scholarly journals Gamete evolution and sperm numbers: sperm competition versus sperm limitation

2014 ◽  
Vol 281 (1791) ◽  
pp. 20140836 ◽  
Author(s):  
Geoff A. Parker ◽  
Jussi Lehtonen
Keyword(s):  
Sperm Competition ◽  
Risk Model ◽  
Population Level ◽  
Concave Function ◽  
Sperm Production ◽  
Sperm Limitation ◽  
Gamete Competition ◽  
The Relationship ◽  
Intensity Model

Both gamete competition and gamete limitation can generate anisogamy from ancestral isogamy, and both sperm competition (SC) and sperm limitation (SL) can increase sperm numbers. Here, we compare the marginal benefits due to these two components at any given population level of sperm production using the risk and intensity models in sperm economics. We show quite generally for the intensity model (where N males compete for each set of eggs) that however severe the degree of SL, if there is at least one competitor for fertilization ( N − 1 ≥ 1), the marginal gains through SC exceed those for SL, provided that the relationship between the probability of fertilization ( F ) and increasing sperm numbers ( x ) is a concave function. In the risk model, as fertility F increases from 0 to 1.0, the threshold SC risk (the probability q that two males compete for fertilization) for SC to be the dominant force drops from 1.0 to 0. The gamete competition and gamete limitation theories for the evolution of anisogamy rely on very similar considerations: our results imply that gamete limitation could dominate only if ancestral reproduction took place in highly isolated, small spawning groups.

scholarly journals The Relationship between Suicidality and Socio-Demographic Variables, Physical Disorders, and Psychiatric Disorders: Results from the Singapore Mental Health Study 2016

2021 ◽  
Vol 18 (8) ◽  
pp. 4365
Author(s):  
Kundadak Ganesh Kudva ◽  
Edimansyah Abdin ◽  
Janhavi Ajit Vaingankar ◽  
Boon Yiang Chua ◽  
Saleha Shafie ◽  
...  
Keyword(s):  
Mental Health ◽  
Suicidal Ideation ◽  
Psychiatric Disorders ◽  
Population Level ◽  
Risk Groups ◽  
Epidemiological Survey ◽  
Health Study ◽  
Physical Disorders ◽  
Mental Health Study ◽  
The Relationship

Suicidality encompasses suicidal ideation, plans, and attempts. This paper aims to establish associations between suicidality and sociodemographic variables, physical disorders, and psychiatric disorders. The Singapore Mental Health Study 2016 was a population-level epidemiological survey, which determined the prevalence of physical disorders, psychiatric disorders, and suicidality. Questionnaires were used to determine socio-demographic information. A total of 6216 respondents were interviewed. Lifetime prevalence of suicidal ideation, planning, and attempts were 7.8%, 1.6%, and 1.6%, respectively. All components of suicidality were more likely in those with major depressive disorder, bipolar disorder, generalized anxiety disorder, alcohol use disorder, and chronic pain. Suicidal ideation and attempts were more likely in those with diabetes. Age above 65, being male, and a monthly household income of ≥ SGD 10,000 were associated with a lower likelihood of suicidal ideation. These findings indicate that there are high-risk groups for whom suicidality is a concern, and for whom interventions may be needed.

scholarly journals Investigating hot-Jupiter inflated radii with hierarchical Bayesian modelling

2018 ◽  
Vol 616 ◽  
pp. A76 ◽  
Author(s):  
Marko Sestovic ◽  
Brice-Olivier Demory ◽  
Didier Queloz
Keyword(s):  
Large Fraction ◽  
Population Level ◽  
Mass Range ◽  
Hierarchical Bayesian ◽  
Incident Flux ◽  
Hot Jupiters ◽  
Probabilistic Relation ◽  
Relationship Of ◽  
The Relationship ◽  
Level Analysis

Context. As of today, hundreds of hot Jupiters have been found, yet the inflated radii of a large fraction of them remain unexplained. A number of mechanisms have been proposed to explain these anomalous radii, however most of these can only work under certain conditions and may not be sufficient to explain the most extreme cases. It is still unclear whether a single mechanism can sufficiently explain the entire distribution of radii, or whether a combination of these mechanisms is needed. Aims. We seek to understand the relationship of radius with stellar irradiation and mass and to find the range of masses over which hot Jupiters are inflated. We also aim to find the intrinsic physical scatter in their radii, caused by unobservable parameters, and to constrain the fraction of hot Jupiters that exhibit inflation. Methods. By constructing a hierarchical Bayesian model, we inferred the probabilistic relation between planet radius, mass, and incident flux for a sample of 286 gas giants. We separately incorporated the observational uncertainties of the data and the intrinsic physical scatter in the population. This allowed us to treat the intrinsic physical scatter in radii, due to latent parameters such as the heavy element fraction, as a parameter to be inferred. Results. We find that the planetary mass plays a key role in the inflation extent and that planets in the range ~0.37−0.98  MJ show the most inflated radii. At higher masses, the radius response to incident flux begins to decrease. Below a threshold of 0.37 ± 0.03  MJ we find that giant exoplanets as a population are unable to maintain inflated radii ≿1.4  RJ but instead exhibit smaller sizes as the incident flux is increased beyond 106 W m−2. We also find that below 1  MJ, there is a cut-off point at high incident flux beyond which we find no more inflated planets, and that this cut-off point decreases as the mass decreases. At incident fluxes higher than ~1.6 × 106 W m−2 and in a mass range 0.37−0.98  MJ, we find no evidence for a population of non-inflated hot Jupiters. Our study sheds a fresh light on one of the key questions in the field and demonstrates the importance of population-level analysis to grasp the underlying properties of exoplanets.

How biases in sperm storage relate to sperm use during oviposition in female yellow dung flies

2021 ◽  
Author(s):  
Marco Demont ◽  
Paul I Ward ◽  
Wolf U Blanckenhorn ◽  
Stefan Lüpold ◽  
Oliver Y Martin ◽  
...  
Keyword(s):  
Sperm Competition ◽  
Sperm Storage ◽  
Adaptive Plasticity ◽  
Strongly Correlated ◽  
Scathophaga Stercoraria ◽  
General Importance ◽  
Copula Duration ◽  
Mixed Paternity ◽  
Paternity Success ◽  
The Relationship

Abstract Precise mechanisms underlying sperm storage and utilization are largely unknown, and data directly linking stored sperm to paternity remain scarce. We used competitive microsatellite PCR to study the effects of female morphology, copula duration and oviposition on the proportion of stored sperm provided by the second of two copulating males (S2) in Scathophaga stercoraria (Diptera: Scathophagidae), the classic model for sperm competition studies. We genotyped all offspring from potentially mixed-paternity clutches to establish the relationship between a second male’s stored sperm (S2) and paternity success (P2). We found consistent skew in sperm storage across the three female spermathecae, with relatively more second-male sperm stored in the singlet spermatheca than in the doublet spermathecae. S2 generally decreased with increasing spermathecal size, consistent with either heightened first-male storage in larger spermathecae, or less efficient sperm displacement in them. Additionally, copula duration and several two-way interactions influenced S2, highlighting the complexity of postcopulatory processes and sperm storage. Importantly, S2 and P2 were strongly correlated. Manipulation of the timing of oviposition strongly influenced observed sperm-storage patterns, with higher S2 when females laid no eggs before being sacrificed than when they oviposited between copulations, an observation consistent with adaptive plasticity in insemination. Our results identified multiple factors influencing sperm storage, nevertheless suggesting that the proportion of stored sperm is strongly linked to paternity (i.e., a fair raffle). Even more detailed data in this vein are needed to evaluate the general importance of sperm competition relative to cryptic female choice in postcopulatory sexual selection.

Relationship of Area-Level Socioeconomic Status Indicators and Nutritional Anemias: Analysis of Folate, Vitamin B12, and Iron Deficiencies

Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 16-17
Author(s):  
Miguel Gonzalez Velez ◽  
Carolyn Mead-Harvey ◽  
Heidi E. Kosiorek ◽  
Yael Kusne ◽  
Leyla Bojanini ◽  
...  
Keyword(s):  
Socioeconomic Status ◽  
Vitamin B12 ◽  
Conflicts Of Interest ◽  
Population Level ◽  
Serum Folate ◽  
Continuous Variables ◽  
Cross Sectional ◽  
The Us ◽  
Relationship Of ◽  
The Relationship

Introduction: Serum folate (SF), vitamin B12 (B12), and iron deficiency (def) are common causes of nutritional anemias (NA). These deficiencies are usually multifactorial, with nutritional and non-nutritional causes playing a role. SF, B12, and iron levels are usually ordered in the setting of anemia, and malnutrition with or without neurologic symptoms. Clinical evidence suggests that these def have a strong dietary component and socioeconomic status (SES). The relationship of NA and area-based SES in the US has not been studied. We aimed to determine the relationship of SES with the prevalence of NA. Methods: We performed a cross-sectional analysis of adult patients with SF, B12 and iron levels at Mayo Clinic Arizona and Florida between 2010 and 2018. Race was classified using the NIH criteria. Normal laboratory values were determined according to our lab reference and the US NHANES III. SF levels (mcg/Lt) were defined as deficient <4, normal ≥4.0, and excess ≥20. B12 levels (ng/L) as deficient <150, borderline 150-400, normal >400-900, and excess ≥900. Iron def was determined by ferritin levels (mcg/L) as low <24, normal 24-336, elevated >336 for men, low <11, normal 11-307, elevated >307 for women. Area-Level SES indicators: Median Household income (MHI), unemployment rate (UR), median gross rent month (MGRM), % uninsured, median house value (MHV), % high school; were geocoded by zip code using the 2014 American Community Survey. Demographics and clinical variables were compared between groups by chi-square test for frequency data or Kruskal Wallis rank-sum test for continuous variables. Results: 202,046 samples from 128,084 patients were analyzed. In the sample-level analysis, there were statistically significant associations between SES and SF def; all SES indicators except UR for B12 def; and no differences for iron def, except % uninsured (Table 1). There was no statistically significant interaction between race and SES for SF def and iron def. Race was a statistically significant modifier between B12 def and MHI (p<0.001), % uninsured (p=0.002), and MHV (p=0.007). Asian and Other race had an increase in odds of B12 def with increasing MHI (Asian OR=1.11 , Other OR=1.18); white race had a decrease in odds of B12 def with increasing MHI (OR=0.95 for a $10,000 increase in MHI). Conclusions: We show significant relationships between SES and NA in the US. Differences were observed between SF def and all the SES indicators without race interactions. There were significant interactions between B12 def, race and SES for pts of White, Asian and Other race. There were no differences between SES and race for iron def. These relationships confirm that NA are related to area-level SES and other social determinants of health. Research regarding the causes of these disparities on a population level are needed. Disclosures No relevant conflicts of interest to declare.

scholarly journals Imminent risk of predation reduces the relative strength of postcopulatory sexual selection in the guppy

2020 ◽  
Vol 375 (1813) ◽  
pp. 20200076
Author(s):  
Alexandra Glavaschi ◽  
Silvia Cattelan ◽  
Alessandro Grapputo ◽  
Andrea Pilastro
Keyword(s):  
Sexual Selection ◽  
Sperm Competition ◽  
Repeated Measures ◽  
Poecilia Reticulata ◽  
Male Reproductive Success ◽  
Sperm Production ◽  
Postcopulatory Sexual Selection ◽  
Repeated Measures Design ◽  
Risk Of Predation ◽  
Livebearing Fish

Fifty years of research on sperm competition has led to a very good understanding of the interspecific variation in sperm production traits. The reasons why this variation is often very large within populations have been less investigated. We suggest that the interaction between fluctuating environmental conditions and polyandry is a key phenomenon explaining such variation. We focus here on imminent predation risk (IPR). IPR impacts significantly several aspects of prey behaviour and reproduction, and it is expected to influence the operation of sexual selection before and after mating. We estimated the effect of IPR on the male opportunity for pre- and postcopulatory sexual selection in guppies ( Poecilia reticulata ), a livebearing fish where females prefer colourful males and mate multiply. We used a repeated-measures design, in which males were allowed to mate with different females either under IPR or in a predator-free condition. We found that IPR increased the total opportunity for sexual selection and reduced the relative contribution of postcopulatory sexual selection to male reproductive success. IPR is inherently variable and our results suggest that interspecific reproductive interference by predators may contribute towards maintaining the variation in sperm production within populations. This article is part of the theme issue ‘Fifty years of sperm competition'.

scholarly journals Conceptual developments in sperm competition: a very brief synopsis

2020 ◽  
Vol 375 (1813) ◽  
pp. 20200061 ◽  
Author(s):  
Geoff A. Parker
Keyword(s):  
Sexual Selection ◽  
Sperm Competition ◽  
Seminal Fluid ◽  
Female Reproduction ◽  
Internal Fertilization ◽  
Seminal Fluid Proteins ◽  
Competition Theory ◽  
Past Half Century ◽  
Mate Acquisition ◽  
Gamete Competition

The past half century has seen the development of the field of post-ejaculatory sexual selection, the sequel to sexual selection for mate-acquisition (pre-ejaculatory) described by Darwin. In richness and diversity of adaptations, post-ejaculatory selection rivals that of pre-ejaculatory sexual selection. Anisogamy—and hence two sexes—likely arose by primeval gamete competition, and sperm competition remains a major force maintaining high sperm numbers. The post-ejaculatory equivalent of male–male competition for matings, sperm competition was an intense ancestral form of sexual selection, typically weakening as mobility and internal fertilization developed in many taxa, when some expenditure became diverted into pre-ejaculatory competition. Sperm competition theory has been relatively successful in explaining variation in relative testes size and sperm numbers per ejaculate and is becoming more successful in explaining variation in sperm phenotype. Sperm competition has generated many other male adaptations such as seminal fluid proteins that variously modify female reproduction towards male interests, and copulatory plugs, prolonged copulations and post-ejaculatory guarding behaviour that reduce female remating probability, many of which result in sexual conflict. This short survey of conceptual developments is intended as a broad overview, mainly as a primer for new researchers. This article is part of the theme issue ‘Fifty years of sperm competition'.

The importance of superior-quality wildlife habitats

2004 ◽  
Vol 80 (1) ◽  
pp. 75-81 ◽  
Author(s):  
Ian D Thompson
Keyword(s):  
Habitat Selection ◽  
Habitat Quality ◽  
Population Level ◽  
Individual Fitness ◽  
Animal Populations ◽  
Cumulative Change ◽  
Few Data ◽  
Managed Landscapes ◽  
The Relationship

While animals may use many habitat types, relatively few are preferred and fewer yet are superior in quality (referring to individual fitness as the measure of quality). Historical reduction in habitat quality for some wildlife species has occurred such that we may now have limited reference to original superior-quality habitats. As time passes, managers may be unaware that superior habitats are slowly disappearing and that the slow but cumulative change is significant to a species at the population level. The perception of superior-quality habitat also changes with each successive generation of managers based on their experiences. This paper raises the concern that retrospective work may often be required to determine past forest habitats and associated animal populations to avoid the risk of falling into a trap of not recognizing ever-declining habitat quality through time and relegating animals to what is in fact much poorer quality habitat than those to which they are actually best adapted. Further, the relationship between relative abundance and habitat quality may often be uncertain owing to maladaptive habitat selection by animals, inappropriate survey timing or interannual population differences. While we have begun to appreciate aspects of habitat selection for many forest species, few data are yet available that relate selected habitats to fitness of individual animals. Hence, while we may have models to predict habitat use, considerable research remains to be done to be able to predict long-term sustainability of species in managed landscapes. Key words: habitat quality, forest management, sustainability, biodiversity

Copulation calls in wild Mueller’s gibbons (Hylobates muelleri)

2019 ◽  
Vol 20 (2) ◽  
pp. 362-374
Author(s):  
Yoichi Inoue ◽  
Waidi Sinun ◽  
Kazuo Okanoya
Keyword(s):  
Mating System ◽  
Social Organization ◽  
Sperm Competition ◽  
Mate Guarding ◽  
Conservation Area ◽  
Mating Activity ◽  
Selective Pressures ◽  
Female Promiscuity ◽  
Vocal Signals ◽  
The Relationship

Abstract Mating activity of a wild Mueller’s gibbon group (Hylobates muelleri) was observed in the Danum Valley Conservation Area, Sabah, Malaysia. The purpose of this study was to investigate the function of copulation calls in gibbons. The female emitted copulation calls at the time of intromission and pelvic thrusting. Copulation calls were composed of two notes and one of them was sung only while mating. Approximately half of copulation calls were sung near the range boundary. Mating with copulation calls sometimes occurred while singing. According to the model that female copulation calls have evolved under the selective pressures of risk of infanticide and sperm competition, copulation calls should be rare in species with little female promiscuity. As gibbons usually live in pair-living social organization and have a monogamous mating system, no vocal signals by female gibbons are considered to be needed. However, clear copulation calls were emitted by the female. It suggests that the relationship between paired gibbons is unstable. Copulation calls by the female Mueller’s gibbon may function to increase mate guarding and strengthen the pair bond.

scholarly journals On the definition of a concentration function relevant to the ROC curve

METRON ◽  
2020 ◽  
Vol 78 (3) ◽  
pp. 271-277
Author(s):  
Mauro Gasparini ◽  
Lidia Sacchetto
Keyword(s):  
Roc Curve ◽  
Population Level ◽  
Concentration Function ◽  
Concentration Curve ◽  
Classification Problems ◽  
The One ◽  
Definition Of ◽  
The Relationship

AbstractThis work provides a definition of concentration curve alternative to the one presented on this journal by Schechtman and Schechtman (Metron 77:171–178, 2019). Our definition clarifies, at the population level, the relationship between concentration and the omnipresent ROC curve in diagnostic and classification problems.

scholarly journals If You Make it Free, Will They Come? Using a Physical Activity Accessibility Model to Understand the Use of a Free Children’s Recreation Pass

2019 ◽  
Vol 16 (7) ◽  
pp. 493-503 ◽  
Author(s):  
Andrew F. Clark ◽  
Joannah Campbell ◽  
Patricia Tucker ◽  
Piotr Wilk ◽  
Jason A. Gilliland
Keyword(s):  
Physical Activity ◽  
Urban Areas ◽  
Population Level ◽  
Target Population ◽  
Activity Levels ◽  
Physical Activity Interventions ◽  
Grade 5 ◽  
Longitudinal Data Collection ◽  
The Relationship

Background: Children’s sedentary lifestyles and low physical activity levels may be countered using population-level interventions. This study examines factors influencing the use of a free community-wide physical activity access pass for grade 5 students (G5AP). Methods: A natural experiment with longitudinal data collection. A sample of 881 children completed the 9-month follow-up survey self-reporting where they used the G5AP. Two analyses were conducted: Getis-Ord GI* geographic cluster analysis of the spatial distribution of users, and logistic regression examining the relationship between use and accessibility (informational, economic, and geographic) and mobility options, while accounting for intrapersonal and interpersonal factors. Results: Overall, 44.9% of children used the G5AP with clusters of high use in urban areas and low use in the suburbs. Other factors significantly related to G5AP included gender (girls), informational accessibility (active recruitment), economic accessibility (median household income), geographic accessibility (facilities within 1.6 km of home), and mobility options (access to Boys & Girls Club bus). Conclusions: This study found that a diverse population of children used the G5AP. To continue being successful, community-based physical activity interventions need to ensure that the intervention increases geographic, economic, and informational accessibility and provides mobility options that are available to the target population.

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