Effects of Different Levels of Inbreeding on Fitness Components in Mimulus guttatus

Evolution ◽  
1993 ◽  
Vol 47 (3) ◽  
pp. 864 ◽  
Author(s):  
John H. Willis
Keyword(s):  
Mimulus Guttatus ◽  
Fitness Components ◽  
Different Levels

scholarly journals THE EFFECTS OF INTERSPECIFIC COMPETITION ON THE DYNAMICS OF A POLYMORPHISM IN AN EXPERIMENTAL POPULATION OF DROSOPHILA MELANOGASTER

Genetics ◽  
1979 ◽  
Vol 92 (4) ◽  
pp. 1315-1328
Author(s):  
Andrew Clark
Keyword(s):  
Drosophila Melanogaster ◽  
Interspecific Competition ◽  
Ecological Genetics ◽  
Chromosome Polymorphism ◽  
Experimental Population ◽  
Fourth Chromosome ◽  
Fitness Components ◽  
Parental Density ◽  
Competing Populations ◽  
Different Levels

ABSTRACT Populations of Drosophila melanogaster with a fourth-chromosome polymorphism were subjected to different levels of competition with Drosophila simulans. The dynamics of the polymorphism and the equilibrium frequencies of the sparkling allele were seen to depend on the competitive level, while the higher productivity of the competing populations was shown to be due to the initial parental density. The effects of competition on fitness components were quantified by fitting the data to both a two-stage selection model and a fertility model. Additional experiments were performed to verify that the interspecific competition caused the changes in fitness. The results are discussed in light of the importance of considering selection components in models of ecological genetics.

Are nest defense behaviours and fitness components linked in white-rumped swallows (Tachycineta leucorrhoa)?

Behaviour ◽  
2019 ◽  
Vol 156 (2) ◽  
pp. 181-201
Author(s):  
Uschi Wischhoff ◽  
Fernando Marques-Santos ◽  
Giselle Bonetti ◽  
Lilian T. Manica ◽  
James J. Roper ◽  
...  
Keyword(s):  
Wild Animal ◽  
Nest Defence ◽  
Costs And Benefits ◽  
Fitness Components ◽  
Trade Off ◽  
Trade Offs ◽  
Animal Populations ◽  
Behavioural Types ◽  
One Year ◽  
Different Levels

Abstract How are personalities maintained in wild animal populations? A possible mechanism is the existence of trade-offs between fitness components (survival and reproductive success) among behavioural types. We investigated this trade-off in white-rumped swallows (Tachycineta leucorrhoa) by capturing adults and monitoring their reproduction over time. We focused on the personality trait of nest defence against a human. We found that swallows with different levels of nest defence had similar probability to return from migration between two years (a proxy for survival). In one year, swallows that defended their nests more boldly were also more likely to succeed. However, nest defence was not linked to nestling weight or number of fledglings. Thus, we found no evidence of a trade-off between fitness components. It is possible that the investigated relationships become relevant only in extreme years that severely alter the costs and benefits of this behaviour.

scholarly journals A sensory bias overrides learned preferences of bumblebees for honest signals in Mimulus guttatus

2021 ◽  
Vol 288 (1948) ◽  
Author(s):  
Ariela I. Haber ◽  
James W. Sims ◽  
Mark C. Mescher ◽  
Consuelo M. De Moraes ◽  
David E. Carr
Keyword(s):  
Floral Scent ◽  
Mimulus Guttatus ◽  
Pollinator Visitation ◽  
Sensory Bias ◽  
Honest Signals ◽  
Signal Honesty ◽  
Floral Volatile ◽  
Selection For ◽  
Pollination Strategy ◽  
Different Levels

Insect pollinators readily learn olfactory cues, and this is expected to select for ‘honest signals' that provide reliable information about floral rewards. However, plants might alternatively produce signals that exploit pollinators' sensory biases, thereby relaxing selection for signal honesty. We examined the innate and learned preferences of Bombus impatiens for Mimulus guttatus floral scent phenotypes corresponding to different levels of pollen rewards in the presence and absence of the innately attractive floral volatile compound β-trans-bergamotene. Bees learned to prefer honest signals after foraging on live M. guttatus flowers, but only exhibited this preference when presented floral scent phenotypes that did not include β-trans-bergamotene. Our results suggest that a sensory bias for β-trans-bergamotene overrides the ability of B. impatiens to use honest signals when foraging on M. guttatus . This may represent a deceptive pollination strategy that allows plants to minimize investment in costly rewards without incurring reduced rates of pollinator visitation.

Dependence of Intergranular Fracture on Boundary Topography and Cohesion

1973 ◽  
Vol 31 ◽  
pp. 150-151
Author(s):  
J. E. Doherty ◽  
A. F. Giamei ◽  
B. H. Kear ◽  
C. W. Steinke
Keyword(s):  
Grain Boundary ◽  
Room Temperature ◽  
Nickel Base Superalloy ◽  
Boundary Shear ◽  
Room Temperature Ductility ◽  
Solid Solution Matrix ◽  
Nickel Base ◽  
Solution Matrix ◽  
Different Levels ◽  
Base Superalloy

Recently we have been investigating a class of nickel-base superalloys which possess substantial room temperature ductility. This improvement in ductility is directly related to improvements in grain boundary strength due to increased boundary cohesion through control of detrimental impurities and improved boundary shear strength by controlled grain boundary micros true tures.For these investigations an experimental nickel-base superalloy was doped with different levels of sulphur impurity. The micros tructure after a heat treatment of 1360°C for 2 hr, 1200°C for 16 hr consists of coherent precipitates of γ’ Ni3(Al,X) in a nickel solid solution matrix.

Immunoenzymatic demonstration of the simultaneous presence of transferrin, hemopexin and albumin in a same hepatocyte and their ultrastructural localization

1978 ◽  
Vol 36 (2) ◽  
pp. 88-89
Author(s):  
M. Kraemer ◽  
J. Foucrier ◽  
J. Vassy ◽  
M.T. Chalumeau
Keyword(s):  
Plasma Proteins ◽  
Rat Hepatocytes ◽  
Ultrastructural Localization ◽  
Carrier Proteins ◽  
Normal Cells ◽  
Adult Rat ◽  
Adult Rat Hepatocytes ◽  
Monospecific Antisera ◽  
Different Levels

Some authors using immunofluorescent techniques had already suggested that some hepatocytes are able to synthetize several plasma proteins. In vitro studies on normal cells or on cells issued of murine hepatomas raise the same conclusion. These works could be indications of an hepatocyte functionnal non-specialization, meanwhile the authors never give direct topographic proofs suitable with this hypothesis.The use of immunoenzymatic techniques after obtention of monospecific antisera had seemed to us useful to bring forward a better knowledge of this problem. We have studied three carrier proteins (transferrin = Tf, hemopexin = Hx, albumin = Alb) operating at different levels in iron metabolism by demonstrating and localizing the adult rat hepatocytes involved in their synthesis.Immunological, histological and ultrastructural methods have been described in a previous work.

Memory Processes, Aging, Cognitive Decline, and Neurodegenerative Diseases

2006 ◽  
Vol 11 (4) ◽  
pp. 304-311 ◽  
Author(s):  
Lars-Göran Nilsson
Keyword(s):  
Cognitive Impairment ◽  
Cognitive Decline ◽  
Neurodegenerative Disease ◽  
Genetic Markers ◽  
Brain Activity ◽  
Memory Performance ◽  
Modeling And Simulations ◽  
Aging And Health ◽  
Explained Variance ◽  
Different Levels

This paper presents four domains of markers that have been found to predict later cognitive impairment and neurodegenerative disease. These four domains are (1) data patterns of memory performance, (2) cardiovascular factors, (3) genetic markers, and (4) brain activity. The critical features of each domain are illustrated with data from the longitudinal Betula Study on memory, aging, and health ( Nilsson et al., 1997 ; Nilsson et al., 2004 ). Up to now, early signs regarding these domains have been examined one by one and it has been found that they are associated with later cognitive impairment and neurodegenerative disease. However, it was also found that each marker accounts for only a very small part of the total variance, implying that single markers should not be used as predictors for cognitive decline or neurodegenerative disease. It is discussed whether modeling and simulations should be used as tools to combine markers at different levels to increase the amount of explained variance.

Implications of Person Fluctuation for the Stability and Validity of Test Scores

Methodology ◽  
2006 ◽  
Vol 2 (4) ◽  
pp. 142-148 ◽  
Author(s):  
Pere J. Ferrando
Keyword(s):  
Item Response ◽  
Test Scores ◽  
Temporal Stability ◽  
Person Fit ◽  
Item Parameters ◽  
Individual Trait ◽  
The Stability ◽  
The Individual ◽  
Different Levels ◽  
Fluctuation Model

In the IRT person-fluctuation model, the individual trait levels fluctuate within a single test administration whereas the items have fixed locations. This article studies the relations between the person and item parameters of this model and two central properties of item and test scores: temporal stability and external validity. For temporal stability, formulas are derived for predicting and interpreting item response changes in a test-retest situation on the basis of the individual fluctuations. As for validity, formulas are derived for obtaining disattenuated estimates and for predicting changes in validity in groups with different levels of fluctuation. These latter formulas are related to previous research in the person-fit domain. The results obtained and the relations discussed are illustrated with an empirical example.

The Emergence and Maintenance of Ethical Leadership in Organizations

2012 ◽  
Vol 11 (1) ◽  
pp. 7-19 ◽  
Author(s):  
Silke Astrid Eisenbeiß ◽  
Steffen R. Giessner
Keyword(s):  
Cultural Values ◽  
Ethical Leadership ◽  
Leadership Behavior ◽  
Peer Group ◽  
Organizational Characteristics ◽  
Future Research ◽  
Environmental Complexity ◽  
Group Influence ◽  
Analysis Society ◽  
Different Levels

The present paper gives a review of empirical research on ethical leadership and shows that still little is known known about the contextual antecedents of ethical leadership. To address this important issue, a conceptual framework is developed that analyzes the embeddedness of organizational ethical leadership. This framework identifies manifest and latent contextual factors on three different levels of analysis – society, industry, and organization – which can affect the development and maintenance of ethical leadership. In particular, propositions are offered about how (1) societal characteristics, notably the implementation and the spirit of human rights in a society and societal cultural values of responsibility, justice, humanity, and transparency; (2) industry characteristics such as environmental complexity, the content of the organizational mandate, and the interests of stakeholder networks; and (3) intra-organizational characteristics, including the organizational ethical infrastructure and the ethical leadership behavior of a leader’s peer group, influence the development and maintenance of ethical leadership in organizations. This list of factors is not exhaustive, but illustrates how the three levels may impact ethical leadership. Implications for managerial practice and future research are discussed.

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