A laboratory study of the feeding behavior of the rhabdocoel Mesostoma ehrenbergii on pond Cladocera

1982 ◽  
Vol 60 (6) ◽  
pp. 1305-1307 ◽  
Author(s):  
Steven S. Schwartz ◽  
Paul D. N. Hebert
Keyword(s):  
Feeding Behavior ◽  
Laboratory Study ◽  
Size Dependent ◽  
Prey Behavior ◽  
Cladoceran Species ◽  
Predation Rates

The predation rates of the rhabdocoel Mesostoma ehrenbergii were determined on a number of cladoceran species. Two means of capturing prey are employed by the flatworm but only active predation was explored in these experiments. It was found that this flatworm is a size-dependent predator with a preference for prey of about 1.2 mm. It was also observed that prey behavior was not an important factor in determining susceptibility to predation. M. ehrenbergii is a voracious predator; individuals consume more than 10 prey/day.

The influence of benthic tundra pond vegetation and prey behavior on Zooplankton predation by the flatworm Mesostoma lingua

1985 ◽  
Vol 63 (7) ◽  
pp. 1617-1621 ◽  
Author(s):  
Hugh J. MacIsaac ◽  
Thomas C. Hutchinson
Keyword(s):  
Daphnia Pulex ◽  
Chironomus Riparius ◽  
Alternative Prey ◽  
Prey Behavior ◽  
Predation Rates ◽  
Branchinecta Paludosa

Experiments were conducted at the Smoking Hills and Tuktoyaktuk, N.W.T., to determine if Mesostoma lingua, a common pond inhabitant, preys selectively on co-occurring Zooplankton, and whether predation rates are affected by the presence of pond vegetation. Experiments were conducted in 250-mL containers at the sites. Mesostoma fed heavily on Daphnia pulex and Chironomus riparius, but not on Branchinecta paludosa or Diaptomus arcticus. The presence of alternative prey led to significant reductions in Daphnia predation rates, while the presence of the pond plants Cladophora insignis and Drepanocladus aduncus, which provide shelter and cover, significantly increased predation rates. The advantage of the moss and algal habitat was largely to the predator.

Role of satiation in the functional response of a piscivore, largemouth bass (Micropterus salmoides)

2000 ◽  
Vol 57 (3) ◽  
pp. 548-556 ◽  
Author(s):  
Timothy E Essington ◽  
James R Hodgson ◽  
James F Kitchell
Keyword(s):  
Functional Response ◽  
Largemouth Bass ◽  
Consumption Rate ◽  
Micropterus Salmoides ◽  
Sustainable Consumption ◽  
Stomach Fullness ◽  
Daily Consumption ◽  
Prey Behavior ◽  
Natural Settings ◽  
Predation Rates

We evaluated whether satiation regulates the predation rates of a piscivore, largemouth bass (Micropterus salmoides), in natural settings. A functional response model indicated that predation rates can be reduced by satiation when mean prey density is high or when prey encounters are highly patchy. We then used bioenergetics modeling to estimate the predation rates of individual bass in four lakes during a 16-year period and used stomach content mass in diet samples to evaluate the variability in daily predation rates. Predation rates, expressed as the proportion (p) of the maximum daily consumption rate, were low (mode = 0.3, mean = 0.4). Stomach fullness (s), expressed as the proportion of the stomach fullness associated with the maximum sustainable consumption rate, was highly variable, and 13% of all bass diets had s > 1, indicating that bass could opportunistically forage at rates exceeding their maximum sustainable rate. The low predation rates and the ability to consume prey at rates exceeding the maximum sustainable rate make it unlikely that satiation was an important constraint on bass predation rates. Thus, satiation effects widely represented in modeling studies may be a rare component in piscivore-prey interactions, while prey behavior may be a more important component governing predation rates.

scholarly journals Predation by invasive Platydemus manokwari flatworms: a laboratory study

2019 ◽  
Vol 54 (1) ◽  
pp. 47-60 ◽  
Author(s):  
Justin Gerlach
Keyword(s):  
Laboratory Study ◽  
Climatic Factors ◽  
Generalist Predator ◽  
Predatory Behaviour ◽  
Chemical Defences ◽  
The Pacific ◽  
The Pacific Ocean ◽  
The Tropics ◽  
Air Circulation ◽  
Predation Rates

Abstract Platydemus manokwari de Beauchamp, 1963 is an invasive flatworm found on islands in the tropics, especially in the Pacific Ocean. It has been implicated in the decline of several snail populations, including the extinction of some Partula species. Its predatory behaviour was investigated to quantify predation rates and elucidate climatic influences. This laboratory study of the invasive flatworm confirms earlier reports that P. manokwari is a generalist predator of snails. It prefers small prey and avoids species defended by copious mucus, chemical defences or a tough integument. Prey are found by following damp mucus trails up to 15 h old. Flatworm activity is limited by temperature and humidity, with peak feeding at 24–30°C and 85–95% humidity. This determines the geographical spread of the species and probably also the effectiveness of arboreal predation. Aboveground air circulation leads to drying, reducing the ability of the flatworms to locate trails and remain active high off the ground. Local climatic factors may dictate how significantly P. manokwari affects snail populations.

Predatory Feeding Behavior of Epischura lacustris (Copepoda, Calanoida) and Prey Defense

1981 ◽  
Vol 38 (3) ◽  
pp. 275-279 ◽  
Author(s):  
C. Kim Wong
Keyword(s):  
Feeding Behavior ◽  
Prey Selection ◽  
Encounter Rate ◽  
Predator Prey ◽  
Bosmina Longirostris ◽  
Size Selection ◽  
Behavioral Preference ◽  
Ceriodaphnia Reticulata ◽  
Predation Rates

The predatory feeding behavior of Epischura lacustris on Bosmina longirostris and Ceriodaphnia reticulata was investigated. Epischura rarely killed Bosmina > 0.40 mm in length, but below this threshold there was no size selection because predation rates were affected mainly by encounter rate and ingestion probability. When presented with Bosmina and Ceriodaphnia, Epischura fed at higher rates on Bosmina which were more easily captured. Epischura showed no true behavioral preference or switching, and its diet included all the prey it could detect, capture, and ingest successfully. Previous diet had no effect on prey selection. Predation rates on Bosmina were not affected by the presence of algal food.Key words: predatory copepod, predator–prey interactions, size selection, switching, prey defense

scholarly journals Survival of prey growing through gape-limited and apex predators

2019 ◽  
Author(s):  
James J. Anderson
Keyword(s):  
Mechanistic Model ◽  
Model Fit ◽  
Adult Survival ◽  
Apex Predators ◽  
Frequency Distributions ◽  
Predator Prey ◽  
Size Dependent ◽  
Predator Size ◽  
Prey Behavior ◽  
Population Recruitment

ABSTRACTA mechanistic model based on first principles of growth and predator-prey behavior introduces the effects of a predator size distribution on the survival of rapidly growing prey. The model, fit to Chinook salmon data, can explain the observed increase in ocean survival with smolt ocean entrance length using different predator size-frequency distributions. The model introduces new dimensions to theories on predator-prey interactions and population recruitment and suggests the possibility that fish recruitment control can be highly variable; sometimes dominated by juvenile growth and encounters with gape-limited predators and other times dominated by adult encounters with apex predators. Additionally, a sensitivity analysis suggests that scale and otolith circuli spacing are insensitive indicators of size-selective mortality but the profile of adult survival with juvenile length provides information on the balance of size-dependent and size-independent mortality processes.

scholarly journals Prey Behavior, Age‐Dependent Vulnerability, and Predation Rates

2008 ◽  
Vol 172 (5) ◽  
pp. 712-725 ◽  
Author(s):  
Susan Lingle ◽  
Alex Feldman ◽  
Mark S. Boyce ◽  
W. Finbarr Wilson
Keyword(s):  
Prey Behavior ◽  
Age Dependent ◽  
Predation Rates

A laboratory study of the vulnerability of prey to predation by three aquatic insects

1988 ◽  
Vol 66 (4) ◽  
pp. 875-878 ◽  
Author(s):  
Randall L. Fuller ◽  
Peter A. DeStaffan
Keyword(s):  
Feeding Behavior ◽  
Laboratory Study ◽  
Aquatic Insects ◽  
Prey Vulnerability ◽  
Differential Movement ◽  
Paragnetina Media

The vulnerability of three different prey (Baetis spp., Ephemerella spp., and Simulium spp.) to predation by Nigronia serricornis (Megaloptera) and Paragnetina media and Agnetina capitata (both Plecoptera) was studied in recirculating Plexiglas chambers. When each prey was tested individually, Simulium was least vulnerable to predation by A. capitata and equally vulnerable with Ephemerella to P. media and N. serricornis. Baetis was the most vulnerable to predacious stoneflies while Baetis and Ephemerella were equally vulnerable to N. serricornis. When prey were tested in mixed assemblages, similar trends in prey vulnerability were seen, except that Ephemerella was more vulnerable than Simulium to P. media and N. serricornis. Our data suggest that Ephemerella is less vulnerable than Baetis to predation by stoneflies; however, they were equally vulnerable to N. serricornis, possibly because of differences in feeding behavior and morphology between stoneflies and N. serricornis. Significantly more Simulium larvae moved to the sides and ceiling plates of the experimental chambers versus the control chambers; this differential movement suggests that the presence of predators may have stimulated escape to an apparently predator-free refuge.

Production and STEM examination of controlled-size silver clusters

1983 ◽  
Vol 41 ◽  
pp. 338-339
Author(s):  
M. A. Listvan ◽  
R. P. Andres
Keyword(s):  
Cluster Size ◽  
Metal Clusters ◽  
Experimental Parameter ◽  
Carbon Films ◽  
Metal Species ◽  
Silver Clusters ◽  
Free Jet ◽  
Size Dependent ◽  
Cluster Properties ◽  
Controllable Size

Knowledge of the function and structure of small metal clusters is one goal of research in catalysis. One important experimental parameter is cluster size. Ideally, one would like to produce metal clusters of regulated size in order to characterize size-dependent cluster properties.A source has been developed which is capable of producing microscopic metal clusters of controllable size (in the range 5-500 atoms) This source, the Multiple Expansion Cluster Source, with a Free Jet Deceleration Filter (MECS/FJDF) operates as follows. The bulk metal is heated in an oven to give controlled concentrations of monomer and dimer which were expanded sonically. These metal species were quenched and condensed in He and filtered to produce areosol particles of a controlled size as verified by mass spectrometer measurements. The clusters were caught on pre-mounted, clean carbon films. The grids were then transferred in air for microscopic examination. MECS/FJDF was used to produce two different sizes of silver clusters for this study: nominally Ag6 and Ag50.

Transfer Technique for Electron Microscopy of Membrance Filter Samples

1974 ◽  
Vol 32 ◽  
pp. 554-555
Author(s):  
Lawrence W. Ortiz ◽  
Bonnie L. Isom
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Pore Size ◽  
Membrane Filters ◽  
Size Dependent

A procedure is described for the quantitative transfer of fibers and particulates collected on membrane filters to electron microscope (EM) grids. Various Millipore MF filters (Millipore AA, HA, GS, and VM; 0.8, 0.45, 0.22 and 0.05 μm mean pore size) have been used with success. Observed particle losses have not been size dependent and have not exceeded 10%. With fibers (glass or asbestos) as the collected media this observed loss is approximately 3%.

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