scholarly journals The consequences of polyandry for sibship structures, distributions of relationships and relatedness, and potential for inbreeding in a wild population

2017 ◽  
Author(s):  
Ryan R. Germain ◽  
Peter Arcese ◽  
Jane M. Reid
Keyword(s):  
Potential Benefit ◽  
Overlapping Generations ◽  
Wild Population ◽  
Multiple Mating ◽  
Indirect Selection ◽  
Pedigree Data ◽  
Complex Interactions ◽  
Song Sparrows ◽  
System Components

AbstractThe evolutionary benefits of simultaneous polyandry (female multiple mating within a single reproductive event) remain elusive. One potential benefit could arise if polyandry alters sibship structures and consequent relationships and relatedness among females’ descendants, and thereby intrinsically reduces future inbreeding risk (the ‘indirect inbreeding avoidance hypothesis’). However such effects have not been quantified in naturally complex reproductive systems that also encompass iteroparity, overlapping generations, sequential polyandry, and polygyny. We used long-term social and genetic pedigree data from song sparrows (Melospiza melodia) to quantify cross-generational consequences of simultaneous polyandry for offspring sibship structures and distributions of relationships and relatedness among possible mates. Simultaneous polyandry decreased full-sibships and increased half-sibships on average, but such effects varied among females and were smaller than would occur in the absence of sequential polyandry or polygyny. Further, while simultaneous polyandry decreased the overall frequencies of possible matings among adult full-sibs, it increased the frequencies of possible matings among adult half-sibs and more distant relatives. These results imply that the intrinsic consequences of simultaneous polyandry for inbreeding risk could cause weak indirect selection on polyandry, but the magnitude and direction of such effects will depend on complex interactions with other mating system components and the form of inbreeding depression.

scholarly journals Climate drivers of plague epidemiology in British India, 1898–1949

2020 ◽  
Vol 287 (1928) ◽  
pp. 20200538
Author(s):  
Warren S. D. Tennant ◽  
Mike J. Tildesley ◽  
Simon E. F. Spencer ◽  
Matt J. Keeling
Keyword(s):  
Predictive Models ◽  
Control Measures ◽  
Climate Data ◽  
British India ◽  
Middle Income ◽  
Middle Income Countries ◽  
Complex Interactions ◽  
The World ◽  
Spatio Temporal

Plague, caused by Yersinia pestis infection, continues to threaten low- and middle-income countries throughout the world. The complex interactions between rodents and fleas with their respective environments challenge our understanding of human plague epidemiology. Historical long-term datasets of reported plague cases offer a unique opportunity to elucidate the effects of climate on plague outbreaks in detail. Here, we analyse monthly plague deaths and climate data from 25 provinces in British India from 1898 to 1949 to generate insights into the influence of temperature, rainfall and humidity on the occurrence, severity and timing of plague outbreaks. We find that moderate relative humidity levels of between 60% and 80% were strongly associated with outbreaks. Using wavelet analysis, we determine that the nationwide spread of plague was driven by changes in humidity, where, on average, a one-month delay in the onset of rising humidity translated into a one-month delay in the timing of plague outbreaks. This work can inform modern spatio-temporal predictive models for the disease and aid in the development of early-warning strategies for the deployment of prophylactic treatments and other control measures.

scholarly journals Can we reestablish a self-sustaining population? A case study on reintroduced Crested Ibis with population viability analysis

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Yashuai Zhang ◽  
Fang Wang ◽  
Zhenxia Cui ◽  
Min Li ◽  
Xia Li ◽  
...  
Keyword(s):  
Sex Ratio ◽  
Population Size ◽  
Carrying Capacity ◽  
Wild Population ◽  
Population Viability Analysis ◽  
Population Viability ◽  
Viability Analysis ◽  
Crested Ibis ◽  
Reintroduced Population

Abstract Background One of the most challenging tasks in wildlife conservation and management is clarifying which and how external and intrinsic factors influence wildlife demography and long-term viability. The wild population of the Crested Ibis (Nipponia nippon) has recovered to approximately 4400, and several reintroduction programs have been carried out in China, Japan and Korea. Population viability analysis on this endangered species has been limited to the wild population, showing that the long-term population growth is restricted by the carrying capacity and inbreeding. However, gaps in knowledge of the viability of the reintroduced population and its drivers in the release environment impede the identification of the most effective population-level priorities for aiding in species recovery. Methods The field monitoring data were collected from a reintroduced Crested Ibis population in Ningshan, China from 2007 to 2018. An individual-based VORTEX model (Version 10.3.5.0) was used to predict the future viability of the reintroduced population by incorporating adaptive patterns of ibis movement in relation to catastrophe frequency, mortality and sex ratio. Results The reintroduced population in Ningshan County is unlikely to go extinct in the next 50 years. The population size was estimated to be 367, and the population genetic diversity was estimated to be 0.97. Sensitivity analysis showed that population size and extinction probability were dependent on the carrying capacity and sex ratio. The carrying capacity is the main factor accounting for the population size and genetic diversity, while the sex ratio is the primary factor responsible for the population growth trend. Conclusions A viable population of the Crested Ibis can be established according to population viability analysis. Based on our results, conservation management should prioritize a balanced sex ratio, high-quality habitat and low mortality.

scholarly journals Prediction of Genetic Contributions and Generation Intervals in Populations With Overlapping Generations Under Selection

Genetics ◽  
1999 ◽  
Vol 151 (3) ◽  
pp. 1197-1210 ◽  
Author(s):  
Piter Bijma ◽  
John A Woolliams
Keyword(s):  
Gene Flow ◽  
Overlapping Generations ◽  
Selective Advantage ◽  
Turnover Time ◽  
Breeding Value ◽  
Age Classes ◽  
Generation Interval ◽  
Young Parents ◽  
Genetic Contributions

Abstract A method to predict long-term genetic contributions of ancestors to future generations is studied in detail for a population with overlapping generations under mass or sib index selection. An existing method provides insight into the mechanisms determining the flow of genes through selected populations, and takes account of selection by modeling the long-term genetic contribution as a linear regression on breeding value. Total genetic contributions of age classes are modeled using a modified gene flow approach and long-term predictions are obtained assuming equilibrium genetic parameters. Generation interval was defined as the time in which genetic contributions sum to unity, which is equal to the turnover time of genes. Accurate predictions of long-term genetic contributions of individual animals, as well as total contributions of age classes were obtained. Due to selection, offspring of young parents had an above-average breeding value. Long-term genetic contributions of youngest age classes were therefore higher than expected from the age class distribution of parents, and generation interval was shorter than the average age of parents at birth of their offspring. Due to an increased selective advantage of offspring of young parents, generation interval decreased with increasing heritability and selection intensity. The method was compared to conventional gene flow and showed more accurate predictions of long-term genetic contributions.

scholarly journals Predicting Rates of Inbreeding in Populations Undergoing Selection

Genetics ◽  
2000 ◽  
Vol 154 (4) ◽  
pp. 1851-1864 ◽  
Author(s):  
John A Woolliams ◽  
Piter Bijma
Keyword(s):  
Overlapping Generations ◽  
Linear Models ◽  
Selection Process ◽  
Correction Term ◽  
Random Mating ◽  
Nonrandom Mating ◽  
Selection Processes ◽  
Genetic Contributions ◽  
The Relationship

AbstractTractable forms of predicting rates of inbreeding (ΔF) in selected populations with general indices, nonrandom mating, and overlapping generations were developed, with the principal results assuming a period of equilibrium in the selection process. An existing theorem concerning the relationship between squared long-term genetic contributions and rates of inbreeding was extended to nonrandom mating and to overlapping generations. ΔF was shown to be ~¼(1 − ω) times the expected sum of squared lifetime contributions, where ω is the deviation from Hardy-Weinberg proportions. This relationship cannot be used for prediction since it is based upon observed quantities. Therefore, the relationship was further developed to express ΔF in terms of expected long-term contributions that are conditional on a set of selective advantages that relate the selection processes in two consecutive generations and are predictable quantities. With random mating, if selected family sizes are assumed to be independent Poisson variables then the expected long-term contribution could be substituted for the observed, providing ¼ (since ω = 0) was increased to ½. Established theory was used to provide a correction term to account for deviations from the Poisson assumptions. The equations were successfully applied, using simple linear models, to the problem of predicting ΔF with sib indices in discrete generations since previously published solutions had proved complex.

scholarly journals Expected Genetic Contributions and Their Impact on Gene Flow and Genetic Gain

Genetics ◽  
1999 ◽  
Vol 153 (2) ◽  
pp. 1009-1020 ◽  
Author(s):  
J A Woolliams ◽  
P Bijma ◽  
B Villanueva
Keyword(s):  
Gene Flow ◽  
Genetic Gain ◽  
Overlapping Generations ◽  
Predictive Accuracy ◽  
Index Theory ◽  
Previous Theory ◽  
Selection Indices ◽  
Breeding Groups ◽  
Genetic Contributions

Abstract Long-term genetic contributions (ri) measure lasting gene flow from an individual i. By accounting for linkage disequilibrium generated by selection both within and between breeding groups (categories), assuming the infinitesimal model, a general formula was derived for the expected contribution of ancestor i in category q (μi(q)), given its selective advantages (si(q)). Results were applied to overlapping generations and to a variety of modes of inheritance and selection indices. Genetic gain was related to the covariance between ri and the Mendelian sampling deviation (ai), thereby linking gain to pedigree development. When si(q) includes ai, gain was related to E[μi(q)ai], decomposing it into components attributable to within and between families, within each category, for each element of si(q). The formula for μi(q) was consistent with previous index theory for predicting gain in discrete generations. For overlapping generations, accurate predictions of gene flow were obtained among and within categories in contrast to previous theory that gave qualitative errors among categories and no predictions within. The generation interval was defined as the period for which μi(q), summed over all ancestors born in that period, equaled 1. Predictive accuracy was supported by simulation results for gain and contributions with sib-indices, BLUP selection, and selection with imprinted variation.

Experimental Simplification of the Excimer Laser-Assisted Nonocclusive Anastomosis (ELANA) Technique

2010 ◽  
Vol 67 (3) ◽  
pp. ons-ons ◽  
Author(s):  
Tristan P.C. van Doormaal ◽  
Albert van der Zwan ◽  
Bon H. Verweij ◽  
Matthijs Biesbroek ◽  
Luca Regli ◽  
...  
Keyword(s):  
Excimer Laser ◽  
Potential Benefit ◽  
Burst Pressure ◽  
Application Time ◽  
Term Survival ◽  
New Techniques ◽  
Recipient Artery ◽  
Saphenous Veins ◽  
Survival Studies

Abstract BACKGROUND: The excimer laser-assisted nonocclusive anastomosis (ELANA) technique facilitates the construction of an end-to-side anastomosis between a donor vessel and a recipient artery without the need to temporarily occlude the recipient artery. OBJECTIVE: To test whether the surgically difficult ELANA technique can be simplified. METHODS: In 42 rabbits, with the aorta as the recipient artery and human saphenous veins as donor grafts, we made 30 conventional ELANAs with 8 microsutures, 90 ELANAs with 4 microsutures (ELANA-4s), 40 ELANAs with 2 microsutures (ELANA-2s), and 90 sutureless ELANAs (SELANAs). SELANA involved a new ring design with 2 pins. ELANA-4, ELANA-2, and SELANA were each combined with 3 different sealants (Bioglue , Tachoseal, and Tisseel ) and compared regarding application time, complications, and burst pressure. RESULTS: The conventional ELANA was constructed in a mean of 14.8 ± 2.6 minutes. All experimental anastomoses were constructed significantly faster; the ELANA-4 in a mean of 10.9 ± 1.3 minutes, the ELANA-2 in a mean of 5.4 ± 1.7 minutes, and the SELANA in a mean of 2.5 ± 1.8 minutes. All ELANA and ELANA-4 anastomoses were sufficiently strong with a burst pressure > 200 mm Hg, except for 1 insufficiently sealed ELANA-4 anastomosis. ELANA-2 was sufficiently strong only with Bioglue, showing a burst pressure < 280 mm Hg. SELANA was sufficiently strong with Bioglue or TachoSil, showing a burst pressure < 260 mm Hg. CONCLUSION: The ELANA technique can be simplified by reducing or even abandoning microsutures. Of the experimental anastomoses tested, we consider the SELANA technique combined with TachoSil of most potential benefit. Long-term survival studies will be performed in animals before we consider using any of these new techniques in patients.

scholarly journals POLLUTION ABATEMENT AS A SOURCE OF STABILIZATION AND LONG-RUN GROWTH

2016 ◽  
Vol 21 (3) ◽  
pp. 644-676 ◽  
Author(s):  
Theodore Palivos ◽  
Dimitrios Varvarigos
Keyword(s):  
Overlapping Generations ◽  
Pollution Abatement ◽  
Short Term ◽  
Overlapping Generations Model ◽  
Environmental Preservation ◽  
Powerful Source ◽  
Long Run ◽  
Stationary Level ◽  
Active Policy

In a two-period overlapping-generations model with production, we consider the damaging impact of environmental degradation on health and consequently life expectancy. Despite the presence of social constant returns to capital, which would otherwise generate unbounded growth, when pollution is left unabated, the economy cannot achieve such a path. Instead, it converges either to a stationary level of capital per worker or to a cycle in which capital per worker oscillates permanently. The government's involvement in environmental preservation proves crucial for both short-term dynamics and long-term prospects of the economy. Particularly, an active policy of pollution abatement emerges as an important engine of long-run economic growth. Furthermore, by eliminating the occurrence of limit cycles, pollution abatement is also a powerful source of stabilization.

scholarly journals Long-term maternal effect on offspring immune response in song sparrows Melospiza melodia

2006 ◽  
Vol 2 (4) ◽  
pp. 573-576 ◽  
Author(s):  
Jane M Reid ◽  
Peter Arcese ◽  
Lukas F Keller ◽  
Dennis Hasselquist
Keyword(s):  
Immune Response ◽  
Time Scales ◽  
Parasitic Infection ◽  
Antibody Responses ◽  
Melospiza Melodia ◽  
Long Term Effects ◽  
Free Living ◽  
Humoral Immune ◽  
Song Sparrows

Knowledge of the causes of variation in host immunity to parasitic infection and the time-scales over which variation persists, is integral to predicting the evolutionary and epidemiological consequences of host–parasite interactions. It is clear that offspring immunity can be influenced by parental immune experience, for example, reflecting transfer of antibodies from mothers to young offspring. However, it is less clear whether such parental effects persist or have functional consequences over longer time-scales, linking a parent's previous immune experience to future immune responsiveness in fully grown offspring. We used free-living song sparrows ( Melospiza melodia ) to quantify long-term effects of parental immune experience on offspring immune response. We experimentally vaccinated parents with a novel antigen and tested whether parental vaccination influenced the humoral antibody response mounted by fully grown offspring hatched the following year. Parental vaccination did not influence offspring baseline antibody titres. However, offspring of vaccinated mothers mounted substantially stronger antibody responses than offspring of unvaccinated mothers. Antibody responses did not differ between offspring of vaccinated and unvaccinated fathers. These data demonstrate substantial long-term effects of maternal immune experience on the humoral immune response of fully grown offspring in free-living birds.

Calcium effects on life-history traits in a wild population of the great tit (Parus major): analysis of long-term data at several spatial scales

Oecologia ◽  
2008 ◽  
Vol 159 (2) ◽  
pp. 463-472 ◽  
Author(s):  
Teddy Albert Wilkin ◽  
Andrew G. Gosler ◽  
Dany Garant ◽  
S. James Reynolds ◽  
Ben C. Sheldon
Keyword(s):  
Life History ◽  
Life History Traits ◽  
Wild Population ◽  
Spatial Scales ◽  
Parus Major ◽  
Great Tit ◽  
Calcium Effects ◽  
Term Data

A trajectories' guide to the state space - learning missing terms in bifurcating ecological systems

2021 ◽  
Author(s):  
Rahel Vortmeyer-Kley ◽  
Pascal Nieters ◽  
Gordon Pipa
Keyword(s):  
Machine Learning ◽  
Differential Equations ◽  
Algal Blooms ◽  
Ecological Systems ◽  
Short Term ◽  
Specific System ◽  
Worst Case ◽  
System Components ◽  
Full Knowledge

<p>Ecological systems typically can exhibit various states ranging from extinction to coexistence of different species in oscillatory states. The switch from one state to another is called bifurcation. All these behaviours of a specific system are hidden in a set of describing differential equations (DE) depending on different parametrisations. To model such a system as DE requires full knowledge of all possible interactions of the system components. In practise, modellers can end up with terms in the DE that do not fully describe the interactions or in the worst case with missing terms.</p><p>The framework of universal differential equations (UDE) for scientific machine learning (SciML) [1] allows to reconstruct the incomplete or missing term from an idea of the DE and a short term timeseries of the system and make long term predictions of the system’s behaviour. However, the approach in [1] has difficulties to reconstruct the incomplete or missing term in systems with bifurcations. We developed a trajectory-based loss metric for UDE and SciML to tackle the problem and tested it successfully on a system mimicking algal blooms in the ocean.</p><p>[1] Rackauckas, Christopher, et al. "Universal differential equations for scientific machine learning." arXiv preprint arXiv:2001.04385 (2020).</p>

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