Reproductive rate and longevity in the waterstrider, Gerris buenoi

1990 ◽  
Vol 68 (2) ◽  
pp. 399-402 ◽  
Author(s):  
Locke Rowe ◽  
G. G. E. Scudder
Keyword(s):  
Egg Production ◽  
Life History Theory ◽  
Reproductive Rate ◽  
Food Level ◽  
Central Component ◽  
Effect Of Food ◽  
Food Conditions ◽  
Female Longevity ◽  
Egg Production Rate ◽  
The Relationship

In this laboratory study, the relationship between egg output and longevity at three food levels is examined in adults of the waterstrider, Gerris buenoi. There was no effect of food level on estimated lifetime fecundity. However, egg production rate was halved under low food conditions. This reduction in reproductive rate was balanced by a near doubling of female longevity under food scarcity. Males lived longer than females, but longevity was not significantly related to food level. Egg fertility was not significantly different across treatments. Body size accounted for less than 5% of the variation in all these variables. These data support a central component of life history theory: the assumption that there is a trade off between reproductive rate and longevity.

Egg Production and Viability in Centropages Typicus: A Laboratory Study on the Effect of Food Concentration

1997 ◽  
Vol 77 (1) ◽  
pp. 257-260 ◽  
Author(s):  
Francisco Guerrero ◽  
Suzanne Nival ◽  
Paul Nival
Keyword(s):  
Production Rate ◽  
Egg Production ◽  
Food Concentration ◽  
Natural Food ◽  
Algal Culture ◽  
Effect Of Food ◽  
Food Conditions ◽  
Egg Production Rate ◽  
Food Media ◽  
Centropages Typicus

The effect of food concentration on the reproductive success of the copepod Centropages typicus (Copepoda: Calanoida) was studied in the laboratory. Three different regimes of food were tested: absence of food, natural food conditions and a food media enriched with an algal culture. The results showed significant differences in egg production rate between regimes of food, but no significant differences in egg viability. A rapid response (24 h) in egg production rate to increment in the quantity of food was noted. Hatching success was not affected by food conditions prevailing during the incubations.

ESTERASE GENOTYPES AND PERFORMANCE TRAITS IN MEAT-TYPE CHICKENS

1977 ◽  
Vol 19 (4) ◽  
pp. 645-650 ◽  
Author(s):  
A. A. Grunder ◽  
E. S. Merritt
Keyword(s):  
Body Weight ◽  
Egg Production ◽  
Major Influence ◽  
Allelic Frequencies ◽  
Reproduction Traits ◽  
Egg Production Rate ◽  
And Performance ◽  
And Control ◽  
The Relationship ◽  
Meat Type

The genotypes at a serum esterase locus were determined for 3208 female meat-type chickens. These birds belonged to three generations of six strains on which records of body-weight and reproduction traits were kept. Allelic frequencies among strains were compared and then a study was made of the relationship between esterase genotype and the following traits: body weight at five ages, age at first egg, survivor egg production, rate of egg production (%), egg weight, fertility and hatchability. Allelic frequencies did not differ in two of three years between replicate control strains but were significantly different in seven of nine comparisons between selected and control strains. Analysis of variance of paired comparisons of genotypes on a within dam family basis revealed only five of the 106 comparisons to be significant. No heterotic effects were indicated. It was concluded that the esterase genotypes studied do not have a major influence on the traits investigated.

A model of egg production by Heterodera schachtii (Nematoda: Heteroderidae)

1991 ◽  
Vol 69 (8) ◽  
pp. 2085-2088 ◽  
Author(s):  
Edward P. Caswell ◽  
Ivan J. Thomason
Keyword(s):  
Egg Production ◽  
Logistic Function ◽  
Heterodera Schachtii ◽  
Threshold Temperature ◽  
Degree Days ◽  
Egg Hatch ◽  
Average Maximum ◽  
Egg Production Rate ◽  
Sugarbeet Cyst Nematode ◽  
The Relationship

Egg production by the sugarbeet cyst nematode, Heterodera schachtii, infecting sugarbeet, Beta vulgaris, was assessed at temperatures of 13, 18, 24, and 30 °C in constant-temperature tanks. The minimum-threshold temperature for degree-day accumulation relative to egg production was identified as 8 °C. The relationship between cumulative degree-days (DD) (base 8 °C) and egg production was examined. Egg production began between 160 and 270 DD after hatch and reached a maximum between 390 and 480 DD. Observed egg production (Y) across all temperatures was described as a logistic function of degree-days: Y = 202/(1 + 23726 e−0.034 DD) (r2 = 0.84; P < 0.05). The model depicts initiation of egg production at 140 DD, a maximum average egg production of 202 eggs per female reached at approximately 410 DD, and a maximum rate of egg production of 1.7 eggs/DD reached at approximately 290 DD. The accuracy of the model was limited because observed cumulative egg production was confounded by egg hatch. Accordingly, the cumulative egg production data were adjusted for egg hatch. The adjusted cumulative egg production (Y) was described as a logistic function of cumulative degree-days: Y = 420/(1 + 3319 e−0.023 DD) (r2 = 0.98; P < 0.05). The function depicts egg production initiated at approximately 120 DD. Average maximum egg production is 420 eggs per female occurring at approximately 680 DD, with a maximum egg-production rate of 2.4 eggs/DD occurring at approximately 350 DD.

scholarly journals Homenagem: Remembering the Life and Work of Abdias Nascimento

2021 ◽  
pp. 002193472110115
Author(s):  
Keisha-Khan Y. Perry ◽  
Anani Dzidzienyo
Keyword(s):  
Military Service ◽  
Black Studies ◽  
Central Component ◽  
Special Issue ◽  
Art And Politics ◽  
Black Politicians ◽  
Brown University ◽  
Black World ◽  
The Relationship

This essay provides a brief introduction to this special issue focused on the life and work of Black Brazilian scholar-activist Abdias Nascimento. The contributors include, Vera Lucia Benedito, Ollie Johnson, Zachary Morgan, Elisa Larkin Nascimento, and Cheryl Sterling who all participated in a 2015 conference at Africana Studies at Brown University. This group of scholars aptly illustrate that Nascimento had long contributed to the internationalization of Black Studies as a field in US academe and he was crucial in establishing Brazil as a central component of the Black World. The essays have much to teach us about Nascimento’s views on the relationship between art and politics, the role of military service in shaping his activism, the significance of black politicians in the reconceptualization of Brazilian democracy, and the importance of preserving archives and expanding our understanding of the Black radical tradition.

scholarly journals The Relationship between Affect Integration and Psychopathology in Patients with Personality Disorder: A Cross-Sectional Study

Medicina ◽  
2021 ◽  
Vol 57 (6) ◽  
pp. 627
Author(s):  
Christina Frederiksen ◽  
Ole André Solbakken ◽  
Rasmus Wentzer Licht ◽  
Carsten René Jørgensen ◽  
Maria Rodrigo-Domingo ◽  
...  
Keyword(s):  
Personality Disorder ◽  
Personality Disorders ◽  
Interpersonal Problems ◽  
Symptom Distress ◽  
Central Component ◽  
Psychotherapeutic Treatment ◽  
Cross Sectional ◽  
Personality Functioning ◽  
Emotional Dysfunction ◽  
The Relationship

Background and Objectives: Emotional dysfunction is considered a key component in personality disorders; however, only few studies have examined the relationship between the two. In this study, emotional dysfunction was operationalized through the Affect Integration Inventory, and the aim was to examine the relationships between the level of affect integration and the levels of symptom distress, interpersonal problems, and personality functioning in patients diagnosed with personality disorder according to the Diagnostic and Statistical Manual of Mental Disorders, fifth edition. Materials and Methods: Within a hospital-based psychiatric outpatient setting, 87 patients with personality disorder referred for treatment were identified for assessment with the Affect Integration Inventory and other measures (e.g., the Symptom Checklist-90, Revised, the Inventory of Interpersonal Problems 64 circumplex version, and the Severity Indices of Personality Problems). Results: The analyses revealed that problems with affect integration were strongly and statistically significantly correlated with high levels of symptom distress, interpersonal problems, and maladaptive personality functioning. Additionally, low scores on the Affect Integration Inventory regarding discrete affects were associated with distinct and differentiated patterns of interpersonal problems. Conclusion: Taken together, emotional dysfunction, as measured by the Affect Integration Inventory, appeared to be a central component of the pathological self-organization associated with personality disorder. These findings have several implications for the understanding and psychotherapeutic treatment of personality pathology. Furthermore, they highlight the importance of considering the integration of discrete affects and their specific contributions in the conceptualization and treatment of emotional dysfunction in patients with personality disorders.

scholarly journals Effect of genotype, age of hens and K/k allele on eggshell quality

2011 ◽  
Vol 56 (No. 5) ◽  
pp. 242-249 ◽  
Author(s):  
Z. Ledvinka ◽  
L. Zita ◽  
M. Hubený ◽  
E. Tůmová ◽  
M. Tyller ◽  
...  
Keyword(s):  
Growth Rate ◽  
Egg Production ◽  
Statistical Significance ◽  
Live Weight ◽  
Shape Index ◽  
Feed Mixture ◽  
Eggshell Quality ◽  
Feather Growth ◽  
Two Factors ◽  
The Relationship

We assessed the influence of the particular genotype, age of layers, feather growth-rate gene, and their mutual interactions on selected indicators of eggshell quality in six groups of hens of the laying type Dominant. The following genotypes were examined in the experiment: Barred Plymouth Rock, Dominant BPR 951 (K) strain, slow-feathering; Barred Plymouth Rock, Dominant BPR 901 (k) strain, fast-feathering; Blue Plymouth Rock, Dominant BLPR 954 (K) strain, slow-feathering; Blue Plymouth Rock, Dominant BLPR 894 (k) strain, fast-feathering; crossbreds of the above strains in the F<sub>1</sub> generation Dominant D 107 blue (K), slow-feathering and Dominant D 107 blue (k), fast-feathering. The layers were fed a feed mixture NP1 (16.64 % CP) from the 20<sup>th</sup> week of age and a feed mixture NP2 (15.02% CP) from the 42<sup>nd</sup> week. Husbandry conditions met the regular requirements of laying hens. Egg production and live weight of hens were monitored for the duration of the experiment (12 months). Eggshell quality was examined at the layers' age of 27, 35 and 56 weeks. The average hen-day egg production for the duration of the experiment (12 months) was not significantly influenced by the particular genotype or the feather growth-rate gene. The varying representation of the feather growth-rate gene significantly (P &le; 0.001) influenced the live weight; similarly, the relationship between the genotype and the representation of K/k alleles was significant. The average egg weight was influenced statistically significantly (P &le; 0.001) by the age of hens, their genotype (P &le; 0.05), feather growth-rate gene (P &le; 0.001), and the relationship between the age and genotype (P &le; 0.001). The age of hens, genotype, and the interaction of these two factors affected the egg shape index, as did the incidence of the feather growth-rate gene within the population (with a statistical significance of P &le; 0.001). The age, genotype and the feather growth-rate gene incidence within the population also significantly affected the eggshell quality indicators. In the eggshell to egg ratio, eggshell thickness and strength, an interaction was determined between the age of hens and their particular genotype. The eggshell colour was also significantly (P &le; 0.001) affected by hens' age, genotype (P &le; 0.001), as well as by the feather growth-rate gene (P &le; 0.001). No significant interaction between the age and the genotype was found for this indicator.

scholarly journals A revision of daily egg production estimation methods, with application to Atlanto-Iberian sardine. 2. Spatially and environmentally explicit estimates of egg production

2011 ◽  
Vol 68 (3) ◽  
pp. 528-536 ◽  
Author(s):  
Miguel Bernal ◽  
Yorgos Stratoudakis ◽  
Simon Wood ◽  
Leire Ibaibarriaga ◽  
Luis Valdés ◽  
...  
Keyword(s):  
Temporal Variability ◽  
Environmental Variables ◽  
Egg Production ◽  
Stock Assessment ◽  
Production Model ◽  
Estimation Methods ◽  
Statistical Framework ◽  
Spatio Temporal ◽  
The Relationship ◽  
Made In

Abstract Bernal, M., Stratoudakis, Y., Wood, S., Ibaibarriaga, L., Uriarte, A., Valdés, L., and Borchers, D. 2011. A revision of daily egg production estimation methods, with application to Atlanto-Iberian sardine. 2. Spatially and environmentally explicit estimates of egg production. – ICES Journal of Marine Science, 68: . A spatially and environmentally explicit egg production model is developed to accommodate a number of assumptions about the relationship between egg production and mortality and associated environmental variables. The general model was tested under different assumptions for Atlanto-Iberian sardine. It provides a flexible estimator of egg production, in which a range of assumptions and hypotheses can be tested in a structured manner within a well-defined statistical framework. Application of the model to Atlanto-Iberian sardine increased the precision of the egg production time-series, and allowed improvements to be made in understanding the spatio-temporal variability in egg production, as well as implications for ecology and stock assessment.

The impact of dietary protein:carbohydrate balance on lifespan and reproduction in Protaetia brevitarsis (Coleoptera: Scarabaeidae: Cetoniinae)

2021 ◽  
pp. 1-8
Author(s):  
S.-H. Kim ◽  
H. Park ◽  
W. Kim ◽  
J.-H. Song ◽  
S.J. Roh ◽  
...  
Keyword(s):  
Reproductive Performance ◽  
Egg Production ◽  
Detailed Knowledge ◽  
Reproductive Senescence ◽  
Egg Hatchability ◽  
Edible Insect ◽  
Age Related ◽  
Medicinal Value ◽  
Egg Production Rate ◽  
The Impact

The establishment of efficient and sustainable production of industrially important insects necessitates the detailed knowledge of the optimal mixture of macronutrients required for maximising their performance and fitness. The white spotted flower chafer, Protaetia brevitarsis (Coleoptera: Scarabaeidae: Cetoniinae), is one of the most important edible insects in East Asia with high nutritional and medicinal value. Here, we report how the ratio of protein to digestible carbohydrate (P:C) in the diet influenced lifespan and reproductive performance in the adults of P. brevitarsis. Throughout their lifespan, beetles were fed ad libitum one of five diets with differing P:C ratio (0:1, 3:7, 1:1, 7:3, 1:0). Both lifespan and the number of eggs produced over the lifetime were maximised at the P:C ratio of 3:7 and declined as the ratio deviated away from this optimal P:C composition. Beetles fed a diet containing only protein (P:C 1:0) not only had the shortest lifespan but also exhibited substantially reduced lifetime egg production compared to those fed the other diets. However, the effects of dietary P:C ratio on daily egg production rate and egg hatchability were marginal. The number of eggs produced at each age stage peaked at the age of week 2 and then gradually declined with increasing age, showing the sign of reproductive senescence. Age-specific egg production was higher in beetles confined to three intermediate P:C ratios (3:7, 1:1, 7:3) than those confined to two extreme P:C ratios (0:1, 1:0) throughout their lifespan. The speed of age-related decrease in reproductive performance was the slowest at P:C 3:7. Our data have implications for optimising the production of this edible insect with emerging economic importance.

Parental allocation of additional food to own health and offspring growth in a variable environment

2009 ◽  
Vol 87 (1) ◽  
pp. 8-19 ◽  
Author(s):  
Patrik Karell ◽  
Hannu Pietiäinen ◽  
Heli Siitari ◽  
Tuomo Pihlaja ◽  
Pekka Kontiainen ◽  
...  
Keyword(s):  
Life History ◽  
Life History Theory ◽  
Blood Parasites ◽  
Food Supplementation ◽  
Additional Food ◽  
Variable Environment ◽  
Blood Sucking ◽  
Offspring Growth ◽  
Future Reproduction ◽  
Food Conditions

Life-history theory predicts increased investment in current reproduction when future reproduction is uncertain and a more balanced investment in current and future reproduction when prospects for both are good. The outcome of the balance in parental allocation depends on which life-history component maximizes the fitness benefits. In our study system, a 3-year vole cycle generates good prospects of current and future reproduction for Ural owls ( Strix uralensis Pallas, 1771) in increase vole phases and uncertain prospects in decrease vole phases. We supplementary-fed Ural owls during the nestling period in 2002 (an increase phase) and 2003 (a decrease phase), and measured offspring growth, parental effort, and physiological health by monitoring haematocrit, leucocyte profiles, intra- and inter-celluar blood parasites, and (in 2003) humoral antibody responsiveness. Food supplementation reduced parental feeding rate in both years, but improved a female parent’s health only in 2002 (an increase phase) and had no effects on males in either year. Nevertheless, supplementary-fed offspring reached higher asymptotic mass and fledged earlier in both years. Furthermore, early fledging reduced offspring exposure to blood-sucking black flies (Diptera, Simuliidae) in the nest. We discuss how parental allocation of resources to current and future reproduction may vary under variable food conditions.

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