Individual Phenotypic Variation Research Articles

Polycystic Ovary Syndrome Markers and Mechanism

Polycystic ovary syndrome (PCOS) is a complex endocrine disorder characterized by hormonal imbalances, metabolic dysregulation, and reproductive abnormalities. This study aims to elucidate the significance of PCOS markers and their mechanisms while outlining the methodology employed. A comprehensive literature review was conducted from 2020 to 2023 using databases like PubMed, ScienceDirect, EMBASE, and Google Scholar. Key search terms included "pathophysiology," "pathogenesis," "PCOS," "marker," and "biomarker," aligned with the PICOT criteria. After removing duplicates, articles underwent a two-phase screening process based on predefined inclusion criteria. Additionally, a marker mechanism flowchart was created using the Biorender application. Results highlighted the pivotal role of various markers in understanding PCOS pathophysiology and guiding clinical management. Anthropometric, visual, metabolic, inflammatory, endocrine, and oxidative stress markers were analyzed for their diagnostic, prognostic, and therapeutic implications in PCOS. The study underscores the importance of marker interactions in personalized PCOS management. Limitations in marker interpretation warrant further research to refine diagnostic accuracy and optimize therapeutic interventions. Integrating marker mechanisms enhances understanding of PCOS heterogeneity and informs targeted treatment approaches tailored to individual phenotypic variations.

Genetic analysis of QTLs for lysine content in four maize DH populations

BackgroundLow levels of the essential amino acid lysine in maize endosperm is considered to be a major problem regarding the nutritional quality of food and feed. Increasing the lysine content of maize is important to improve the quality of food and feed nutrition. Although the genetic basis of quality protein maize (QPM) has been studied, the further exploration of the quantitative trait loci (QTL) underlying lysine content variation still needs more attention.ResultsEight maize inbred lines with increased lysine content were used to construct four double haploid (DH) populations for identification of QTLs related to lysine content. The lysine content in the four DH populations exhibited continuous and normal distribution. A total of 12 QTLs were identified in a range of 4.42–12.66% in term of individual phenotypic variation explained (PVE) which suggested the quantitative control of lysine content in maize. Five main genes involved in maize lysine biosynthesis pathways in the QTL regions were identified in this study.ConclusionsThe information presented will allow the exploration of candidate genes regulating lysine biosynthesis pathways and be useful for marker-assisted selection and gene pyramiding in high-lysine maize breeding programs.

Visualisation of gene expression within the context of tissues using an X-ray computed tomography-based multimodal approach

The development of an organism is orchestrated by the spatial and temporal expression of genes. Accurate visualisation of gene expression patterns in the context of the surrounding tissues offers a glimpse into the mechanisms that drive morphogenesis. We developed correlative light-sheet fluorescence microscopy and X-ray computed tomography approach to map gene expression patterns to the whole organism`s 3D anatomy. We show that this multimodal approach is applicable to gene expression visualized by protein-specific antibodies and fluorescence RNA in situ hybridisation offering a detailed understanding of individual phenotypic variations in model organisms. Furthermore, the approach offers a unique possibility to identify tissues together with their 3D cellular and molecular composition in anatomically less-defined in vitro models, such as organoids. We anticipate that the visual and quantitative insights into the 3D distribution of gene expression within tissue architecture, by multimodal approach developed here, will be equally valuable for reference atlases of model organisms development, as well as for comprehensive screens, and morphogenesis studies of in vitro models.

Unraveling phenotypic variance in metabolic syndrome through multi-omics.

Complex multi-omics effects drive the clustering of cardiometabolic risk factors, underscoring the imperative to comprehend how individual and combined omics shape phenotypic variation. Our study partitions phenotypic variance in metabolic syndrome (MetS), blood glucose (GLU), triglycerides (TG), high-density lipoprotein cholesterol (HDL-C), and blood pressure through genome, transcriptome, metabolome, and exposome (i.e., lifestyle exposome) analyses. Our analysis included a cohort of 62,822 unrelated individuals with white British ancestry, sourced from the UK biobank. We employed linear mixed models to partition phenotypic variance using the restricted maximum likelihood (REML) method, implemented in MTG2 (v2.22). We initiated the analysis by individually modeling omics, followed by subsequent integration of pairwise omics in a joint model that also accounted for the covariance and interaction between omics layers. Finally, we estimated the correlations of various omics effects between the phenotypes using bivariate REML. Significant proportions of the MetS variance were attributed to distinct data sources: genome (9.47%), transcriptome (4.24%), metabolome (14.34%), and exposome (3.77%). The phenotypic variances explained by the genome, transcriptome, metabolome, and exposome ranged from 3.28% for GLU to 25.35% for HDL-C, 0% for GLU to 19.34% for HDL-C, 4.29% for systolic blood pressure (SBP) to 35.75% for TG, and 0.89% for GLU to 10.17% for HDL-C, respectively. Significant correlations were found between genomic and transcriptomic effects for TG and HDL-C. Furthermore, significant interaction effects between omics data were detected for both MetS and its components. Interestingly, significant correlation of omics effect between the phenotypes was found. This study underscores omics' roles, interaction effects, and random-effects covariance in unveiling phenotypic variation in multi-omics domains.

Phenotypic evaluation of genetic resistance to the tick Rhipicephalus (Boophilus) microplus in Argentine Creole cattle

The objective of this work was to characterize the Argentine Creole cattle breed through the identification of individual phenotypic variations in the levels of infestation with Rhipicephalus (Boophilus) microplus. We evaluated 179 heifers exposed to successive artificial infestations from 2015 to 2018, achieving a total of 663 observations. Tick counts were assessed with the linear mixed model, considering year of evaluation, time of infestation, dam's age and nutritional status during the evaluated period as fixed effects. The average tick count value obtained allowed to classify the breed as highly resistant to the tick charge (99.3%). Although the previous nutritional condition of the animals did not affect the individual charge response, weight gain during the trial showed a significantly negative correlation. We conclude that the Argentine Creole breed is an attractive genetic alternative for cattle breeding in endemic regions, either as a pure breed or a cross-breed.

Hierarchical Variation in Phenotypic Flexibility across Timescales and Associated Survival Selection Shape the Dynamics of Partial Seasonal Migration.

AbstractPopulation responses to environmental variation ultimately depend on within-individual and among-individual variation in labile phenotypic traits that affect fitness and resulting episodes of selection. Yet complex patterns of individual phenotypic variation arising within and between time periods, as well as associated variation in selection, have not been fully conceptualized or quantified. We highlight how structured patterns of phenotypic variation in dichotomous threshold traits can theoretically arise and experience varying forms of selection, shaping overall phenotypic dynamics. We then fit novel multistate models to 10 years of band-resighting data from European shags to quantify phenotypic variation and selection in a key threshold trait underlying spatioseasonal population dynamics: seasonal migration versus residence. First, we demonstrate substantial among-individual variation alongside substantial between-year individual repeatability in within-year phenotypic variation ("flexibility"), with weak sexual dimorphism. Second, we demonstrate that between-year individual variation in within-year phenotypes ("supraflexibility") is structured and directional, consistent with the threshold trait model. Third, we demonstrate strong survival selection on within-year phenotypes-and hence on flexibility-that varies across years and sexes, including episodes of disruptive selection representing costs of flexibility. By quantitatively combining these results, we show how supraflexibility and survival selection on migratory flexibility jointly shape population-wide phenotypic dynamics of seasonal movement.

Epigenetic Modifications May Regulate the Activation of the Hypopharyngeal Gland of Honeybees (Apis Mellifera) During Winter.

DNA methylation is an epigenetic modification primarily responsible for individual phenotypic variation. This modification has been reported to play an important role in caste, brain plasticity, and body development in honeybees (Apis mellifera). Here, we report the DNA methylation profile of honeybee hypopharyngeal glands, from atrophy in winter to arousal in the following spring, through the use of whole-genome bisulfite sequencing. Consistent with previous studies in other Apis species, we found low methylation levels of the hypopharyngeal gland genome that were mostly of the CG type. Notably, we observed a strong preference for CpG methylation, which was localized in promoters and exon regions. This result further indicated that, in honeybees, DNA methylation may regulate gene expression by mediating alternative splicing, in addition to silencing gene in the promoter regions. After assessment by correlation analysis, we identified seven candidate proteins encoded by differentially methylated genes, including aristaless-related homeobox, forkhead box protein O, headcase, alpha-amylase, neural-cadherin, epidermal growth factor receptor, and aquaporin, which are reported to be involved in cell growth, proliferation, and differentiation. Hypomethylation followed by upregulated expression of these candidates suggested that DNA methylation may play significant roles in the activation of hypopharyngeal glands in overwintering honeybees. Overall, this study elucidates epigenetic modification differences in honeybee hypopharyngeal glands by comparing an inactive winter state to an aroused state in the following spring, which could provide further insight into the evolution of insect sociality and regulatory plasticity.

Are There Different Phenotypes in Geographic Atrophy of AMD? - Pilot Study on Differentiation Using Multimodal Imaging

Geographic atrophy (GA) in patients with age-related macular degeneration (AMD) involves a loss of photoreceptors (PR), retinal pigment epithelium (RPE) and choriocapillaris (CC). For treatment decisions, it is crucial to discern which of these layers the damage originates, subsequently spreading to the others. It has long been thought that the RPE, with its accumulation of lipofuscin, is the site of primary damage in the development of GA. However, histological studies have shown that in some patients, the PR are affected first, followed by secondary damage to the RPE and CC, and in others regression of the CC is the first manifestation. The aim of this study was to use multimodal imaging to determine the extent of the damage at the levels of the PR, RPE and CC, to characterise the individual phenotypic variations of GA and to investigate the corresponding functional impairment. Twenty eyes of 20 patients (mean age 78 years; 14 female, 6 male) with the clinical diagnosis of GA were examined by means of fundus autofluorescence (FAF) to evaluate the damage to the RPE, en face SD-OCT at the level of the PR to characterise the area of cell loss in this layer and OCT angiography (OCT-A, AngioVue, Optovue; 50 µm CC-segmentation with localization below the RPE) to assess regression of the CC. The affected area of each layer was measured. Best-corrected visual acuity (BCVA) test and fundus correlated automated 10° microperimetry (MAIA Microperimetry, CENTERVUE; 4-2 strategy, 68 stimuli) were performed in all patients. The results of these examinations were evaluated and correlated. All eyes showed a different extent of the areas of atrophy in the PR, RPE and CC. The layer with the largest area of atrophy was the RPE in 13 eyes (65%), the PR in 3 eyes (15%) and the CC in 4 eyes (20%). While the visual loss depended entirely on the presence of foveal sparing, microperimetry revealed a correlation between the extent of detectable functional deficit and the largest atrophic area. Multimodal imaging with FAF, en face OCT, OCT-A and a correlation with microperimetry enables a clinical phenotypic differentiation in GA as well as a more precise characterisation of the associated functional impairment. This confirms clinically the histologically demonstrated diversity of the damaged structure (PR, RPE or CC) in patients with GA. However, the variations identified in this pilot study must be confirmed in Reading Center-based larger cohorts. The approach described here may lead to differentiated consideration of the anatomical and functional aspects of the disease and turn out to be helpful in patient selection as well as in identifying and monitoring future therapeutic approaches.

Computational 3D histological phenotyping of whole zebrafish by X-ray histotomography.

Organismal phenotypes frequently involve multiple organ systems. Histology is a powerful way to detect cellular and tissue phenotypes, but is largely descriptive and subjective. To determine how synchrotron-based X-ray micro-tomography (micro-CT) can yield 3-dimensional whole-organism images suitable for quantitative histological phenotyping, we scanned whole zebrafish, a small vertebrate model with diverse tissues, at ~1 micron voxel resolutions. Micro-CT optimized for cellular characterization (histotomography) allows brain nuclei to be computationally segmented and assigned to brain regions, and cell shapes and volumes to be computed for motor neurons and red blood cells. Striking individual phenotypic variation was apparent from color maps of computed densities of brain nuclei. Unlike histology, the histotomography also allows the study of 3-dimensional structures of millimeter scale that cross multiple tissue planes. We expect the computational and visual insights into 3D cell and tissue architecture provided by histotomography to be useful for reference atlases, hypothesis generation, comprehensive organismal screens, and diagnostics.

The Utility of Rodent Models of Stress for Disentangling Individual Vulnerability to Depression and Cardiovascular Comorbidity.

This review offers a perspective of the utility of rodent models of stress for identifying sources of individual vulnerability to depression and cardiovascular disease comorbidity. Differential stress susceptibility is found in rodents exposed to repeated social defeat as a function of their coping style. Specifically, passive coping rodents show an increase in inflammatory processes within the brain that favour the development of depressive-like symptoms and cardiovascular abnormalities. Similarly, only a sub-group of rats develops depressive-like symptoms following chronic mild stress exposure. Cardiovascular changes differ depending on individual stress susceptibility and may be related to an imbalance in the autonomic regulation of cardiac function in stress vulnerable subjects. Rodent models of stress that take into account individual phenotypic variations are useful for a better understanding of the role of neuroinflammatory and autonomic processes in the development of comorbid depression and cardiovascular disease under stressful conditions.

Phenotypic determinants of inter‐individual variability of litter consumption rate in a detritivore population

The metabolic theory of ecology predicts resource consumption rates of animals from their body mass, but other phenotypic traits might affect individual resource consumption rate. In this paper, we used a hierarchical framework to examine relationships between phenotypic traits thought to constrain variation in per capita resource consumption rate. Physiological and behavioural traits were assumed to be important in mediating the control of morphology and sex on consumption. We conducted a longitudinal study aiming to relate the consumption rate of submerged leaf litter to sex, morphological, physiological and behavioural traits in an aquatic detritivore population. Then, we analysed the pattern of trait covariation using structural equation modelling (SEM). We observed broad and repeatable inter‐individual variation in leaf consumption rate and other phenotypic traits. We found that expressing litter consumption rate relative to the time individuals spent feeding revealed and increased the effect of body mass and sex differences, respectively. Accordingly, SEM analyses showed that time allocated to resource acquisition mediated body mass and sex effects on apparent litter consumption rate whose variation was also accounted for by an indicator of activity‐specific metabolic rate. Substantial variation in resource consumption rate was due to sex difference whereas body mass was of secondary importance. Individual phenotypic trait variations strongly altered consumer–resource relationships. Therefore, we encourage studies on consumers’ intraspecific variability to advance knowledge about phenotypic determinants of individual resource consumption, an important link between individuals and ecosystems.

Thermal plasticity due to parental and early-life environments in the jacky dragon (Amphibolurus muricatus).

Developmental plasticity creates marked variation in individual phenotypes when the environment is patchy, such as when the thermal environment varies. Plasticity may occur in response to the environment experienced during an individual's lifetime or to the environment experienced by parents (transgenerational plasticity), and may be adaptive if it enhances fitness. In particular, plasticity in thermal traits, such as preferred temperatures and thermal limits, may improve performance and fitness based on temperatures in the local environment. This study examined the influence of parental and offspring thermal environments (duration of access to a basking lamp) on offspring thermal traits (preferred temperatures and panting threshold) in jacky dragons (Agamidae: Amphibolurus muricatus). Long-bask parental environments led, indirectly, to higher preferred temperatures of offspring due to increased offspring body mass compared to offspring of short-bask parents. The increase in median temperature preference was associated with a higher voluntary minimum body temperature and a narrower preference range, suggesting tradeoffs in thermal behavior and a matching of offspring preferences to the parental environment. Parental thermal treatment did not influence offspring panting threshold. Instead, the panting threshold tended to be higher in offspring that were reared in the long-bask treatment compared to those in the short-bask treatment, suggesting longer basking environments increased thermal tolerance. Parental and offspring thermal environment did not exhibit any interactive effect on thermal traits. The results indicate that thermal environments experienced by lizards can have both transgenerational and within-generation impacts on thermal traits, thus influencing how populations respond to fluctuating or changing climates.

Early Homo, plasticity and the extended evolutionary synthesis.

The Modern Synthesis led to fundamental advances in understandings of human evolution. For human palaeontology, a science that works from ancestral phenotypes (i.e. the fossil record), particularly important have been perspectives used to help understand the heritable aspects of phenotypes and how fossil individuals might then be aggregated into species, and relationships among these groups understood. This focus, coupled with the fragmentary nature of the fossil record, however, means that individual phenotypic variation is often treated as unimportant 'noise', rather than as a source of insight into population adaptation and evolutionary process. The emphasis of the extended evolutionary synthesis on plasticity as a source of phenotypic novelty, and the related question of the role of such variation in long-term evolutionary trends, focuses welcome attention on non-genetic means by which novel phenotypes are generated and in so doing provides alternative approaches to interpreting the fossil record. We review evidence from contemporary human populations regarding some of the aspects of adult phenotypes preserved in the fossil record that might be most responsive to non-genetic drivers, and we consider how these perspectives lead to alternate hypotheses for interpreting the fossil record of early genus Homo. We conclude by arguing that paying closer attention to the causes and consequences of intraspecific phenotypic variation in its own right, as opposed to as noise around a species mean, may inspire a new generation of hypotheses regarding species diversity in the Early Pleistocene and the foundations for dispersal and regional diversification in Homo erectus and its descendants.

(Re)appreciating the role of life history in eco‐evolutionary dynamics

(Re)appreciating the role of life history in eco‐evolutionary dynamics

LemurFaceID: a face recognition system to facilitate individual identification of lemurs

BackgroundLong-term research of known individuals is critical for understanding the demographic and evolutionary processes that influence natural populations. Current methods for individual identification of many animals include capture and tagging techniques and/or researcher knowledge of natural variation in individual phenotypes. These methods can be costly, time-consuming, and may be impractical for larger-scale, population-level studies. Accordingly, for many animal lineages, long-term research projects are often limited to only a few taxa. Lemurs, a mammalian lineage endemic to Madagascar, are no exception. Long-term data needed to address evolutionary questions are lacking for many species. This is, at least in part, due to difficulties collecting consistent data on known individuals over long periods of time. Here, we present a new method for individual identification of lemurs (LemurFaceID). LemurFaceID is a computer-assisted facial recognition system that can be used to identify individual lemurs based on photographs.ResultsLemurFaceID was developed using patch-wise Multiscale Local Binary Pattern features and modified facial image normalization techniques to reduce the effects of facial hair and variation in ambient lighting on identification. We trained and tested our system using images from wild red-bellied lemurs (Eulemur rubriventer) collected in Ranomafana National Park, Madagascar. Across 100 trials, with different partitions of training and test sets, we demonstrate that the LemurFaceID can achieve 98.7% ± 1.81% accuracy (using 2-query image fusion) in correctly identifying individual lemurs.ConclusionsOur results suggest that human facial recognition techniques can be modified for identification of individual lemurs based on variation in facial patterns. LemurFaceID was able to identify individual lemurs based on photographs of wild individuals with a relatively high degree of accuracy. This technology would remove many limitations of traditional methods for individual identification. Once optimized, our system can facilitate long-term research of known individuals by providing a rapid, cost-effective, and accurate method for individual identification.

Environmental influence on the phenotype of ant workers revealed by common garden experiment

Many organism traits vary along environmental gradients. Common garden experiments provide powerful means to disentangle the role of intrinsic factors, such as genetic or maternal effects, from extrinsic environmental factors in shaping phenotypic variation. Here, we investigate body size and lipid content variation in workers of the socially polymorphic ant Formica selysi along several independent elevation gradients in Switzerland. We compare field-collected workers and workers sampled as eggs from the same colonies but reared in common laboratory conditions. Overall, field-collected workers from high elevation are larger than those from low elevation, but the trend varies substantially among valleys. The same pattern is recovered when the eggs are reared in a common garden, which indicates that body size variation along elevation gradients and valleys is partly explained by genetic or maternal effects. However, both body size and lipid content exhibit significantly greater variation in field-collected workers than in laboratory-reared workers. Hence, much of the phenotypic variation results from a plastic response to the environment, rather than from genetic differences. Eggs from different elevations also show no significant difference in development time in the common garden. Overall, selection on individual worker phenotypes is unlikely to drive the altitudinal distribution of single- and multiple-queen colonies in this system, as phenotypic variation tends to be plastic and can be decoupled from social structure. This study provides insights into the interplay between individual phenotypic variation and social organization and how the two jointly respond to differing environmental conditions.

Interactions between a Candidate Gene for Migration (ADCYAP1), Morphology and Sex Predict Spring Arrival in Blackcap Populations.

Avian research has begun to reveal associations between candidate genes and migratory behaviors of captive birds, yet few studies utilize genotypic, morphometric, and phenological data from wild individuals. Previous studies have identified an association between ADCYAP1 polymorphism and autumn migratory behavior (restlessness, or zugunruhe), but little is known about the relationship between ADCYAP1 and spring migratory behavior. The timing of spring migration and arrival to the breeding ground are phenological traits which could be particularly favorable for establishing territories and acquiring mates, thus important to fitness and reproductive success. Here, we investigated how individual genotypic ADCYAP1 variation and phenotypic variation (wing length and shape) of blackcaps (Sylvia atricapilla) affect spring arrival date across nine natural populations in Europe. We hypothesized that longer alleles should be associated with earlier spring arrival dates and expected the effect on arrival date to be stronger for males as they arrive earlier. However, we found that longer wings were associated with earlier spring arrival to the breeding grounds for females, but not for males. Another female-specific effect indicated an interaction between ADCYAP1 allele size and wing pointedness on the response of spring arrival: greater allele size had a positive effect on spring arrival date for females with rounder wings, while a negative effect was apparent for females with more pointed wings. Also, female heterozygotes with pointed wing tips arrived significantly earlier than both homozygotes with pointed wings and heterozygotes with round wings. Stable isotope ratios (δ 2 H) of a subset of blackcaps captured in Freiburg in 2011 allowed us also to assign individuals to their main overwintering areas in northwest (NW) and southwest (SW) Europe. NW males arrived significantly earlier to the Freiburg breeding site than both SW males and females in 2011. NW females had more pointed wing tips compared to SW females, but no difference in ADCYAP1 allele size was found between the different migration routes.

Genetic recapitulation of human pre-eclampsia risk during convergent evolution of reduced placental invasiveness in eutherian mammals

The relationship between phenotypic variation arising through individual development and phenotypic variation arising through diversification of species has long been a central question in evolutionary biology. Among humans, reduced placental invasion into endometrial tissues is associated with diseases of pregnancy, especially pre-eclampsia, and reduced placental invasiveness has also evolved, convergently, in at least 10 lineages of eutherian mammals. We tested the hypothesis that a common genetic basis underlies both reduced placental invasion arising through a developmental process in human placental disease and reduced placental invasion found as a derived trait in the diversification of Euarchontoglires (rodents, lagomorphs, tree shrews, colugos and primates). Based on whole-genome analyses across 18 taxa, we identified 1254 genes as having evolved adaptively across all three lineages exhibiting independent evolutionary transitions towards reduced placental invasion. These genes showed strong evidence of enrichment for associations with pre-eclampsia, based on genetic-association studies, gene-expression analyses and gene ontology. We further used in silico prediction to identify a subset of 199 genes that are likely targets of natural selection during transitions in placental invasiveness and which are predicted to also underlie human placental disorders. Our results indicate that abnormal ontogenies can recapitulate major phylogenetic shifts in mammalian evolution, identify new candidate genes for involvement in pre-eclampsia, imply that study of species with less-invasive placentation will provide useful insights into the regulation of placental invasion and pre-eclampsia, and recommend a novel comparative functional-evolutionary approach to the study of genetically based human disease and mammalian diversification.

Predictors of Individual Variation in Movement in a Natural Population of Threespine Stickleback (Gasterosteus aculeatus).

Species abundances and distributions are inherently tied to individuals' decisions about movement within their habitat. Therefore, integrating individual phenotypic variation within a larger ecological framework may provide better insight into how populations structure themselves. Recent evidence for consistent individual differences in behaviour prompts the hypothesis that variation in behavioural types might be related to variation in movement in natural environments. In a multiyear mark-recapture study, we found that individual sticklebacks exhibited consistent individual differences in behaviour both within a standardized testing arena designed to measure exploratory behaviour and within a river. Therefore, we asked whether individual differences in movement in a natural river were related to an individual's exploratory behavioural type. We also considered whether body condition and/or the individual's habitat or social environment use was related to movement. There was no evidence that an individual's exploratory behavioural type was related to movement within the river. Instead, an individual's habitat use and body condition interacted to influence natural movement patterns. Individuals in good condition were more likely to move further in the river, but only if they inhabited a vegetated complex part of the river; body condition had no influence on movement in those individuals inhabiting open areas of the river. Our results suggest that individual traits could help improve predictions about how populations may distribute themselves within patchy and complex environments.

Individual phenotypic variation reduces interaction strengths in a consumer–resource system

Natural populations often show variation in traits that can affect the strength of interspecific interactions. Interaction strengths in turn influence the fate of pairwise interacting populations and the stability of food webs. Understanding the mechanisms relating individual phenotypic variation to interaction strengths is thus central to assess how trait variation affects population and community dynamics. We incorporated nonheritable variation in attack rates and handling times into a classical consumer–resource model to investigate how variation may alter interaction strengths, population dynamics, species persistence, and invasiveness. We found that individual variation influences species persistence through its effect on interaction strengths. In many scenarios, interaction strengths decrease with variation, which in turn affects species coexistence and stability. Because environmental change alters the direction and strength of selection acting upon phenotypic traits, our results have implications for species coexistence in a context of habitat fragmentation, climate change, and the arrival of exotic species to native ecosystems.