Interspecific Morphogens Regulating Prey-Predator Relationships in Protozoa

Kuhlmann, Hans-Werner; Heckmann, Klaus

doi:10.1126/science.227.4692.1347

Cited by 112 publications

(78 citation statements)

References 11 publications

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“…Although the induced defence is energetically more costly than the constitutive form, it is very effective, especially when prey can adjust the extent of their reaction to the real predatory threat (Tollrian & Harvell 1999). This has been thoroughly studied in several ciliates from the genera Euplotes, Colpidium and Coleps (Kuhlmann & Heckmann 1985, Fyda & Wią ckowski 1998, Wickham & Gugenberger 2008 as well as in green algae (Lürling & Van Donk 1996) and cyanobacteria (Fia8kowska & Pajdak-Stós 2002). Our observations strongly support the results obtained by Fia8kowska & Pajdak-Stós (2002), in that Phormidium adapts its induced defence to grazer pressure and density.…”

Section: Effects Of Pseudomicrothorax On Induced Defence In Phormidiumsupporting

confidence: 84%

Dynamics of cyanobacteria–ciliate grazer activity in bitrophic and tritrophic microcosms

Fyda¹,

Fiałkowska²,

Pajdak‐Stós³

2010

Aquat. Microb. Ecol.

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Direct and indirect interactions among components of bitrophic and tritrophic communities were studied using laboratory microcosms. The filamentous cyanobacterium Phormidium sp., capable of inducible defence, was used as the primary producer. Phormidium reacts to ciliate attacks by withdrawing inside a polysaccharide envelope, overproducing exopolysaccharide material and remaining in dense and compact clumps. All of these defences are induced by the ciliate Pseudomicrothorax dubius, a specialised grazer of filamentous cyanobacteria, representing the second trophic level in our system. The gymnostomatid ciliate Homalozoon vermiculare, which preys on Pseudomicrothorax but does not directly affect cyanobacteria, was the top predator within the microcosm community. The experiment showed that Homalozoon, very effective in a simple bitrophic cascade, had little effect on its prey when Phormidium was introduced into the system. Under grazer pressure, the cyanobacterium defended itself against the grazer by creating clumps of entangled filaments that also served as refuges for Pseudomicrothorax from Homalozoon. The prey ciliate Pseudomicrothorax reacts to cyanobacterial defence by increasing its encystation rate. Gradually decreasing grazing pressure resulted in a diminished Phormidium defence reaction, which enabled Pseudomicrothorax to resume feeding on filaments. Changing the extent of induced defence in Phormidium thus resulted in the stabilisation of the microcosm community.KEY WORDS: Ciliated protozoa · Homalozoon · Induced defence · Phormidium · Predator-prey interactions · Pseudomicrothorax Resale or republication not permitted without written consent of the publisherAquat Microb Ecol 59: [45][46][47][48][49][50][51][52][53] 2010 and stability of the E. coli population increased following the invasion. Ko8aczyk and Wią ckowski (1997) showed reduced predation on ciliate Euplotes octocarinatus by Stylonychia mytilus in the presence of an abundant green flagellate population, which served as alternative food for the predator. Trophic cascade interactions are also modified when the prey has access to refuges (Křivan 1998) or activates predatorinduced defences (Fia8kowska & Pajdak-Stós 1997, Fyda 1998, Tollrian & Harvell 1999, Pajdak-Stós et al. 2001. These predator-induced defences include adaptive prey behaviours, such as predator avoidance reactions or escape responses, as well as the use of refuges that make prey less susceptible to predator attacks and consequently, reduce predator-prey oscillations. In addition, low refuge carrying capacity leads to stability of predator-prey dynamics, while stability is lost when the carrying capacity of the refuge is high (Křivan 1998). In the presence of their predators, some ciliates reveal induced defences consisting of cell shape changes, as in the case of Colpidium (Fyda 1998), or develop additional spines, as in Onychodromus quadricornutus and Aspidisca turrita (Wicklow 1997). Likewise, in the presence of their predators, several Euplotes species enlarge ce...

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Section: Effects Of Pseudomicrothorax On Induced Defence In Phormidiumsupporting

confidence: 84%

Dynamics of cyanobacteria–ciliate grazer activity in bitrophic and tritrophic microcosms

Fyda¹,

Fiałkowska²,

Pajdak‐Stós³

2010

Aquat. Microb. Ecol.

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“…These include both fixed and inducible morphologies (Havel 1987). Among defensive changes in prey architecture that have been ex-per-mentally verified are: formation of colonies by previously single-celled Scenedesmus when exposed to herbivorous zooplankton (Hessen & Van Donk 1993, Lampert et al 1994; growth of neck spines by Daphnia when exposed to kairomones of invertebrate predators, a process which is stage-and concentration-dependent (Tollrian 1993); development of extended wings and ridges by grazing ciliates when exposed to larger predatory ciliates (Kuhlmann & Heckmann 1985); and growth of spines by rotifers to deter predation by larger zooplankton (Stemberger & Gilbert 1987). In at least 2 of these cases, the prey apparently perceived the presence of the predator through polypeptides released by the predator.…”

Section: Predation Avoidance and The Arms Racementioning

confidence: 99%

Organism life cycles, predation, and the structure of marine pelagic ecosystems

Verity¹,

Smetacek²

1996

Mar. Ecol. Prog. Ser.

588

362

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This paper explores the notion that the theoretical basis for contemporary research concerning the structure and function of marine pelagic ecosystems is self-limiting. While some findings such as the microbial food web have extended our knowledge of the biological components of the upper water column and their relationships to fluxes of materials and energy, they have not advanced our understanding of why specific pelagic forms occur in time and space, and why only some attain dominant status and contribute the bulk of biogenic fluxes emanating from the mixed layer. It is argued here that a major impediment to improved conceptual models is the historic focus on resource-dnven or 'bottom-up' factors as being the dominant variables structuring planktonic ecosystems. Evidence is presented that predation or 'top-down' trophic effects may be equally important in specifying the occurrence of particular taxa, the biomass within adjacent trophic levels, and the morphology of dominant herbivores and carnivores. It is suggested that key species, because of unique combinations of life history strategies, metabolic demands, and physiological performance, may exert a dominant role in the extent to which predatory interactions cascade through pelagic food webs. There is considerable evidence of evolution of predation avoidance strategies among phytoplankton and zooplankton. It is proposed that future research might profitably be directed toward the question of how the pelagic environment selects for life histories and morphologles of organisms under conditions when resource availability and predation are both significant structural buttresses. Methodological approaches should include detailed studies of dominant key taxa from different environments, with the goal of identifying the crlt~cal aspects of life history, behavior, or morphology which account for their success.

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“…Due to its abundance, its ubiquitous distribution, and the ease of culturing this ciliate, Euplotes species have been extensively studied. Consequently, it is well recognized that taxa-related differences exist in morphogenetic patterns (Frankel, 1989), mating inductions (Heckmann and Kuhlmann, 1986;Luporini and Miceli, 1986), the ability to form cysts (MartinGonzales et al, 1998), and prey-predator interactions (Kuhlmann and Heckmann, 1985;Morelli and Verni, 1996).…”

Section: Introductionmentioning

confidence: 99%