Ontogenetic Shifts in the Ability of the Cladoceran, Moina macrocopa Straus and Ceriodaphnia cornuta Sars to Utilize Ciliated Protists as Food Source

Abstract

The ontogenetic diet shifts and age specific ability of the two cladoceran species Moina macrocopa and Ceriodaphnia cornuta to derive energy from ciliated protists have been investigated in laboratory. The postembryonic developmental rates and life table demography (longevity, age and size at first reproduction, fecundity and intrinsic rate of natural increase) of the cladocerans have been elucidated on algae (Chlorella vulgaris) and the ciliated protists (Tetrahymena pyriformis, Colpoda (c.f.) steini) as food. For either of the cladoceran, the somatic growth rate and average body size at first reproduction were higher with algal diet. During initial stages of development (0-5 days), either cladoceran realized higher rate of somatic growth on algal diet, subsequently ciliated protists supported significantly higher growth rate than the alga. Algal and ciliate diets did not differ in maximum body size (C. cornuta: 539-554 μm; M. macrocopa: 1274.8-1309 μm) reached by either of the cladocerans. The maximum body sizes were larger than size at first reproduction with either of the ciliated protists, however, with algal diet the maximum body sizes did not differ from the size at first reproduction in each case. In case of C. cornuta the generation time (20.5 ± 0.3 days on ciliate; 15.6 ± 0.17 days on algal diet), reproductive rates (net reproductive rate: 20.05 ± 3.2 on ciliate; 15.5 ± 1.2 on algal diet), and average life expectancy at hatching (27 ± 0.8 days on ciliate; 22.7 ± 0.71 days on alga) were higher, whereas the size at first reproduction (482 μm on ciliate; 521 μm on alga) was smaller with the ciliate than with an algal diet. The algal and the ciliate diets did not differ in survival (life expectancy at hatching: 9.2 ± 0.7 days) and fecundity (NRR: 23.6 ± 2.4) for M. macrocopa. The two ciliates used in the experiment did not differ in their performance as food source for either cladoceran species. Our results suggest that both the cladoceran species are able to utilize smaller ciliate (e.g., T. pyriformis, C. (c.f.) steini) as food; however with differential ability to derive energy from the ciliate diet and this ability is size and age structured in both cases.

Why are there so many kinds of planktonic consumers? The answer lies in the allometric diet breadth

“…We consider that ADBM building of real webs (Petchey et al, 2008) would enable: (i) to detect the relevant intraguild relationships based on body size (Woodward & Hildrew, 2002), (ii) to quantify the omnivore rates of linkage in the web and their strength in each community (Kumar & Hwang, 2008) and (iii) to test the possible role of mixotrophic algae which combines resource use to outcompete specialist (Tittel et al, 2003;Carrillo et al, 2006). At the moment, our study illustrates that local plankton diversity of a given food web is maintained as a result of the broad range of body sizes of both consumer and resource species, which allows a weakly overlap of diet as Hutchinson (1959) guessed and as demonstrated by the fact that this structure is different from those of vertically segregated communities.…”

Cascading effects of larval Crucian carp introduction on phytoplankton and microbial communities in a paddy field: top‐down and bottom‐up controls

“…Therefore the size range of 0.7-63 lm agrees with the feeding size range of cladoceran species found in our mesocosms. The cascading effects was more prominent in smaller sizes (<15 lm) because the dominant cladoceran species was Moina macrocopa (Yamazaki et al 2010), which can feed on small cells such as Aerobacter aerogenes (2.5 · 1 lm; Stuart et al 1931), but not effectively on cells in larger fractions such as small-sized ciliates Tetrahymena pyriformis (35 · 18 lm) especially in the earlier growth stage (Kumar and Hwang 2008). Other cladoceran species observed in our mesocosms, Bosmina, Ceriodaphnia, Chydoridae, Scapholeberis, and Macrothrichidae spp., were also shown to feed primarily on small cells (<15 lm; Geller and Mu¨ller 1981; Kawabata and Urabe 1998;Nandini et al 2002).…”

The impact of nigorobuna crucian carp larvae/fry stocking and rice-straw application on the community structure of aquatic organisms in Japanese rice fields

“…Meanwhile, the decline of Moina may support the latter notion. Moina macrocopa, which lives in Japanese rice fields [20], feeds efficiently on a wide range of sizes of plankton particle, from the bacterium Escherichia coli (2 lm long and 0.5 lm wide) to the ciliate Tetrahymena pyriformis (50 lm long and 30 lm wide; [37,38]). As Euglena, Halteria, and Coleps are mainly below 50 lm in cross-sectional diameter [20], Moina seemed to be able to feed on these protozoa.…”