The relationship between handling time and cortisol release rates changes as a function of brain parasite densities in California killifish Fundulus parvipinnis

2016 ◽  
Vol 88 (3) ◽  
pp. 1125-1142 ◽  
Author(s):  
K. L. Weinersmith ◽  
A. F. Hanninen ◽  
A. Sih ◽  
R. McElreath ◽  
R. L. Earley
Keyword(s):  
Handling Time ◽  
Release Rates ◽  
Fundulus Parvipinnis ◽  
Cortisol Release ◽  
The Relationship

Predation by Euseius scutalis (Acari: Phytoseiidae) on Tetranychus urticae and Eutetranychus orientalis (Acari: Tetranychidae): effect of prey density and developmental stage

2021 ◽  
Author(s):  
Theodoros I. Stathakis ◽  
Eleftheria V. Kapaxidi ◽  
Georgios Th. Papadoulis ◽  
Nikos E. Papanikolaou
Keyword(s):  
Developmental Stage ◽  
Tetranychus Urticae ◽  
Prey Density ◽  
Spider Mite ◽  
Handling Time ◽  
Agricultural Pests ◽  
Release Rates ◽  
Density Dependent Mortality ◽  
Euseius Scutalis ◽  
Two Spotted Spider Mite

Predation ability is a key component determining the suppression of agricultural pests by natural enemies. The aim of this study is to evaluate the effect of prey density and developmental stage on the predation of Euseius scutalis (Acari: Phytoseiidae) on the two-spotted spider mite, Tetranychus urticae (Acari: Tetranychidae) and the oriental red mite, Eutetranychus orientalis (Acari: Tetranychidae). For this purpose, laboratory functional response experiments were conducted using female adults of E. scutalis. Results indicated that the predator causes an inverse density dependent mortality to larvae, nymphs and adults of the two-spotted spider mite, as well as the oriental red mite. The random predator equation was used to fit the data. E. scutalis handling time increased significantly with T. urticae and E. orientalis developmental stage. The maximum number of T. urticae prey consumed was 48.3 larvae, 28.5 nymphs and 11.0 adults, where the corresponding values for E. orientalis were 48.8, 32.2 and 18.2 larvae, nymphs and adults, respectively. Estimated handling times and attack rates of E. scutalis on larvae, nymphs and adults of T. urticae were 0.4970 h and 0.1058 h-1, 0.8435 h and 0.1395 h-1, and 2.1834 h and 0.0835 h-1, respectively. The corresponding values on larvae, nymphs and adults of E. orientalis were 0.4920 h and 0.1166 h-1, 0.7452 h and 0.1361 h-1, and 1.3186 h and 0.0597 h-1, respectively. The results of this study may be indicative of the predation ability of adults of E. scutalis on these notorious pests, providing a basis for determining release rates appropriate for various pest densities.

The Relationship Between Prey Size and Handling Time and Prey Size and Capture Success in 3 Sympatric Species of Dasyurid Marsupials

1988 ◽  
Vol 15 (6) ◽  
pp. 615 ◽  
Author(s):  
MC Calver ◽  
JS Bradley ◽  
DR King
Keyword(s):  
Linear Regression ◽  
Prey Size ◽  
Handling Time ◽  
Prey Type ◽  
Sympatric Species ◽  
Niche Separation ◽  
Simple Linear Regression ◽  
Predator Species ◽  
The Relationship ◽  
Better Than

Regressions of handling time on prey weight were determined for the dasyurids Srninthopsis hirtipes, S. ooldea and Ningaui spp. preying on grasshoppers and cockroaches in the laboratory. In all cases, a simple linear regression fitted the relationships better than logarithmic models. The slopes of the regression lines were steeper for grasshopper prey than for cockroach prey in all species, and for each prey type the slopes for the predators were ranked in order of predator weight. Capture efficiency, defined as the proportion of successful attacks, did not vary significantly between predator species and prey types, and all predators showed declining capture efficiencies with increasing prey size. Niche separation in these dasyurids does not appear to be based on different optimal prey sizes for each species.

Selection of Prey by Size in Ningaui Yvonneae

1996 ◽  
Vol 44 (3) ◽  
pp. 319 ◽  
Author(s):  
AP Woolnough ◽  
SM Carthew
Keyword(s):  
Energy Efficient ◽  
Prey Size ◽  
Handling Time ◽  
Optimal Foraging Theory ◽  
Large Prey ◽  
Small Prey ◽  
Upper Limit ◽  
The Relationship ◽  
Prey Items ◽  
Selection Of

The small dasyurid marsupial, Ningaui yvonneae, feeds opportunistically on invertebrates dominated by the orders Hymenoptera, Coleoptera and Araneae, but is capable of, and will, consume vertebrates such as skinks. When presented with a choice of prey N. yvonneae exhibited a strong preference for prey items on the basis of size. It consistently selected small prey items over large prey items. Small prey items represented the most energy-efficient prey option as the ningaui can more efficiently capture, subdue and consume them than it can larger prey. The relationship between prey size and handling time was exponential, indicating that there is an upper limit to the ability of N. yvonneae to process prey. Moreover, smaller cockroaches provided greater energy gain than larger ones, indicating that the costs of eating larger cockroaches energetically outweighed the energy return. These results are in agreement with optimal foraging theory.

The relationship between prey selectivity and growth and survival in a larval fish

1997 ◽  
Vol 54 (7) ◽  
pp. 1504-1512 ◽  
Author(s):  
C M Mayer ◽  
D H Wahl
Keyword(s):  
Prey Size ◽  
Larval Fish ◽  
Handling Time ◽  
Prey Preference ◽  
Small Fish ◽  
Large Prey ◽  
Growth And Survival ◽  
Early Juvenile ◽  
The Relationship ◽  
Better Than

We examined prey preference, growth, and survival of small larval (8-10 mm total length (TL)), large larval (11-17 mm TL), and early juvenile (>18 mm TL) walleye (Stizostedion vitreum) in laboratory aquaria and field mesocosms using multiple prey assemblages that included cladoceran, copepod, and rotifer prey of varied sizes. Both prey taxa and size affected prey preference during the larval period. All sizes of walleye avoided rotifer and nauplii prey. Small and large larvae selected for intermediate-sized (0.4-0.9 mm) cladoceran prey and selected against large prey (>0.9 mm) of both taxa. Although neither capture efficiency nor handling time differed between prey taxa, larvae oriented more frequently towards cladoceran prey suggesting that they were more visible than copepods to these small fish. Larval walleye that were fed exclusively cladoceran prey survived better than fish that were fed other prey. Early juveniles selected primarily on the basis of prey size, choosing large copepods and cladocerans. Prey taxa did not affect early juvenile growth or survival. Prey taxa and prey size interacted with predator size to influence selectivity and its effect on growth and survival. Consequently, these factors must be considered in combination when examining the importance of foraging decisions in young fish.

scholarly journals Do Females in a Unisexual-Bisexual Species Complex Differ in Their Behavioral Syndromes and Cortisol Production?

Biology ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 186
Author(s):  
James J. Muraco ◽  
Dillon J. Monroe ◽  
Andrea S. Aspbury ◽  
Caitlin R. Gabor
Keyword(s):  
Behavioral Syndromes ◽  
Release Rates ◽  
Behavioral Type ◽  
Behavioral Traits ◽  
Sailfin Molly ◽  
Amazon Molly ◽  
Poecilia Formosa ◽  
Mate Acquisition ◽  
The Difference ◽  
Cortisol Release

Studies of suites of correlated behavioral traits (i.e., behavioral syndromes) aid in understanding the adaptive importance of behavioral evolution. Behavioral syndromes may be evolutionarily constrained, preventing behaviors from evolving independently, or they may be an adaptive result of selection on the correlation itself. We tested these hypotheses by characterizing the behavioral syndromes in two sympatric, closely related species and testing for differences between the species. We studied the unisexual Amazon molly (Poecilia formosa) and one of its bisexual, parent species, the sailfin molly (P. latipinna). Sympatric female sailfin and Amazon mollies compete for mating which could affect the behavioral syndromes found in each species. We identified a behavioral syndrome between exploration and activity in both species that did not differ between species. Additionally, we explored the relationship between a stress response hormone, cortisol, and behavioral type, and did not detect a relationship. However, P. formosa differed from P. latipinna in their cortisol release rates. Behavioral syndromes may be constrained in this complex, aiding in mate acquisition for P. formosa by virtue of having a similar behavioral type to P. latipinna. The difference between the females in cortisol release rates may be a useful mate identification cue for males to offset higher mating mistakes associated with the similar behavioral types.

BIOCLIMATIC STUDIES OF THE APHID PARASITE PRAON EXSOLETUM: I. EFFECTS OF TEMPERATURE ON THE FUNCTIONAL RESPONSE OF FEMALES TO VARYING HOST DENSITIES

1968 ◽  
Vol 100 (7) ◽  
pp. 728-741 ◽  
Author(s):  
P. S. Messenger
Keyword(s):  
Functional Response ◽  
Host Density ◽  
Handling Time ◽  
Temperature Level ◽  
Wide Range ◽  
Aphid Parasite ◽  
Response Equation ◽  
Effects Of Temperature ◽  
Temperature Levels ◽  
The Relationship

AbstractUsing bioclimatic chambers to provide diurnally fluctuating temperature and humidity conditions, the relationship between fecundity of females of the aphid parasite, Praon exsoletum (Nees), and different host densities, was examined over a wide range of mean temperatures. At each temperature level the number of eggs laid by females was found to vary with host density in accordance with the functional response curve (disc equation) of Holling. Superparasitism was common at all temperature levels studied, and, irrespective of host density, eggs were found laid at random with respect to hosts present. The functional response equation was thus modified so that number of hosts attacked was determined by both number of hosts present and number of eggs laid. Using this modified disc equation, the bioclimatic characteristics of parasite oviposition were examined from rhc standpoint of varying temperature levels. Oviposition was limited to mean temperatures between 8° and 29°C; near these limits the maximum number of eggs laid and the maximum number of hosts attacked were low. At medial mean temperatures (13°–24°) the number of eggs laid per parasite was high, averaging between 70 and 110 each 12-hour day. At these same medial temperatures, according to the modified disc equation, the average "handling" time per oviposition attack was shortest, and the parasite effective searching rate fastest. Averaged over a 12-hour day (this parasite does not oviposit in darkness), females of P. exsoletum were capable of laying from seven to nine eggs per hour at temperatures between 15° and 24° respectively. In all cases, the number of hosts attacked varied with numbers of eggs laid in accordance with Thompson’s superparasitism formula.

scholarly journals Breast cancer: Is grief a risk factor?

2018 ◽  
Vol 64 (7) ◽  
pp. 595-600
Author(s):  
Nathália Carolina Nhimi Miranda de Paula ◽  
Jacqueline Antônia Matias Martins ◽  
Lorena Maciel Amaral ◽  
Paula Rhana ◽  
Eduardo Carlos Tavares ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Risk Factor ◽  
Environmental Factors ◽  
Tobacco Use ◽  
High Capacity ◽  
Methodological Errors ◽  
Hereditary Factors ◽  
Cortisol Release ◽  
The Relationship ◽  
Cancer Studies

SUMMARY Cancer is characterized by the disordered growth of cells that have high capacity of invasion to the tissues and organs. One of the types of tumour that has national incidence and high mortality is breast cancer. Studies show that in addition to hereditary factors, lifestyle and environmental factors, there are factors related to emotional distress (mourning), which interfere with the development of breast cancer. Thus, it is necessary to investigate if the experience of mourning can trigger the appearance of the tumour. For this, an integrative review was performed to verify the existence of the relationship between mourning and development of breast cancer, which presented contradictory results. Methodological errors and lack of access to important information, such as alcohol and tobacco use, were pointed out as the main causes of the contradiction found. A possible mechanism involving cortisol release has been proposed, but more research is needed to make it clear whether the association between mourning and breast cancer really exists, and by what path.

Lipid metabolism during fasting

2001 ◽  
Vol 281 (4) ◽  
pp. E789-E793 ◽  
Author(s):  
Michael D. Jensen ◽  
Karin Ekberg ◽  
Bernard R. Landau
Keyword(s):  
Fatty Acid ◽  
Fatty Acid Oxidation ◽  
Acid Output ◽  
Acid Oxidation ◽  
Release Rates ◽  
Triglyceride Fatty Acid ◽  
Glycerol Uptake ◽  
The Relationship ◽  
Vldl Triglyceride ◽  
Intracellular Triglyceride

These studies were conducted to understand the relationship between measures of systemic free fatty acid (FFA) reesterification and regional FFA, glycerol, and triglyceride metabolism during fasting. Indirect calorimetry was used to measure fatty acid oxidation in six men after a 60-h fast. Systemic and regional (splanchnic, renal, and leg) FFA ([3H]palmitate) and glycerol ([3H]glycerol) kinetics, as well as splanchnic triglyceride release, were measured. The rate of systemic FFA reesterification was 366 ± 93 μmol/min, which was greater ( P < 0.05) than splanchnic triglyceride fatty acid output (64 ± 6 μmol/min), a measure of VLDL triglyceride fatty acid export. The majority of glycerol uptake occurred in the splanchnic and renal beds, although some leg glycerol uptake was detected. Systemic FFA release was approximately double that usually present in overnight postabsorptive men, yet the regional FFA release rates were of the same proportions previously observed in overnight postabsorptive men. In conclusion, FFA reesterification at rest during fasting far exceeds splanchnic triglyceride fatty acid output. This indicates that nonhepatic sites of FFA reesterification are important, and that peripheral reesterification of FFA exceeds the rate of simultaneous intracellular triglyceride fatty acid oxidation.

Paper 12: Derivation of Furnace Heat Transfer from Fluid Dynamic Behaviour

1965 ◽  
Vol 180 (10) ◽  
pp. 109-117
Author(s):  
D. Anson
Keyword(s):  
Heat Transfer ◽  
Dynamic Behaviour ◽  
Fluid Dynamic ◽  
Radiant Heat ◽  
Local Heat ◽  
Radiant Heat Transfer ◽  
Release Rates ◽  
Air Mixing ◽  
Mixing Rates ◽  
The Relationship

The principles underlying radiant heat transfer in boiler furnaces are fundamentally simple, but their application requires a knowledge of empirical quantities describing the emissivity of the flame and the boiler surfaces and the relationship between their geometries. This paper draws attention to the dependence of local heat release rates on fuel/air mixing. In the case of a downshot coal-fired furnace, the performance of which was investigated in detail, the size and position of the effective flame envelope could be derived from a knowledge of the flow and mixing rates. These in turn should be capable of being measured on isothermal models, and research should be directed to this end.

Interstellar gas in the central region of the Galaxy

1967 ◽  
Vol 31 ◽  
pp. 239-251 ◽  
Author(s):  
F. J. Kerr
Keyword(s):  
Central Region ◽  
Galactic Plane ◽  
Neutral Hydrogen ◽  
Continuum Emission ◽  
Galactic Centre ◽  
Interstellar Gas ◽  
Hydrogen Recombination ◽  
The Galaxy ◽  
Centre Region ◽  
The Relationship

A review is given of information on the galactic-centre region obtained from recent observations of the 21-cm line from neutral hydrogen, the 18-cm group of OH lines, a hydrogen recombination line at 6 cm wavelength, and the continuum emission from ionized hydrogen.Both inward and outward motions are important in this region, in addition to rotation. Several types of observation indicate the presence of material in features inclined to the galactic plane. The relationship between the H and OH concentrations is not yet clear, but a rough picture of the central region can be proposed.

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