A Protozoon (Dileptus; Ciliata) Predatory upon Metazoa

Brown, Harley P.; Jenkins, Marie M.

doi:10.1126/science.136.3517.710

Cited by 11 publications

(6 citation statements)

References 3 publications

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“…Systematics used are those of Lynn & Small (2000). Feeding types are the particle size-class grazed (pico-, nano-or microplanktonic) and whether the ciliates are primarily interception or filter feeders, based on literature summarized by Foissner et al (1999) as well as specialized literature (Brown & Jenkins 1962, Jonsson 1986, Müller 1991, Kivi & Setälä 1995, 2imek et al 1995, Kenter et al 1996, Jürgens & 2imek 2000, Weisse et al 2001. R 2 values are the proportion shared variance between the species and either the cluster to which they belong, or the cluster where the R 2 value is the next highest.…”

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“…They could presumably counterbalance effects arising from P-depleted algae (Hochstädter 2000) by bacterivory and experience less grazing pressure owing to reduced daphnid biomass. The largest size class (>100 µm), as well as Clusters 1 and 9 (made up of ciliates such as Lacrymaria, Paradileptus and Dileptus), while in part algivorous, are also predacious, feeding on other ciliates, rotifers 258 Gaedke & Wickham: Seasonal and long-term dynamics of ciliates and large algae (Brown & Jenkins 1962, Foissner et al 1999. They were, therefore, less likely to be competitors with, or prey of, cladocerans, and in fact, with the exception of July, had weak or no correlations with cladoceran biomass.…”

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Ciliate dynamics in response to changing biotic and abiotic conditions in a large, deep lake (Lake Constance)

Gaedke¹,

Wickham²

2004

Aquat. Microb. Ecol.

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From 1987 to 1998, ciliates and their prey and predator communities in Lake Constance (which is large, deep and meso-eutrophic) were intensively studied as the lake underwent reoligotrophication. Ciliate biomass exhibited the bimodal seasonal distribution typical for mesoeutrophic lakes, with high biomass in spring and summer and low biomass in winter and during the clear-water phase. Cluster analysis produced 9 groups of temporally co-occurring ciliate morphotypes with potentially similar ecological characteristics. The clusters exhibited a larger seasonality than found in the size distribution, showing that size alone failed to capture some ciliate seasonal dynamics. Ciliate biomass declined by approx. 30% during the 12 yr of study, i.e. considerably less than daphnids (and total phosphorus). This yielded a significant increase in the ratio between summer ciliate and daphnid biomass as re-oligotrophication progressed, in contrast to previous studies. Few indications for a mechanistic link between phosphorus concentrations (which declined 3-fold during the study period) and ciliate biomass or community composition via group-specific food concentrations were found. The relative contribution of 3 of the 9 clusters changed as re-oligotrophication progressed. Ciliate size distribution was related to re-oligotrophication and daphnid biomass in summer. The smallest and largest ciliates gained importance when daphnids decreased, whereas the biomass of large ciliates declined. Generally, summer daphnid biomass had a greater predictive power for attributes of the ciliate community than the other factors studied (phosphorus, prey biomass, copepod biomass). The extent of bottom-up and top-down control of ciliates appeared to be time-and groupspecific. Overall, the ciliate community exhibited remarkably recurrent seasonal patterns, despite major alternations in abiotic and biotic conditions. KEY WORDS: Ciliates · Long-term observations · Bottom-up control · Top-down control · Eutrophication · Daphnids · Copepods Resale or republication not permitted without written consent of the publisherAquat Microb Ecol 34: [247][248][249][250][251][252][253][254][255][256][257][258][259][260][261] 2004 ton) may be closely linked and subject to external forcing by climate and nutrient changes.In Lake Constance, which is large, deep and mesoeutrophic, intensive investigations of the planktonic ciliate community revealed recurrent seasonal patterns in ciliate abundances and taxonomic community composition from 1987to 1989(Müller 1989. Biomass peaks developed in early spring immediately after the onset of phytoplankton growth, and in summer/autumn after the clear-water phase, during which time ciliate biomass was low. In spring, small algivorous ciliates such as Balanion planctonicum were typical, while the summer community was characterized by a somewhat higher variability in taxonomical composition and feeding types (Müller 1989. Laboratory studies provided insight into ciliate ingestion and production rates, preferred algal...

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confidence: 99%

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confidence: 99%

Ciliate dynamics in response to changing biotic and abiotic conditions in a large, deep lake (Lake Constance)

Gaedke¹,

Wickham²

2004

Aquat. Microb. Ecol.

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“…Since previous laboratory and field studies have shown the incidence of predation on triclads to be highly variable and dependent on the type of predator (Jennings, 1957 ;Brown & Jenkins, 1962;Young & Reynoldson, 1965 ;Davies, 1969 ;Davies & Reynoldson, 1971;Coward & Piedilato, 1972 ;Wright, 1975 ;Beveridge, 1982), the proposition that rhabdoids generally act as anti-predator devices by being distasteful must be seriously questioned .…”

Section: Discussionmentioning

confidence: 99%

Distribution, abundance, and size of rhabdoids in Dugesia polychroa. (Turbellaria: Tricladida)

Wrona

1986

Hydrobiologia

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The ontogenetic changes in the distribution, abundance, and size of rhabdoids were examined in an undisturbed laboratory population of Dugesia polychroa. Irrespective of triclad age, rhabdoids in the epidermis and parenchyma were more abundant on the dorsal than the ventral side of the body. No significant differences were found in the abundance of epidermal or parenchymal rhabdoids among the anterior, medial, and posterior regions of the body. Rhabdoid number and size changed significantly with triclad age, with a marked depression coinciding with the onset of cocoon production . Rhabdoid discharge was correlated with physical and/or physiological disturbance and occurred in the absence of any overt environmental disturbance. Simple allometric relationships were observed between rhabdoid size and number on one hand and body plan area on the other. Different allometric trends were observed from field-collected individuals compared to the undisturbed laboratory population . The potential function of rhabdoids in the Tricladida is discussed in light of these findings .

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“…Damselfly and dragonfly nymphs appear to be the only predators of any importance (Young and Reynoldson, 1965). Young Dugesia, however, may be attacked and consumed by the protozoan Dileptus if the concentration of the latter is high (Brown and Jenkins, 1962).…”

Section: Nutritionmentioning

confidence: 99%