ORCID Profile
0000-0001-7186-5288
Current Organisation
French National Centre for Scientific Research
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In Research Link Australia (RLA), "Research Topics" refer to ANZSRC FOR and SEO codes. These topics are either sourced from ANZSRC FOR and SEO codes listed in researchers' related grants or generated by a large language model (LLM) based on their publications.
Evolutionary Impacts of Climate Change | Population, Ecological and Evolutionary Genetics | Genetics | Quantitative Genetics (incl. Disease and Trait Mapping Genetics)
Ecosystem Adaptation to Climate Change | Effects of Climate Change and Variability on Australia (excl. Social Impacts) | Expanding Knowledge in the Biological Sciences |
Publisher: Elsevier BV
Date: 08-2017
DOI: 10.1016/J.JHIN.2017.05.005
Abstract: Sepsis is a condition widely observed outside critical care areas. To examine the application of sepsis screening tools for early recognition of sepsis in general hospitalized patients to: (i) identify the accuracy of these tools (ii) determine the outcomes associated with their implementation and (iii) describe the implementation process. A systematic review method was used. PubMed, CINAHL, Cochrane, Scopus, Web of Science, and Embase databases were systematically searched for primary articles, published from January 1990 to June 2016, that investigated screening tools or alert mechanisms for early identification of sepsis in adult general hospitalized patients. The review protocol was registered with PROSPERO (CRD42016042261). More than 8000 citations were screened for eligibility after duplicates had been removed. Six articles met the inclusion criteria testing two types of sepsis screening tools. Electronic tools can capture, recognize abnormal variables, and activate an alert in real time. However, accuracy of these tools was inconsistent across studies with only one demonstrating high specificity and sensitivity. Paper-based, nurse-led screening tools appear to be more sensitive in the identification of septic patients but were only studied in small s les and particular populations. The process of care measures appears to be enhanced however, demonstrating improved outcomes is more challenging. Implementation details are rarely reported. Heterogeneity of studies prevented meta-analysis. Clinicians, researchers and health decision-makers should consider these findings and limitations when implementing screening tools, research or policy on sepsis recognition in general hospitalized patients.
Publisher: American Association for the Advancement of Science (AAAS)
Date: 27-05-2022
Abstract: The rate of adaptive evolution, the contribution of selection to genetic changes that increase mean fitness, is determined by the additive genetic variance in in idual relative fitness. To date, there are few robust estimates of this parameter for natural populations, and it is therefore unclear whether adaptive evolution can play a meaningful role in short-term population dynamics. We developed and applied quantitative genetic methods to long-term datasets from 19 wild bird and mammal populations and found that, while estimates vary between populations, additive genetic variance in relative fitness is often substantial and, on average, twice that of previous estimates. We show that these rates of contemporary adaptive evolution can affect population dynamics and hence that natural selection has the potential to partly mitigate effects of current environmental change.
Publisher: California Digital Library (CDL)
Date: 03-05-2022
Publisher: Oxford University Press (OUP)
Date: 14-09-2023
Publisher: Springer Science and Business Media LLC
Date: 03-01-2021
Publisher: Oxford University Press (OUP)
Date: 06-2019
Abstract: Additive genetic variance in relative fitness (σA2(w)) is arguably the most important evolutionary parameter in a population because, by Fisher’s fundamental theorem of natural selection (FTNS Fisher RA. 1930. The genetical theory of natural selection. 1st ed. Oxford: Clarendon Press), it represents the rate of adaptive evolution. However, to date, there are few estimates of σA2(w) in natural populations. Moreover, most of the available estimates rely on Gaussian assumptions inappropriate for fitness data, with unclear consequences. “Generalized linear animal models” (GLAMs) tend to be more appropriate for fitness data, but they estimate parameters on a transformed (“latent”) scale that is not directly interpretable for inferences on the data scale. Here we exploit the latest theoretical developments to clarify how best to estimate quantitative genetic parameters for fitness. Specifically, we use computer simulations to confirm a recently developed analog of the FTNS in the case when expected fitness follows a log-normal distribution. In this situation, the additive genetic variance in absolute fitness on the latent log-scale (σA2(l)) equals (σA2(w)) on the data scale, which is the rate of adaptation within a generation. However, due to inheritance distortion, the change in mean relative fitness between generations exceeds σA2(l) and equals (exp(σA2(l))−1). We illustrate why the heritability of fitness is generally low and is not a good measure of the rate of adaptation. Finally, we explore how well the relevant parameters can be estimated by animal models, comparing Gaussian models with Poisson GLAMs. Our results illustrate 1) the correspondence between quantitative genetics and population dynamics encapsulated in the FTNS and its log-normal-analog and 2) the appropriate interpretation of GLAM parameter estimates.
Publisher: California Digital Library (CDL)
Date: 12-06-2020
Publisher: Mark Allen Group
Date: 02-01-2017
DOI: 10.12968/JOWC.2017.26.1.28
Abstract: Surgical site infections (SSIs) are serious postoperative complications that may lead to undesired patient outcomes. Previous research has used survey and chart audit methods to describe wound care practices. However, little research has been published using contemporaneous observations to describe the surgical wound management practices of nurses. The aim of this study was to prospectively describe surgical nurses' postoperative wound care practices and the extent to which observed surgical wound practices aligned with evidence-based guideline recommendations. In this cross-sectional prospective study, we observed a convenience s le of 60 nurses from four surgical units using a specifically developed observational audit tool. Inter-rater reliability for this tool was assessed during the observation period. Of 60 observed episodes of wound care, post-procedure hand hygiene (n=49, 81.7%) was less evident compared with pre-procedure hand hygiene practice (n=57, 95%). Over one-third of nurses observed did not correctly use clean gloves (n=16, 38.1%) and one in five did not properly use sterile gloves (n=4, 22%). More than half of surgical nurses (n=37, 61.7%) did not educate patients on post-discharge wound management. Fewer than a quarter (n=14, 23.3%) of wound care events were recorded on both wound assessment charts and patients' progress notes. Inter-rater reliability testing indicated good agreement (intra-class correlation coefficient 0.859 95% CI: 0.771–0.923 p .0005). Despite surgical wound care guideline recommendations on aseptic technique compliance, patient education, wound assessment and documentation practices, there is a clear gap between recommended and observed wound care practice. This study highlights an area where clinical practice is not reflective of evidence-based recommendations, suggesting that to minimise SSI as an adverse event, practice should be evaluated and strategies incorporating evidence into practice are explored.
Publisher: Wiley
Date: 18-03-2016
DOI: 10.1111/JAN.12953
Abstract: To describe an integrative review protocol to analyse and synthesize peer-reviewed research evidence in relation to engagement of patients and their families in communication during transitions of care to, in and from acute care settings. Communication at transitions of care in acute care settings can be complex and challenging, with important information about patients not always clearly transferred between responsible healthcare providers. Involving patients and their families in communication during transitions of care may improve the transfer of clinical information and patient outcomes and prevent adverse events during hospitalization and following discharge. Recently, optimizing patient and family participation during care transitions has been acknowledged as central to the implementation of patient-centred care. Integrative review with potential for meta-analysis and application of framework synthesis. The review will evaluate and synthesize qualitative and quantitative research evidence identified through a systematic search. Primary studies will be selected according to inclusion criteria. Data collection, quality appraisal and analysis of the evidence will be conducted by at least two authors. Nine electronic databases (including CINAHL and Medline) will be searched. The search will be restricted to 10 years up to December 2013. Data analysis will include content and thematic analysis. The review will seek to identify all types of patient engagement activities employed during transitions of care communication. The review will identify enablers for and barriers to engagement for patients, families and health professionals. Key strategies and tools for improving patient engagement, clinical communication and promoting patient-centred care will be recommended based on findings.
Publisher: California Digital Library (CDL)
Date: 16-05-2019
Publisher: Public Library of Science (PLoS)
Date: 26-01-2017
Publisher: Springer Science and Business Media LLC
Date: 12-04-2023
DOI: 10.1186/S12862-023-02113-1
Abstract: The shape of the semicircular canals of the inner ear of living squamate reptiles has been used to infer phylogenetic relationships, body size, and life habits. Often these inferences are made without controlling for the effects of the other ones. Here we examine the semicircular canals of 94 species of extant limbed lepidosaurs using three-dimensional landmark-based geometric morphometrics, and analyze them in phylogenetic context to evaluate the relative contributions of life habit, size, and phylogeny on canal shape. Life habit is not a strong predictor of semicircular canal shape across this broad s le. Instead, phylogeny plays a major role in predicting shape, with strong phylogenetic signal in shape as well as size. Allometry has a limited role in canal shape, but inner ear size and body mass are strongly correlated. Our wide s ling across limbed squamates suggests that semicircular canal shape and size are predominantly a factor of phylogenetic relatedness. Given the small proportion of variance in semicircular canal shape explained by life habit, it is unlikely that unknown life habit could be deduced from semicircular canal shape alone. Overall, semicircular canal size is a good estimator of body length and even better for body mass in limbed squamates. Semiaquatic taxa tend to be larger and heavier than non-aquatic taxa, but once body size and phylogeny are accounted for, they are hard to distinguish from their non-aquatic relatives based on bony labyrinth shape and morphology.
Publisher: Elsevier BV
Date: 09-2013
Publisher: University of Chicago Press
Date: 2016
DOI: 10.1086/684158
Abstract: Heterogeneity in fitness components consists of fixed heterogeneity due to latent differences fixed throughout life (e.g., genetic variation) and dynamic heterogeneity generated by stochastic variation. Their relative magnitude is crucial for evolutionary processes, as only the former may allow for adaptation. However, the importance of fixed heterogeneity in small populations has recently been questioned. Using neutral simulations (NS), several studies failed to detect fixed heterogeneity, thus challenging previous results from mixed models (MM). To understand the causes of this discrepancy, we estimate the statistical power and false positive rate of both methods and apply them to empirical data from a wild rodent population. While MM show high false-positive rates if confounding factors are not accounted for, they have high statistical power to detect real fixed heterogeneity. In contrast, NS are also subject to high false-positive rates but always have low power. Indeed, MM analyses of the rodent population data show significant fixed heterogeneity in reproductive success, whereas NS analyses do not. We suggest that fixed heterogeneity may be more common than is suggested by NS and that NS are useful only if more powerful methods are not applicable and if they are complemented by a power analysis.
Publisher: Wiley
Date: 20-09-2016
Publisher: Wiley
Date: 18-07-2011
Publisher: Elsevier BV
Date: 08-2018
Publisher: Elsevier BV
Date: 02-2023
Publisher: Oxford University Press (OUP)
Date: 2016
Publisher: Wiley
Date: 16-02-2018
DOI: 10.1111/JEB.13246
Abstract: Temporal fluctuations in the strength and direction of selection are often proposed as a mechanism that slows down evolution, both over geological and contemporary timescales. Both the prevalence of fluctuating selection and its relevance for evolutionary dynamics remain poorly understood however, especially on contemporary timescales: unbiased empirical estimates of variation in selection are scarce, and the question of how much of the variation in selection translates into variation in genetic change has largely been ignored. Using long-term in idual-based data for a wild rodent population, we quantify the magnitude of fluctuating selection on body size. Subsequently, we estimate the evolutionary dynamics of size and test for a link between fluctuating selection and evolution. We show that, over the past 11 years, phenotypic selection on body size has fluctuated significantly. However, the strength and direction of genetic change have remained largely constant over the study period that is, the rate of genetic change was similar in years where selection favoured heavier vs. lighter in iduals. This result suggests that over shorter timescales, fluctuating selection does not necessarily translate into fluctuating evolution. Importantly however, in idual-based simulations show that the correlation between fluctuating selection and fluctuating evolution can be obscured by the effect of drift, and that substantially more data are required for a precise and accurate estimate of this correlation. We identify new challenges in measuring the coupling between selection and evolution, and provide methods and guidelines to overcome them.
Publisher: Springer Science and Business Media LLC
Date: 17-05-2011
Publisher: Wiley
Date: 16-08-2017
DOI: 10.1111/EVO.13296
Abstract: Hybridization is increasingly recognized as a significant evolutionary process, in particular because it can lead to introgression of genes from one species to another. A striking pattern of discordance in the amount of introgression between mitochondrial and nuclear markers exists such that substantial mitochondrial introgression is often found in combination with no or little nuclear introgression. Multiple mechanisms have been proposed to explain this discordance, including positive selection for introgressing mitochondrial variants, several types of sex-biases, drift, negative selection against introgression in the nuclear genome, and spatial expansion. Most of these hypotheses are verbal, and have not been quantitatively evaluated so far. We use in idual-based, multilocus, computer simulations of secondary contact under a wide range of demographic and genetic scenarios to evaluate the ability of the different mechanisms to produce discordant introgression. Sex-biases and spatial expansions fail to produce substantial mito-nuclear discordance. Drift and nuclear selection can produce strong discordance, but only under a limited range of conditions. In contrast, selection on the mitochondrial genome produces strong discordance, particularly when dispersal rates are low. However, commonly used statistical tests have little power to detect this selection. Altogether, these results dismiss several popular hypotheses, and provide support for adaptive mitochondrial introgression.
Publisher: Elsevier BV
Date: 05-2019
Publisher: Elsevier BV
Date: 05-2019
DOI: 10.1016/J.AUCC.2018.03.009
Abstract: Transitioning a patient from the operating theatre (OT) to the intensive care unit (ICU) is a dynamic and complex process. Handover of the critically ill postoperative patient can contribute to procedural and communication errors. Standardised protocols are means for structuring and improving handover content. Both have been shown to be effective in reducing information omission and improve communication during this transition period. The aim of this uncontrolled before and after study was to improve handover processes and communication about the care for critically ill patients transferred from OT to ICU. Thirty-two OT to ICU handovers (16 before and 16 after implementation) were observed. Using a structured tool, we documented who was present, participated in, and initiated handover during ICU admission. Where and when handover was performed, information provided, distractions and interruptions, and handover duration were also recorded. Unstructured field notes and diagrams provided information on staff interaction. Following implementation, semistructured interviews with 27 participants were conducted to understand participants' perceptions of intervention acceptability and to determine factors influencing intervention implementation and spread. Following implementation, a "hands-off" approach was observed with fewer technical tasks completed during handover (43.8% before implementation vs 12.5% after implementation) without an increase in handover time. A single, multidisciplinary handover most often led by the anaesthetist was observed after implementation. Despite these improvements, the use of the physical checklist was not observed in practice, and an situation, background, assessment, recommendation (SBAR) format was not followed. Anaesthetists leading the handover did not view the handover checklist as being beneficial to their practice although some nurses were observed to use the checklist as a prompt for additional information. A single, multidisciplinary handover demonstrated improvement in handover practice despite low uptake of the protocol checklist. Further information is required to inform targeted strategies to improve uptake and sustainability although broader interdisciplinary engagement and commitment may be helpful.
Publisher: Wiley
Date: 29-08-2018
DOI: 10.1111/EVO.13573
Abstract: Quantitative genetic analyses require extensive measurements of phenotypic traits, a task that is often not trivial, especially in wild populations. On top of instrumental measurement error, some traits may undergo transient (i.e., nonpersistent) fluctuations that are biologically irrelevant for selection processes. These two sources of variability, which we denote here as measurement error in a broad sense, are possible causes for bias in the estimation of quantitative genetic parameters. We illustrate how in a continuous trait transient effects with a classical measurement error structure may bias estimates of heritability, selection gradients, and the predicted response to selection. We propose strategies to obtain unbiased estimates with the help of repeated measurements taken at an appropriate temporal scale. However, the fact that in quantitative genetic analyses repeated measurements are also used to isolate permanent environmental instead of transient effects requires that the information content of repeated measurements is carefully assessed. To this end, we propose to distinguish "short-term" from "long-term" repeats, where the former capture transient variability and the latter help isolate permanent effects. We show how the inclusion of the corresponding variance components in quantitative genetic models yields unbiased estimates of all quantities of interest, and we illustrate the application of the method to data from a Swiss snow vole population.
Publisher: University of Chicago Press
Date: 2021
DOI: 10.1086/711755
Publisher: Elsevier BV
Date: 11-2015
Publisher: Wiley
Date: 29-12-2015
DOI: 10.1111/OIK.03026
Publisher: Wiley
Date: 25-09-2022
DOI: 10.1111/GEB.13591
Abstract: Organisms in arid and semi‐arid regions are frequently exposed to climatic extremes and accordingly among the most vulnerable to climate change. Studies of seasonal differences in vital rates, which mediate effects of climate on viability, are rare in arid species, limiting ability to project population trends. We quantified survival patterns for two bird communities as a function of exposure to temperature extremes in winter and summer, then projected survival patterns to 2104. Semi‐arid eastern Australia. 1986–2016 1986–2104. Birds. Using mark–recapture time‐dependent Cormack–Jolly–Seber models and data for 37 species from two ‐year ringing programmes, we tested for effects on 6‐monthly survival of exposure to temperatures and °C. We then predicted future survival for different emission scenarios, testing whether changes in survival associated with warming winters would be sufficient to offset the effects of rising summer temperatures. Survival probability declined strongly with increasing exposure to days °C and to a lesser extent to days °C, with temperature extremes explaining 43 and 13% of temporal variation in survival among years, respectively. Summer survival patterns were similar across avian guilds but only survival of nectarivores declined in winter. Our models predict that gains in winter survival will not offset reductions in summer survival. Annual survival is predicted to decline substantially by the end of the century: from .63 in 1986 to .43 in 2104 under an optimistic emission scenario and to .11 under a pessimistic scenario. We highlight the significance of temperature extremes for species' persistence in arid and semi‐arid regions, comprising 70% of Australia's landmass, and 40% globally. Our demography‐based results are consistent with physiological‐based projections evaluating avian survival in arid and semi‐arid regions globally and suggest rising summer temperatures pose a risk to population persistence in these regions.
Publisher: Oxford University Press (OUP)
Date: 07-10-2020
Abstract: Should females prefer older males as mates? Male survival to old age might indicate the presence of fitness-enhancing genes that increase offspring fitness. However, many correlational studies show that mating with older males can lower female fecundity and even reduce offspring fitness due to epigenetic or germline mutation effects. One problem in quantifying female choice based on male age is that age is usually confounded with mating history. This begs a question: Do females choose males based on their age or their mating history? The answer requires an experimental approach, but few such studies exist. Here, we test if experimentally induced variation in the mating history of old and young males (12-week difference in postmaturity age) affects female choice in the eastern mosquitofish (Gambusia holbrooki). To vary mating history, adult males were either allowed to freely mate with females for 3 weeks or they only had visual contact with females. Immediately thereafter, we ran four-choice mating trials, using association time, to test the effects of male age and mating history (2 × 2 design) on male attractiveness. Females did not show a clear preference for males based on either characteristic. This was not due to a lack of female choice: females spent significantly more time with larger males. In addition, female choice was significantly repeatable across four trials: twice as a virgin and twice as a nonvirgin. Finally, female mating status (virgin or nonvirgin) did not affect her choice of mate, although virgin females spent significantly more time associating with test males.
Publisher: MDPI AG
Date: 24-06-2019
DOI: 10.3390/NU11061417
Abstract: Malnutrition is a common and complex problem in hospitals. This study used an integrated knowledge translation approach to develop, implement, and evaluate a multifaceted, tailored intervention to improve nutrition care, delivery, and intake among acute medical inpatients. This observational, pre-post study was conducted in a medical ward at a public hospital in Australia. The intervention was co-developed with key stakeholders and targeted three levels: in iduals (nutrition intake magnets at patient bedsides), the ward (multidisciplinary hospital staff training), and the organisation (foodservice system changes). Observational data were collected pre- and post-intervention on patient demographics, food intakes, and the mealtime environment. Data were entered into SPSS and analysed using descriptive and inferential statistics. Ethical approval was gained through the hospital and university ethics committees. A total of 207 patients were observed 116 pre- and 91 post-intervention. After intervention implementation, patients’ mean energy and protein intakes (in proportion to their estimated requirements) were significantly higher and the number of patients eating adequately doubled (p 0.05). In summary, a multifaceted, pragmatic intervention, tailored to the study context and developed and implemented alongside hospital staff and patients, seemed to be effective in improving nutrition practices and patient nutrition intakes on an acute medical ward.
Publisher: Wiley
Date: 13-01-2016
DOI: 10.1111/SCS.12279
Abstract: Existing practice strategies for actively involving patients in care during hospitalisation are poorly understood. The aim of this study was to explore how healthcare professionals engaged patients in communication associated with care transitions. An instrumental, collective case study approach was used to generate empirical data about patient transitions in care. A purposive s le of key stakeholders representing (i) patients and their families (ii) hospital discharge planning team members and (iii) healthcare professionals was recruited in five Australian health services. In idual and group semi-structured interviews were conducted to elicit detailed explanations of patient engagement in transition planning. Interviews lasted between 30 and 60 minutes and were digitally recorded and transcribed verbatim. Data collection and analysis were conducted simultaneously and continued until saturation was achieved. Thematic analysis was undertaken. Five themes emerged as follows: (i) organisational commitment to patient engagement (ii) the influence of hierarchical culture and professional norms on patient engagement (iii) condoning in idual healthcare professionals' orientations and actions (iv) understanding and negotiating patient preferences and (v) enacting information sharing and communication strategies. Most themes illustrated how patient engagement was enabled however, barriers also existed. Our findings show that strong organisational and professional commitment to patient-centred care throughout the organisation was a consistent feature of health services that actively engaged patients in clinical communication. Understanding patients' needs and preferences and having both formal and informal strategies to engage patients in clinical communication were important in how this involvement occurred.
Publisher: Oxford University Press (OUP)
Date: 06-2019
Abstract: It is increasingly common for studies of evolution in natural populations to infer the quantitative genetic basis of fitness (e.g., the additive genetic variance for relative fitness), and of relationships between traits and fitness (e.g., the additive genetic covariance of traits with relative fitness). There is a certain amount of tension between the theory that justifies estimating these quantities, and methodological considerations relevant to their empirical estimation. In particular, the additive genetic variances and covariances involving relative fitness are justified by the fundamental and secondary theorems of selection, which pertain to relative fitness on the scale that it is expressed. However, naturally-occurring fitness distributions lend themselves to analysis with generalized linear mixed models (GLMMs), which conduct analysis on a different scale, typically on the scale of the logarithm of expected values, from which fitness is expressed. This note presents relations between evolutionary change in traits, and the rate of adaptation in fitness, and log quantitative genetic parameters of fitness, potentially reducing the discord between theoretical and methodological considerations to the operationalization of the secondary and fundamental theorems of selection.
Publisher: Wiley
Date: 22-01-2019
DOI: 10.1111/JOCN.14766
Publisher: Cold Spring Harbor Laboratory
Date: 02-02-2016
DOI: 10.1101/038604
Abstract: In natural populations, quantitative trait dynamics often do not appear to follow evolutionary predictions: Despite abundant ex les of natural selection acting on heritable traits, conclusive evidence for contemporary adaptive evolution remains rare for wild vertebrate populations, and phenotypic stasis seems to be the norm. This so-called ‘stasis paradox’ highlights our inability to predict evolutionary change, which is especially concerning within the context of rapid anthropogenic environmental change. While the causes underlying the stasis paradox are hotly debated, comprehensive attempts aiming at a resolution are lacking. Here we apply a quantitative genetic framework to in idual-based long-term data for a wild rodent population and show that despite a positive association between body mass and fitness, there has been a genetic change towards lower body mass. The latter represents an adaptive response to viability selection favouring juveniles growing up to become relatively small adults, i.e. with a low potential adult mass, which presumably complete their development earlier. This selection is particularly strong towards the end of the snow-free season, and it has intensified in recent years, coinciding which a change in snowfall patterns. Importantly, neither the negative evolutionary change, nor the selective pressures that drive it, are apparent on the phenotypic level, where they are masked by phenotypic plasticity and a non-causal (i.e. non-genetic) positive association between body mass and fitness, respectively. Estimating selection at the genetic level thereby enabled us to uncover adaptive evolution in action, and to identify the corresponding phenotypic selective pressure. We thereby demonstrate that natural populations can show a rapid and adaptive evolutionary response to a novel selective pressure, and that explicitly (quantitative) genetic models are able to provide us with an understanding of the causes and consequences of selection that is superior to purely phenotypic estimates of selection and evolutionary change.
Publisher: Mark Allen Group
Date: 02-06-2017
Publisher: Public Library of Science (PLoS)
Date: 05-11-2019
Publisher: California Digital Library (CDL)
Date: 14-11-2019
Publisher: Wiley
Date: 10-02-2020
DOI: 10.1111/JEB.13595
Abstract: Resting metabolic rate (RMR) is a potentially important axis of physiological adaptation to the thermal environment. However, our understanding of the causes and consequences of in idual variation in RMR in the wild is h ered by a lack of data, as well as analytical challenges. RMR measurements in the wild are generally characterized by large measurement errors and a strong dependency on mass. The latter is problematic when assessing the ability of RMR to evolve independently of mass. Mixed models provide a powerful and flexible tool to tackle these challenges, but they have rarely been used to estimate repeatability of mass-independent RMR from field data. We used respirometry to obtain repeated measurements of RMR in a long-term study population of snow voles (Chionomys nivalis) inhabiting an environment subject to large circadian and seasonal fluctuations in temperature. Using both uni- and bivariate mixed models, we quantify in idual repeatability in RMR and decompose repeatability into mass-dependent and mass-independent components, while accounting for measurement error. RMR varies among in iduals, that is, is repeatable (R = .46) and strongly co-varies with BM. Indeed, much of the repeatability of RMR is attributable to in idual variation in BM, and the repeatability of mass-independent RMR is reduced by 41% to R = .27. These empirical results suggest that the evolutionary potential of RMR independent of mass may be severely constrained. This study illustrates how to leverage bivariate mixed models to model field data for metabolic traits, correct for measurement error and decompose the relative importance of mass-dependent and mass-independent physiological variation.
Publisher: The Royal Society
Date: 13-07-2022
Abstract: Mistletoes are hemiparasitic plants and keystone species in many ecosystems globally. Given predicted increases in drought frequency and intensity, mistletoes may be crucial for moderating drought impacts on community structure. Dependent on host vascular flows, mistletoes can succumb to stress when water availability falls, making them susceptible to mortality during drought. We counted mistletoe across greater than 350 000 km 2 of southeastern Australia and conducted standardized bird surveys between 2016 and 2021, spanning a major drought event in 2018–2019. We aimed to identify predictors of mistletoe abundance and mortality and determine whether mistletoes might moderate drought impacts on woodland birds. Live mistletoe abundance varied with tree species composition, land use and presence of mistletoebirds. Mistletoe mortality was widespread, consistent with high 2018/2019 summer temperatures, low 2019/2020 summer rainfall and the interaction between summer temperatures and rainfall in 2019/2020. The positive association between surviving mistletoes and woodland birds was greatest in the peak drought breeding seasons of 2018/2019 and 2019/2020, particularly for small residents and insectivores. Paradoxically, mistletoes could moderate drought impacts on birds, but are themselves vulnerable to drought-induced mortality. An improved understanding of the drivers and dynamics of mistletoe mortality is needed to address potential cascading trophic impacts associated with mistletoe die-off.
Publisher: Wiley
Date: 12-10-2021
DOI: 10.1111/EVO.14371
Abstract: Many studies ask whether young or older males are better at acquiring mates. Even so, how age affects reproductive success is still poorly understood because male age and mating history are confounded in most studies: older males usually have more mating experience. To what extent does mating history rather than age explain variation in male mating success? And how do mating history and male age determine paternity when there is also postcopulatory sexual selection? Here, we experimentally manipulated the mating history of old and young males in the eastern mosquitofish (Gambusia holbrooki). We then recorded male mating behavior and share of paternity (1259 offspring from 232 potential sires) when they competed for mates and fertilizations. Old males, and males with no mating experience, spent significantly more time approaching females, and attempting to mate, than did young males and those with greater mating experience. Male age and mating history interacted to affect paternity: old males benefited from having previous mating experience, but young males did not. Our results highlight that the age-related changes in male reproductive traits and in paternity that have been described in many taxa may be partly attributable to male mating history and not simply to age itself.
Publisher: Wiley
Date: 22-10-2020
DOI: 10.1111/JEB.13712
Abstract: Age‐related changes in parental phenotypes or genotypes can impact offspring fitness, but separating germline from nongermline transgenerational effects of ageing is difficult for wild populations. Further, in cooperatively breeding species, in addition to parental ages, the age of ‘helpers’ attending offspring may also affect juvenile performance. Using a 30‐year study of a cooperative breeder with very high rates of extra‐pair paternity, the superb fairy‐wren ( Malurus cyaneus ), we investigated the effects of maternal, paternal and helper ages on three measures of offspring performance: nestling weight, juvenile survival to independence and recruitment to the breeding population. Mothers with a longer lifespan had offspring with higher juvenile survival, indicating selective disappearance, but the effect of maternal age on juvenile survival was of similar magnitude but negative. For extra‐pair offspring, there was no evidence of any effect of the ages of either the genetic sire or the cuckolded ‘social’ father. However, for within‐pair offspring, there was a positive effect of paternal age on juvenile survival, which we suggest may be driven by sexual selection. There were positive associations between the average age of helpers attending a nest and two of the three aspects of offspring performance these effects were stronger than any of the effects of parental age. In general, the multiple associations between offspring fitness and the ages of adults around them appeared to be driven more by age‐related changes in environmental effects than by age‐related changes in the germline.
Publisher: Cold Spring Harbor Laboratory
Date: 12-01-2018
DOI: 10.1101/247189
Abstract: Quantitative genetic analyses require extensive measurements of phenotypic traits, a task that is often not trivial, especially in wild populations. On top of instrumental measurement error, some traits may undergo transient ( i.e . non-persistent) fluctuations that are biologically irrelevant for selection processes. These two sources of variability, which we denote here as measurement error in a broad sense, are possible causes for bias in the estimation of quantitative genetic parameters. We illustrate how in a continuous trait transient effects with a classical measurement error structure may bias estimates of heritability, selection gradients, and the predicted response to selection. We propose strategies to obtain unbiased estimates with the help of repeated measurements taken at an appropriate temporal scale. However, the fact that in quantitative genetic analyses repeated measurements are also used to isolate permanent environmental instead of transient effects, requires a re-assessment of the information content of repeated measurements. To do so, we propose to distinguish “short-term” from “long-term” repeats, where the former capture transient variability and the latter the permanent effects. We show how the inclusion of the corresponding variance components in quantitative genetic models yields unbiased estimates of all quantities of interest, and we illustrate the application of the method to data from a Swiss snow vole population.
Location: Switzerland
Location: Australia
Start Date: 2013
End Date: 2015
Funder: Foundation for Science and Technology
View Funded ActivityStart Date: 2021
End Date: 2024
Funder: Australian Research Council
View Funded ActivityStart Date: 12-2021
End Date: 01-2023
Amount: $417,328.00
Funder: Australian Research Council
View Funded Activity