| 1. |
- Götze, Karl, et al.
(författare)
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Plasma neurofilament light chain in memory clinic practice: Evidence from a real-life study.
- 2023
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Ingår i: Neurobiology of disease. - : Elsevier BV. - 1095-953X .- 0969-9961. ; 176
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Tidskriftsartikel (refereegranskat)abstract
- To explore the accuracy of plasma neurofilament light chain (NfL) as a biomarker for diagnosis and staging of cognitive impairment, in a large cohort with of previously diagnosed patients in clinical practice.Retrospective, cross-sectional, monocentric study, from a tertiary memory clinic. Patients underwent cerebrospinal fluid core Alzheimer's disease (AD) biomarker evaluation using ELISA or Elecsys methods, and plasma NfL analysis using the single molecule array technology. The patients' biomarker data were examined for associations with: i/cognitive status ii/presence of neurodegenerative disease and iii/diagnostic groups. Associations between core CSF biomarkers and plasma NfL were determined.Participants (N=558, mean age=69.2±8.8, 56.5% women) were diagnosed with AD (n=274, considering dementia and MCI stages), frontotemporal dementia (FTD, n=55), Lewy body disease (LBD, n=40, considering MCI and dementia stages), other neurodegenerative diseases, n=57 (e.g Supranuclear Palsy, Corticobasal syndrome), non-neurodegenerative cognitive impairment (NND, n=79, e.g. vascular lesions, epilepsy or psychiatric disorders) or subjective cognitive impairment (SCI, n=53). Mean plasma NfL (log, pg/mL) levels were higher in neurodegenerative than non-neurodegenerative disorders (1.35±0.2 vs 1.16±0.23, p<0.001), higher in all diagnostic groups than in SCI (1.06±0.23) p<0.001), and associated with the stage of cognitive impairment (p<0.001). The addition of plasma NfL to a clinical model (age, MMSE and APOE ε4 carriership) marginally improved the discrimination of degenerative from non-degenerative disorders in ROC analysis (AUC clinical model: 0.81, 95% CI=[0.77;0.85] AUC clinical model + plasma NfL: AUC=0.83 95% CI=[0.78;0.87], delta Akaike information criterion=-11.7).Plasma NfL could help discrimination between degenerative and non-degenerative cognitive disorders, albeit not better than comprehensive clinical evaluation.
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| 2. |
- Josefsson, Jonas, et al.
(författare)
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Improving scientific rigour in conservation evaluations and a plea deal for transparency on potential biases
- 2020
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Ingår i: Conservation Letters. - : Wiley. - 1755-263X. ; 13:5
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Forskningsöversikt (refereegranskat)abstract
- The delivery of rigorous and unbiased evidence on the effects of interventions lay at the heart of the scientific method. Here we examine scientific papers evaluating agri-environment schemes, the principal instrument to mitigate farmland biodiversity declines worldwide. Despite previous warnings about rudimentary study designs in this field, we found that the majority of studies published between 2008 and 2017 still lack robust study designs to strictly evaluate intervention effects. Potential sources of bias that arise from the correlative nature are rarely mentioned, and results are still promoted by using a causal language. This lack of robust study designs likely results from poor integration of research and policy, while the erroneous use of causal language and an unwillingness to discuss bias may stem from publication pressures. We conclude that scientific reporting and discussion of study limitations in intervention research must improve and propose some practices toward this goal.
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| 3. |
- Paquet, Matthieu
(författare)
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Begging and feeding responses vary with relatedness and sex of provisioners in a cooperative breeder
- 2022
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Ingår i: Animal Behaviour. - : Elsevier BV. - 0003-3472 .- 1095-8282. ; 185, s. 49-71
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Tidskriftsartikel (refereegranskat)abstract
- Begging behaviour can provide information on offspring hunger levels and be used by parents to adjust food provisioning efforts. In cooperative breeders, helpers also provide care by feeding the young. However, how helpers of different sex and relatedness to the offspring respond to begging behaviour has rarely been studied in cooperatively breeding species, which limits our understanding of the indirect and/or direct benefits that helpers may obtain by responding to offspring demand. Here, we used a cooperatively breeding bird, the sociable weaver, Philetairus socius, to investigate how nest intervisit intervals of breeders and different types of helpers, distinguished by sex and relatedness, varied with acoustic begging. Moreover, we tested whether these different classes of provisioners experienced distinct levels of begging. Our results show that only breeding males, but not breeding females or helpers of any sex and relatedness to the nestlings, returned faster to the nest to feed after experiencing more begging calls. When contrasted directly, we confirmed a statistically supported difference in responses to begging between male and female breeders. Surprisingly, second-order relatives experienced more begging calls than the other classes of more related helpers and breeders. These results show that we might find differences in how provisioners respond to begging levels when classifying group members according to their potential fitness gains. In sociable weavers, the benefits and costs of adjusting feeding efforts to begging seem to differ with sex and life history stage. Experimental and more detailed investigations on begging-feeding interactions are necessary to understand the origin and prevalence of these differences across cooperatively breeding systems. (c) 2021 The Author(s). Published by Elsevier Ltd on behalf of The Association for the Study of Animal Behaviour. This is an open access article under the CC BY license (http://creativecommons.org/licenses/ by/4.0/).
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| 4. |
- Paquet, Matthieu
(författare)
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Communal Behavior
- 2017
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Ingår i: Encyclopedia of Animal Cognition and Behavior. - Cham : Springer International Publishing. ; , s. 1-3
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 5. |
- Paquet, Matthieu
(författare)
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Contrasting associations between nestling telomere length and pre and postnatal helpers' presence in a cooperatively breeding bird
- 2021
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Ingår i: Oecologia. - : Springer Science and Business Media LLC. - 0029-8549 .- 1432-1939. ; 196, s. 37-51
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Tidskriftsartikel (refereegranskat)abstract
- Studies on cooperative breeders have addressed the effects of non-breeding 'helpers' on reproduction and parental care, but the consequences for offspring physiology and long-term survival are less understood. Helpers are expected to benefit offspring, but their presence can also lead to decreased pre- or post-natal parental reproductive effort. To examine whether prenatal and postnatal helpers influence offspring condition, we conducted a whole-clutch cross-fostering experiment in sociable weavers (Philetairus socius) that altered the nestlings' social environment (presence/absence of helpers). We tested whether relative telomere length (rTL), an indicator of somatic maintenance, was influenced by prenatal and/or postnatal presence of helpers 9 and 17 days after hatching, and whether rTL predicted long-term survival. Nine days after hatching, we found an overall positive effect of postnatal helpers on rTL: for nestlings with prenatal helpers, a reduction in the number of helpers post-hatch was associated with shorter telomeres, while nestlings swapped from nests without helpers to nests with helpers had a larger rTL. However, when prenatal helpers were present, an increased number of helpers after hatching led to shorter telomeres. Nine-day old chicks with longer rTL tended to be more likely to survive over the 5 years following hatching. However, close to fledging, there was no detectable effect of the experiment on rTL and no link between rTL and survival. This experimental study of a wild cooperative breeder, therefore, presents partial support for the importance of the presence of helpers for offspring rTL and the link between early-life telomere length and long-term survival.
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| 6. |
- Paquet, Matthieu
(författare)
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Disentangling climatic and nest predator impact on reproductive output reveals adverse high-temperature effects regardless of helper number in an arid-region cooperative bird
- 2021
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Ingår i: Ecology Letters. - : Wiley. - 1461-023X .- 1461-0248. ; 25, s. 151-162
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Tidskriftsartikel (refereegranskat)abstract
- Climate exerts a major influence on reproductive processes, and an understanding of the mechanisms involved and which factors might mitigate adverse weather is fundamental under the ongoing climate change. Here, we study how weather and nest predation influence reproductive output in a social species, and examine whether larger group sizes can mitigate the adverse effects of these factors. We used a 7-year nest predator-exclusion experiment on an arid-region cooperatively breeding bird, the sociable weaver. We found that dry and, especially, hot weather were major drivers of nestling mortality through their influence on nest predation. However, when we experimentally excluded nest predators, these conditions were still strongly associated with nestling mortality. Group size was unimportant against nest predation and, although positively associated with reproductive success, it did not mitigate the effects of adverse weather. Hence, cooperative breeding might have a limited capacity to mitigate extreme weather effects.
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| 7. |
- Paquet, Matthieu
(författare)
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Examining the link between relaxed predation and bird coloration on islands
- 2020
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Ingår i: Biology Letters. - : The Royal Society. - 1744-9561 .- 1744-957X. ; 16
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Tidskriftsartikel (refereegranskat)abstract
- Insular ecosystems share analogous ecological conditions, leading to patterns of convergent evolution that are collectively termed as the 'island syndrome'. In birds, part of this syndrome is a tendency for a duller plumage, possibly as a result of relaxed sexual selection. Despite this global pattern, some insular species display a more colourful plumage than their mainland relatives, but why this occurs has remained unexplained. Here, we examine the hypothesis that these cases of increased plumage coloration on islands could arise through a relaxation of predation pressure. We used comparative analyses to investigate whether average insular richness of raptors of suitable mass influences the plumage colourfulness and brightness across 110 pairs of insular endemic species and their closest mainland relatives. As predicted, we find a likely negative relationship between insular coloration and insular predation while controlling for mainland predation and coloration, suggesting that species were more likely to become more colourful as the number of insular predators decreased. By contrast, plumage brightness was not influenced by predation pressure. Relaxation from predation, together with drift, might thus be a key mechanism of species phenotypic responses to insularity.
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| 8. |
- Paquet, Matthieu
(författare)
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Females adjust maternal hormone concentration in eggs according to male condition in a burying beetle
- 2020
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Ingår i: Hormones and Behavior. - : Elsevier BV. - 0018-506X .- 1095-6867. ; 121
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Tidskriftsartikel (refereegranskat)abstract
- In birds and other vertebrates, there is good evidence that females adjust the allocation of hormones in their eggs in response to prenatal environmental conditions, such as food availability or male phenotype, with profound consequences for life history traits of offspring. In insects, there is also evidence that females deposit juvenile hormones (JH) and ecdysteroids (ESH) in their eggs, hormones that play a key role in regulating offspring growth and metamorphosis. However, it is unclear whether females adjust their hormonal deposition in eggs in response to prenatal environmental conditions. Here we address this gap by conducting an experiment on the burying beetle Nicrophorus vespilloides, in which we manipulated the presence of the male parent and the size of the carcass used for breeding at the time of laying. We also tested for effects of the condition (i.e., body mass) of the parents. We then recorded subsequent effects on JH and ESH concentrations in the eggs. We found no evidence for an effect of these prenatal environmental conditions (male presence and carcass size) on hormonal concentration in the eggs. However, we found that females reduced their deposition of JH when mated with heavier males. This finding is consistent with negative differential allocation of maternal hormones in response to variation in the body mass of the male parent. We encourage further work to investigate the role of maternally derived hormones in insect eggs.
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| 9. |
- Paquet, Matthieu, et al.
(författare)
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Integrated population models poorly estimate the demographic contribution of immigration
- 2021
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Ingår i: Methods in Ecology and Evolution. - 2041-210X. ; 12, s. 1899-1910
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Tidskriftsartikel (refereegranskat)abstract
- Estimating the contribution of demographic parameters to changes in population growth is essential for understanding why populations fluctuate. Integrated population models (IPMs) offer a possibility to estimate the contributions of additional demographic parameters, for which no data have been explicitly collected-typically immigration. Such parameters are often subsequently highlighted as important drivers of population growth. Yet, accuracy in estimating their temporal variation, and consequently their contribution to changes in population growth rate, has not been investigated. To quantify the magnitude and cause of potential biases when estimating the contribution of immigration using IPMs, we simulated data (using northern wheatear Oenanthe oenanthe population estimates) from controlled scenarios to examine potential biases and how they depend on IPM parameterization, formulation of priors, the level of temporal variation in immigration and sample size. We also used empirical data on populations with known rates of immigration: Soay sheep Ovis aries and Mauritius kestrel Falco punctatus with zero immigration and grey wolf Canis lupus in Scandinavia with near-zero immigration. IPMs strongly overestimated the contribution of immigration to changes in population growth in scenarios when immigration was simulated with zero temporal variation (proportion of variance attributed to immigration = 63% for the more constrained formulation and real sample size) and in the wild populations, where the true number of immigrants was zero or near-zero (kestrel 19.1%-98.2%, sheep 4.2%-36.1% and wolf 84.0%-99.2%). Although the estimation of the contribution of immigration in the simulation study became more accurate with increasing temporal variation and sample size, it was often not possible to distinguish between an accurate estimation from data with high temporal variation versus an overestimation from data with low temporal variation. Unrealistically, large sample sizes may be required to estimate the contribution of immigration well. To minimize the risk of overestimating the contribution of immigration (or any additional parameter) in IPMs, we recommend to: (a) look for evidence of variation in immigration before investigating its contribution to population growth, (b) simulate and model data for comparison to the real data and (c) use explicit data on immigration when possible.
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| 10. |
- Paquet, Matthieu
(författare)
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Maternal allocation in relation to weather, predation and social factors in a colonial cooperative bird
- 2021
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Ingår i: Journal of Animal Ecology. - : Wiley. - 0021-8790 .- 1365-2656. ; 90, s. 1122-1133
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Tidskriftsartikel (refereegranskat)abstract
- Females may adjust prenatal allocation in relation to ecological conditions that affect reproductive success, such as weather conditions or predation risk. In cooperative breeders, helpers might also influence reproductive success, and previous studies suggest that females can lay smaller eggs or larger clutches when breeding with more helpers. Although recent work suggests that helper effects can vary according to climatic variables, how social and ecological factors interact to shape prenatal allocation is poorly understood.Here, we examine how ecological and social components of the breeding environment covary with egg mass and clutch size, using as a model the sociable weaver Philetairus socius, a colonial, cooperatively breeding passerine. The study spanned 9 years and included over 1,900 eggs from over 550 clutches. Our analyses combined natural variation in weather conditions (rainfall before each reproductive event) with a nest predator-exclusion experiment and continuous monitoring of the mother's social environment, allowing us to estimate how individual females adjust allocation to reproduction as their number of helpers varies.We found that egg mass varied consistently within females and did not clearly differ in relation to rainfall or predation risk. Contrary to previous studies, there was no evidence for plastic adjustments as females gained and lost helpers, and egg mass was instead better predicted by mother size and identity.Females laid larger clutches when breeding in environments where predation risk was experimentally reduced and after higher rainfall levels. Yet, there was no evidence for increasing clutch size as the number of helpers increased, nor for an interaction between helper effects and ecological factors.We conclude that while sociable weaver females can vary their clutch size, they show high individual consistency in egg mass. In addition, we found no evidence that females may maximize fitness through plastic prenatal allocation in relation to the number of helpers, or that the presence/absence of helper effects is modulated by rainfall levels or predation risk. These results challenge our current knowledge on some of the possible benefits of breeding with helpers and call for more long-term analyses on reproductive allocation adjustments in other cooperative systems.
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| 11. |
- Paquet, Matthieu
(författare)
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Offspring are predisposed to beg more towards females in the burying beetle Nicrophorus vespilloides
- 2018
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Ingår i: Animal Behaviour. - : Elsevier BV. - 0003-3472 .- 1095-8282. ; 141, s. 195-201
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Tidskriftsartikel (refereegranskat)abstract
- In species with biparental care, begging offspring may preferentially associate with or beg more towards one of their parents. Such preferences may reflect that the benefits of begging vary with the parent's sex given that females and males often differ in the amount of care they provide and/or in their responsiveness to begging levels. Alternatively, they may reflect the outcome of sexual conflict over care as females may deposit compounds into eggs tha tatter offspring begging behaviour such that it increases male contributions towards care. For example, females might use male presence during egg laying as a cue for whether they might receive male assistance in care. Here, we studied offspring begging behaviour towards male and female parents in the burying beetle Nicrophorus vespilloides by manipulating male presence or absence during egg laying and providing larvae with a simultaneous choice between an unfamiliar female and male adult beetle. We then recorded begging behaviour of (1) naive newly hatched larvae that had no prior experience of a parent and (2) larvae after 24 h of care by foster parents. Larvae showed a clear preference for associating with and begging towards females both when naive and after 24 h of care. We found no evidence for prenatal maternal effects on larval begging behaviour. Our study reveals that offspring are predisposed to preferentially beg towards females independently of prior experiences with parents and highlights the importance of considering responses of begging offspring to parental attributes, such as the parent's sex, for our understanding of family conflicts. (C) 2018 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.
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| 12. |
- Paquet, Matthieu, et al.
(författare)
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Quantifying the links between land use and population growth rate in a declining farmland bird
- 2019
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Ingår i: Ecology and Evolution. - : Wiley. - 2045-7758. ; 9, s. 868-879
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Tidskriftsartikel (refereegranskat)abstract
- Land use is likely to be a key driver of population dynamics of species inhabiting anthropogenic landscapes, such as farmlands. Understanding the relationships between land use and variation in population growth rates is therefore critical for the management of many farmland species. Using 24 years of data of a declining farmland bird in an integrated population model, we examined how spatiotemporal variation in land use (defined as habitats with Short and Tall ground vegetation during the breeding season) and habitat-specific demographic parameters relates to variation in population growth taking into account individual movements between habitats. We also evaluated contributions to population growth using transient life table response experiments which gives information on contribution of past variation of parameters and real-time elasticities which suggests future scenarios to change growth rates. LTRE analyses revealed a clear contribution of Short habitats to the annual variation in population growth rate that was mostly due to fledgling recruitment, whereas there was no evidence for a contribution of Tall habitats. Only 18% of the variation in population growth was explained by the modeled local demography, the remaining variation being explained by apparent immigration (i.e., the residual variation). We discuss potential biological and methodological reasons for high contributions of apparent immigration in open populations. In line with LTRE analysis, real-time elasticity analysis revealed that demographic parameters linked to Short habitats had a stronger potential to influence population growth rate than those of Tall habitats. Most particularly, an increase of the proportion of Short sites occupied by Old breeders could have a distinct positive impact on population growth. High-quality Short habitats such as grazed pastures have been declining in southern Sweden. Converting low-quality to high-quality habitats could therefore change the present negative population trend of this, and other species with similar habitat requirements.
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| 13. |
- Paquet, Matthieu, et al.
(författare)
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Why we should care about movements: Using spatially explicit integrated population models to assess habitat source-sink dynamics
- 2020
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Ingår i: Journal of Animal Ecology. - : Wiley. - 0021-8790 .- 1365-2656. ; 89, s. 2922-2933
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Tidskriftsartikel (refereegranskat)abstract
- Assessing the source-sink status of populations and habitats is of major importance for understanding population dynamics and for the management of natural populations. Sources produce a net surplus of individuals (per capita contribution to the metapopulation > 1) and will be the main contributors for self-sustaining populations, whereas sinks produce a deficit (contribution < 1). However, making these types of assessments is generally hindered by the problem of separating mortality from permanent emigration, especially when survival probabilities as well as moved distances are habitat-specific. To address this long-standing issue, we propose a spatial multi-event integrated population model (IPM) that incorporates habitat-specific dispersal distances of individuals. Using information about local movements, this IPM adjusts survival estimates for emigration outside the study area. Analysing 24 years of data on a farmland passerine (the northern wheatearOenanthe oenanthe), we assessed habitat-specific contributions, and hence the source-sink status and temporal variation of two key breeding habitats, while accounting for habitat- and sex-specific local dispersal distances of juveniles and adults. We then examined the sensitivity of the source-sink analysis by comparing results with and without accounting for these local movements. Estimates of first-year survival, and consequently habitat-specific contributions, were higher when local movement data were included. The consequences from including movement data were sex specific, with contribution shifting from sink to likely source in one habitat for males, and previously noted habitat differences for females disappearing. Assessing the source-sink status of habitats is extremely challenging. We show that our spatial IPM accounting for local movements can reduce biases in estimates of the contribution by different habitats, and thus reduce the overestimation of the occurrence of sink habitats. This approach allows combining all available data on demographic rates and movements, which will allow better assessment of source-sink dynamics and better informed conservation interventions.
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| 14. |
- Pärt, Tomas, et al.
(författare)
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Unclear relationships between mean survival rate and its environmental variance in vertebrates
- 2024
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Ingår i: Ecology and Evolution. - : Wiley. - 2045-7758. ; 14:3
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Tidskriftsartikel (refereegranskat)abstract
- Current environmental changes may increase temporal variability of life history traits of species thus affecting their long-term population growth rate and extinction risk. If there is a general relationship between environmental variances (EVs) and mean annual survival rates of species, that relationship could be used as a guideline for analyses of population growth and extinction risk for populations, where data on EVs are missing. For this purpose, we present a comprehensive compilation of 252 EV estimates from 89 species belonging to five vertebrate taxa (birds, mammals, reptiles, amphibians and fish) covering mean annual survival rates from 0.01 to 0.98. Since variances of survival rates are constrained by their means, particularly for low and high mean survival rates, we assessed whether any observed relationship persisted after applying two types of commonly used variance stabilizing transformations: relativized EVs (observed/mathematical maximum) and logit-scaled EVs. With raw EVs at the arithmetic scale, mean–variance relationships of annual survival rates were hump-shaped with small EVs at low and high mean survival rates and higher (and widely variable) EVs at intermediate mean survival rates. When mean annual survival rates were related to relativized EVs the hump-shaped pattern was less distinct than for raw EVs. When transforming EVs to logit scale the relationship between mean annual survival rates and EVs largely disappeared. The within-species juvenile-adult slopes were mainly positive at low (<0.5) and negative at high (>0.5) mean survival rates for raw and relativized variances while these patterns disappeared when EVs were logit transformed. Uncertainties in how to interpret the results of relativized and logit-scaled EVs, and the observed high variation in EV's for similar mean annual survival rates illustrates that extrapolations of observed EVs and tests of life history drivers of survival–EV relationships need to also acknowledge the large variation in these parameters.
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| 15. |
- Vrillon, Agathe, et al.
(författare)
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Comparison of CSF and plasma NfL and pNfH for Alzheimer’s disease diagnosis: a memory clinic study
- 2023
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Ingår i: Journal of Neurology. - 0340-5354 .- 1432-1459.
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Tidskriftsartikel (refereegranskat)abstract
- Plasma neurofilament light chain (NfL) is a promising biomarker of axonal damage for the diagnosis of neurodegenerative diseases. Phosphorylated neurofilament heavy chain (pNfH) has demonstrated its value in motor neuron diseases diagnosis, but has less been explored for dementia diagnosis. In a cross-sectional study, we compared cerebrospinal fluid (CSF) and plasma NfL and pNfH levels in n = 188 patients from Lariboisière Hospital, Paris, France, including AD patients at mild cognitive impairment stage (AD-MCI, n = 36) and dementia stage (n = 64), non-AD MCI (n = 38), non-AD dementia (n = 28) patients and control subjects (n = 22). Plasma NfL, plasma and CSF pNfH levels were measured using Simoa and CSF NfL using ELISA. The correlation between CSF and plasma levels was stronger for NfL than pNfH (rho = 0.77 and rho = 0.52, respectively). All neurofilament markers were increased in AD-MCI, AD dementia and non-AD dementia groups compared with controls. CSF NfL, CSF pNfH and plasma NfL showed high performance to discriminate AD at both MCI and dementia stages from control subjects [AUC (area under the curve) = 0.82–0.91]. Plasma pNfH displayed overall lower AUCs for discrimination between groups compared with CSF pNfH. Neurofilament markers showed similar moderate association with cognition. NfL levels displayed significant association with mediotemporal lobe atrophy and white matter lesions in the AD group. Our results suggest that CSF NfL and pNfH as well as plasma NfL levels display equivalent performance in both positive and differential AD diagnosis in memory clinic settings. In contrast to motoneuron disorders, plasma pNfH did not demonstrate added value as compared with plasma NfL.
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