Adult Traits Research Articles

Complex sexual-social environments produce high boldness and low aggression behavioral syndromes

IntroductionEvidence of animal personality and behavioral syndromes is widespread across animals, yet the development of these traits remains poorly understood. Previous research has shown that exposure to predators, heterospecifics, and urbanized environments can influence personality and behavioral syndromes. Yet, to date, the influence of early social experiences with conspecifics on the development of adult behavioral traits is far less known. We use swordtail fish (Xiphophorus nigrensis), a species with three genetically-determined male mating strategies (courtship display, coercion, or mixed strategy) to assess how different early-life social experiences shape adult behavioral development.MethodsWe raised female swordtails from birth to adulthood in density-controlled sexual-social treatments that varied in the presence of the type of male mating tactics (coercers only, displayers only, coercers and displayers, and mixed-strategists only). At adulthood, we tested females’ boldness, shyness, aggression, sociality, and activity.ResultsWe found that the number of different mating strategies females were raised with (social complexity) shaped behavioral development more than any individual mating strategy. Females reared in complex environments with two male mating tactics were bolder, less shy, and less aggressive than females reared with a single male mating tactic (either courtship only or coercion only). Complex sexual-social environments produced females with behavioral syndromes (correlations between aggression and activity, shyness and aggression, and social interaction and activity), whereas simple environments did not.DiscussionImportantly, the characteristics of these socially-induced behavioral syndromes differ from those driven by predation, but converge on characteristics emerging from animals found in urban environments. Our findings suggest that complexity of the sexual-social environment shapes the development of personality and behavioral syndromes to facilitate social information gathering. Furthermore, our research highlights the previously overlooked influence of sexual selection as a significant contributing factor to diverse behavioral development.

CD27 on human memory B cells-more than just a surface marker.

Immunological memory protects the human body from re-infection with an earlier recognized pathogen. This memory comprises the durable serum antibody titres provided by long-lived plasma cells and the memory T and B cells with help from other cells. Memory B cells are the main precursor cells for new plasma cells during a secondary infection. Their formation starts very early in life, and they continue to form and undergo refinements throughout our lifetime. While the heterogeneity of the human memory B-cell pool is still poorly understood, specific cellular surface markers define most of the cell subpopulations. CD27 is one of the most commonly used markers to define human memory B cells. In addition, there are molecular markers, such as somatic mutations in the immunoglobulin heavy and light chains and isotype switching to, for example, IgG. Although not every memory B cell undergoes somatic hypermutation or isotype switching, most of them express these molecular traits in adulthood. In this review, I will focus on the most recent knowledge regarding CD27+ human memory B cells in health and disease, and describe how Ig sequencing can be used as a tool to decipher the evolutionary pathways of these cells.

Contrasting Views of Autism Spectrum Traits in Adults, Especially in Self-Reports vs. Informant-Reports for Women High in Autism Spectrum Traits.

There is uncertainty among researchers and clinicians about how to best measure autism spectrum dimensional traits in adults. In a sample of adults with high levels of autism spectrum traits and without intellectual disability (probands, n = 103) and their family members (n = 96), we sought to compare self vs. informant reports of autism spectrum-related traitsand possible effects of sex on discrepancies. Using correlational analysis, we found poor agreement between self- and informant-report measures for probands, yet moderate agreementfor family members. We found reporting discrepancy was greatest for female probands, often self-reporting more autism-related behaviors. Our findings suggest that autism spectrum traits are often underrecognized by informants, making self-report data important to collect in clinical and research settings.

Multivariate analyses of molecular genetic associations between childhood psychopathology and adult mood disorders and related traits.

Ubiquitous associations have been detected between different types of childhood psychopathology and polygenic risk scores based on adult psychiatric disorders and related adult outcomes, indicating that genetic factors partly explain the association between childhood psychopathology and adult outcomes. However, these analyses in general do not take into account the correlations between the adult trait and disorder polygenic risk scores. This study aimed to further clarify the influence of genetic factors on associations between childhood psychopathology and adult outcomes by accounting for these correlations. Using a multivariate multivariable regression, we analyzed associations of childhood attention-deficit/hyperactivity disorder (ADHD), internalizing, and social problems, with polygenic scores (PGS) of adult disorders and traits including major depression, bipolar disorder, subjective well-being, neuroticism, insomnia, educational attainment, and body mass index (BMI), derived for 20,539 children aged 8.5-10.5 years. After correcting for correlations between the adult phenotypes, major depression PGS were associated with all three childhood traits, that is, ADHD, internalizing, and social problems. In addition, BMI PGS were associated with ADHD symptoms and social problems, while neuroticism PGS were only associated with internalizing problems and educational attainment PGS were only associated with ADHD symptoms. PGS of bipolar disorder, subjective well-being, and insomnia were not associated with any childhood traits. Our findings suggest that associations between childhood psychopathology and adult traits like insomnia and subjective well-being may be primarily driven by genetic factors that influence adult major depression. Additionally, specific childhood phenotypes are genetically associated with educational attainment, BMI and neuroticism.

Schizotypal ambivalence is associated with schizophrenia-spectrum and borderline personality traits in young adults: Converging results from three interview studies

Ambivalence has a longstanding history in schizophrenia-spectrum and borderline personality psychopathology, although it has been largely overlooked in current psychopathology research. The Schizotypal Ambivalence Scale (SAS) provides a brief, psychometrically sound questionnaire for assessing ambivalence characteristic of the schizotypy spectrum. We conducted three interview studies examining associations of the SAS with impairment, schizophrenia-spectrum psychopathology, borderline personality disorder, and mood disorders in independent samples of young adults (n’s = 57, 151, 162). Despite being conducted in different regions with differing designs, results showed good convergence across the three studies. SAS scores were robustly associated with impairment, schizophrenia-spectrum psychopathology and personality traits, and borderline personality traits (typically medium effects). Furthermore, significant associations of the SAS with the interview-outcome measures remained after partialling variance associated with neuroticism. The results support the construct validity of schizotypal ambivalence and the SAS. Recommendations for future study are provided.

Adult Personality and Its Relationship with Stress Level, Coping Mechanism and Academic Performance among Undergraduate Nursing Students

Background: Stress related to nursing education and clinical placement encounters by students since the beginning of their nursing course has been an issue of concern. This study aims to examine the prevalence of adult personality traits and their relationship with stress levels, coping mechanisms and academic performance among nursing students. Methods: This cross-sectional study was conducted among 92 nursing students at Universiti Kebangsaan Malaysia (UKM). The Big Five Inventory (BFI), Student Nurse Stress Index and Brief COPE instruments were used to measure the respondents’ personality traits, stress level and coping mechanisms, respectively. Data were analysed using IBM SPSS version 26. Results: The most prevalent personality trait of the students was openness (mean = 33.58). Conscientiousness (r = –0.226, P = 0.030) and neuroticism (r = 0.326, P = 0.002) are significantly related to stress level. Extraversion (r = 0.219, P = 0.036), conscientiousness (r = 0.206, P = 0.049) and openness (r = 0.219, P = 0.036) show significant relationships with the approach coping mechanism, while agreeableness (r = –0.257, P = 0.013) and neuroticism (r = 0.297, P = 0.004) show significant relationships with the avoidant coping mechanism. However, no significant relationship was noted between personality traits and academic performance (r = 1.000, P > 0.05). Conclusion: Knowledge of ones’ personality traits may benefit students in understanding themselves and in using the best ways to cope with their stress while studying nursing.

The Lack of Alterations in Metabolites in the Medial Prefrontal Cortex and Amygdala, but Their Associations with Autistic Traits, Empathy, and Personality Traits in Adults with Autism Spectrum Disorder: A Preliminary Study

Proton magnetic resonance spectroscopy (1H-MRS) has shown inconsistent alterations in brain metabolites of adults with autism spectrum disorder (ASD). We investigated brain metabolites in the medial prefrontal cortex and amygdala of 24 drug-naive adults with ASD and no intellectual disability and 24 non-ASD control subjects, using 3 T 1H-MRS. Adults with ASD showed no significant differences from control in glutamate, glutamate plus glutamine, N-acetylaspartate, glycerophosphorylcholine plus phosphorylcholine, creatine plus phosphocreatine, or myo-inositol in either region. However, ASD subjects did show significant correlations of localized brain metabolites with autistic traits, empathy deficits, and personality traits using the Autism-Spectrum Quotient, Questionnaire of Cognitive and Affective Empathy, Interpersonal Reactivity Index, and NEO Personality Inventory-Revised. These findings should be taken as preliminary or exploratory.

Gene-diet interaction in response to defatted flaxseed flour supplementation on obesity-related traits in Chinese overweight and obese adults: A randomized controlled trial

Effects of dietary fiber on obesity-related traits in previous studies were inconsistent. The aim of the present study was to explore whether variants in genes related to satiety and appetite can modulate the effect of dietary fiber on obesity-related traits. Fifty-one overweight or obese adults were randomly allocated to two groups to consume control biscuits (n = 24) or biscuits containing defatted flaxseed flour (n = 27) at breakfast for 8 wk. Four single-nucleotide polymorphisms related to satiety and appetite were genotyped: rs11076023 on the FTO gene, rs16147 on the NPY gene, rs155971 on the PCSK1 gene, and rs6265 on the BDNF gene. A linear regression model was used to evaluate the gene-diet interaction between obesity-related traits. Compared with control biscuits, defatted flaxseed-flour biscuits significantly reduced body weight (P = 0.001) and body mass index (BMI) (P = 0.001) in A-allele carriers (AA + AT) of rs11076023 on the FTO gene but not in non-carriers (TT) (P for the interaction = 0.005 and 0.006) and decreased fasting serum glucose in participants with CC genotype (P = 0.019) but had less effect in T-allele carriers (TT + TC) (P = 0.021) of rs16147 on the NPY gene (P for the interaction = 0.002). Compared with the control biscuits, defatted flaxseed flour significantly reduced body weight (P < 0.001) in T-allele carriers (TT + TC) of rs155971 on the PCSK1 gene but not in non-carriers (CC) (P for the interaction = 0.041) and reduced body weight (P = 0.001) and BMI (P < 0.001) in A-allele carriers (AA + AG) of rs6265 on the BDNF gene but not non-carriers (GG) (P for the interaction = 0.017 and 0.018). Variants of genes related to satiety and appetite could modulate the effect of defatted flaxseed flour on obesity-related traits.

Psychometric Properties, Factor Structure, and Validity of the Sensitivity to Threat and Affiliative Reward Scale in Children and Adults.

Callous-Unemotional (CU) traits identify children at high risk of antisocial behavior. A recent theoretical model proposed that CU traits arise from low sensitivity to threat and affiliation. To assess these dimensions, we developed the parent- and self-reported Sensitivity to Threat and Affiliative Reward Scale (STARS) and tested its psychometric properties, factor structure, and construct validity. Samples 1 (N =3 03; age 3-10; United States) and 2 (N = 854 age 5-9; Spain) were children and Sample 3 was 514 young adults (Mage = 19.89; United States). In Sample 1, differential item functioning and item response theory techniques were used to identify the best-performing items from a 64-item pool, resulting in 28 items that functioned equivalently across age and gender. Factor analysis indicated acceptable fit for the theorized two-factor structure with separate threat and affiliation factors in all three samples, which showed predictive validity in relation to CU traits in children and psychopathic traits in young adults.

The Relationship Between Behavior Aspects of Executive Functions and Personality Traits in Healthy Young Adults.

Executive functions (ЕF) are complex cognitive processes that govern our behavior and thoughts. Associations between personality traits and executive functions clarify the mechanisms of a person's ability to function in everyday situations. The main goal of this study was to explore different personality dimensions relevant to the prediction of two different executive functions - Inhibition and Working Memory. The Big Five Inventory and the Adult Executive Functioning Inventory (ADEXI) were administered on a community sample comprising 549 young adults aged 18-35years (mean age 22.10years, SD 3.13). After controlling for age, gender and level of education, Conscientiousness and Extraversion were the most predictive personality traits, while Neuroticism and Agreeableness made specific contributions to the prediction of one of the two executive measures: Working Memory or Inhibition. Specifically, high Conscientiousness and Extraversion with low Neuroticism were significant predictors of Working Memory ability. On the other hand, high Conscientiousness and Agreeableness with low Extraversion predicted better Inhibition ability. These findings support the conclusion that these dimensions of individual differences seem to have numerous points of overlap at both psychological and neurobiological levels, but differences between these constructs are still significant.

Comparative assessment outcome of the cognitive and developmental traits in adults with listening difficulties

Objective This study was designed to determine the cognitive ability and developmental disorder traits in adults with listening difficulties (LiD) who show difficulties in comprehending verbal information in noisy environments despite having normal hearing. Methods Thirty adults who complained of LiD during their activities of daily living volunteered to participate. We conducted memory and attention assessments using auditory and visual tasks. Moreover, we evaluated the developmental characteristics of the participants psychologically using questionnaires for autism-spectrum disorder (ASD) and attention-deficit hyperactivity disorder (ADHD). Results The results of the auditory and verbal tasks were lower than that of visual tasks and that some participants showed lower scores on cognitive tests. Approximately 26.7% of the participants had ASD, whereas 16.7% had ADHD, and it showed a higher proportion of ASD or ADHD in participants with LiD. The outcomes of the cognitive and developmental assessment scores were not significantly correlated with the participants’ personal factors. Conclusion These findings imply that adults with LiD may also have cognitive problems and some of them showed developmental traits. It is needed to consider the cognitive and developmental characteristics of adults with LiD during evaluation in practice through hearing and listening tests along with cognitive assessments.

Adult Personality and Its Relationship with Stress Level, Coping Mechanism and Academic Performance among Undergraduate Nursing Students.

Stress related to nursing education and clinical placement encounters by students since the beginning of their nursing course has been an issue of concern. This study aims to examine the prevalence of adult personality traits and their relationship with stress levels, coping mechanisms and academic performance among nursing students. This cross-sectional study was conducted among 92 nursing students at Universiti Kebangsaan Malaysia (UKM). The Big Five Inventory (BFI), Student Nurse Stress Index and Brief COPE instruments were used to measure the respondents' personality traits, stress level and coping mechanisms, respectively. Data were analysed using IBM SPSS version 26. The most prevalent personality trait of the students was openness (mean = 33.58). Conscientiousness (r = -0.226, P = 0.030) and neuroticism (r = 0.326, P = 0.002) are significantly related to stress level. Extraversion (r = 0.219, P = 0.036), conscientiousness (r = 0.206, P = 0.049) and openness (r = 0.219, P = 0.036) show significant relationships with the approach coping mechanism, while agreeableness (r = -0.257, P = 0.013) and neuroticism (r = 0.297, P = 0.004) show significant relationships with the avoidant coping mechanism. However, no significant relationship was noted between personality traits and academic performance (r = 1.000, P > 0.05). Knowledge of ones' personality traits may benefit students in understanding themselves and in using the best ways to cope with their stress while studying nursing.

Integrating multi-locus genome-wide association studies with transcriptomic data to identify genetic loci underlying adult root trait responses to drought stress in flax (Linum usitatissimum L.)

Water stress is a major constraint on crop production and, root systems are one of the key features of plants determining drought tolerance and yield. In this study, five root morphological traits and their stability indices were evaluated at the reproductive stage on an association panel consisting of 120 diverse Linum usitatissimum accessions grown under well-watered and water-limiting conditions. To identify quantitative trait loci (QTL) and candidate genes positively influencing root traits under drought, combined multi-locus genome-wide association studies (ML-GWAS) and transcriptomic data analysis were carried out. A total of 112 QTL were identified accounting for 0.45–24.28 % of the phenotypic variation for root-related traits. Fifty QTL were detected by at least two ML-GWAS models, and 26 were co-located with previously reported QTL associated with yield-related traits under drought and early root and shoot development. Phenotypic differences between two contrasting subsets of accessions for the traits assessed were attributable to the accumulation of positive QTL alleles (PQTL), where the subset with the largest number of PQTL registered 154 % and 69 % greater total root length and yield under drought stress, respectively, than the subset with the fewest PQTL. Transcriptomic data analysis identified 766 differentially expressed genes (DEGs) responsive to drought stress in 108 QTL. Annotation of the 766 DEGs yielded functional genes involved in root development, stomatal closure, ROS (reactive oxygen species) scavenging, and hormone responses, among others. Taken together, the combined use of GWAS and transcriptomic data analyses provide the foundation for our enhanced understanding of root trait morphological changes in response to drought stress, and to achieve superior yield resilience/stability under water shortages in flax through enhanced molecular breeding. All data supporting the findings of this study are available within the paper and within its Supplementary data • Large genetic variation observed for adult root traits under drought and irrigated conditions. • Root traits explained 25–32 % of yield variation under drought stress. • A total of 112 QTL were identified for root traits and their stability indices in flax. • Twenty-six QTL co-located with previously reported QTL for yield traits under drought and root and shoot development. • Transcriptomic data analysis identified 766 drought responsive differentially expressed genes within the LD blocks of 108 significant QTL.

Impact of breeding for reduced methane emissions in New Zealand sheep on maternal and health traits.

Enteric methane emissions from ruminants account for ∼35% of New Zealand’s greenhouse gas emissions. This poses a significant threat to the pastoral sector. Breeding has been shown to successfully lower methane emissions, and genomic prediction for lowered methane emissions has been introduced at the national level. The long-term genetic impacts of including low methane in ruminant breeding programs, however, are unknown. The success of the New Zealand sheep industry is currently heavily reliant on the prolificacy, fecundity and survival of adult ewes. The objective of this study was to determine genetic and phenotypic correlations between adult maternal ewe traits (live weight, body condition score, number of lambs born, litter survival to weaning, pregnancy scanning and fleece weight), faecal and Nematodirus egg counts and measures of methane in respiration chambers. More than 9,000 records for methane from over 2,200 sheep measured in respiration chambers were collected over 10 years. Sheep were fed on a restricted diet calculated as approximately twice the maintenance. Methane measures were converted to absolute daily emissions of methane measured in g per day (CH4/day). Two measures of methane yield were recorded: the ratio of CH4 to dry matter intake (g CH4/kg DMI; CH4/DMI) and the ratio of CH4 to total gas emissions (CH4/(CH4 + CO2)). Ewes were maintained in the flocks for at least two parities. Non-methane trait data from over 8,000 female relatives were collated to estimate genetic correlations. Results suggest that breeding for low CH4/DMI is unlikely to negatively affect faecal egg counts, adult ewe fertility and litter survival traits, with no evidence for significant genetic correlations. Fleece weight was unfavourably (favourably) correlated with CH4/DMI (rg = −0.21 ± 0.09). Live weight (rg = 0.3 ± 0.1) and body condition score (rg = 0.2 ± 0.1) were positively correlated with methane yield. Comparing the two estimates of methane yield, CH4/DMI had lower heritability and repeatability. However, correlations of both measures with adult ewe traits were similar. This suggests that breeding is a suitable mitigation strategy for lowering methane yield, but wool, live weight and fat deposition traits may be affected over time and should be monitored.

Local Agricultural Management Filters Morphological Traits of the South American Palm Weevil (Rhynchophorus palmarum L.; Coleoptera: Curculionidae) in Ornamental Palm Plantations

Insect pests show phenotypic plasticity as a function of resource availability and limiting conditions. Although Rhynchophorus palmarum displays high variation in certain morphological traits, it is still not clear how and which of these are being filtered along agricultural management gradients in palm plantations. This study assesses the influence of biophysical structure of ornamental palm plantations and agrochemical use on morphological traits of adults in 15 permanent plots of ornamental palm plantations in Veracruz, Mexico. A total of 4972 adults were and their body length, pronotum width, rostrum length, and mesothorax depth were measured. Body length and mesothorax depth of adults of both sexes were greater in plantations with a high diversity of palm species and frequency of fertilizer use. Rostrum length of females increased as a function of palm density, and pronotum width of both sexes was positively related with the use of insecticides. Local characteristics of agricultural management of palm plantations might filter integrated, adaptative, and environment-specific phenotypes. This is the first ecological study of the south American palm weevil that provides new insights on the current intensive management of ornamental palm plantations that far from controlling, benefits current geographic expansion, demographic outbreak, and economic impact of this pest.

Life history trade-offs associated with exposure to low maternal capital are different in sons compared to daughters: Evidence from a prospective Brazilian birth cohort.

BackgroundEnvironmental exposures in early life explain variability in many physiological and behavioural traits in adulthood. Recently, we showed that exposure to a composite marker of low maternal capital explained the clustering of adverse behavioural and physical traits in adult daughters in a Brazilian birth cohort. These associations were strongly mediated by whether or not the daughter had reproduced by the age of 18 years. Using evolutionary life history theory, we attributed these associations to trade-offs between competing outcomes, whereby daughters exposed to low maternal capital prioritised investment in reproduction and defence over maintenance and growth. However, little is known about such trade-offs in sons.MethodsWe investigated 2,024 mother–son dyads from the same birth cohort. We combined data on maternal height, body mass index, income, and education into a composite “maternal capital” index. Son outcomes included reproductive status at the age of 18 years, growth trajectory, adult anthropometry, body composition, cardio-metabolic risk, educational attainment, work status, and risky behaviour (smoking, violent crime). We tested whether sons' early reproduction and exposure to low maternal capital were associated with adverse outcomes and whether this accounted for the clustering of adverse outcomes within individuals.ResultsSons reproducing early were shorter, less educated, and more likely to be earning a salary and showing risky behaviour compared to those not reproducing, but did not differ in foetal growth. Low maternal capital was associated with a greater likelihood of sons' reproducing early, leaving school, and smoking. High maternal capital was positively associated with sons' birth weight, adult size, and staying in school. However, the greater adiposity of high-capital sons was associated with an unhealthier cardio-metabolic profile.ConclusionExposure to low maternal investment is associated with trade-offs between life history functions, helping to explain the clustering of adverse outcomes in sons. The patterns indicated future discounting, with reduced maternal investment associated with early reproduction but less investment in growth, education, or healthy behaviour. However, we also found differences compared to our analyses of daughters, with fewer physical costs associated with early reproduction. Exposure to intergenerational “cycles of disadvantage” has different effects on sons vs. daughters, hence interventions may have sex-specific consequences.

Decision-making under stress: Executive functions, analytical intelligence, somatic markers, and personality traits in young adults

The main goal of the study was to scrutinize mediating and moderating mechanisms identified in line with the predictions of Somatic Marker Hypothesis (SMH) and Dual Process Theory of the effect of acute stress on decision making. The sample group of the research comprised of 61 (31 females, 30 males) healthy university students aged between 18 and 23 (x̄ = 21, SD = 1.28). Data measurement tools were Skin Conductance Response Measurement, Iowa Gambling Test, Wisconsin Card Sorting Test, Wechsler Memory Scale-III Spatial Span Subtest, Stroop Test TBAG Form, Wechsler Adult Intelligence Matrix Reasoning Subtest, Stress Rating Scale, The State-Trait Anxiety Inventory, Big Five Personality Traits Scale, Ways of Coping Inventory, Beck Depression Inventory. The findings indicated that acute stress gives rise to decision-making failures by suppressing the SCR emphasized in SMH and mental processes defined in System 2. Furthermore, neuroticism had a moderating role in the relationship between stress and decision-making. Accordingly, the abovementioned theories cannot separately be sufficient to explain decision-making under stress; but, the predictions of these theories can complement each other to thoroughly make out the physiological and cognitive mechanisms of decision-making.

Evolution of Type D Personality Traits After Cochlear Implantation in Severely Hearing Impaired Adults 55 Years and Older: An Exploratory Prospective, Longitudinal, Controlled, Multicenter Study.

To study the evolution of type D personality traits in older adults after cochlear implantation compared with a control group of severely hearing impaired older adults who did not receive a cochlear implant (CI). The influence of COVID-19 on this evolution was also explored. Type D personality combines a high degree of negative affectivity (NA) and social inhibition (SI). In this prospective, longitudinal, controlled multicenter exploratory study, 76 older CI users and 21 severely hearing impaired controls without CI were included. The CI group and the control group did not differ significantly regarding age, formal education, residual hearing, Type D Scale-14 (DS14) total score, NA, and SI at baseline. Type D personality traits were assessed with the DS14 at baseline (T0) and 14 months later (T14). Type D personality traits differed significantly over time between the CI group and the control group (p < 0.001). In the CI group, the DS14 total score (mean delta T = -6.63; p < 0.001), NA (mean delta T = -3.26; p < 0.001), and SI (mean delta T = -3.37; p < 0.001) improved significantly over time (delta T = T14-T0), whereas no significant difference was found in the control group. Significantly fewer subjects were categorized as type D personalities in the CI group (delta T = -12; p = 0.023) at T14, whereas no significant change was found in the control group (delta T = 3; p = 0.250). COVID-19 did not influence the evolution of type D personality traits significantly in the CI group. Cochlear implantation has a positive effect on type D personality traits in older adults with a severe-to-profound hearing impairment.

Evaluation of Body Size Indicators for Morphological Analyses in Two Sister Species of Genus Dorcus (Coleoptera, Lucanidae).

The relationship between trait and body size, i.e., the scaling relationship or static allometry, is an essential concept for investigating trait size. However, usage of an inappropriate body size indicator can lead to misinterpretation of morphology. In this study, we examined several possible body size indicators in two closely related stag beetle species, Dorcus rectus and Dorcus amamianus. We raised animals in captivity and used pupal weight as a measure of true, or overall body size, and then evaluated six adult morphological traits to test whether these traits could be reliably used as body size indicators in static scaling relationship comparisons. We analyzed two comparisons, between sexes in same species and between species in same sex. We showed that the most appropriate body size indicators differ depending on the comparisons. Our results indicated that the scaling relationship of focal traits could be over- or under-estimated depending on which body size indicators are used.

Early-life vitamin B12 orchestrates lipid peroxidation to ensure reproductive success via SBP-1/SREBP1 in Caenorhabditis elegans.

Vitamin B12 (B12) deficiency is a critical problem worldwide. Such deficiency in infants has long been known to increase the propensity to develop obesity and diabetes later in life through unclear mechanisms. Here, we establish a Caenorhabditis elegans model to study how early-life B12 impacts adult health. We find that early-life B12 deficiency causes increased lipogenesis and lipid peroxidation in adult worms, which in turn induces germline defects through ferroptosis. Mechanistically, we show the central role of the methionine cycle-SBP-1/SREBP1-lipogenesis axis in programming adult traits by early-life B12. Moreover, SBP-1/SREBP1 participates in a crucial feedback loop with NHR-114/HNF4 to maintain cellular B12 homeostasis. Inhibition of SBP-1/SREBP1-lipogenesis signaling and ferroptosis later in life can reverse disorders in adulthood when B12 cannot. Overall, this study provides mechanistic insights into the life-course effects of early-life B12 on the programming of adult health and identifies potential targets for future interventions for adiposity and infertility.