Reproductive success of the rotifer Brachionus calyciflorus feeding on ciliates and flagellates of different trophic modes

Abstract

SUMMARY 1. The nutritional value of the bacterivorous ciliate Tetrahymena pyriformis and the algivorous ciliate Coleps sp., as well as the heterotrophic flagellate Chilomonas paramecium and the autotrophic flagellate Cryptomonas ovata, were investigated in population growth experiments using the rotifer B. calyciflorus. The two ciliates, both flagellates, which were of similar size, shape and mobility, were each offered as a sole diet and as a supplement to the alga Monoraphidium minutum, known to support reproduction of B. calyciflorus. 2. To further test nutritional differences between the prey organisms, prey selection experiments were conducted in which B. calyciflorus was able to select between the bacterivorous and algivorous ciliate, and between the heterotrophic and autotrophic flagellate. 3. The results demonstrated that both ciliates and the heterotrophic flagellate were not sufficient to support reproduction of B. calyciflorus when offered as a sole diet. They were, however, a good supplement to algal prey (except for the bacterivorous ciliate T. pyriformis). In the prey selection experiments, B. calyciflorus positively selected for the algivorous Coleps sp. and the autotrophic C. ovata. 4. Overall, ciliates and heterotrophic flagellates may enhance survival of B. calyciflorus, but reproduction of the rotifer is likely to rely on algal prey. Both higher population growth of B. calyciflorus when fed the algivorous Coleps and the autotrophic Cryptomonas, along with their positive selection, give evidence for prey specific differences in nutrition, with algivorous or autotrophic prey species tending to be of higher nutritional value.

Effect of Single Species or Mixed Algal (Chlorella vulgaris andScenedesmus acutus) Diets on the Life Table Demography ofBrachionus calyciflorus andBrachionus patulus (Rotifera: Brachionidae)

“…In the present study, these values were lower but, under comparable conditions, were close to 7 days. Similarly, the gross and net reproductive rates observed in our study were lower but within the range documented earlier [26]; the rate of population increase observed here was much closer to that reported earlier (0.32 d Ϫ1 [15]). Much of the data on the life table demography of B. calyciflorus given in the literature is not readily comparable to our work because of the use of different growth conditions in relation to algal species, densities, incubation temperatures and other test conditions.…”

“…This food concentration is well above above the incipient limiting level (ILL ഠ 2.5 μg mL Ϫ1 DW) known for Brachionus [30]. The use of food densities above ILL ensures optimal growth rates [15].…”

“…has received considerable attention in literature [14]. While many species feed on simple spherical alga such as Chlorella, other types of food organisms such as Scenedesmus, Cryptomonas and even ciliates have also been used in feeding and population growth experiments [15]. It is generally known that Brachionus shows better reproductive output when grown on green algae than on other prey types such as ciliates and yeasts [14,16].…”

Demography and feeding behavior of Stenostomum leucops (Dugés, 1828)

“…However, it appears that they are not a good source of nutrients. It has been shown that ingesting Paramecium allows predators satisfy their metabolic demands but the carbon input is insufficient to permit adequate reproduction in cladocerans, copepods and rotifers (De Biase et al, 1990;Mohr and Adrian, 2002). The quality of the different diets was reflected in the turbellarian population growth even when the diet consisted only of algae or detritus; this suggests that S. leucops acquires different nutrients, the availability of which, in turn, affects its demographic parameters.…”

Food Web Paradigms: The Biochemical View on Trophic Interactions

“…Thus, the ciliate metazooplankton link may be very variable when looking at the ciliate species level, but not necessarily on the biochemical level. Generally, although influenced by protists species, algae rather than bacteria seem to be important in providing nutritious food for zooplankton, including the indirect way via ingestion by protozoans (MOHR and ADRIAN, 2002;WEITHOFF and WACKER, 2007).…”