scholarly journals Linked supergenes underlie split sex ratio and social organization in an ant

2021 ◽  
Vol 118 (46) ◽  
pp. e2101427118
Author(s):  
German Lagunas-Robles ◽  
Jessica Purcell ◽  
Alan Brelsford
Keyword(s):  
Sex Ratio ◽  
Population Level ◽  
Theoretical Work ◽  
Female Offspring ◽  
Future Research ◽  
Genomic Conflict ◽  
Theoretical Predictions ◽  
Empirical Tests ◽  
Formica Podzolica ◽  
Relatedness Asymmetry

Sexually reproducing organisms usually invest equally in male and female offspring. Deviations from this pattern have led researchers to new discoveries in the study of parent–offspring conflict, genomic conflict, and cooperative breeding. Some social insect species exhibit the unusual population-level pattern of split sex ratio, wherein some colonies specialize in the production of future queens and others specialize in the production of males. Theoretical work predicted that worker control of sex ratio and variation in relatedness asymmetry among colonies would cause each colony to specialize in the production of one sex. While some empirical tests supported theoretical predictions, others deviated from them, leaving many questions about how split sex ratio emerges. One factor yet to be investigated is whether colony sex ratio may be influenced by the genotypes of queens or workers. Here, we sequence the genomes of 138 Formica glacialis workers from 34 male-producing and 34 gyne-producing colonies to determine whether split sex ratio is under genetic control. We identify a supergene spanning 5.5 Mbp that is closely associated with sex allocation in this system. Strikingly, this supergene is adjacent to another supergene spanning 5 Mbp that is associated with variation in colony queen number. We identify a similar pattern in a second related species, Formica podzolica. The discovery that split sex ratio is determined, at least in part, by a supergene in two species opens future research on the evolutionary drivers of split sex ratio.

scholarly journals Linked supergenes underlie split sex ratio and social organization in an ant

2021 ◽  
Author(s):  
German Lagunas-Robles ◽  
Jessica Purcell ◽  
Alan Brelsford
Keyword(s):  
Sex Ratio ◽  
Sex Allocation ◽  
Empirical Studies ◽  
Population Level ◽  
Theoretical Work ◽  
Female Offspring ◽  
Genomic Region ◽  
Genomic Conflict ◽  
Theoretical Predictions ◽  
Formica Podzolica

AbstractSexually reproducing organisms usually invest equally in male and female offspring. Deviations from this pattern have led researchers to new discoveries in the study of parent-offspring conflict, genomic conflict, and cooperation. Some social insect species exhibit the unusual population-level pattern of split sex ratio, wherein some colonies specialize in the production of future queens and others specialize in the production of males. Theoretical work focused on the relatedness asymmetries emerging from haplodiploid inheritance, whereby queens are equally related to daughters and sons, but their daughter workers are more closely related to sisters than to brothers, led to a series of testable predictions and spawned many empirical studies of this phenomenon. However, not all empirical systems follow predicted patterns, so questions remain about how split sex ratio emerges. Here, we sequence the genomes of 138 Formica glacialis workers from 34 male-producing and 34 gyne-producing colonies to determine whether split sex ratio is under genetic control. We identify a supergene spanning 5.5 Mbp that is closely associated with sex allocation in this system. Strikingly, this supergene is adjacent to another supergene spanning 5 Mbp that is associated with variation in colony queen number. We identify a similar pattern in a second related species, Formica podzolica. The discovery that split sex ratio is determined, at least in part, by a supergene in two species opens a new line of research on the evolutionary drivers of split sex ratio.Significance StatementSome social insects exhibit split sex ratio, wherein some colonies produce future queens and others produce males. This phenomenon spawned many influential theoretical studies and empirical tests, both of which have advanced our understanding of parent-offspring conflicts and cooperation. However, some empirical systems did not follow theoretical predictions, indicating that researchers lack a comprehensive understanding of the drivers of split sex ratio. Here, we show that split sex ratio is associated with a large genomic region in two ant species. The discovery of a genetic basis for sex allocation in ants provides a novel explanation for this phenomenon, particularly in systems where empirical observations deviate from theoretical predictions.

scholarly journals Magnetospheric Structure of Rotation-Powered Neutron Stars

1992 ◽  
Vol 128 ◽  
pp. 56-77 ◽  
Author(s):  
Jonathan Arons
Keyword(s):  
Radio Emission ◽  
Gamma Radiation ◽  
Heavy Ions ◽  
Theoretical Work ◽  
Future Research ◽  
Observational Constraints ◽  
Polar Caps ◽  
Recent Theoretical Work ◽  
Density Flow ◽  
Promising Avenue

AbstractI survey recent theoretical work on the structure of the magnetospheres of rotation-powered pulsars, within the observational constraints set by their observed spindown, their ability to power synchrotron nebulae and their ability to produce beamed collective radio emission, while putting only a small fraction of their energy into incoherent X- and gamma radiation. I find no single theory has yet given a consistent description of the magnetosphere, but I conclude that models based on a dense outflow of pairs from the polar caps, permeated by a lower density flow of heavy ions, are the most promising avenue for future research.

scholarly journals From individual to population level: Temperature and snow cover modulate fledging success through breeding phenology in greylag geese (Anser anser)

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Didone Frigerio ◽  
Petra Sumasgutner ◽  
Kurt Kotrschal ◽  
Sonia Kleindorfer ◽  
Josef Hemetsberger
Keyword(s):  
Ambient Temperature ◽  
Reproductive Output ◽  
Population Level ◽  
Egg Laying ◽  
Future Research ◽  
Breeding Phenology ◽  
Anser Anser ◽  
Fledging Success ◽  
Average Annual Temperature ◽  
Greylag Geese

AbstractLocal weather conditions may be used as environmental cues by animals to optimize their breeding behaviour, and could be affected by climate change. We measured associations between climate, breeding phenology, and reproductive output in greylag geese (Anser anser) across 29 years (1990–2018). The birds are individually marked, which allows accurate long-term monitoring of life-history parameters for all pairs within the flock. We had three aims: (1) identify climate patterns at a local scale in Upper Austria, (2) measure the association between climate and greylag goose breeding phenology, and (3) measure the relationship between climate and both clutch size and fledging success. Ambient temperature increased 2 °C across the 29-years study period, and higher winter temperature was associated with earlier onset of egg-laying. Using the hatch-fledge ratio, average annual temperature was the strongest predictor for the proportion of fledged goslings per season. There is evidence for an optimum time window for egg-laying (the earliest and latest eggs laid had the lowest fledging success). These findings broaden our understanding of environmental effects and population-level shifts which could be associated with increased ambient temperature and can thus inform future research about the ecological consequences of climate changes and reproductive output in avian systems.

scholarly journals The Influence of a Seedling Recruitment Strategy and a Clonal Architecture on a Spatial Genetic Structure of a Salvia brachyodon (Lamiaceae) Population

Plants ◽  
2020 ◽  
Vol 9 (7) ◽  
pp. 828
Author(s):  
Ivan Radosavljević ◽  
Oleg Antonić ◽  
Dario Hruševar ◽  
Josip Križan ◽  
Zlatko Satovic ◽  
...  
Keyword(s):  
Genetic Structure ◽  
Seedling Recruitment ◽  
Spatial Genetic Structure ◽  
Population Level ◽  
Significant Negative Correlation ◽  
Recruitment Strategy ◽  
Future Research ◽  
Clonal Architecture ◽  
Surrounding Areas ◽  
Spatial Genetic Analysis

By performing a high-resolution spatial-genetic analysis of a partially clonal Salvia brachyodon population, we elucidated its clonal architecture and seedling recruitment strategy. The sampling of the entire population was based on a 1 × 1 m grid and each sampled individual was genotyped. Population-genetic statistics were combined with geospatial analyses. On the population level, the presence of both sexual and clonal reproduction and repeated seedling recruitment as the prevailing strategy of new genets establishment were confirmed. On the patch level, a phalanx clonal architecture was detected. A significant negative correlation between patches’ sizes and genotypic richness was observed as young plants were not identified within existing patches of large genets but almost exclusively in surrounding areas. The erosion of the genetic variability of older patches is likely caused by the inter-genet competition and resulting selection or by a random die-off of individual genets accompanied by the absence of new seedlings establishment. This study contributes to our understanding of how clonal architecture and seedling recruitment strategies can shape the spatial-genetic structure of a partially clonal population and lays the foundation for the future research of the influence of the population’s clonal organization on its sexual reproduction.

scholarly journals The validity of Performance Environment Perception Scales: Environmental predictors of citizenship performance

2010 ◽  
Vol 16 (1) ◽  
pp. 180-190
Author(s):  
Arthur E. Poropat
Keyword(s):  
Work Environment ◽  
Organizational Development ◽  
Future Research ◽  
Environmental Predictors ◽  
New Instrument ◽  
Confirmatory Factor ◽  
Theoretical Predictions ◽  
Citizenship Performance ◽  
Environment Perception ◽  
And Performance

AbstractThis research examined the validity of Performance Environment Perception Scales (PEPS), a new instrument designed to assess performance-relevant aspects of the work environment. A sample of 156 employees of an Australian university completed PEPS and their supervisors rated their task and citizenship performance. Confirmatory Factor Analysis showed PEPS to have a valid factor structure, and PEPS were found to be significantly correlated with citizenship performance, but not with task performance. Although this finding is consistent with theoretical predictions, PEPS are apparently the first measures of work environment perceptions that have confirmed this. Thus PEPS show promise as measures for use in future research and organizational development projects that focus on relationships between the work environment and performance. Limitations of the research and implications for the validity of PEPS, as well as for future research and practice, are discussed.

A test of the interpersonal-psychological theory of suicidal behaviour in a sample of mental health outpatients

2018 ◽  
Vol 49 (3) ◽  
pp. 430-445 ◽  
Author(s):  
Sarojini Naidoo ◽  
Steven Collings
Keyword(s):  
Mental Health ◽  
Suicidal Behaviour ◽  
Suicide Ideation ◽  
Psychological Theory ◽  
Interactive Effects ◽  
Future Research ◽  
Cross Sectional ◽  
Theoretical Predictions ◽  
Cross Sectional Design ◽  
Interpersonal Psychological Theory

Suicidality is a growing mental health problem, with statistics for South Africa being in line with global estimates. There has, however, been relatively little empirical advancement in the conceptualization of suicidal behaviour in recent years. Joiner’s interpersonal-psychological theory of suicidal behaviour is a relatively new theory that appears to hold promise for advancing our understanding of the mechanisms that underlie suicidal behaviour. The theory proposes that people die by suicide because they want to and because they can. This study sought to test two key hypotheses of the interpersonal-psychological theory of suicidal behaviour using a cross-sectional design and a sample of 239 mental health outpatients. Consistent with theoretical predictions, levels of suicidal ideation were significantly predicted by the interactive effects of high levels of thwarted belongingness and perceived burdensomeness in the presence of high levels of hopelessness in relation to both of these distressing states; with estimates of risk for suicide being most strongly predicted by the interactive effects of suicide ideation and an acquired capability for suicide. These findings are discussed in terms of their implications for theory, practice, and future research.

scholarly journals Perspectives from animal demography on incorporating evolutionary mechanism into plant population dynamics

2018 ◽  
Author(s):  
Maria Paniw
Keyword(s):  
Environmental Change ◽  
Evolutionary Dynamics ◽  
Natural Populations ◽  
Population Level ◽  
Plant Population ◽  
Future Research ◽  
Phenotypic Traits ◽  
Plant Population Dynamics ◽  
Future Research Agenda ◽  
Powerful Approach

AbstractWith a growing number of long-term, individual-based data on natural populations available, it has become increasingly evident that environmental change affects populations through complex, simultaneously occurring demographic and evolutionary processes. Analyses of population-level responses to environmental change must therefore integrate demography and evolution into one coherent framework. Integral projection models (IPMs), which can relate genetic and phenotypic traits to demographic and population-level processes, offer a powerful approach for such integration. However, a rather artificial divide exists in how plant and animal population ecologists use IPMs. Here, I argue for the integration of the two sub-disciplines, particularly focusing on how plant ecologists can diversify their toolset to investigate selection pressures and eco-evolutionary dynamics in plant population models. I provide an overview of approaches that have applied IPMs for eco-evolutionary studies and discuss a potential future research agenda for plant population ecologists. Given an impending extinction crisis, a holistic look at the interacting processes mediating population persistence under environmental change is urgently needed.

scholarly journals Incorporating biomarkers in ecological risk assessment of chemical contaminants of soils

2007 ◽  
Vol 26 (2) ◽  
pp. 120-137
Author(s):  
A. J. Reinecke ◽  
S. A. Reinecke ◽  
M. S. Maboeta ◽  
J. P. Odendaal ◽  
R. Snyman
Keyword(s):  
Risk Assessment ◽  
South African ◽  
Field Experiments ◽  
Early Stage ◽  
Population Level ◽  
Diagnostic Tools ◽  
Future Research ◽  
Chemical Contaminants ◽  
Toxic Response ◽  
Future Research Directions

Soil is an important but complex natural resource which is increasingly used as sink for chemicals. The monitoring of soil quality and the assessment of risks posed by contaminants have become crucial. This study deals with the potential use of biomarkers in the monitoring of soils and the assessment of risk resulting from contamination. Apart from an overview of the existing literature on biomarkers, the results of various of our field experiments in South African soils are discussed. Biomarkers may have potential in the assessment of risk because they can indicate at an early stage that exposure has taken place and that a toxic response has been initiated. It is therefore expected that early biomarkers will play an increasing role as diagnostic tools for determining exposure to chemicals and the resulting effects. They may have predictive value that can assist in the prevention or minimising of risks. The aim of this study was to investigate the possibilities of using our results on biomarker responses of soil dwelling organisms to predict changes at higher organisational levels (which may have ecological implications). Our recent experimental results on the evaluation of various biomarkers in both the laboratory and the field are interpreted and placed in perspective within the broader framework of response biology. The aim was further to contribute to the development and application of biomarkers in regulatory risk assessment schemes of soils. This critical review of our own and recent literature on biomarkers in ecotoxicology leads to the conclusion that biomarkers can, under certain conditions, be useful tools in risk assessment. Clear relationships between contamination loads in soil organisms and certain biomarker responses were determined in woodlice, earthworms and terrestrial snails. Clear correlations were also established in field experiments between biomarker responses and changes at the population level. This indicated that, in spite of the fact that direct mechanistic links are still not clarified, biomarkers may have the potential to provide early indications of forthcoming changes at higher organisational levels. Ways are proposed in which biomarkers could be used in the future in risk assessment schemes of soils and future research directions are suggested. 

scholarly journals Recruitment sex ratios in gray-tailed voles (Microtus canicaudus) in response to density, sex ratio, and season

2003 ◽  
Vol 81 (8) ◽  
pp. 1306-1311 ◽  
Author(s):  
Monica L Bond ◽  
Jerry O Wolff ◽  
Sven Krackow
Keyword(s):  
Population Density ◽  
Sex Ratio ◽  
Resource Competition ◽  
Sex Ratios ◽  
Female Offspring ◽  
High Population ◽  
Reproductive Value ◽  
High Population Density ◽  
Adult Sex Ratio ◽  
Sex Ratio Adjustment

We tested predictions associated with three widely used hypotheses for facultative sex-ratio adjustment of vertebrates using eight enclosed populations of gray-tailed voles, Microtus canicaudus. These were (i) the population sex ratio hypothesis, which predicts that recruitment sex ratios should oppose adult sex-ratio skews, (ii) the local resource competition hypothesis, which predicts female-biased recruitment at low adult population density and male-biased recruitment at high population density, and (iii) the first cohort advantage hypothesis, which predicts that recruitment sex ratios should be female biased in the spring and male biased in the autumn. We monitored naturally increasing population densities with approximately equal adult sex ratios through the spring and summer and manipulated adult sex ratios in the autumn and measured subsequent sex ratios of recruits. We did not observe any significant sex-ratio adjustment in response to adult sex ratio or high population density; we did detect an influence of time within the breeding season, with more female offspring observed in the spring and more male offspring observed in the autumn. Significant seasonal increases in recruitment sex ratios indicate the capacity of female gray-tailed voles to manipulate their offspring sex ratios and suggest seasonal variation in the relative reproductive value of male and female offspring to be a regular phenomenon.

scholarly journals Rapid comeback of males: evolution of male-killer suppression in a green lacewing population

2018 ◽  
Vol 285 (1877) ◽  
pp. 20180369 ◽  
Author(s):  
Masayuki Hayashi ◽  
Masashi Nomura ◽  
Daisuke Kageyama
Keyword(s):  
Sex Ratio ◽  
Female Offspring ◽  
Mitochondrial Haplotype ◽  
Green Lacewing ◽  
Haplotype Variation ◽  
Male Killing ◽  
Significant Difference ◽  
High Prevalence ◽  
Laboratory Line ◽  
Male Killer

Evolutionary theory predicts that the spread of cytoplasmic sex ratio distorters leads to the evolution of host nuclear suppressors, although there are extremely few empirical observations of this phenomenon. Here, we demonstrate that a nuclear suppressor of a cytoplasmic male killer has spread rapidly in a population of the green lacewing Mallada desjardinsi . An M. desjardinsi population, which was strongly female-biased in 2011 because of a high prevalence of the male-killing Spiroplasma endosymbiont, had a sex ratio near parity in 2016, despite a consistent Spiroplasma prevalence. Most of the offspring derived from individuals collected in 2016 had 1 : 1 sex ratios in subsequent generations. Contrastingly, all-female or female-biased broods appeared frequently from crossings of these female offspring with males derived from a laboratory line founded by individuals collected in 2011. These results suggest near-fixation of a nuclear suppressor against male killing in 2016 and reject the notion that a non-male-killing Spiroplasma variant has spread in the population. Consistently, no significant difference was detected in mitochondrial haplotype variation between 2011 and 2016. These findings, and earlier findings in the butterfly Hypolimnas bolina in Samoa, suggest that these quick events of male recovery occur more commonly than is generally appreciated.

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