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Plant–plant interactions, often studied in the context of plant traits, are considered crucial assembly mechanisms for plant communities and offer insights into how neighbours affect growth. Three key questions regarding these interactions have theoretical importance but limited empirical support: (1) does similarity in plant traits enhance competitive interactions among species, (2) is the "competitive environment" determined through plant traits of the resident species, and (3) do greater species diversity and niche use result in increased competition among co‐occurring species. Here we use a simple experimental design to directly test these foundational questions.In a mesocosm experiment using native grassland fragments, we investigated our questions simultaneously by manipulating trait relationships among resident and colonizing plants. To assess the net impact of neighbours on plant growth, we measured the degree of suppression experienced by focal plants compared to growth in the absence of neighbours. We further tested whether trait‐function relationships are context‐dependent by modifying available resources.Contrary to the limiting similarity hypothesis, we found that reduced overall dissimilarity mitigated neighbour‐induced growth suppression, with more negative effects occurring among dissimilar neighbours. The influence of trait dissimilarity depended on nutrient context and was stronger under increased resource availability. We found little support for the idea that specific plant traits are "functional" in creating competitive environments: no community traits (community weighted means) were associated with net neighbour effects. In contrast, resource supply significantly affected species interactions, with increased resources exacerbating negative neighbour effects on plant growth.We found that plant trait dissimilarity does function in competition but is contingent on resource context. However, trait values were not inherently competitive: traits may have physiological functions but did not function in focal plants' competitive response. We provide some of the limited data directly testing the core mechanisms of community assembly. We encourage such direct experimental tests as they are essential to building an understanding of ecological processes. Read the free Plain Language Summary for this article on the Journal blog. [ABSTRACT FROM AUTHOR]

Phylogenetic and functional diversity are theorised to increase invasion resistance. Experimentally testing whether plant communities higher in these components of diversity are less invasible is an important step for guiding restoration designs.To investigate how phylogenetic and functional diversity of vegetation affect invasion resistance in a restoration setting, we used experimental prairie restoration plots. The experiment crossed three levels of phylogenetic diversity with two levels of functional diversity while species richness was held constant. We allowed invaders to colonise plots; these included native species from neighbouring plots and non‐native invasive species from a surrounding old field. We tested if invader biomass was influenced by phylogenetic and functional diversity, and phylogenetic and hierarchical trait distances between invaders and planted species. We binned each invader into three categories: native species from neighbouring experimental plots (site‐specific invaders), native species not part of the experimental species pool (native invaders) or non‐native species (non‐native invaders).Counter to expectation, both non‐native and native invaders became more abundant in more phylogenetically diverse plots. However, plots with higher abundance of planted Asteraceae, a dominant family of the tallgrass prairie, had lower invader biomass for both native and non‐native invaders.We also found that hierarchical trait differences shaped invasion. The species that became most abundant were non‐native invaders that were taller, and native invaders with low specific leaf area relative to planted species. Site‐specific invaders were not influenced by any plot‐level diversity metrics tested.Synthesis and application: Our results suggest that greater phylogenetic diversity may lower resistance to invasion. This effect may be due to more even but sparser niche packing in high‐diversity plots, associated with greater availability of unsaturated niche space for colonisation. However, trait composition fostered invasion resistance in two ways in our study. First, establishment of native species with strongly dominant traits may confer invasion resistance. Second, species mixes that optimise trait differences between planted vegetation and likely invaders may enhance invasion‐resistance. [ABSTRACT FROM AUTHOR]

Abstract The dissimilarity and hierarchy of trait values that characterize niche and fitness differences, respectively, have been increasingly applied to infer mechanisms driving community assembly and to explain species co‐occurrence patterns. Here, we predict that limiting similarity should result in the spatial segregation of functionally similar species, while functionally similar species will be more likely to co‐occur either due to environmental filtering or due to competitive exclusion of inferior competitors (hereafter hierarchical competition). We used a fully mapped 50‐ha subtropical forest plot in southern China to explore how pairwise spatial associations between saplings and between adult trees were influenced by trait dissimilarity and hierarchy in order to gain insight into assembly mechanisms. We assessed pairwise spatial associations using two summary statistics of spatial point patterns at different spatial scales and compared the effects of trait dissimilarity and trait hierarchy of different functional traits on the interspecific spatial associations. These comparisons allow us to disentangle the effects of limiting similarity, environmental filtering, and hierarchical competition on species co‐occurrence. We found that trait dissimilarity was generally negatively related to interspecific spatial associations for both saplings and adult trees across spatial scales, meaning that species with similar trait values were more likely to co‐occur and thus supporting environmental filtering or hierarchical competition. We further found that trait hierarchy outweighed trait dissimilarity in structuring pairwise spatial associations, suggesting that hierarchical competition played a more important role in structuring our forest community than environmental filtering across life stages. This study employed a novel method, by offering the integration of pairwise spatial association and trait dissimilarity as well as trait hierarchy, to disentangle the relative importance of multiple assembly mechanisms in structuring co‐occurrence patterns, especially the mechanisms of environmental filtering and hierarchical competition, which lead to indistinguishable co‐occurrence patterns. This study also reinforced the importance of trait hierarchy rather than trait dissimilarity in driving neighborhood competition.

Plant communities are predicted to be more resistant to invasion if they are highly productive, harbor species with similar functional traits to invaders, or support species with high competitive potential. However, the strength of competition may decrease with increasing abiotic stress if species more heavily invest in traits that confer stress tolerance over competitive ability, potentially influencing community trait–resistance relationships. Recent research examining how community traits influence invasion resistance has been predominantly focused on single vegetation types, and results between studies are often conflicting. Few studies have evaluated the extent to which abiotic factors and community traits interact to influence invasion along vegetation gradients. Here, we use an in situ seed addition experiment to examine how above‐ and below‐ground plant traits and vegetation type interact to influence community resistance to invasion by a recently introduced annual grass, Ventenata dubia, along a productivity gradient in eastern Oregon, USA. To measure invasion resistance, we evaluated V. dubia biomass in seeded subplots with varying trait compositions across three vegetation types situated along a productivity gradient: scab‐flats (sparsely vegetated dwarf‐shrublands), low sage‐steppe, and ephemeral wet meadows. Trait–resistance relationships were highly context dependent. In wet meadows (the most productive sites), resistance to invasion increased with increasing resident biomass and as community weighted mean trait values for specific leaf area, fine‐to‐total root volume, and height become more similar to V. dubia's trait values, although these relationships were relatively weak. We did not find evidence that neighboring species influenced invasion resistance in less productive vegetation types, in contrast to our expectations that facilitative interactions may increase with decreasing productivity as posited by the stress‐gradient hypothesis. Unlike V. dubia, which heavily invaded all three vegetation types, introduced species with similar trait values, including Bromus tectorum, were not abundant throughout the study area demonstrating V. dubia's unique ability to take advantage of available resources. Our results illustrate how community traits and site productivity interact to influence community resistance to invasion and highlight that communities with lower overall biomass and few functionally similar species to V. dubia may be at the greatest risk for invasion. [ABSTRACT FROM AUTHOR]

The assumption that differences in species' traits reflect their different niches has long influenced how ecologists infer processes from assemblage patterns. For instance, many assess the importance of environmental filtering versus classical limiting-similarity competition in driving biological invasions by examining whether invaders' traits are similar or dissimilar to those of residents, respectively. However, mounting evidence suggests that hierarchical differences between species' trait values can distinguish their competitive abilities (e.g. for the same resource) instead of their niches. Whether such trait-mediated hierarchical competition explains invasions and structures assemblages is less explored. We integrate morphological, dietary, physiological and behavioural trait analyses to test whether environmental filtering, limiting-similarity competition or hierarchical competition explain invasions by fire ants on ant assemblages. We detect both competition mechanisms; invasion success is not only explained by limiting similarity in body size and thermal tolerance (presumably allowing the invader to exploit different niches from residents), but also by the invader's superior position in trait hierarchies reflecting competition for common trophic resources. We find that the two mechanisms generate complex assemblage-level functional diversity patterns—overdispersion in some traits, clustering in others—suggesting their effects are likely missed by analyses restricted to a few traits and composite trait diversity measures. [ABSTRACT FROM AUTHOR]

Background and aims: The "competition-trait similarity" and "competition-trait hierarchy" hypotheses can be used to predict competitive outcomes between terrestrial plant species in response to environmental variation. However, their validity in aquatic plants remains poorly understood, particularly in terms of variation in the water exchange rate (WER). Methods: We compared competitive outcomes and variation in functional traits in two pairs of submerged macrophytes (Vallisneria natans vs. Myriophyllum aquaticum and V. natans vs. Myriophyllum spicatum) at three levels of WER using the replacement series method. Results: We found that the relative competitive ability of V. natans consistently decreased with increasing WER and decreasing the planting proportion of V. natans. Under these conditions, V. natans experienced reduced plant nutrient content and the inhibition of dissolved carbon dioxide absorption, which eventually shifted this species from a stronger to weaker competitor. With increasing WER and decreasing the planting proportion of V. natans, the below-:above-ground biomass ratio and root diameter increased, while the root length and specific root length decreased, for V. natans. In contrast, all of these traits exhibited the opposite patterns for the co-cultured Myriophyllum species. In addition, the branch number per plant mass increased in V. natans but exhibited no change in co-cultured Myriophyllum species under the same conditions. Conclusions: Our results indicate that WER affected the outcome of interspecies competition between submerged macrophyte species. Moreover, the relative competitive ability of each species within a pair was more strongly linked to species competition-trait hierarchy than to competition-trait similarity. [ABSTRACT FROM AUTHOR]

Carmona et al. (2019) have recently published the results of a well‐designed experiment examining the effect of functional traits on the outcome of competition. Their main conclusions were that (a) trait hierarchies better predict the strength of competition than trait differences, and (b) the consideration of intraspecific trait variation improves our ability to predict the strength of competition.They applied multi‐model inference by averaging regression coefficients. This approach is strongly criticized because it averages regression coefficients for which the meaning is conditional on the other predictors included in the model.In this paper, their data were re‐analysed using alternative methods. The results only partly support the original conclusions in that trait hierarchy proved to be obviously important in height, but not in the other three traits.Synthesis. Intraspecific trait variation contributes to a better understanding of the relationship between traits and competitive interactions. On the other hand, traits measured in focal individuals may be both drivers and consequences of competition, which makes the interpretation of the relationship more difficult. [ABSTRACT FROM AUTHOR]

The dissimilarity and hierarchy of trait values that characterize niche and fitness differences, respectively, have been increasingly applied to infer mechanisms driving community assembly and to explain species co‐occurrence patterns. Here, we predict that limiting similarity should result in the spatial segregation of functionally similar species, while functionally similar species will be more likely to co‐occur either due to environmental filtering or due to competitive exclusion of inferior competitors (hereafter hierarchical competition).We used a fully mapped 50‐ha subtropical forest plot in southern China to explore how pairwise spatial associations between saplings and between adult trees were influenced by trait dissimilarity and hierarchy in order to gain insight into assembly mechanisms. We assessed pairwise spatial associations using two summary statistics of spatial point patterns at different spatial scales and compared the effects of trait dissimilarity and trait hierarchy of different functional traits on the interspecific spatial associations. These comparisons allow us to disentangle the effects of limiting similarity, environmental filtering, and hierarchical competition on species co‐occurrence.We found that trait dissimilarity was generally negatively related to interspecific spatial associations for both saplings and adult trees across spatial scales, meaning that species with similar trait values were more likely to co‐occur and thus supporting environmental filtering or hierarchical competition. We further found that trait hierarchy outweighed trait dissimilarity in structuring pairwise spatial associations, suggesting that hierarchical competition played a more important role in structuring our forest community than environmental filtering across life stages.This study employed a novel method, by offering the integration of pairwise spatial association and trait dissimilarity as well as trait hierarchy, to disentangle the relative importance of multiple assembly mechanisms in structuring co‐occurrence patterns, especially the mechanisms of environmental filtering and hierarchical competition, which lead to indistinguishable co‐occurrence patterns. This study also reinforced the importance of trait hierarchy rather than trait dissimilarity in driving neighborhood competition. [ABSTRACT FROM AUTHOR]

Aims: Trait-based coexistence theories are useful to explain community processes. The aim was to distinguish which theory played a more important role in explaining the invasion mechanism of Caragana microphylla into communities in the Eurasian semi-arid grassland region. Method: We conducted a water condition (WC) × neighbouring plant diversity (NSD) experiment, measured functional dispersion (FDis) and biomass of neighbours, absolute and hierarchical distances between neighbours and C. microphylla for plant height, specific leaf area and leaf dry matter content (LDMC), and explored the relative effect of each predictor on neighbour-effect intensity index (NIntA) on C. microphylla. Results: Significant effect of NSD was direct or mediated by cascading effects between FDis and biomass of neighbours, significant effect of WC was direct or mediated by LDMC hierarchical distance, shoot biomass of neighbours mediated indirect effects of both NSD and WC on the NIntA on C. microphylla. None of the trait absolute distances was employed to explain the variability of the NIntA on C. microphylla. Conclusions: The reduction of NSD or water could decrease the inhibitory effects of neighbours on C. microphylla by increasing vacant niches or increasing the LDMC hierarchical distance between neighbours and C. microphylla, respectively, suggesting that vacant niches and competition-trait hierarchy played more important roles than competition-trait similarity in explaining shrub invasion processes in the Eurasian semi-arid grassland region. [ABSTRACT FROM AUTHOR]

Genomic prediction of complex traits, say yield, benefits from including information on correlated component traits. Statistical criteria to decide which yield components to consider in the prediction model include the heritability of the component traits and their genetic correlation with yield. Not all component traits are easy to measure. Therefore, it may be attractive to include proxies to yield components, where these proxies are measured in (high-throughput) phenotyping platforms during the growing season. Using the Agricultural Production Systems Simulator (APSIM)-wheat cropping systems model, we simulated phenotypes for a wheat diversity panel segregating for a set of physiological parameters regulating phenology, biomass partitioning, and the ability to capture environmental resources. The distribution of the additive quantitative trait locus effects regulating the APSIM physiological parameters approximated the same distribution of quantitative trait locus effects on real phenotypic data for yield and heading date. We use the crop growth model APSIM-wheat to simulate phenotypes in three Australian environments with contrasting water deficit patterns. The APSIM output contained the dynamics of biomass and canopy cover, plus yield at the end of the growing season. Each water deficit pattern triggered different adaptive mechanisms and the impact of component traits differed between drought scenarios. We evaluated multiple phenotyping schedules by adding plot and measurement error to the dynamics of biomass and canopy cover. We used these trait dynamics to fit parametric models and P-splines to extract parameters with a larger heritability than the phenotypes at individual time points. We used those parameters in multi-trait prediction models for final yield. The combined use of crop growth models and multi-trait genomic prediction models provides a procedure to assess the efficiency of phenotyping strategies and compare methods to model trait dynamics. It also allows us to quantify the impact of yield components on yield prediction accuracy even in different environment types. In scenarios with mild or no water stress, yield prediction accuracy benefitted from including biomass and green canopy cover parameters. The advantage of the multi-trait model was smaller for the early-drought scenario, due to the reduced correlation between the secondary and the target trait. Therefore, multi-trait genomic prediction models for yield require scenario-specific correlated traits.

Genomic prediction of complex traits, say yield, benefits from including information on correlated component traits. Statistical criteria to decide which yield components to consider in the prediction model include the heritability of the component traits and their genetic correlation with yield. Not all component traits are easy to measure. Therefore, it may be attractive to include proxies to yield components, where these proxies are measured in (high-throughput) phenotyping platforms during the growing season. Using the Agricultural Production Systems Simulator (APSIM)-wheat cropping systems model, we simulated phenotypes for a wheat diversity panel segregating for a set of physiological parameters regulating phenology, biomass partitioning, and the ability to capture environmental resources. The distribution of the additive quantitative trait locus effects regulating the APSIM physiological parameters approximated the same distribution of quantitative trait locus effects on real phenotypic data for yield and heading date. We use the crop growth model APSIM-wheat to simulate phenotypes in three Australian environments with contrasting water deficit patterns. The APSIM output contained the dynamics of biomass and canopy cover, plus yield at the end of the growing season. Each water deficit pattern triggered different adaptive mechanisms and the impact of component traits differed between drought scenarios. We evaluated multiple phenotyping schedules by adding plot and measurement error to the dynamics of biomass and canopy cover. We used these trait dynamics to fit parametric models and P-splines to extract parameters with a larger heritability than the phenotypes at individual time points. We used those parameters in multi-trait prediction models for final yield. The combined use of crop growth models and multi-trait genomic prediction models provides a procedure to assess the efficiency of phenotyping strategies and compare methods to model trait dynamics. It also allows us to quantify the impact of yield components on yield prediction accuracy even in different environment types. In scenarios with mild or no water stress, yield prediction accuracy benefitted from including biomass and green canopy cover parameters. The advantage of the multi-trait model was smaller for the early-drought scenario, due to the reduced correlation between the secondary and the target trait. Therefore, multi-trait genomic prediction models for yield require scenario-specific correlated traits. [ABSTRACT FROM AUTHOR]

Mõttus and colleagues (2017) reported evidence that the unique variance in specific personality characteristics captured by single descriptive items often displayed trait-like properties of cross-rater agreement, rank-order stability, and heritability. They suggested that the personality hierarchy should be extended below facets to incorporate these specific characteristics, called personality nuances. The present study attempted to replicate these findings, employing data from 6,287 individuals from 6 countries (Australia, Canada, Czech Republic, Denmark, Japan, and United States). The same personality measure—240-item Revised NEO Personality Inventory—and statistical procedures were used. The present findings closely replicated the original results. When the original and current results were meta-analyzed, the unique variance of nearly all items (i.e., items' scores residualized for all broader personality traits) showed statistically significant cross-rater agreement (median =.12) and rank-order stability over an average of 12 years (median =.24), and the unique variance of the majority of items had a significant heritable component (median =.14). These 3 item properties were intercorrelated, suggesting that items systematically differed in the degree of reflecting valid unique variance. Also, associations of items' unique variance with age, gender, and body mass index (BMI) replicated across samples and tracked with the original findings. Moreover, associations between item residuals and BMI obtained from one group of people allowed for a significant incremental prediction of BMI in an independent sample. Overall, these findings reinforce the hypotheses that nuances constitute the building blocks of the personality trait hierarchy, their properties are robust and they can be useful. [ABSTRACT FROM AUTHOR]

Investigations of forest community structure and dynamics have been facilitated by the use of neighbourhood models that examine the interactions between a focal tree and its neighbours using a fixed radius. However, different studies have chosen different radii without clear reasons, hampering the understanding of mechanisms structuring tree communities.Using functional trait and tree demography data from the Luquillo subtropical forest in Puerto Rico, we compared fixed‐neighbourhood models with a canopy overlap model, in which tree crown overlap is used as an indicator of neighbourhood crowding. Analyses that combine functional trait and demographic data provide a mechanistic understanding of observed patterns of community structure and dynamics as they provide insights into the linkages between phenotypes and the environment.Overall, canopy overlap models had better support when compared to neighbourhood models using a fixed radius, suggesting that the fixed radius approach does not capture the full extent of competitive interactions among trees. Moreover, the effects of functional neighbourhood on tree survival and growth differ depending on the type of approach used and lead to different conclusions with respect to the drivers of tree community dynamics.Synthesis. In summary, our findings highlight the utility of neighbourhood models based on tree crown overlap, and suggest that applying this same approach to different plots and forests will facilitate comparisons across systems and improve our understanding of the mechanisms that drive the structure and dynamics of tree communities. Our findings highlight the utility of neighbourhood models based on tree crown overlap, and suggest that applying this same approach to different plots and forests will facilitate comparisons across systems and improve our understanding of the mechanisms that drive the structure and dynamics of tree communities. [ABSTRACT FROM AUTHOR]

As distinct community assembly processes can produce similar community patterns, assessing the ecological mechanisms promoting coexistence in hyperdiverse rainforests remains a considerable challenge. We use spatially explicit neighbourhood models of tree growth to quantify how functional trait and phylogenetic similarities predict variation in growth and crowding effects for the 315 most abundant tree species in a 25-ha lowland rainforest plot in Ecuador. We find that functional trait differences reflect variation in (1) species maximum potential growth, (2) the intensity of interspecific interactions for some species, and (3) species sensitivity to neighbours. We find that neighbours influenced tree growth in 28% of the 315 focal tree species. Neighbourhood effects are not detected in the remaining 72%, which may reflect the low statistical power to model rare taxa and/or species insensitivity to neighbours. Our results highlight the spectrum of ways in which functional trait differences can shape community dynamics in highly diverse rainforests. [ABSTRACT FROM AUTHOR]

Based on a modified trait hierarchy of body-size units, the feasibility for bioassessment of water pollution using body-size distinctness of planktonic ciliates was studied in a semi-enclosed bay, northern China. An annual dataset was collected at five sampling stations within a gradient of heavy metal contaminants. Results showed that: (1) in terms of probability density, the body-size spectra of the ciliates represented significant differences among the five stations; (2) bootstrap average analysis demonstrated a spatial variation in body-size rank patterns in response to pollution stress due to heavy metals; and (3) the average body-size distinctness ( Δ z + ) and variation in body-size distinctness ( Λ z + ), based on the modified trait hierarchy, revealed a clear departure pattern from the expected body-size spectra in areas with pollutants. These results suggest that the body-size diversity measures based on the modified trait hierarchy of the ciliates may be used as a potential indicator of marine pollution. [ABSTRACT FROM AUTHOR]

The link between species' functional traits and competitive abilities has been described as a major factor structuring plant communities. However, two diverging hypotheses have been proposed to explain this process: competition-trait similarity and competition-trait hierarchy., We performed a greenhouse experiment to determine whether grasses' root foraging strategies, from acquisitive or conservative functional groups, are linked to plant competitive ability and to test which hypothesis better explains interactions during the early stage of grass establishment under contrasting growth conditions., Two grass species of each functional group were grown with and without a neighbour under two levels of water and phosphorus supplies. Three functional traits related to plant competitive ability were measured on all plants grown without neighbours: specific root length ( SRL), root phosphorus use efficiency and root length density. Above-ground biomass was measured on plants grown with and without neighbours to evaluate the intensity of plant interaction., We demonstrated that for the three traits the intensity of interaction is driven mainly by hierarchical trait distance, that is, trait distance between target and neighbour, and not by trait similarity. Growth conditions strongly affected the significance of the relation between hierarchical distances and competition intensity. For the SRL hierarchical distance, this effect may be due to the most competitive species (with high SRL) being strongly impacted by water shortage, which modified the competitive hierarchy. Trait plasticity in response to stresses also appeared an important factor influencing the competitive ability of species, that is, species with the most plastic SRL in response to P stress were also the most competitive under P stress., A strong hierarchy exists among grasses' competitive abilities in non-limiting growth conditions that is linked to their root functional traits and investment in the root system. Consequently, our results support the trait hierarchy hypothesis in its ability to describe competitive interaction among grasses during early stages of establishment., Our study provides evidence that root functional hierarchical trait distance and plasticity explain how grasses interact with their neighbours. This distance enables species to be ranked according to their competitive ability; however, this ranking may be influenced by the growth conditions and traits considered. [ABSTRACT FROM AUTHOR]

Preliminary explorations of the trait model for personality disorders provided in Diagnostic and Statistical Manual of Mental Disorders (5th ed.; DSM-5) Section III suggest that the factor structure of proposed traits includes 5 higher order factors that resemble other dimensional trait models of personality. These prior investigations have been based on self-reported data obtained from personality questionnaires, as has much of the research literature from which such trait models have evolved. However, the DSM-5 itself involves judgments made by clinicians about their patients. Thus, it is important to examine whether this factor structure identified in recent studies can also be found in clinician rating data. This study examined the hierarchical structure of the 25 proposed DSM-5 traits in patient ratings provided by a sample of 337 mental health professionals. Exploratory factor analysis revealed a hierarchical structure that resembled previously reported trait structures. As with a prior investigation by Wright et al. (2012), the various solutions estimated in the hierarchy of the DSM-5 traits resembled existing models of common mental disorders, temperament, and personality pathology. [ABSTRACT FROM AUTHOR]

Winter wheat resistance is an efficient and environmentally friendly means to controlling aphids. By using principal component analysis and correlation analysis, we evaluated the resistance of 10 winter wheat varieties or lines from three countries to the following three aphid species: Sitobion avenae, Rhopalosiphum padi, and Schizaphis graminum. The data show that Batis was susceptible to Si. avenae and R. padi, but had adverse effect on the development of Sc. graminum; Astron was advantageous to WG and rm of Si. avenae and R. padi, but not to Sc. graminum; Amigo was resistant to Sc. graminum and R. padi, but susceptible to Si. avenae; 98-10-35 was resistant to Si. avenae and R. padi, but not to Sc. graminum; 98-10-30 was adverse to growth and fecundity of Si. avenae, but better for Sc. graminum and R. padi; Xiaoyan22 was susceptible to Sc. graminum, but not to R. padi; Ww2730 were resistant to Si. avenae, but susceptible to Sc. graminum; 186tm was susceptible to R. padi, but caused high mortality for Si. avenae and Sc. graminum. Correlation analysis suggests the wheat varieties or lines that were resistant to Si. avenae were always resistant to R. padi, but susceptible to Sc. graminum. However, the overall similarities in resistance classifications were not because of the same phenotypic characters of the wheat varieties or lines. We conclude that the wheat varieties or lines had specific different resistances to the three aphid species, and the resistant traits (antibiosis) can be defined at two or more hierarchical levels. There was even a stronger "trade-off" for the comparison of Si. avenae versus Sc. graminum and R. padi versus Sc. graminum. Received: Fe [ABSTRACT FROM AUTHOR]

A multidimensional trait system has been proposed for representing personality disorder (PD) features in the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) to address problematic classification issues such as comorbidity. In this model, which may also assist in providing scaffolding for the underlying structure of major forms of psychopathology more generally, 25 primary traits are organized by 5 higher order dimensions: Negative Affect, Detachment, Antagonism, Disinhibition, and Psychoticism. We examined (a) the generalizability of the structure proposed for DSM-5 PD traits, and (b) the potential for an integrative hierarchy based upon DSM-5 PD traits to represent the dimensions scaffolding psychopathology more generally. A large sample of student participants (N = 2,461) completed the Personality Inventory for DSM-5, which operationalizes the DSM-5 traits. Exploratory factor analysis replicated the initially reported 5-factor structure, as indicated by high factor congruencies. The 2-, 3-, and 4-factor solutions estimated in the hierarchy of the DSM-5 traits bear close resemblance to existing models of common mental disorders, temperament, and personality pathology. Thus, beyond the description of individual differences in personality disorder, the trait dimensions might provide a framework for the metastructure of psychopathology in the DSM-5 and the integration of a number of ostensibly competing models of personality trait covariation. [ABSTRACT FROM AUTHOR]

Abstract: The residual structure after removing a general factor of personality (GFP) was studied using 77 scales from 8 personality inventories completed by the Eugene-Springfield Community Sample. The GFP itself loaded scales consistent with social effectiveness, such as confidence, self-directedness, empathy, achievement, and low emotional distress. Five remaining factors were rotated orthogonally. They resembled several of the so-called Big Five dimensions, including Agreeableness, Conscientiousness, and Openness to experience. Both the GFP and the supplemental factors were related to others’ ratings of the respondents, participation in specific activities, and several demographic variables. [Copyright &y& Elsevier]

Abstract: As it evolves, the World Wide Web (the Web) increasingly reveals the potential to enhance new aspects of our daily lives. While some take full advantage of the Web''s diverse and cutting edge offerings, others choose to limit the extent of their utilization to a small subset of the Web''s available functions. Recognizing this variation, a growing body of research investigates the drivers of usage behavior on the Web. Individual differences, namely broad personality and IT-specific traits, are highlighted within this stream as important predictors of Web use. Although substantial progress has been made, an important issue still facing trait research in this area is the absence of a theory-grounded basis for inter-relating broad personality and IT-specific traits. As a result, the accumulation of extant trait research is characterized by a disjointed assortment of trait constructs lacking clear theoretical linkages with one another. Additionally, while numerous studies have investigated isolated Web usage behaviors, an important outcome that remains under-investigated is the extent of an individual''s utilization of the Web overall. Addressing these issues, the current study leverages the hierarchical view of traits to develop a theory-grounded, integrative model of broad personality and IT-specific traits. After developing the hierarchical model, the integrated network of traits is positioned as a direct antecedent of Web utilization and empirically tested via a two-stage field survey of 230 Web users. The results corroborate most of the hypotheses, providing support for the hierarchical view and extending the knowledge base on Web-user behavior. Overall, this study unifies disjointed personality and IT-specific trait constructs and offers theoretical guidance for future studies, introducing a much-needed ground for cumulative tradition within this stream. [Copyright &y& Elsevier]