Effects Of Food Quantity Research Articles

Daily energy ingestion by the predatory Ranatra montezuma (Heteroptera) on two prey types: Importance of prey behaviour

We studied the effects of food quantity (prey biomass), nutritional quality (prey-biomass energy equivalent), and food availability (prey behaviour) on the daily energy ingestion and instar duratio...

Food-elicited calls in chimpanzees: effects of food quantity and divisibility

Food-elicited calls in chimpanzees: effects of food quantity and divisibility

Population growth rates of two closely related rotifer species: effects of food quantity, particle size, and nutritional quality

SUMMARY. 1. The relationship between population growth rates and the concentrations of several algal species was determined in laboratory experiments with the rotifers Brachionus rubens and B. calyciflorus.2. The effects of food quantity were well described by a modified Monod model with a threshold for zero population growth. The model parameters depended on particle size and nutritional quality of the food algae. Differences between the rotifer species were significant and reflected their varying food‐size preferences.3. For each rotifer species, thresholds were lowest for algae in the most readily ingested size range. The lowest thresholds were 0.07–0.09 mgC 1−1 with algae of about 5 μm equivalent spherical diameter (ESD) for B. rubens, and 0.19 mgC 1−1 with algae of about 10 μm ESD for B. calyciflorus.4. Maximal growth rates (rmax) were slightly below 0.8 day−1 for both rotifers with most algal species. The highest rmax values for both rotifers were observed when Cyclotella meneghiniana was provided as food. With this alga, B. calyciflorus had a significantly higher rmax (1.02 day−1) than B. rubens (0.838 day−1).5. From a comparison of the relationship between growth rates and ingestion rates, Chlamydomonas reinhardii appeared to be of low nutritional quality for B. rubens.6. Egg ratios were related to growth rate and were not influenced by the algal food used. Egg development times and average mortality rates were estimated from the relationship between egg ratio and growth rate. B. calyciflorus appeared to have a high average mortality rate (0.383 day−1) compared to B. rubens (0.083 day−1).

The Effect of Food Quantity on Feeding and Metabolic Expenditure in Cladocera

AbstractThe effect of Chlorella concentration on total metabolic expenditure, basal metabolism and filtering and ingestion rates was studied in juvenile and adult females of three cladoceran species. No significant influence of food concentration on basal metabolism was found, whereas total metabolic expenditure depended on Chlorella concentration. Total metabolic expenditure in cladocerans was subdivided into: basal metabolism and expenditure on filtration, locomotion and specific dynamic action (SDA). Significant positive correlations were observed between expenditure on filtration and filtering rate and between expenditures on SDA and ingestion rate.

Effect of food quantity and quality on egg production of Acartia tonsa Dana from East Lagoon, Galveston, Texas

The nutritional value of natural particle diets on egg production of Acartia tonsa from subtropical East Lagoon was studied from April to November 1981. During the summer, monospecific blooms of dinoflagelates and chloromonads dominated the natural particle assemblages. But during the spring and fall, the inorganic fraction was dominant and chlorophyll concentrations were lower. At ambient concentrations of natural particles from East Lagoon, specific egg production rates were correlated in stepwise multiple regressions with temperature, salinity, and C:N ratio but not phytoplankton pigment concentrations. For stepwise multiple regression including all natural particle concentrations, specific egg production rates were correlated with C:N ratio, average particle diameter, percent nanoparticles (5–20 μm), and percent phytoplankton picoparticles. A nonlinear regression developed for the entire data set revealed that above the critical chlorophyll concentration (∼ 5 μg 1 −1 at all temperatures), an increase in temperature of 4°C caused about the same increase in specific egg production rates as a decrease in salinity from 30 to 10‰, or a decrease in C:N ratio from 10 to 5. On a seasonal scale, temperature is the dominant influence on egg production of A. tonsa in East Lagoon where temperature ranges from 10 to 30°C but on shorter time scales food quality, food quantity or salinity may influence egg production rates as much as temperature.

Effects of food quality and quantity on the survival, development, and egg production of Gladioferens pectinatus (Brady) (Copepoda : Calanoida)

Effects of food quality and quantity on certain fitness traits of G. pectrnatus were examined to develop methods of culture. Five generations were successfully reared on excess Isochrysis galbana, despite intense inbreeding. The effect of food quantity was tested using outcrossed offspring fed I. Galbana at four concentrations. Generation time (from hatching to egg) decreased from 43.2 days at 1 × 104 cells ml-1 (lowest concentration) to 19.6 days at 5 × 105 cells ml-1 (highest concentration). An increase occurred in female body length (0.88 to 1.01 mm) and egg number (21.2 to 51.3) with increasing food concentration, and the total number of adults produced per brood was significantly lower at 1 × 104 cells ml-1. Results on a Dunaliella tertiolecta diet were similar to those for I. Galbana at the one food concentration tested (1 × 105-2 × 105 cells ml-1); however, unlike I. galbana, D. tertiolecta did not sustain viable egg production and was therefore nutritionally inadequate for multiple generation culture. Larval mortality was high on diets of Tetraselmis chuii and Phaeodactylum tricornutum. Body lengths and egg numbers of cultured females fed I. Galbana were greater than those of the 'wild' parental females, thus indicating the suitability of the culture conditions.

The effects of food quantity and quality on emergence time in the cinnabar moth

In North America some introduced cinnabar moth populations have been dense since their establishment and extensively defoliate their food plants annually. Other populations fluctuate and defoliate all the available tansy ragwort only every 3 to 4 years. The hypothesis that annual food limitation should select for early moth emergence was tested by comparing temperature thresholds and development times for pupae from these two types of populations. Data do not support this hypothesis. Introduced populations living at different climates and of different European origins have similar temperature thresholds and development times. An alternative hypothesis is that moth emergence is synchronized with the time of tansy ragwort flowering. This is supported by the observation in laboratory studies that larvae which feed on flowers produce larger pupae than those which feed only on leaves. Also field studies show that larvae developing early in the summer and the early emerging moths tend to be smaller, which supports the hypothesis that larvae developing in the middle to late part of the season do better.

The effect of food quantity and quality on the growth, birth-rate and longevity of Daphnia hyalina Leydig

To study experimentally the relation between zooplankton and phytoplankton, laboratory cultures of Daphnia hyalina Leydig were set up. The combined influence of food quality and quantity on growth, birth-rate and longevity was measured. The effect of seven different food regimes was tested. Natural unfiltered lake water from the eutrophic lake Tjeukemeer was used in one regime. The food value of the natural unfiltered lake water appeared to be relatively low, which was most likely caused by the abundance of large sized algae in the lake water.