Implications for prey selection by mechanosensory predators

“…1 D). This oscillatory flow is caused by the periodic flapping movements of the mouthparts and has been reported in other calanoids by Koehl and Strickler (198 1) and Price et al (1983).…”

“…Gig&e and Dill (1979) attempted to measure the "acoustic" signals produced by Daphnia and Diaptomus by gluing the animals to an insect pin that was attached to the diaphragm of an uncalibrated transistor radio earphone; at best, this method detects the cuticle vibrations of zooplankters, but it cannot detect the water flows produced by zooplankton prey. Strickler and his coworkers have successfully used high-speed cinematography to study the feeding and swimming behavior of calanoids (Koehl and Strickler 1981;Strickler 1982;Cowles and Strickler 1983;Price et al 1983). They measured water flow velocities (both magnitude and direction) by observing the displacements of dye streams or particles suspended in the water.…”

The influence of a severe reservoir drawdown on springtime zooplankton and larval fish assemblages in Red Willow Reservoir, Nebraska

“…Calanoid copepods create currents to obtain small food particles (1 mm to 1 mm), whereas cyclopoid copepods are grasping feeders that eat larger food items (Maly and Maly 1974;Kerfoot 1978;Wong 1984). As turbidity and Chl-a increased, food items for calanoids could have decreased while those for cyclopoids increased; alternatively, calanoids may have had difficulty detecting their food items as a result of the increased turbidity (Strickler 1982;Andrews 1983;Arruda et al 1983;Price et al 1983;DeMott 1986;Legier-Visser et al 1986;Van Alstyne 1986). It is also possible that changes in zooplankton abundance and assemblage composition were a consequence of changes in predation by a larval fish assemblage that was dissimilar between pre-drawdown and post-drawdown (sensu Martin et al 1981;Turner et al 2005;Olds et al 2014).…”