scholarly journals The Relative Importance of Arthropods and Fruits in Foraging Behavior of Omnivorous Tanagers (Thraupidae): The Comparison of Three Methods

The Condor ◽  
2003 ◽  
Vol 105 (1) ◽  
pp. 135-139 ◽  
Author(s):  
Kazuya Naoki
Keyword(s):  
Foraging Behavior ◽  
Foraging Ecology ◽  
Food Type ◽  
Relative Importance ◽  
Time Budgets ◽  
Food Items ◽  
Data Analyses ◽  
Initial Observation ◽  
The Difference ◽  
Bird Foraging

Abstract I quantified the foraging ecology of omnivorous Tangara tanagers with three methods commonly used in the study of foraging behavior. The relative importance of two food types, arthropods and fruits, varied largely depending on which method was used for data analyses. Arthropod foraging was more important than fruit foraging when calculated using the duration of foraging. In contrast, fruit foraging was more important when characterized by the food taken at initial observation and the total number of food items taken. This bias was probably caused by the difference in distribution and abundance of these two food types. Although numerous studies have used the frequency of initial observations to quantify bird foraging behavior, this method tends to underestimate the importance of highly rewarding but scarce food types in time budgets and tends to overestimate the same food type in the number of food items in birds' diets. Importancia Relativa de Artrópodos y Frutos en el Comportamiento de Forrajeo de las Tangaras Omnívoras (Thraupidae): Comparación de Tres Métodos Resumen. Cuantifiqué la ecología de forrajeo de las tangaras omnívoras del género Tangara con tres métodos comúnmente utilizados en el estudio del comportamiento de forrajeo. La importancia relativa de dos tipos de alimento, artrópodos y frutos, varió significativamente dependiendo de qué método se utilizó para analizar los datos. El forrajeo de artrópodos fue más importante que el forrajeo de frutos cuando calculado utilizando duración del forrajeo. En contraste, el forrajeo de frutos fue más importante cuando caracterizado por el tipo de alimento consumido en observación inicial y el número total de alimentos consumidos. Este sesgo fue causado probablemente por la diferencia en distribución y abundancia de estos dos tipos de alimento. Muchos estudios han utilizado la frecuencia de observaciones iniciales para cuantificar el comportamiento de forrajeo de las aves. Sin embargo, este método tiende a subestimar la importancia de aquellos alimentos, de alta recompensa pero escasos, en términos del tiempo invertido en su búsqueda. Al mismo tiempo, este método tiende a sobrestimar estos mismos tipos de alimento cuando se considera el número de artículos alimenticios en la dieta de las aves.

scholarly journals Contributions of source population and incubation temperature to phenotypic variation of hatchling Chinese skinks

2020 ◽  
Author(s):  
Hong-Liang Lu ◽  
Yan-Fu Qu ◽  
Hong Li ◽  
Xiang Ji
Keyword(s):  
Body Mass ◽  
Phenotypic Variation ◽  
Incubation Temperature ◽  
Tail Length ◽  
Population Variation ◽  
Phenotypic Traits ◽  
Source Population ◽  
Relative Importance ◽  
The Difference ◽  
Hatchling Size

Abstract Phenotypic plasticity and local adaptation are viewed as the main factors that result in between-population variation in phenotypic traits, but contributions of these factors to phenotypic variation vary between traits and between species and have only been explored in a few species of reptiles. Here, we incubated eggs of the Chinese skink (Plestiodon chinensis) from 7 geographically separated populations in Southeast China at 3 constant temperatures (24, 28, and 32 °C) to evaluate the combined effects of clutch origin, source population, and incubation temperature on hatchling traits. The relative importance of these factors varied between traits. Nearly all examined hatchling traits, including body mass, snout–vent length (SVL), tail length, head size, limb length, tympanum diameter, and locomotor speed, varied among populations and were affected by incubation temperature. Measures for hatchling size (body mass and SVL) varied considerably among clutches. Source population explained much of the variation in hatchling body mass, whereas incubation temperature explained much of the variation in other examined traits. Our results indicate that between-population variation in hatchling traits of P. chinensis likely reflects the difference in natural incubation conditions and genetic divergence.

An extensive study of the foraging ecology of beavers (Castor canadensis) in relation to habitat quality

2004 ◽  
Vol 82 (6) ◽  
pp. 922-933 ◽  
Author(s):  
D Gallant ◽  
C H Bérubé ◽  
E Tremblay ◽  
L Vasseur
Keyword(s):  
Habitat Quality ◽  
Foraging Behaviour ◽  
Foraging Ecology ◽  
Castor Canadensis ◽  
Central Place ◽  
Foraging Theory ◽  
Extensive Study ◽  
Food Items ◽  
Partial View ◽  
Selection Of

The objective of this study was to examine the foraging behaviour of the beaver (Castor canadensis Kuhl, 1820) and to explain its selection of terrestrial woody plant species according to central place foraging theory. Limitations in variety of food items in most studies with regard to size and (or) distance from the central place and information on availability of forage choices give a partial view of the subject. In this study, the theory is tested in a natural environment with high variability in food items with regard to these factors. Foraging choices by beavers were inspected by measuring variables on cut and uncut trees of every species encountered within 1 m of trail systems made by 25 beaver colonies in Kouchibouguac National Park in New Brunswick, Canada, thereby quantifying the availability of the different food items. The effect of habitat quality (food availability) on the foraging behaviour of beavers was also tested. The results of this study suggest that with increasing distance from the pond, beavers in high-quality habitats selected fewer, but larger, trees and are more species selective. This selectivity was diminished in habitats of lower quality. The results of this study are consistent with the predictions of the central foraging theory.

scholarly journals Foraging behavior and diet of the vulnerable Cinereous Warbling-finch Poospiza cinerea (Aves, Emberizidae)

2014 ◽  
Vol 74 (4) ◽  
pp. 821-827 ◽  
Author(s):  
U Wischhoff ◽  
F Marques-Santos ◽  
M Rodrigues
Keyword(s):  
South America ◽  
Foraging Behavior ◽  
Rare Species ◽  
Feeding Habits ◽  
Reproductive Organs ◽  
Substrate Use ◽  
Food Items ◽  
Niche Specialization ◽  
Study Sites ◽  
Central South

The Cinereous Warbling-finch Poospiza cinerea is a globally vulnerable Emberizidae passerine, patchily distributed and rare in the open savannah of central South America. Attributes of rare species include niche specificity such as feeding habits. To verify possible niche specialization in this species we aimed to describe its foraging habits related to substrate use, foraging and substrate height, attack maneuvers, and consumed food items. We monitored two groups at two study sites and sampled foraging events with intervals of 15 minutes. The substrates used in greater frequency were foliage and reproductive organs. Foraging and substrate height varied widely with study area. The attack maneuver adopted in greater frequency was glean. Most food items attacked were small invertebrates. Big invertebrates included Lepidoptera, Hemiptera, Coleoptera, Hymenoptera and Orthoptera. Poospiza cinerea was also recorded foraging in mixed bird flocks with seven other species. The generalist foraging behavior of the species cannot be associate to its rarity.

The Effect of Bow Shape on the Springing/Whipping Response of a Large Ocean-Going Vessel: Investigated by an Experimental Method

2007 ◽  
Author(s):  
Gaute Storhaug ◽  
Torgeir Moan
Keyword(s):  
Fatigue Damage ◽  
Transfer Functions ◽  
Vertical Vibration ◽  
Full Scale ◽  
Relative Importance ◽  
High Frequency Response ◽  
Bow Flare ◽  
Excitation Mechanisms ◽  
The Difference ◽  
Wave Induced

Wave induced vibrations often referred to as springing and/or whipping increase the fatigue and extreme loading in ship hull girders. Both effects are disregarded in current ship rules. Various numerical codes exist for predicting the wave induced vibrations, but so far they are not considered reliable. Another means to investigate the importance of the high frequency response, although more resource demanding, is to carry out full scale measurements and/or model tests. Recently, full scale measurements of blunt ships have been carried out by DNV, and in this paper one of these ships was considered and tested in a towing tank to evaluate the additional fatigue damage due to the wave induced vibrations. Different excitation sources may excite the 2-node vertical vibration mode depending on ship design, and it is not straight forward to determine which is more important. The relative importance of the excitation mechanisms are investigated by two approaches in this paper. The first approach separates the whipping from springing to illustrate their relative importance based on basic theory in combination with model test results. The linear and second order transfer functions are utilized in this procedure. The second approach deals with the effect of the bow design on the additional fatigue damage. Three different bows were tested. The first bow design is identical to the real ship. The second bow design is a simplified version of the first one, by removing the bulb and flare. The third bow is fundamentally different from the two former blunt bows. Bow three is sharp pointed with a vertical sharp stem and vertical ship sides. The results indicate that the importance of whipping depends on the sea state, but that it is of similar importance as springing for the sea states that contributes most to the fatigue damage. Moreover, the difference in the additional fatigue damage due to wave induced vibrations for different bow shapes is moderate. This indicates that vessels with pointed bows and without pronounced bow flare, such as LNG vessels, may have a similar contribution from wave induced vibrations. Modern container vessels, which are more slender, but with pronounced bow flares should be further investigated.

scholarly journals Seasonal variation on diet of juvenile Elops saurus Linnaeus, 1766 (Ladyfish) in the Parnaiba River Delta

2020 ◽  
Vol 32 ◽  
Author(s):  
Tatiane Araujo Santos ◽  
Thamires Souza Gonçalves ◽  
Patricia Silva do Nascimento ◽  
Cézar Augusto Freire Fernandes ◽  
Francisca Edna de Andrade Cunha
Keyword(s):  
High Frequency ◽  
Rainy Season ◽  
Stomach Contents ◽  
Dry Season ◽  
River Delta ◽  
Frequency Of Occurrence ◽  
Relative Importance ◽  
Dry Period ◽  
Food Items ◽  
Importance Index

Abstract: Aim Identify seasonal variations in the diet of juvenile living in the estuary of the Parnaíba River Delta. Methods Food items were identified through analysis of stomach contents, and later submitted to analysis by regular methods for Frequency of Occurrence (FO), Frequency Numerical (FN), Gravimetric Frequency (FW) and Relative Importance Index (IRI). Results Juvenile diet of Elops saurus that inhabit the lagoons in the Parnaíba delta was composed in order decreasing of importance by Osteichthyes (Teleostei), Insecta and Crustacea in addition to Polychaeta and Nematoda. It was also observed a high frequency of occurrence of fragments of plastics in the diet. In the rainy season, 17 items were recorded in the diet, whereas in the dry season only 7 items were present. Relative Importance Index showed high presence of the Teleostei fish (69.93%) on diet of E. saurus during the rainy season, whereas during the dry period the insects of the families Corixidae (43.25%) and Dysticidae (39.16%). Conclusions With the study it was possible to identify that juvenile are piscivorous in the rainy season when there is a higher availability of prey in the environment and insectivores in the dry season when it reduces the supply of food, indicating feeding flexibility to environmental alterations.

scholarly journals Rumen degradation and fractional outflow rates of nitrogen supplements given to cattle eating sodium hydroxide-treated straw

1986 ◽  
Vol 55 (2) ◽  
pp. 387-398 ◽  
Author(s):  
K. Amaning-Kwarteng ◽  
R. C. Kellaway ◽  
Jane Leibholz ◽  
A. C. Kirby
Keyword(s):  
Sodium Hydroxide ◽  
Cotton Seed ◽  
Relative Importance ◽  
High Intake ◽  
Protein Supplements ◽  
Rumen Degradation ◽  
Cotton Seed Meal ◽  
Meat Meal ◽  
The Difference

1. Six rumen and abomasal cannulated heifers were used to study the effects of intake on the fractional outflow rates (FOR) of chromium-mordanted cotton-seed meal (Cr-CSM) and meat meal (Cr-MM), CrEDTA, ytterbium and lignin from the rumen. Values of FOR of Cr-CSM and Cr-MM were combined with values of nitrogen disappearance from the protein supplements, placed in porous synthetic (nylon) bags and incubated within the rumen (P), to calculate effective degradation (D)of CSM and MM when fed to heifers eating sodium hydroxide-treated straw. Also, N degradation in vivo (V) was measured as the difference between abomasal N flow and the sum of flows of microbial and endogenous N.2. FOR were positively related to intake and differences between supplements were significant (p<0.01). FOR pertaining to high and low intakes respectively were 0.073 and 0.052 for Cr-CSM, 0.082 and 0.071 for Cr-MM, 0.030 and 0.023 for lignin, 0.082 and 0.073 for CrEDTA and 0, 044 and 0.035 for Yb.3. A rise of 28.8 and 13.4% in FOR of Cr-CSM and Cr-MM respectively, associated with an increase in intake from maintenance to 1.5 times maintenance, resulted in 10.7 and 2.2% reductions inD, 24 h after feeding, for CSM and MM respectively.4. With the exception of CSM at the high intake, estimates ofVwere underestimated byDand were 8.6–25.0% greater than theDvalues when time of incubation (t)= ∞. The two techniques, however, ranked the degradation of the two supplements in the same order at both levels of intake.5. Underestimation ofVbyDmay be attributable to underestimation ofP, overestimation of FOR (both resulting in underestimation ofD) or overestimation ofVdue to biases associated with the estimation of this part of the comparison. The relative importance of these factors remains to be determined.

Relative importance of host and plant semiochemicals in the foraging behavior of Trichogramma achaeae, an egg parasitoid of Tuta absoluta

2019 ◽  
Vol 92 (4) ◽  
pp. 1479-1488 ◽  
Author(s):  
Lessando Gontijo ◽  
Pasquale Cascone ◽  
Massimo Giorgini ◽  
Marco Michelozzi ◽  
Hígor S. Rodrigues ◽  
...  
Keyword(s):  
Foraging Behavior ◽  
Egg Parasitoid ◽  
Tuta Absoluta ◽  
Relative Importance ◽  
Trichogramma Achaeae

scholarly journals Serum Sclerostin Levels in Patients with Ankylosing Spondylitis and Rheumatoid Arthritis: A Systematic Review and Meta-Analysis

2017 ◽  
Vol 2017 ◽  
pp. 1-7 ◽  
Author(s):  
Jianfeng Shi ◽  
Haijian Ying ◽  
Juping Du ◽  
Bo Shen
Keyword(s):  
Rheumatoid Arthritis ◽  
Systematic Review ◽  
Ankylosing Spondylitis ◽  
Meta Analysis ◽  
Cochrane Library ◽  
Healthy Controls ◽  
Data Analyses ◽  
Standard Mean Difference ◽  
The Difference ◽  
Sclerostin Level

Objective. Current studies of serum sclerostin levels in AS and RA patients are inconsistent. This meta-analysis was performed to identify the association of serum sclerostin level with AS and RA patients. Methods. Embase, PubMed, MEDLINE, and Cochrane Library databases (up to 25 January 2017) were used to collect all relevant published articles. Studies were pooled and standard mean difference (SMD) with 95% confidence interval (CI) was calculated. All data analyses were performed using RevMan 5.3. Results. Totally eight studies of AS including 420 AS patients and 317 healthy controls (HC) and three studies of RA including 145 RA patients and 127 HC were finally included in this meta-analysis. The results revealed that the serum sclerostin levels in both AS patients (SMD=-0.14; 95% CI=[-0.39,0.11]; P=0.28) and RA patients (SMD=-0.10; 95% CI=[-0.34,0.15]; P=0.43) were not significantly different from those in HC. Conclusion. The difference of serum sclerostin levels in AS and RA patients was not significantly different from HC, indicating that the sclerostin may not associate with the development of AS and RA.

scholarly journals Spatial and seasonal changes in the diet of Oligosarcus hepsetus (Characiformes, Characidae) in a Brazilian Reservoir

2005 ◽  
Vol 65 (1) ◽  
pp. 1-8 ◽  
Author(s):  
F. G Araújo ◽  
C. C Andrade ◽  
R. N Santos ◽  
A. F. G. N Santos ◽  
L. N Santos
Keyword(s):  
Seasonal Changes ◽  
Prey Capture ◽  
Gut Contents ◽  
Relative Importance ◽  
Food Items ◽  
Dietary Shifts ◽  
Index Of Relative Importance ◽  
Almost All ◽  
Previous Autumn ◽  
Very High

We assessed spatial and seasonal changes in the diet of Oligosarcus hepsetus in order to describe the strategy developed by this species that allows their very high abundance in Lajes reservoir, Rio de Janeiro, Brazil. Fish samplings were carried out using gill nets, deployed during ca. 12 and 24 hours, between April 2001 and May 2002. A total of 289 individuals were examined, of which 97 showed gut contents. We used the index of relative importance (IRI) to compare probable dietary shifts, and the frequency of occurrence (% OC) to analyze possible ontogenetic influences on feeding. O. hepsetus showed carnivorous habits, feeding preferably on fish and insects, the latter of which occurred in 71.0% of the guts presenting contents. O. hepsetus consumed different items along the three reservoir zones: insects (61.0% IRI) and Cichla monoculus (38.9% IRI) in the lower zone; Lepidoptera (57.0% IRI) in the middle zone; and C. monoculus (77.0% IRI) in the upper zone. Food items changed seasonally with C. monoculus predominating in autumn 2001, and Hymenoptera and Lepidoptera in the winter. In spring almost all food was Lepidoptera (99.8% IRI), while in the summer Hemiptera dominated in the diet. In autumn 2002 Hemiptera (97.0% IRI) was dominant, in significant contrast with the previous autumn. Individuals smaller than 190 mm SL fed heavily on insects, while fishes predominated in the diet of individuals larger than 190 mm SL. Shifts in prey-capture ability among length classes suggest decreasing intraspecific competition. A higher food plasticity seems to be the strategy employed by this opportunist species, which used food resources available in the reservoir.

Relative importance of liver, kidney, and substrates in epinephrine-induced increased gluconeogenesis in humans

2003 ◽  
Vol 285 (4) ◽  
pp. E819-E826 ◽  
Author(s):  
Christian Meyer ◽  
Michael Stumvoll ◽  
Stephen Welle ◽  
Hans J. Woerle ◽  
Morey Haymond ◽  
...  
Keyword(s):  
Blood Flow ◽  
Renal Blood Flow ◽  
Relative Importance ◽  
Substrate Availability ◽  
Glucose Release ◽  
Renal Uptake ◽  
Hepatic Glucose ◽  
Liver And Kidney ◽  
The Difference ◽  
Hepatic Glucose Release

Splanchnic and renal net balance measurements indicate that lactate and glycerol may be important precursors for epinephrine-stimulated gluconeogenesis (GNG) in liver and kidney, but the effects of epinephrine on their renal and hepatic conversion to glucose in humans have not yet been reported. We therefore used a combination of renal balance and isotopic techniques in nine postabsorptive volunteers to measure systemic and renal GNG from these precursors before and during a 3-h infusion of epinephrine (270 pmol · kg–1 · min–1) and calculated hepatic GNG as the difference between systemic and renal rates. During infusion of epinephrine, renal and hepatic GNG from lactate increased 4- to 6-fold and accounted for ∼85 and 70% of renal and hepatic glucose release, respectively, at the end of study; renal and hepatic GNG from glycerol increased ∼1.5- to 2-fold and accounted for ∼7–9% of renal and hepatic glucose release at the end of study. The increased renal GNG from lactate and glycerol was due not only to their increased renal uptake (∼3.3- and 1.4-fold, respectively) but also increased renal gluconeogenic efficiency (∼1.8- and 1.5-fold). The increased renal uptake of lactate and glycerol was wholly due to their increased arterial concentrations, since their renal fractional extraction remained unchanged and renal blood flow decreased. We conclude that 1) lactate is the predominant precursor for epinephrine-stimulated GNG in both liver and kidney, 2) hepatic and renal GNG from lactate and glycerol are similarly sensitive to stimulation by epinephrine, and 3) epinephrine increases renal GNG from lactate and glycerol by increasing substrate availability and the gluconeogenic efficiency of the kidney.

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