Brachionus Patulus Research Articles

The zooplankton and environmental characteristics of Yardantsi Reservoir, Gusau, Nigeria

Zooplankton play an important role in the faunal biodiversity of aquatic ecosystems as they assist in transferring algal energy to higher trophic levels through grazing and also eliminate harmful algae from water. The zooplankton and environmental characteristics of Yardantsi Reservoir were studied in order to provide essential information on this important ecosystem that serves as domestic and irrigation water supply, and fishing ground. Samples for water quality and zooplankton analyses were collected from the reservoir from May, 2015 to April, 2017 using standard methods. Three groups of zooplankton (Copepoda, Cladocera and Rotifera) comprising of thirteen genera were encountered. Rotifera (36.69%) and Cladocera (34.44%) were numerically dominant during the rainy and dry seasons, respectively. The highest zooplankton abundance (5646), species richness (11), Shannon-Weiner index (2.25) and Margalef's index (1.16) were observed during the rainy season. Axes 1 and 2 of the principal component analysis (PCA) explained 74.82% and 11.89% of the zooplankton-environmental variable relationship. Diaphanosoma sp, Eubranchipus sp, Kellicottia sp and Macrothrix sp were mostly influenced by NO3, BOD, depth, pH and dissolved oxygen while Cyclops sp and Daphnia were mostly influenced by changes in alkalinity, hardness and chloride. Brachionus patulus, the dominant species in the reservoir was mostly influenced by PO4-P. The study shows that the reservoir is slightly polluted and it is essential to adopt effective management strategies such as reduced agricultural run-offs and riparian animal grazing to prevent further deterioration of water quality.

Proporción óptima de alimento en el mantenimiento de La cepa del rotífero Brachionus patulus (Müller, 1786), bajo Condiciones de laboratorio.

Se da a conocer la proporción óptima de alimento en el mantenimiento de Brachionus patulus cepa Ciénaga de Lorica en condiciones de laboratorio. Se empleó como alimento Chlorella sp. y una mezcla de Chlorella sp. Y levadura Saccharomyces cereviseae en concentración de 50X104cel.ml-1. Inoculando rotíferos en volúmenes de 250 ml con densidad inicial de 5 rot.ml-1; se evaluaron los factores poblacionales tomando como criterio cuatro proporciones diferentes con tres réplicas por tratamiento así: Chlorella sp. en concentración de 50x104cel.ml- 1, mezcla de Chlorella sp. y levadura en proporción 70:30 (35:15x104cel.ml-1), 30:70 (15:35x104cel.ml-1) y 50:50 (25:25x104cel.ml-1) respectivamente. La proporción de la mezcla 25:25x10 4cel.ml- 1 resultó ser óptima para el mantenimiento de la cepa en este caso, obteniendo con ella las mayores densidades (268.5rot.ml-1), tasa instantánea de crecimiento (0.44 rot.día -1), tiempo de duplicación (1.56 días) y producción diaria (26.4 rot.ml -1.día-1) de las poblaciones.

Testing the cost of reproduction with the rotifer Brachionus patulus at different pH levels

In the present work, we tested the hypothesis that the cost of reproduction was evident under stressful conditions with the rotifer Brachionus patulus at different pH levels (5–10 at 1 unit intervals). We used sublethal pH levels (pH 5, 9, and 10) to simulate stressful conditions. We analyzed the correlations between age-specific fecundity (m 1, m 2, m 3, …) versus future survival (l x + 1, l x + 2, l x + 3, … for the entire lifespan) (survival costs) and future expectation of reproduction (\( V_{ 1}^{*} , \, V_{ 2}^{*} , \, V_{ 3}^{*} , \ldots \) for the entire lifespan) (reproductive costs), using the data obtained from life table demographic studies of B. patulus under stressful and favorable (pH 6, 7, and 8) pH levels. The results showed that significant negative correlations were observed between age-specific fecundity and future survival and future expectation of reproduction at all tested pH levels, indicating that costs of reproduction exist in the rotifer B. patulus under stressful and favorable pH conditions. However, the percentage of statistically significant negative correlations from total correlations of survival and reproductive costs differed greatly, depending on the tested pH conditions. The percentage of significant negative correlation of reproductive costs is significantly higher under stressful pH conditions (pH 5, 9, and 10) than favorable pH conditions (pH 6, 7, and 8). For survival costs, the same trends are also observed, suggesting that the costs of reproduction were more obvious under stressful pH than favorable pH.

Predatory rotifer Asplanchna brightwellii mediated competition outcome between Brachionus calyciflorus and Brachionus patulus (Rotifera)

In the present study, we evaluated the effects of a graded series of different intensities of predation by predatory rotifer Asplanchna brightwellii (0, 1, 2, 5, 10 and 20 ind. per 50 ml) on the competition outcome between two herbivorous rotifers, Brachionus calyciflorus (196 ± 12 μm in length) and Brachionus patulus (145 ± 8 μm in length), at high (3 × 106 cells ml−1) and low (0.5 × 106 cells ml−1) algae food (Chlorella pyrenoidosa) levels. Under low predation intensity (0, 1, 2, 5 predators), B. patulus was able to outcompete and coexist with B. calyciflorus at low and high food level, respectively. Further, increased predation intensity decreased competitive ability of B. patulus at each food level, and it was eliminated from the culture assemblage at high predation intensity (20 predators). However, B. calyciflorus could persist under the highest predation intensity in this experiment. Population growth rate of B. calyciflorus was affected by food level, not by predation intensity, while that of B. patulus showed a reverse result. The maximum population density of B. patulus was significantly influenced by both predation intensity and food level, but for that of B. calyciflorus, food level was the only influence factor. The results suggest that the competition outcome between herbivorous rotifer species with different body sizes are not only affected by food level but also influenced by the predation intensity.

Body size and population growth of Brachionus patulus (Rotifera) in relation to heavy metal (copper and mercury) concentrations

The effect of different sublethal concentrations of Cu+ 2 and Hg+ 2 was evaluated on the population growth and morphometry (body width and postero-lateral spines) of Brachionus patulus. When exposed to Cu+ 2 at lower concentrations (i.e., 2.5% and 5.0% of LC50), the population growth of B. patulus did not differ significantly from controls, while at the corresponding conditions, Hg+ 2 had adverse effects. The rate of population increase (r) varied from 0.13 to 0.28 per day, depending on the metal type and its concentration in the medium. In general, increase in metal concentration decreased the rate of population increase. When the daily growth rate was plotted as function of population density over the entire growth phase, a significantly inverse relation was obtained for controls and in treatments containing lower concentrations (2.5 and 5% of LC50) of heavy metals. However, under higher metal concentrations, the relation between population density and the daily growth rate became non-significant. Morphometric data showed that Cu caused larger bodied individuals, while the opposite effect was resulted due to Hg+ 2. Postero-lateral spines of B. patulus were also significantly influenced by the concentration of Cu+ 2 or Hg+ 2. Thus, compared to controls, there was reduction in the spine length, at low concentrations of Cu+ 2, but at all the four tested levels of Hg+ 2. Our data suggested that in addition to the population growth rate, morphometric measurements need to be considered for understanding the impact of heavy metals to brachionid rotifers.

Combined influence of food level and inoculation density on competition between Anuraeopsis fissa and Brachionus patulus or Brachionus macracanthus (Rotifera: Brachionidae)

We tested separately the effect of two taxonomically related rotifers (B. patulus and B. macracanthus) on the population dynamics of another species (A. fissa) at low (0.5 ×10 6) and high food levels (1.5 × 106 cells/ml of Chlorella vulgaris) using different inoculation densities (0–100%). We also quantified the impact of A. fissa on the two brachionid species. Regardless of the presence of the competing species, an increase in the availability of food led to increase in the abundances of the three rotifers. The population growth of B. patulus, B. macracanthus, or A. fissa was affected negatively when cultured together with another species. An increase in the initial density of any one of the competing species became advantageous to maintain a certain population size. At a low algal food level, B. patulus was able to suppress A. fissa more strongly than B. macracanthus. On the other hand, at a high food level, B. macracanthus suppressed the population of A. fissa more strongly than B. patulus. Peak population densities for A. fissa varied from about 150 to 1000 ind./ml, depending on food density and the presence of competitors. The rate of population increase (r) of A. fissa, B. patulus, and B. macracanthus increased with an increase in food availability but decreased with increasing initial density of the competitor. Both Brachionus spp. experienced negative growth rates in the presence of A. fissa, especially at a high initial density of the latter.

Combined effects of sediment and lead (PbCl2) on the demography of Brachionus patulus (Rotifera: Brachionidae)

We studied the response of Brachionus patulus to different concentrations of the heavy metal Pb in the presence and absence of sediments. We conducted acute (LC50) and chronic (life table demography and population growth) toxicity tests using sediment levels of 0, 30 and 280 mg l−1 (=0, 17 and 170 NTU) and Pb at 0, 0.06 and 0.6 mg l−1. Experiments were conducted at 20 ± 1°C on a horizontal shaker and algal food (Chlorella vulgaris) was added at a density of 1.0 × 106 cells ml−1. The median lethal concentration (LC50 ± 95% Confidence intervals) of PbCl2 for B. patulus was 6.15 ± 1.08 mg l−1. Age-specific survivorship and fecundity curves showed increase in turbidity level resulted in decreased survival and offspring production of the rotifers. Increase in Pb concentration too had a negative effect on the survival and reproductive output of B. patulus. Statistically, average lifespan, life expectancy at birth, gross and net reproductive rates and the rate of population increase were all significantly influenced by the concentration of Pb, turbidity level as well as the interaction of Pb concentration × turbidity level. Rotifers exposed to 170 NTU did not grow regardless of the heavy metal concentration in the medium. Similarly, B. patulus exposed to 0.6 mg l−1 Pb did not survive beyond 10 days regardless of the turbidity level in the medium. The rate of population increase of B. patulus derived from the growth experiments was negative in all treatments containing Pb as low as 0.06 mg l−1 or turbidity level as low as 17 NTU. In treatments containing Pb or sediments, there existed no relation between the egg ratio and the population density.

Effect of Cadmium and Chromium Toxicity on the Demography and Population Growth of Brachionus calyciflorus and Brachionus patulus (Rotifera)

This paper reports on the assessment of the effect of Cd+2 and Cr+6 to the rotifers Brachionus calyciflorus and B. patulus using life table demography and population growth. Based on acute toxicity tests, cadmium was nearly 100 times more toxic than chromium for both the rotifer species. Age-specific fecundity curves of both the brachionids showed increased offspring beyond the age of 4 days and after that the production nearly stabilized for about 10 days and later declined. At any given treatment, B. calyciflorus had the higher rate of offspring production than B. patulus. For any given rotifer, increased metal concentration (Cd or Cr) resulted in decreased offspring production. While chromium at a concentration of 8.0 mg L−1, permitted reproduction in B. calyciflorus, the egg production of B. patulus was inhibited at half that level (4.0 mg L−1). Cd at concentrations as low as 0.056 mg L−1 caused 10–30% reduction in survivorship and reproductive parameters of B. calyciflorus. The lowest chromium concentration chosen for B. calyciflorus (0.5 mg L−1) had, however, a lower impact (2–22%) on the life history variables. Corresponding values of life history variables for B. patulus at the lowest Cd (0.0028 mg L−1) and Cr (0.25 mg L−1) concentrations varied greatly (2–40% and < 1–24%, respectively). Compared to controls, both the rotifer species in Cd or Cr treatments had lower densities. In controls, B. calyciflorus reached a peak abundance of about 100 ind. mL−1, while the corresponding value for B. patulus was slightly higher (120 ind. mL−1). The rate of population increase (r) derived from the population growth data varied from +0.42 to −0.40 depending on the concentration of the heavy metal in the medium.

Life History Characteristics of Asplanchnopus multiceps (Rotifera) Fed Rotifer and Cladoceran Prey

Members of rotifer family Asplanchnidae are important invertebrate predators in freshwater communities. Although a considerable amount of information exists on species of Asplanchna, relatively less is known about Asplanchnopus. We isolated Asplanchnopus multiceps from the littoral of a small river in the State of Hidalgo in Central Mexico and separated a clone in our cultures. The gut content analysis of some animals collected from the field revealed the presence of cladocerans and rotifers, and therefore we cultured A. multiceps on a food mixture comprising littoral rotifers and cladocerans. We conducted population growth experiments of A. multiceps using six prey types (cladocerans: Macrothrix triserialis, Alona rectangula and Pleuroxus aduncus; rotifers, Brachionus patulus, B. macracanthus and B. urceolaris). The prey species (A. rectangula and B. patulus) on which the highest growth rates were observed were used to test the life-table demographic patterns in A. multiceps. All experiments were conducted in 50 ml containers with 25 ml of the medium and at three food levels (0.5, 1.0 and 2.0 ind. ml−1 for the cladocerans, and 2.0, 4.0 and 8.0 ind. ml−1 for the rotifers) with four replicates at each treatment. The spines of M. triserialis and B. macracanthus were apparently effective deterrents against Asplanchnopus predation since both these diets resulted in low, and sometimes negative, growth rates of the predator. The average lifespan and net reproductive rate of A. multiceps ranged from 3.8 to 8.4 days and 2.6 to 12.2 ind. female−1, respectively, on A. rectangula; and from 5.0 to 9.4 days and 1.6–18.4 ind. female−1, respectively, on B. patulus. The rate of population increase of A. multiceps ranged from 0.1 to 0.8 d−1, depending on the prey type and density. The role of A. multiceps in structuring littoral rotifer and cladoceran communities is discussed.

Caracterización limnológica de la laguna de Cashibococha (UcayaliPerú) durante el año 2001

Durante el año 2001 se realizaron muestreos bimensuales en tres estaciones fijas en la laguna de Cashibococha (Ucayali, Perú). Cashibococha presenta aguas de color verdoso a café oscuro, con pH entre 6 a 6,8, Conductividad entre 10 y 30µS.cm −1 , Transparencia de 21 a 59 cm y Alcalinidad Total entre 14 y 22 mg CaCO3 / L . La temperatura superficial del agua osciló entre 24,4 y 37 ºC y el Oxígeno Disuelto entre 1,3 y 7,4 mg/ L. Los análisis bacteriológicos registraron recuentos de aerobios mesófilos entre 350 y 3600 UFC/ mL. Los coliformes totales oscilaron entre 3 y 43 NMP/ 100 mL. Se diferenciaron 47 especies pertenecientes a 20 familias de macrófitas acuáticas; el mayor número de especies se reportó durante la época de Transición − Creciente (octubre − noviembre), debido a la inundación del bosque. Fueron identificadas 52 especies de fitoplancton, la División Chlorophyta fue la mas dominante. La comunidad fitoplanctónica está dominada por las especies Actinastrum hantzschi, Spirogyra sp., Eudorina elegans, Pandorina morum y Closterium kuetzingui. Se diferenciaron 54 especies de Zooplancton. Los rotíferos fue el taxa dominante. La densidad de zooplancton está dominada por Brachionus patulus macracanthus y Polyarthra vulgaris. Fueron identificadas 66 especies de peces, pertenecientes a 55 géneros, 11 familias y 4 órdenes. El orden dominante en diversidad y abundancia fue el de Characiformes, Curimata vittata fue la especie dominante en la comunidad de peces en éstas áreas litorales. Los índices de diversidad fueron superiores a 3,0 bits. ind –1 , en todas las estaciones y lugares de muestreo. De igual manera los valores de equitabilidad fueron superiores a 0,8 en todas las estaciones y lugares de muestreo.

Composição do Zooplâncton em diferentes ambientes do lago Camaleão, na ilha da Marchantaria, Amazonas, Brasil

Este trabalho teve o objetivo de verificar a ocorrência e a distribuição dos principais grupos de zooplâncton em três diferentes sub-habitats do lago Camaleão: canal, macrófitas aquáticas e floresta alagada, no período de cheia (agosto de 1996). Nos três ambientes estudados, Cladocera, Copepoda e Rotifera ocorreram com abundância relativa diferentes. No canal, Cladocera ocorreu com maior número de espécies e de indivíduos, sendo dominante a espécie Bosminopsis deitersi (89%). Na floresta alagada Cladocera e Copepoda foram igualmente dominantes, ressaltando-se que somente ocorreram as formas imaturas de copépodes, náuplios e copepoditos. Nas macrófitas, o grupo de maior ocorrência foi Rotifera, com a dominância de Lecane quadrídentata, Keratella americana e Brachionus patulus seguido de copépodes (formas imaturas) e de cladóceros, estes na maioria da família Chydoridae (21.4%).

Competition between the Rotifers Brachionus patulus and Euchlanis dilatata: Effect of Algal Food Level and Relative Initial Densities of Competing Species

We tested the effect of different algal (Chlorella vulgaris) levels and inoculation densities on the outcome of competition between the rotifers Euchlanis dilatata and Brachionus patulus. The experiment was performed in 36 transparent jars, each with 20 ml of a test medium. We used three Chlorella levels: 0.75 × 106, 1.5 × 106, and 3.0 × 106 cells/ml. For each algal level, we used five different ratios of initial inoculation density. The population growth experiments were terminated after 19 days. Regardless of inoculation densities, an increase in food level resulted in an increased population abundance of both rotifer species. Regardless of food concentration,E. dilatatawas able to outcompete B. patulus at all inoculation densities when grown together. However, when Chlorella was offered in low concentration and there was a higher ratio of Brachionus to Euchlanis at the onset of the experiment, both rotifer species coexisted in more or less equal densities until the end of the experiments. When the food level was enhanced, E. dilatata totally eliminated B. patulus. The rate of population growth ranged from 0.002 to 0.578 for B. patulus and from 0.006 to 0.447 for E. dilatata. The results are discussed with respect to the factors influencing the outcome of competition between species.

Combined effects of food level and inoculation density on competition between Brachionus patulus (Rotifera) and the cladocerans Ceriodaphnia dubia and Moina macrocopa

Competition among cladocerans and rotifers is of considerable interest not only due to their close similarity in life history strategies, but also due to the considerable overlap they exhibit in their feeding habits. In tropical waterbodies, several genera of cladocerans, including Ceriodaphnia and Moina occur, simultaneously with rotifers. We tested over a period of 3 weeks the combined effects of food (0.5×106 and 1.5×106 cells ml−1 of Chlorella) level and rotifer density on the competition between B. patulus and C. dubia and M. macrocopa using population growth experiments. For each cladoceran species we used 30 test jars of 50 ml capacity. The initial density of cladocerans was 0.2 ind ml−1, while for B. patulus it was either 1 ind ml−1 or 5 ind ml−1. Neither the maximal population density nor the rate of population increase (r) of C. dubia was significantly affected by B. patulus. However, for M. macrocopa, both these variables were negatively affected by the rotifers. The combined effects of low food level and high initial density of B. patulus resulted in a 50% reduction in the peak population density of M. macrocopa. The population growth of B. patulus was negatively influenced by the presence of C. dubia and M. macrocopa. The results of the competition experiments conducted in the present study between cladocerans and rotifers suggest the existence of a more complex and delicate interaction than is generally thought.

Population growth of Asplanchna sieboldi fed two Brachionus spp. (Rotifera) raised on green alga and baker's yeast

We conducted population growth experiments of A. sieboldi using Brachionus calyciflorus and Brachionus patulus as prey. The prey rotifers were mass cultured separately on Chlorella vulgaris, Saccharomyces cerevisiae or on their mixture. Data on population growth of A. sieboldi showed prey type and food density-related differences. At any given prey concentration, both B. calyciflorus and B. patulus raised on a mixture of alga and yeast, resulted in higher abundance of the predator than those raised solely on alga or yeast. The rate of population increase per day (r) of A. sieboldi increased with increasing prey density for both prey species. However, predators grown on B. patulus showed higher r values compared to those grown on B. calyciflorus.

Combined effects of mercury and algal food density on the population dynamics of Brachionus patulus (Rotifera).

Combined effects of mercury and algal food density on the population dynamics of Brachionus patulus (Rotifera).

Effect of Methyl Parathion on the Population Growth of the Rotifer Brachionus patulus (O. F. Müller) under Different Algal Food (Chlorella vulgaris) Densities

The population growth of the rotifer Brachionus patulus was studied under a combination of different concentrations of Chlorella vulgaris and methyl parathion. To obtain sublethal concentrations of the pesticide a 24-h LC50 bioassay was performed under two food densities (1.5 and 3.0×106 cells ml−1) using neonate rotifers. For the population growth experiments, seven toxicant concentrations were used ranging from 0.16 to 10.0 mg L−1 and four food densities (0.75, 1.5, 3.0, and 6.0×106 cells ml−1), each with four replicates and thus in all, 128 test jars. A medium with Chlorella alone and without toxicant acted as control. The initial density of the rotifers in each replicate were 5 individual ml−1. Experiments were conducted for 20 days. The LC50 values of B. patulus were 8.8 and 10.7 mg L−1 at low and high algal food density, respectively. Data on the population growth studies revealed a significant effect of both food density and toxicant concentration on the maximum abundance, day at which maximum abundance was reached, and rate of population increase per day. At any toxicant concentration, an increase in food density reduced the toxicity of methyl parathion to rotifers. In controls the maximum rotifer density under the highest food level (6×106 cells ml−1) was 795±46 individuals ml−1. The rate of population increase per day (r) in controls varied from 0.22±0.01 to 0.34±0.01 depending on food density. Algal food density had a significant influence in reducing the toxicity of methyl parathion to B. patulus under both acute and chronic toxicity test conditions.

Combined effects of food concentration and the herbicide 2,4-dichlorophenoxyacetic acid on the population dynamics of Brachionus patulus (Rotifera).

Herbicides are important in crop protection and management. A number of them including 2,4-D (2,4-dichlorophenoxyacetic acid), however, may reach water bodies and eventually affect the non-target organisms such as rotifers. In the present work, we studied the influence of 6 concentrations viz. 0 (control), 100, 200, 300, 400 and 500 mg l-1 of 2,4-D on the population growth of the rotifer Brachionus patulus under two algal (Chlorella) food levels (0.5 x 10(6) and 1.5 x 10(6) cells ml-1). Regardless of herbicide concentration, the population growth of B. patulus was dependent on the algal food levels, in that an increase in algal food level supported a better population growth. Similarly at any Chlorella density, the herbicide had a negative influence on the population growth of B. patulus. Herbicide level of 500 mg l-1 inhibited population growth of B. patulus beyond 5 days. Rotifers grown under low food density and high herbicide concentration (300 mg l-1 or above) were completely eliminated after day 15. The rate of population increase (r) (mean +/- standard error) in the controls varied from 0.46 +/- 0.002 and 0.55 +/- 0.004 under 0.5 x 10(6) and 1.5 x 10(6) cells ml-1 of Chlorella, respectively. The r values became negative under both, low and high food levels, at or beyond 300 mg l-1 of 2,4-D. The maximal population abundance (ind. ml-1) in controls varied from 294 +/- 9 to 503 +/- 21 under low and high food levels of Chlorella, respectively. The role of algae in mitigating adverse effects of high herbicide concentrations to rotifers has been discussed.

Competition between Brachionus calyciflorus Pallas and Brachionus patulus (Müller) (Rotifera) in relation to algal food concentration and initial population density

Competitive laboratory experiments between Brachionus calyciflorus and B. patulus were conducted at low (1×106 cells ml−1) and high (3×106 cells ml−1) densities of Chlorella vulgaris and four initial inoculation densities (numerically, 100% B. calyciflorus; 75% B. calyciflorus + 25% B. patulus; 50% each of the two species; 25% B. calyciflorus + 75% B. patulus and 100% B. patulus). Population densities were enumerated and the medium was changed daily for 20 days. B. patulus was a superior competitor in low food density regardless of inoculation density. At high food density, B. calyciflorus showed higher population growth in the first week but thereafter was outcompeted by B. patulus regardless of initial density. When grown alone, B. calyciflorus reached peak abundances (mean ± standard error) of 31±3 and 81±7 individuals ml−1 at low and high food densities, respectively. The corresponding values for B. patulus were 130±2 and 306±13. The adverse effects of B. patulus on the peak abundances of B. calyciflorus were higher at low food concentration. Data on egg ratios (eggs female−1) revealed an inverse relation with population abundance of both tested rotifer species. Our results indicated that the rate of population increase of a species was not a good indicator of its competitive ability. Instead, the ability to reproduce under continuously diminishing food resources (until a threshold level) was responsible for the competitive edge of B. patulus over B. calyciflorus. This was further influenced by the relative inoculation densities of the tested rotifer species and the offered food densities.

The Combined Effects of Food and Temperature on the Life History Parameters of Brachionus patulusMULLER (Rotifera)

AbstractThe combined effects of different levels of temperature (15°, 25° and 35°C) and food Chlorella (1,2 and 4 × 106 cells/ml) on the life history parameters (lifespan, life expectancy, net reproductive rate, intrinsic rate of increase, developmental time, and generation time) of a laboratory population of the rotifer Brachionus patulus were investigated. Both food and temperature, independently and in interaction, significantly influenced nearly all the parameters. The reproductive performance was a direct function of the food level, but the magnitude of food effect was temperature‐dependent. The observed temperature × food interaction effects are explained in terms of the energetics of resource apportionment between metabolism and reproduction.

Effect of food level on body size and egg size in a growing population of the rotifer Brachionus patulus MULLER

Effect of food level on body size and egg size in a growing population of the rotifer Brachionus patulus MULLER