scholarly journals Urban resources limit pair coordination over offspring provisioning

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Davide Baldan ◽  
Jenny Q. Ouyang
Keyword(s):  
Empirical Studies ◽  
Theoretical Models ◽  
Rural Site ◽  
Fragmented Habitat ◽  
House Wrens ◽  
Evolutionary Conflict ◽  
Fitness Consequences ◽  
Habitat Composition ◽  
Parental Strategies ◽  
Suburban Site

Abstract The amount of care parents provide to the offspring is complicated by an evolutionary conflict of interest (‘sexual conflict’) between the two parents. Recent theoretical models suggest that pair coordination of the provisioning may reduce this conflict and increase parent and offspring fitness. Despite empirical studies showing that pair coordination is common in avian species, it remains unclear how environmental and ecological conditions might promote or limit the ability of parents to coordinate care. We compared the level of pair coordination, measured as alternation and synchrony of the nest visits, of house wrens Troglodytes aedon pairs breeding in a rural (10 nests) and a suburban (9 nests) site and investigated how differences in parental behaviours were related to habitat composition, prey abundance and how they ultimately related to reproductive success. We found that parents alternated and synchronized their nest visits more in the rural site compared to the suburban one. The suburban site is characterized by a more fragmented habitat with more coniferous trees and less caterpillar availability. Offspring from the rural site were heavier at fledging than at the suburban site. Taken together, these results suggest that environmental conditions play an important role on the emergence of coordinated parental care and that considering environmental variables is pivotal to assess the fitness consequences of parental strategies.

Emerging Syndromes

2017 ◽  
Author(s):  
Kelly C. Allison ◽  
Jennifer D. Lundgren
Keyword(s):  
Empirical Studies ◽  
Theoretical Models ◽  
Future Research ◽  
Night Eating Syndrome ◽  
Statistical Manual ◽  
Night Eating ◽  
Diagnostic And Statistical Manual ◽  
Impairment In Functioning ◽  
Atypical Anorexia Nervosa ◽  
Comorbid Psychopathology

The Diagnostic and Statistical Manual, fifth edition, of the American Psychiatric Association (2013) has designated several disorders under the diagnosis of otherwise specified feeding and eating disorder (OSFED). This chapter evaluates three of these, night eating syndrome (NES), purging disorder (PD), and atypical anorexia nervosa (atypical AN). It also reviews orthorexia nervosa, which has been discussed in the clinical realm as well as the popular press. The history and definition for each is reviewed, relevant theoretical models are presented and compared, and evidence for the usefulness of the models is described. Empirical studies examining the disorders’ independence from other disorders, comorbid psychopathology, and, when available, medical comorbidities, are discussed. Distress and impairment in functioning seem comparable between at least three of these emerging disorders and threshold eating disorders. Finally, remaining questions for future research are summarized.

scholarly journals A Systematic Review on Attachment and Sleep at Preschool Age

Children ◽  
2021 ◽  
Vol 8 (10) ◽  
pp. 895
Author(s):  
Catarina Perpétuo ◽  
Eva Diniz ◽  
Manuela Veríssimo
Keyword(s):  
Systematic Review ◽  
Attachment Security ◽  
Biological Process ◽  
Sleep Problems ◽  
Empirical Studies ◽  
Theoretical Models ◽  
Preschool Age ◽  
Future Research ◽  
Parent Child Relationships ◽  
Present Systematic Review

Sleep is a biological process that impacts nearly every domain of a child’s life. Sleep-wake regulation influences and it is highly influenced by developmental variables related to parent-child relationships, such as attachment. The main goal of the present systematic review is to analyze and integrate the findings of empirical studies investigating the relations between attachment and sleep in preschool age, a period marked by important developmental changes that challenge both attachment system and sleep-wake regulation. A database search was performed using a combination of relevant keywords, leading to the identification of 524 articles, with 19 manuscripts assessed for eligibility; finally, seven studies (2344 children) were included. Overall, the findings were not consistent, with some studies reporting significant associations between attachment security and sleep quality, as well as between attachment insecurity and sleep problems, whereas others did not find significant associations. The results are discussed in light of the available theoretical models and integrated in the context of measurement approaches to attachment and sleep heterogeneity, aiming to guide future research on the topic.

scholarly journals Whose trait is it anyways? Coevolution of joint phenotypes and genetic architecture in mutualisms

2021 ◽  
Vol 288 (1942) ◽  
pp. 20202483
Author(s):  
Anna M. O’Brien ◽  
Chandra N. Jack ◽  
Maren L. Friesen ◽  
Megan E. Frederickson
Keyword(s):  
Association Studies ◽  
Single Species ◽  
Genome Wide Association Studies ◽  
Interacting Species ◽  
Fitness Effects ◽  
Evolutionary Conflict ◽  
Fitness Consequences ◽  
Genome Wide ◽  
Fitness Benefits ◽  
Multiple Genomes

Evolutionary biologists typically envision a trait’s genetic basis and fitness effects occurring within a single species. However, traits can be determined by and have fitness consequences for interacting species, thus evolving in multiple genomes. This is especially likely in mutualisms, where species exchange fitness benefits and can associate over long periods of time. Partners may experience evolutionary conflict over the value of a multi-genomic trait, but such conflicts may be ameliorated by mutualism’s positive fitness feedbacks. Here, we develop a simulation model of a host–microbe mutualism to explore the evolution of a multi-genomic trait. Coevolutionary outcomes depend on whether hosts and microbes have similar or different optimal trait values, strengths of selection and fitness feedbacks. We show that genome-wide association studies can map joint traits to loci in multiple genomes and describe how fitness conflict and fitness feedback generate different multi-genomic architectures with distinct signals around segregating loci. Partner fitnesses can be positively correlated even when partners are in conflict over the value of a multi-genomic trait, and conflict can generate strong mutualistic dependency. While fitness alignment facilitates rapid adaptation to a new optimum, conflict maintains genetic variation and evolvability, with implications for applied microbiome science.

Research on capital structure determinants: a review and future directions

2017 ◽  
Vol 13 (2) ◽  
pp. 106-132 ◽  
Author(s):  
Satish Kumar ◽  
Sisira Colombage ◽  
Purnima Rao
Keyword(s):  
Capital Structure ◽  
Meta Analysis ◽  
Empirical Studies ◽  
Secondary Data ◽  
Theoretical Models ◽  
Order Theory ◽  
Organizational Level ◽  
Future Research ◽  
Content Type ◽  
The Impact

Purpose The purpose of this paper is to study the status of studies on capital structure determinants in the past 40 years. This paper highlights the major gaps in the literature on determinants of capital structure and also aims to raise specific questions for future research. Design/methodology/approach The prominence of research is assessed by studying the year of publication and region, level of economic development, firm size, data collection methods, data analysis techniques and theoretical models of capital structure from the selected papers. The review is based on 167 papers published from 1972 to 2013 in various peer-reviewed journals. The relationship of determinants of capital structure is analyzed with the help of meta-analysis. Findings Major findings show an increase of interest in research on determinants of capital structure of the firms located in emerging markets. However, it is observed that these regions are still under-examined which provides more scope for research both empirical and survey-based studies. Majority of research studies are conducted on large-sized firms by using secondary data and regression-based models for the analysis, whereas studies on small-sized firms are very meager. As majority of the research papers are written only at the organizational level, the impact of leverage on various industries is yet to be examined. The review highlights the major determinants of capital structure and their relationship with leverage. It also reveals the dominance of pecking order theory in explaining capital structure of firms theoretically as well as statistically. Originality/value The paper covers a considerable period of time (1972-2013). Among very few review papers on capital structure research, to the best of authors’ knowledge; this is the first review to identify what is missing in the literature on the determinants of capital structure while offering recommendations for future studies. It also synthesize the findings of empirical studies on determinants of capital structure statistically.

scholarly journals A meta-analysis of the quantitative studies in continuance intention to use an information system

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Frank Bivar Franque ◽  
Tiago Oliveira ◽  
Carlos Tam ◽  
Fernando de Oliveira Santini
Keyword(s):  
Information System ◽  
Meta Analysis ◽  
Empirical Studies ◽  
Theoretical Models ◽  
Temporal Analysis ◽  
Perceived Usefulness ◽  
Intention To Use ◽  
Continuance Intention ◽  
Content Type

PurposeThis study aims to describe, synthesise and clarify the findings of published studies on individual continuance intention to use an information system (IS), considering the fact that the number of studies in the continuance intention context are growing exponentially and cover several different subjects.Design/methodology/approachThe research uses meta- and weight analysis by taking 115 empirical studies from continuance intention to use an IS. The data are presented in different views using significant and non-significant relationships from all the studies. Furthermore, it uses hierarchical linear meta-analysis to analyse potential moderators that can influence continuance intention.FindingsThe results reveal that affective commitment, attitude, satisfaction, hedonic value and flow are the best predictors of continuance intention to use an IS. Sample size, individualism, uncertainty avoidance and long-term orientation moderate the relationship of perceived usefulness on continuance intention. Power distance, masculinity and indulgence moderate relationship satisfaction on continuance intention.Practical implicationsThe results reveal that continuance intention to use an IS has been studied in different countries, with different cultures; therefore, IS providers should have diversified managing strategies, to ensure the satisfaction of users and long-term usage of their IS.Originality/valueThe study provides a systematic overview of the most relevant variables used in the literature, including a temporal analysis of the theoretical models, highlighting the evolution of the constructs and presents a moderation analysis.

Parasitism, immune response, and egg production of the spearhead bluet (Coenagrion hastulatum) damselfly

2017 ◽  
Vol 95 (5) ◽  
pp. 367-372
Author(s):  
Kari M. Kaunisto ◽  
Pipsa Kaunisto ◽  
Jaakko J. Ilvonen ◽  
Jukka Suhonen
Keyword(s):  
Immune Response ◽  
Egg Production ◽  
Parasite Species ◽  
Wing Length ◽  
Empirical Studies ◽  
Theoretical Models ◽  
Water Mites ◽  
Negative Effect ◽  
Different Populations ◽  
Individual Size

Theoretical models predict that parasites reduce reproductive success of their hosts, but very few empirical studies have given support to this. Using the spearhead bluet (Coenagrion hastulatum (Charpentier, 1825)) damselfly, we tested how immune response, wing length, and the number of both endo- and ecto-parasites affect egg production of host damselflies. The study was conducted with four different populations in southwest Finland. We found a negative association between endoparasitic gregarines and number of host eggs. Furthermore, immune response increased with the number of water mites, but decreased with the number of eggs. Contrary to previous studies with other damselfly species, the number of ectoparasitic water mites did not affect the number of eggs. Moreover, wing length, used as an indicator of individual size, was not associated with egg numbers. The negative effect of gregarine parasites on egg numbers is likely to affect the composition of host populations, i.e., damselflies that show higher resistance to these endoparasites will have more of their offspring represented in subsequent generations. In future, more experimental research on the varying effects of different parasite species on the number of eggs is needed.

Parent-Offspring Conflict in Budgerigars

Behaviour ◽  
1985 ◽  
Vol 94 (1-2) ◽  
pp. 1-39 ◽  
Author(s):  
Judy Stamps ◽  
Anne Clark ◽  
Pat Arrowood ◽  
Barbara Kus
Keyword(s):  
Theoretical Models ◽  
Food Delivery ◽  
Conflict Theory ◽  
Brood Reduction ◽  
Theoretical Interest ◽  
Genetic Conflict ◽  
Female Counterstrategy ◽  
Males And Females ◽  
And Performance ◽  
Parental Strategies

AbstractDespite widespread theoretical interest in genetic conflict between parents and offspring, there is little empirical evidence that it exists in nature. Theoretical models suggest two outcomes of conflict not predicted by alternate theories: (1) offspring that control the allocation of parental investment might show escalated demand behaviours (e.g., begging) and demand more resources than they could efficiently use and (2) parents might evolve behavioural counterstrategies which prevented offspring from obtaining extra resources, but which were more costly than a "laissez-faire" parental strategy allowing offspring control. These predictions were tested in budgerigars, (Melopsittacus undulatus) in large flight cages at Davis, California. Budgerigar clutches hatch extremely asynchronously, yet all nestlings grew at similar rates and fledged at similar sizes and ages. This independence of hatch order and performance seemed due primarily to the mother budgerigar's allofeeding strategy: females allofed offspring mainly on the basis of size, and only secondarily attended to begging rate. Offspring of a given age and size were treated the same by their mothers regardless of hatch order, and offspring undersized for their age were fed as if they were younger. In contrast, male budgerigars attended to offspring begging rates. Males tended to initiate feeding bouts when offspring begged, and to allofeed vigorous beggers more often. Variance in male allofeeding behaviour allowed comparisons of size-matched families in which females performed nearly all of the allofeeds to nestlings (= female-fed families) with families in which males and females both allofed nestlings (= male-aided families). The parent controlled the allocation of food in female-fed families, while offspring had greater control over food allocation in male-fed families. As was predicted by conflict theory, the female counterstrategy was effective but potentially costly: the food delivery rate of females was only half as fast as males'. Conversely, offspring control resulted in an escalation of beg rate for the same degree of need (as measured by size and growth), and male-aided offspring obtained nearly three times more regurgitations than female-fed nestlings, yet grew at comparable rates and fledged at comparable sizes and ages. Hence, offspring demanded and obtained more food than they could effectively use. Other avian parents also seem to use effective but potentially costly counterstrategies, and other avian offspring may demand more food than they require. Even if initial hatch asynchronies functioned in brood reduction, the parental strategies described here would allow parents to retain control over the timing and conditions for offspring loss.

scholarly journals Sperm morphology and sperm velocity in passerine birds

2008 ◽  
Vol 276 (1659) ◽  
pp. 1175-1181 ◽  
Author(s):  
Stefan Lüpold ◽  
Sara Calhim ◽  
Simone Immler ◽  
Tim R Birkhead
Keyword(s):  
Sperm Morphology ◽  
Empirical Studies ◽  
Theoretical Models ◽  
Study Groups ◽  
Passerine Birds ◽  
Single Family ◽  
Sperm Velocity ◽  
Evolutionary Forces ◽  
Wide Range ◽  
Main Determinants

Sperm velocity is one of the main determinants of the outcome of sperm competition. Since sperm vary considerably in their morphology between and within species, it seems likely that sperm morphology is associated with sperm velocity. Theory predicts that sperm velocity may be increased by enlarged midpiece (energetic component) or flagellum length (kinetic component), or by particular ratios between sperm components, such as between flagellum length and head size. However, such associations have rarely been found in empirical studies. In a comparative framework in passerine birds, we tested these theoretical predictions both across a wide range of species and within a single family, the New World blackbirds (Icteridae). In both study groups, sperm velocity was influenced by sperm morphology in the predicted direction. Consistent with theoretical models, these results show that selection on sperm morphology and velocity are likely to be concomitant evolutionary forces.

scholarly journals The evolution of parental cooperation in birds

2015 ◽  
Vol 112 (44) ◽  
pp. 13603-13608 ◽  
Author(s):  
Vladimír Remeš ◽  
Robert P. Freckleton ◽  
Jácint Tökölyi ◽  
András Liker ◽  
Tamás Székely
Keyword(s):  
Sexual Selection ◽  
Parental Care ◽  
Social Environment ◽  
Bird Species ◽  
Theoretical Models ◽  
Model System ◽  
Social Effects ◽  
Species Ranges ◽  
Parental Strategies ◽  
Life History Variables

Parental care is one of the most variable social behaviors and it is an excellent model system to understand cooperation between unrelated individuals. Three major hypotheses have been proposed to explain the extent of parental cooperation: sexual selection, social environment, and environmental harshness. Using the most comprehensive dataset on parental care that includes 659 bird species from 113 families covering both uniparental and biparental taxa, we show that the degree of parental cooperation is associated with both sexual selection and social environment. Consistent with recent theoretical models parental cooperation decreases with the intensity of sexual selection and with skewed adult sex ratios. These effects are additive and robust to the influence of life-history variables. However, parental cooperation is unrelated to environmental factors (measured at the scale of whole species ranges) as indicated by a lack of consistent relationship with ambient temperature, rainfall or their fluctuations within and between years. These results highlight the significance of social effects for parental cooperation and suggest that several parental strategies may coexist in a given set of ambient environment.

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