Fish assemblage convergence along stream environmental gradients: an intercontinental analysis

Species that pass through similar environmental filters, regardless of geographic proximity or evolutionary history, are expected to share many traits, resulting in similar assemblage trait distributions. Convergence of assemblage trait distributions among different biotic regions would indicate that consistent ecological processes produce repeated patterns of adaptive evolution. This study analyzes trait–environment relationships across multiple stream fish assemblages representing evolutionarily divergent faunas. We hypothesized that trait–environment patterns converge across regional faunas in response to a common set of environmental filters acting on functional traits. One hundred and ninety‐seven species and forty streams were sampled from five regions: Belize, Benin, Brazil, Cambodia and USA. By examining trait–environment plots, multiple congruent trait–environment patterns were found across all regions, indicative of a consistent set of environmental filters acting on local community assembly. The consistency of these patterns strongly suggests that water velocity and habitat structural complexity function as universal environmental filters, producing similar assemblage trait distributions in streams across all regions. Bivariate relationships were not universal, and only one of the associations between a single functional trait and single environmental variable was statistically significant across all five regions. Strong phylogenetic signal was found in traits and habitat use, which implies that niche conservatism also influenced assemblage trait distributions. Overall, results support the idea that habitat templates structure trait distributions of stream fish assemblages and do so in a consistent manner.     

Personality predicts ectoparasite abundance in an asocial sciurid

Parasitism is a consequence of complex interactions between host, parasite, and their shared environment, and host behavior can influence parasite risk. Animal personality (i.e., consistent behavioral differences that are repeatable across time and context) can influence parasitism with more explorative individuals typically hosting greater parasite loads. Host “sociality” is known to impact parasite risk with more social individuals typically at higher risk of acquiring or transmitting parasites, but other behaviors could also be important. We quantified personality in least chipmunks (Tamias minimus), including repeatability of behavioral traits, and determined whether these personality traits affected ectoparasite prevalence and abundance. We measured personality using standardized hole‐board tests and quantified ectoparasitism of 39 least chipmunks over 2 years at a site in southeastern Manitoba, Canada. We found that activity and exploration were repeatable within the context of the hole‐board test for least chipmunks, which suggests that these traits reflect personality. More exploratory individuals hosted a greater abundance of ectoparasites compared to less exploratory individuals. Our results are consistent with past studies implicating personality as a factor in host–parasite dynamics and suggest that exploration may be an important behavioral correlate of parasite acquisition.     

Does Subjective Rating Reflect Behavioural Coding? Personality in 2 Month-Old Dog Puppies: An Open-Field Test and Adjective-Based Questionnaire

A number of studies have recently investigated personality traits in non-human species, with the dog gaining popularity as a subject species for research in this area. Recent research has shown the consistency of personality traits across both context and time for adult dogs, both when using questionnaire based methods of investigation and behavioural analyses of the dogs’ behaviour. However, only a few studies have assessed the correspondence between these two methods, with results varying considerably across studies. Furthermore, most studies have focused on adult dogs, despite the fact that an understanding of personality traits in young puppies may be important for research focusing on the genetic basis of personality traits. In the current study, we sought to evaluate the correspondence between a questionnaire based method and the in depth analyses of the behaviour of 2-month old puppies in an open-field test in which a number of both social and non-social stimuli were presented to the subjects. We further evaluated consistency of traits over time by re-testing a subset of puppies. The correspondence between methods was high and test- retest consistency (for the main trait) was also good using both evaluation methods. Results showed clear factors referring to the two main personality traits ‘extroversion,’ (i.e. the enthusiastic, exuberant approach to the stimuli) and ‘neuroticism,’ (i.e. the more cautious and fearful approach to the stimuli), potentially similar to the shyness-boldness dimension found in previous studies. Furthermore, both methods identified an ‘amicability’ dimension, expressing the positive interactions the pups directed at the humans stranger, and a ‘reservedness’ dimension which identified pups who largely chose not to interact with the stimuli, and were defined as quiet and not nosey in the questionnaire.     

Animal personality: what are behavioural ecologists measuring?

The discovery that an individual may be constrained, and even behave sub‐optimally, because of its personality type has fundamental implications for understanding individual‐ to group‐level processes. Despite recent interest in the study of animal personalities within behavioural ecology, the field is fraught with conceptual and methodological difficulties inherent in any young discipline. We review the current agreement of definitions and methods used in personality studies across taxa and systems, and find that current methods risk misclassifying traits. Fortunately, these problems have been faced before by other similar fields during their infancy, affording important opportunities to learn from past mistakes. We review the tools that were developed to overcome similar methodological problems in psychology. These tools emphasise the importance of attempting to measure animal personality traits using multiple tests and the care that needs to be taken when interpreting correlations between personality traits or their tests. Accordingly, we suggest an integrative theoretical framework that incorporates these tools to facilitate a robust and unified approach in the study of animal personality.     

Political Attitudes Develop Independently of Personality Traits

The primary assumption within the recent personality and political orientations literature is that personality traits cause people to develop political attitudes. In contrast, research relying on traditional psychological and developmental theories suggests the relationship between most personality dimensions and political orientations are either not significant or weak. Research from behavioral genetics suggests the covariance between personality and political preferences is not causal, but due to a common, latent genetic factor that mutually influences both. The contradictory assumptions and findings from these research streams have yet to be resolved. This is in part due to the reliance on cross-sectional data and the lack of longitudinal genetically informative data. Here, using two independent longitudinal genetically informative samples, we examine the joint development of personality traits and attitude dimensions to explore the underlying causal mechanisms that drive the relationship between these features and provide a first step in resolving the causal question. We find change in personality over a ten-year period does not predict change in political attitudes, which does not support a causal relationship between personality traits and political attitudes as is frequently assumed. Rather, political attitudes are often more stable than the key personality traits assumed to be predicting them. Finally, the results from our genetic models find that no additional variance is accounted for by the causal pathway from personality traits to political attitudes. Our findings remain consistent with the original construction of the five-factor model of personality and developmental theories on attitude formation, but challenge recent work in this area.     

The evolutionary fitness of personality traits in a small-scale subsistence society

The maintenance of personality variation remains an unexplained puzzle in evolutionary biology. Despite evidence among non-humans that personality variation affects fitness, few data exist to assess the personality–fitness relationship in humans. Among Tsimane forager–horticulturalists (n = 632), we test whether personality traits (assessed using a 43-item Big Five Inventory administered orally in native language) predict fertility, offspring survivorship, age of first reproduction, and other fitness correlates (extramarital affairs, conflicts, social visitation, food production, and several health measures). Among men, several personality factors associate with higher fertility, more time spent producing food and social visitation. Among women, the relationship between personality and fitness varies across regions of Tsimane territory. The only case of an intermediate personality level associated with highest fitness was found for Industriousness in men. We find that personality factors positively associated with fitness do not associate with greater health costs, although greater Extraversion and Openness may lead to more conflicts among men. Factor heritability ranges from 60% for Prosociality and Extraversion to 8% for Neuroticism. We interpret our results in light of evolutionary models that explain maintenance of personality variation, including incomplete directional selection, mutation–selection balance, condition-dependent reaction norms and fluctuating selection based on sex or spatial variability in selection pressures.     

Context Matters: Multiple Novelty Tests Reveal Different Aspects of Shyness-Boldness in Farmed American Mink (Neovison vison)

Animal personality research is receiving increasing interest from related fields, such as evolutionary personality psychology. By merging the conceptual understanding of personality, the contributions to both fields of research may be enhanced. In this study, we investigate animal personality based on the definition of personality traits as underlying dispositional factors, which are not directly measurable, but which predispose individuals to react through different behavioural patterns. We investigated the shyness-boldness continuum reflected in the consistency of inter-individual variation in behavioural responses towards novelty in 47 farmed American mink (Neovison vison), which were raised in identical housing conditions. Different stages of approach behaviour towards novelty, and how these related within and across contexts, were explored. Our experimental design contained four tests: two novel object tests (non-social contexts) and two novel animated stimuli tests (social contexts). Our results showed consistency in shyness measures across multiple tests, indicating the existence of personality in farmed American mink. It was found that consistency in shyness measures differs across non-social and social contexts, as well as across the various stages in the approach towards novel objects, revealing that different aspects of shyness exist in the farmed American mink. To our knowledge this is the first study to reveal aspects of the shyness-boldness continuum in the American mink. Since the mink were raised in identical housing conditions, inherited factors may have been important in shaping the consistent inter-individual variation. Body weight and sex had no effect on the personality of the mink. Altogether, our results suggest that the shyness-boldness continuum cannot be explained by a simple underlying dispositional factor, but instead encompasses a broader term of hesitating behaviour that might comprise several different personality traits.     

Using genetic variation to disentangle the complex relationship between food intake and health outcomes

Diet is considered as one of the most important modifiable factors influencing human health, but efforts to identify foods or dietary patterns associated with health outcomes often suffer from biases, confounding, and reverse causation. Applying Mendelian randomization in this context may provide evidence to strengthen causality in nutrition research. To this end, we first identified 283 genetic markers associated with dietary intake in 445,779 UK Biobank participants. We then converted these associations into direct genetic effects on food exposures by adjusting them for effects mediated via other traits. The SNPs which did not show evidence of mediation were then used for MR, assessing the association between genetically predicted food choices and other risk factors, health outcomes. We show that using all associated SNPs without omitting those which show evidence of mediation, leads to biases in downstream analyses (genetic correlations, causal inference), similar to those present in observational studies. However, MR analyses using SNPs which have only a direct effect on the exposure on food exposures provided unequivocal evidence of causal associations between specific eating patterns and obesity, blood lipid status, and several other risk factors and health outcomes.     

I Know How You Feel: The Warm-Altruistic Personality Profile and the Empathic Brain

The ability to empathize with other people is a critical component of human social relationships. Empathic processing varies across the human population, however it is currently unclear how personality traits are associated with empathic processing. This study was designed to test the hypothesis that specific personality traits are associated with behavioral and biological indicators of improved empathy. Extraversion and Agreeableness are personality traits designed to measure individual differences in social-cognitive functioning, however each trait-dimension includes elements that represent interpersonal social functioning and elements that do not represent interpersonal social functioning. We tested the prediction that interpersonal elements of Extraversion (Warmth) and Agreeableness (Altruism) are associated with empathy and non-interpersonal elements of Extraversion and Agreeableness are not associated with empathy. We quantified empathic processing behaviorally (empathic accuracy task using video vignettes) and within the brain (fMRI and an emotional perspective taking task) in 50 healthy subjects. Converging evidence shows that highly warm and altruistic people are well skilled in recognizing the emotional states of other people and exhibit greater activity in brain regions important for empathy (temporoparietal junction and medial prefrontal cortex) during emotional perspective taking. A mediation analysis further supported the association between warm-altruistic personality and empathic processing; indicating that one reason why highly warm-altruistic individuals may be skilled empathizers is that they engage the temporoparietal junction and medial prefrontal cortex more. Together, these findings advance the way the behavioral and neural basis of empathy is understood and demonstrates the efficacy of personality scales to measure individual differences in interpersonal social function.     

Stability in Activity and Boldness Across Time and Context in Captive Siberian Dwarf Hamsters

Individual personality is an important source of variation in animal behavior. However, few studies have examined the reliability of individual behaviors across both time and context for even common temperament traits such as boldness, especially in mammals. We tested a laboratory colony of Siberian dwarf hamsters (Phodopus sungorus) in two similar assays, a tunnel maze and an open field, both provisioned with a home nestbox for shelter. Animals were tested in each assay at three ages, beginning at weaning. Principal components analysis on each assay identified an axis of activity level in both tests, boldness and reactivity in the tunnel maze, and nestbox orientation in the open field. All traits were moderately (7–18%) heritable. Individual activity level was the most reliably consistent trait, both within and between tests. Tunnel maze boldness, tunnel maze reactivity, and open field nestbox orientation did not correlate at any age. Correlation between boldness and activity changes from positive to negative as animals age, while reactivity was consistently negatively associated with activity. A negative correlation emerged in adults between open field activity and nestbox orientation. These results suggest that either development or habituation results in different personality trait associations in an individual over time. Individual temperament traits such as general activity level may be quite stable, but caution should be used in generalizing single assays to represent boldness across time and across contexts.     

Analysis of single nucleotide polymorphisms variation associated with important economic and computed tomography measured traits in Texel sheep

Sheep are an important part of the global agricultural economy. Growth and meat production traits are significant economic traits in sheep. The Texel breed is the most popular terminal sire breed in the UK, mainly selected for muscle growth and lean carcasses. This is a study based on a genome-wide association approach that investigates the links between some economically important traits, including computed tomography (CT) measurements, and molecular polymorphisms in UK Texel sheep. Our main aim was to identify single nucleotide polymorphisms (SNP) associated with growth, carcass, health and welfare traits of the Texel sheep breed. This study used data from 384 Texel rams. Data comprised ten traits, including two CT measured traits. The phenotypic data were placed in four categories: growth traits, carcass traits, health traits and welfare traits. De-regressed estimated breeding values (EBV) for these traits together with sire genotypes derived with the Ovine 50 K SNP array of Illumina were jointly analysed in a genome wide association analysis. Eight novel chromosome-wise significant associations were found for carcass, growth, health and welfare traits. Three significant markers were intronic variants and the remainder intergenic variants. This study is a first step to search for genomic regions controlling CT-based productivity traits related to body and carcass composition in a terminal sire sheep breed using a 50 K SNP genome-wide array. Results are important for the further development of strategies to identify causal variants associated with CT measures and other commercial traits in sheep. Independent studies are needed to confirm these results and identify candidate genes for the studied traits.     

Historical and ecological divergence among populations of Monttea chilensis (Plantaginaceae), an endemic endangered shrub bordering the Atacama Desert,Chile

The coastal deserts of northern Chile show an important latitudinal gradient of aridity with more arid areas to the north of the Atacama Desert than to the south. Several plant species have disjunct distributions that correspond with the extremes of this latitudinal gradient. In this study, using genetic (chloroplast and nuclear DNA), morphological (vegetative and floral traits of various kinds) and climatic and topographic information, we explored ecological and historical events that have putatively shaped patterns of variation among Monttea chilensis populations—a species that shows this disjunct distribution. Through phylogeographic and phylogenetic analyses, two divergent lineages were identified located at the latitudinal extremes. The lineage located northern lineage (NG) of the Atacama Desert showed more genetic diversity and better-resolved phylogeographic structure than the southern lineage (SG). Considerable morphological variation across the geographical range corresponds with these genetic groups. We observed contrasting relationships between floral and vegetative traits: populations from the most arid region NG possessed larger flowers, but smaller vegetative values, and vice versa. Niche modelling and multivariate analyses, including environmental data, revealed different environmental requirements for each lineage. NG plants occur in regions with warmer and drier climatic conditions and at higher altitudes, while SG populations inhabit colder and more humid environments and lower altitudes. The evolutionary history of M. chilensis exhibits a phylogeographical footprint consistent with past fragmentation and allopatric differentiation, where the hyper-arid zone formed by the Atacama Desert clearly acted as an important gene flow barrier. This barrier has led to considerable differentiation in morphology and ecology, resulting in two ecotypes or geographical races, suggesting incipient speciation promoted by local adaptation and geographical isolation.     

Personality,Metabolic Rate and Aerobic Capacity

Personality traits and cardiorespiratory fitness in older adults are reliable predictors of health and longevity. We examined the association between personality traits and energy expenditure at rest (basal metabolic rate) and during normal and maximal sustained walking. Personality traits and oxygen (VO₂) consumption were assessed in 642 participants from the Baltimore Longitudinal Study of Aging. Results indicate that personality traits were mostly unrelated to resting metabolic rate and energy expenditure at normal walking pace. However, those who scored lower on neuroticism (r =  −0.12) and higher on extraversion (r = 0.11), openness (r = 0.13), and conscientiousness (r = 0.09) had significantly higher energy expenditure at peak walking pace. In addition to greater aerobic capacity, individuals with a more resilient personality profile walked faster and were more efficient in that they required less energy per meter walked. The associations between personality and energy expenditure were not moderated by age or sex, but were in part explained by the proportion of fat mass. In conclusion, differences in personality may matter the most during more challenging activities that require cardiorespiratory fitness. These findings suggest potential pathways that link personality to health outcomes, such as obesity and longevity.     

Individual personalities predict social behaviour in wild networks of great tits (Parus major)

Social environments have an important effect on a range of ecological processes, and form a crucial component of selection. However, little is known of the link between personality, social behaviour and population structure. We combine a well‐understood personality trait with large‐scale social networks in wild songbirds, and show that personality underpins multiple aspects of social organisation. First, we demonstrate a relationship between network centrality and personality with ‘proactive’ (fast‐exploring) individuals associating weakly with greater numbers of conspecifics and moving between flocks. Second, temporal stability of associations relates to personality: ‘reactive’ (slow‐exploring) birds form synergistically stable relationships. Finally, we show that personality influences social structure, with males non‐randomly distributed across groups. These results provide strong evidence that songbirds follow alternative social strategies related to personality. This has implications not only for the causes of social network structure but also for the strength and direction of selection on personality in natural populations.     

The persistence of gender stereotypes in the face of changing sex roles: Evidence contrary to the sociocultural model

Prevailing explanations for gender differences rest upon the sociocultural model, which treats personality as a consequence of socialization for social roles. Though sex roles and attitudes toward them have changed dramatically in the United States over the past three decades, a review of 18 longitudinal studies of gender stereotypes and self-ratings shows stability in perceptions of sex-typed personality traits. Our study of 3600 students surveyed in six waves from 1974 to 1991 also shows stability and even a slight increase in sex typing. This accumulating evidence is inconsistent with the sociocultural explanation. It is more consistent with the currently emerging sociobiological research that holds gender differences reflect innate differences between the sexes resulting from their different reproductive strategies. We conclude that valid social psychological explanations for gendered personality traits cannot rest upon sociocultural models alone but must include interaction of this unchanging genetic underlay with changeable social structures and processes.     

高原鼠兔个性特征的地理变异及其对环境的适应

个性特征是指动物稳定且可遗传的综合行为特征,反映出其对特定环境的适应。限制性假说认为个性特征主要受遗传因素制约,个体间行为的表达差异不以环境条件而发生随意性改变;然而,适应性假说则认为个性特征主要由环境因素决定,生活于相同环境中的物种,其个性特征将产生趋同现象。本研究通过比较2个高原鼠兔地理种群的个性特征,检验适应性假说和限制性假说的相关预测。结果表明,刚察县高原鼠兔野外种群个体的行为特征聚为3类,玛沁县则为2类。实验室内驯化2-3个月后,两个地理种群个体行为特征聚为1类。两地理种群个体的观察、攀爬行为及边缘区域活动、移动累计时间均无显著差异,但静止累计时间存在明显地理差异。个体的中心区域活动累计时间在野外和驯化后均存在明显差异,且与地理空间的交互作用不显著。两地理种群之间个体的温顺性无明显差异;心率亦无显著差异。高原鼠兔个性特征中主要行为参数无显著的地理差异,主要由遗传因素决定,验证了限制性假说的相关预测。     

The impact of Neglected Tropical Diseases (NTDs) on health and wellbeing in sub-Saharan Africa (SSA): A case study of Kenya

Neglected Tropical Diseases (NTDs) remain endemic to many regions of sub-Saharan Africa (SSA) left behind by socioeconomic progress. As such, these diseases are markers of extreme poverty and inequity that are propagated by the political, economic, social, and cultural systems that affect health and wellbeing. As countries embrace and work towards achieving the Sustainable Development Goals (SDGs), the needs of such vulnerable populations need to be addressed in local and global arenas. The research uses primary qualitative data collected from five NTD endemic counties of Kenya: interviews key informants (n = 21) involved in NTD implementation programs and focus groups (n = 5) of affected individuals. Informed by theories of political ecology of health, the research focuses on post-devolution Kenya and identifies the political, economic, social, and cultural factors that propagate NTDs and their effects on health and wellbeing. Our findings indicate that structural factors such as competing political interests, health worker strikes, inadequate budgetary allocations, economic opportunity, marginalization, illiteracy, entrenched cultural norms and practices, poor access to water, sanitation and housing, all serve to propagate NTD transmission and subsequently affect the health and wellbeing of populations. As such, we recommend that post-devolution Kenya ensures local political, economic and socio-cultural structures are equitable, sensitive and responsive to the needs of all people. We also propose poverty alleviation through capacity building and empowerment as a means of tackling NTDs for sustained economic opportunity and productivity at the local and national level.     

Stream diatoms exhibit weak niche conservation along global environmental and climatic gradients

Niche conservatism (NC) describes the scenario in which species retain similar characteristics or traits over time and space, and thus has potentially important implications for understanding their biogeographic distributions. Evidence consistent with NC includes similar niche properties across geographically distant regions. We investigated whether NC was evident in stream diatom morphospecies by modeling species responses to environmental and climatic variables in a set of calibration sites (from the US) and then evaluated the models with test sets (from France, Finland, New Zealand, Antilles and La Réunion). We also examined whether diatom species showed congruency in environmental niche optima and niche breadths between the study regions, and whether species occupancy and functional traits influenced the observed patterns. We used boosted regression tree models with local environmental variables and climatic variables as predictors. We detected low NC in both environmental and climate models and a lack of consistent differences in NC between widely distributed and regionally rare species and among functional groups. For all species, diatom environmental and climatic optima varied clearly between the regions but showed some positive relationships especially for pH and total phosphorus. Diatom niche breadths were only weakly correlated between the US and the other regions. We demonstrated that diatoms showed overall relatively little NC globally, and NC was especially low for climatic variables. Collectively, these findings suggest that there may exist locally adapted lineages within the diatom morphospecies or diatoms possess some adaptation potential for differences in temperature. We argue that in diatoms, environmental and especially climate models may not be transferrable in space globally but need regional diatom data for calibration because species niches seem to differ among geographical regions.     

Pets and Happiness: Examining the Association between Pet Ownership and Wellbeing

Are pets associated with happiness in their owners? Some research has demonstrated positive connections between pets and the physical health of their owners, and more recently, research has shown the beneficial effects of pets on the negative aspects of mental health as well. However, much less research has focused on the relation between pets and the positive aspects of mental health, such as happiness. In the current study, 263 American adults completed an online survey using Amazon Mechanical Turk. Results indicate that pet owners were more satisfied with their lives than non-owners, but did not differ on other wellbeing measures, personality measures, emotion regulation, or need satisfaction. Dog owners scored higher on all aspects of wellbeing compared with cat owners, and differed on a number of other measures, including the Big Five personality traits, emotion regulation strategies, and need satisfaction. The relationship between type of pet owned and wellbeing was mediated by the Big Five personality traits (extraversion, agreeableness, and neuroticism, specifically), emotion regulation strategy, and need satisfaction. In addition, self-identified “dog people,” relative to “cat people,” showed similar patterns to those of dog owners, but the effects were often smaller and non-significant. Although there may not be many differences between those who own pets and those who do not, clearly owning a dog is associated with beneficial outcomes. Implications and future directions are discussed.