989 resultados para Animal populations


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The Maya of the Yucatan region have a long history of keeping the native stingless bees (subfamily Meliponinae). However, market forces in the last few decades have driven the Maya to favor the use of invasive Africanized honey bees (Apis mellifera scutellata) for producing large quantities of high quality honey that has an international market. Furthermore, the native bees traditionally used by the Maya are now disappearing, along with the practice of keeping them. ^ An interdisciplinary approach was taken in order to determine the social factors behind the decrease in stingless beekeeping and the ecological driving forces behind their disappearance from the wild. Social research methods included participant observation with stingless beekeepers, Apis beekeepers, and marketing intermediaries. Ecological research methods included point observations of commonly known melliferous and polliniferous plants along transects in three communities with different degrees of human induced ecosystem disturbance. ^ The stingless bee species most important to the Maya, Melipona beecheii, has become extremely rare, and this has caused a breakdown of stingless beekeeping tradition, compounded with the pressure of the market economy, which fuels Apis beekeeping and has lessened the influence of traditional practices. The community with the heaviest amount of human induced ecosystem disturbance also had the highest degree of dominance of Apis mellifera, while the area with the most intact ecosystem had the highest diversity of stingless bees, though Apis mellifera was still the dominant species. Aggressive competitive behavior involving physical attacks by Apis mellifera against stingless bees was observed on several occasions, and this is a new observation previously unreported by science. ^

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Acknowledgments RRP was supported by a PhD-studentship from the University of Valladolid (co-funded by Banco Santander, RR 30/04/2014). Financial support was provided by ECOCYCLES (BIODIVERSA 2008, Era-net European project, EUI2008-03658 and NERC NE/G002045/1 to XL) and ECOVOLE projects (CGL2012-35348; Ministerio de Economía y Competitividad of Spain). The article also contributes to project ECOTULA (CGL2015-66962-C2-1-R). We held all the necessary licenses and permits for conducting this work (JJLL, FM and RRP held animal experimentation permits of level B for Spain, and a capture permit was provided by the Consejería de Fomento y Medio Ambiente, Junta de Castilla y León (Expte: EP/CYL/665/2014)). We thank two anonymous reviewers for providing and constructive comments to improve the manuscript.

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Sex change, or sequential hermaphroditism, occurs in the plant and animal kingdoms and often determines a predominance of the first sex. Our aim was to explore changes in sex ratios within the range of the species studied: Patella vulgata and Patella depressa. The broad-scale survey of sex with size of limpets covered a range of latitudes from Zambujeira do Mar (southern Portugal) to the English Channel. Indirect evidence was found for the occurrence of protandry in P. vulgata populations from the south of England, with females predominating in larger size-classes; cumulative frequency distributions of males and females were different; sex ratios were biased towards males and smallest sizes of males were smaller than the smallest sizes of females. In contrast in Portugal females were found in most size-classes of P. vulgata. In P. depressa populations from the south coast of England and Portugal females were interspersed across most size-classes; size distributions of males and females and size at first maturity of males and females did not differ. P. depressa did, however, show some indications of the possibility of slight protandry occurring in Portugal. The test of sex ratio variation with latitude indicated that P. vulgata sex ratios might be involved in determining the species range limit, particularly at the equatorward limit since the likelihood of being male decreased from the south coast of England to southern Portugal. Thus at the southern range limit, sperm could be in short supply due to scarcity of males contributing to an Allee effect.

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Sex change, or sequential hermaphroditism, occurs in the plant and animal kingdoms and often determines a predominance of the first sex. Our aim was to explore changes in sex ratios within the range of the species studied: Patella vulgata and Patella depressa. The broad-scale survey of sex with size of limpets covered a range of latitudes from Zambujeira do Mar (southern Portugal) to the English Channel. Indirect evidence was found for the occurrence of protandry in P. vulgata populations from the south of England, with females predominating in larger size-classes; cumulative frequency distributions of males and females were different; sex ratios were biased towards males and smallest sizes of males were smaller than the smallest sizes of females. In contrast in Portugal females were found in most size-classes of P. vulgata. In P. depressa populations from the south coast of England and Portugal females were interspersed across most size-classes; size distributions of males and females and size at first maturity of males and females did not differ. P. depressa did, however, show some indications of the possibility of slight protandry occurring in Portugal. The test of sex ratio variation with latitude indicated that P. vulgata sex ratios might be involved in determining the species range limit, particularly at the equatorward limit since the likelihood of being male decreased from the south coast of England to southern Portugal. Thus at the southern range limit, sperm could be in short supply due to scarcity of males contributing to an Allee effect.

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[EN] The hawksbill sea turtle (Eretmochelys imbricata) is a circumglobal tropical species listed as Critically Endangered by the IUCN. While it is known that at least one stock occurs around the rookeries of São Tome and Principe and Bioko Islands, the eastern Atlantic remains genetically unexplored. We present the first analysis of mitochondrial DNA (mtDNA) sequences (n = 28) of hawksbill juveniles in a foraging aggregation at the Cape Verde Islands, an archipelago located in the eastern Atlantic. The mean size (minimun curve carapace length) of the studied individuals was 42.45 cm.

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[EN] Despite the considerable population genetic and connectivity research on the hawksbill sea turtle (Eretmochelys imbricata) and the species being critically endangered, the eastern Atlantic remains understudied. We present the first analysis of mitochondrial DNA (mtDNA) sequences (n = 28) of hawksbill juveniles in a foraging aggregation at the Cape Verde Islands. Our results showed three haplotypes non-reported in any nesting population to date, with one of them accounting for 68% of the samples. These three haplotypes were closely related to each other but highly divergent from all known Caribbean and Western Atlantic haplotypes.

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1. Genomewide association studies (GWAS) enable detailed dissections of the genetic basis for organisms' ability to adapt to a changing environment. In long-term studies of natural populations, individuals are often marked at one point in their life and then repeatedly recaptured. It is therefore essential that a method for GWAS includes the process of repeated sampling. In a GWAS, the effects of thousands of single-nucleotide polymorphisms (SNPs) need to be fitted and any model development is constrained by the computational requirements. A method is therefore required that can fit a highly hierarchical model and at the same time is computationally fast enough to be useful. 2. Our method fits fixed SNP effects in a linear mixed model that can include both random polygenic effects and permanent environmental effects. In this way, the model can correct for population structure and model repeated measures. The covariance structure of the linear mixed model is first estimated and subsequently used in a generalized least squares setting to fit the SNP effects. The method was evaluated in a simulation study based on observed genotypes from a long-term study of collared flycatchers in Sweden. 3. The method we present here was successful in estimating permanent environmental effects from simulated repeated measures data. Additionally, we found that especially for variable phenotypes having large variation between years, the repeated measurements model has a substantial increase in power compared to a model using average phenotypes as a response. 4. The method is available in the R package RepeatABEL. It increases the power in GWAS having repeated measures, especially for long-term studies of natural populations, and the R implementation is expected to facilitate modelling of longitudinal data for studies of both animal and human populations.

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Repeatability of behavioural and physiological traits is increasingly a focus for animal researchers, for which fish have become important models. Almost all of this work has been done in the context of evolutionary ecology, with few explicit attempts to apply repeatability and context dependency of trait variation toward understanding conservation-related issues. Here, we review work examining the degree to which repeatability of traits (such as boldness, swimming performance, metabolic rate and stress responsiveness) is context dependent. We review methods for quantifying repeatability (distinguishing between within-context and across-context repeatability) and confounding factors that may be especially problematic when attempting to measure repeatability in wild fish. Environmental factors such temperature, food availability, oxygen availability, hypercapnia, flow regime and pollutants all appear to alter trait repeatability in fishes. This suggests that anthropogenic environmental change could alter evolutionary trajectories by changing which individuals achieve the greatest fitness in a given set of conditions. Gaining a greater understanding of these effects will be crucial for our ability to forecast the effects of gradual environmental change, such as climate change and ocean acidification, the study of which is currently limited by our ability to examine trait changes over relatively short time scales. Also discussed are situations in which recent advances in technologies associated with electronic tags (biotelemetry and biologging) and respirometry will help to facilitate increased quantification of repeatability for physiological and integrative traits, which so far lag behind measures of repeatability of behavioural traits.

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Introduction : Les taux d’obésité et de diabète de type 2 et leurs complications sont plus élevés chez les populations autochtones que chez la population générale. Une des raisons pour ces taux très élevés de complications est la résistance culturelle des autochtones envers les soins de santé contemporains souvent dus aux traitements culturellement inadéquats pour ces affections. Afin d’adresser cette problématique, l’équipe sur les médecines autochtones antidiabétiques des Instituts de recherche en santé du Canada (ÉMAAD-IRSC) a étudié 17 plantes de la pharmacopée traditionnelle des Cris de la Nation de la Baie James, dont le peuplier baumier Populus balsamifera. Objectifs : Le but de cette présente étude est d’examiner les effets de P. balsamifera sur les contenus lipidiques de l’intestin ainsi que la composition des protéines clés impliquées dans le métabolisme des lipides. Matériel et méthodes : Les souris étaient assignées à huit semaines de diètes, soit la diète standard (CHOW), une diète à forte teneur lipidique (HFD) ou une HFD avec ajout de 125 mg/kg de Populus balsamifera. Résultats : Les résultats ont montré que les teneurs totales de l’intestin en cholestérol, en phospholipides et en triglycérides ne sont pas influencées par l’absence ou la présence de l’extrait de P. balsamifera. La teneur en acides gras a significativement augmenté dans le traitement HFD comparé au groupe contrôle CHOW. Le traitement avec P. balsamifera a significativement réduit le contenu d’acides gras dans le jéjunum vers des valeurs observées pour la diète contrôle. Une modification non significative a été notée dans l’expression des protéines FAS, CPT-1, ACC-P. Conclusion : Ces résultats renforcent davantage le potentiel d’utilisation de l’extrait de peuplier baumier dans le contexte de forte prévalence d’obésité dans les populations autochtones.

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Introduction : Les taux d’obésité et de diabète de type 2 et leurs complications sont plus élevés chez les populations autochtones que chez la population générale. Une des raisons pour ces taux très élevés de complications est la résistance culturelle des autochtones envers les soins de santé contemporains souvent dus aux traitements culturellement inadéquats pour ces affections. Afin d’adresser cette problématique, l’équipe sur les médecines autochtones antidiabétiques des Instituts de recherche en santé du Canada (ÉMAAD-IRSC) a étudié 17 plantes de la pharmacopée traditionnelle des Cris de la Nation de la Baie James, dont le peuplier baumier Populus balsamifera. Objectifs : Le but de cette présente étude est d’examiner les effets de P. balsamifera sur les contenus lipidiques de l’intestin ainsi que la composition des protéines clés impliquées dans le métabolisme des lipides. Matériel et méthodes : Les souris étaient assignées à huit semaines de diètes, soit la diète standard (CHOW), une diète à forte teneur lipidique (HFD) ou une HFD avec ajout de 125 mg/kg de Populus balsamifera. Résultats : Les résultats ont montré que les teneurs totales de l’intestin en cholestérol, en phospholipides et en triglycérides ne sont pas influencées par l’absence ou la présence de l’extrait de P. balsamifera. La teneur en acides gras a significativement augmenté dans le traitement HFD comparé au groupe contrôle CHOW. Le traitement avec P. balsamifera a significativement réduit le contenu d’acides gras dans le jéjunum vers des valeurs observées pour la diète contrôle. Une modification non significative a été notée dans l’expression des protéines FAS, CPT-1, ACC-P. Conclusion : Ces résultats renforcent davantage le potentiel d’utilisation de l’extrait de peuplier baumier dans le contexte de forte prévalence d’obésité dans les populations autochtones.

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The Pine Wood Nematode (PWN) Bursaphelenchus xylophilus is a severe forest pathogen in countries where it has been introduced and is considered a worldwide quarantine organism. In this study, protein markers for differentiating populations of this nematode were identified by studying differences among four selected Iberian and one American population. These populations were compared by quantitative proteomics (iTRAQ). From a total of 2860 proteins identified using the public database from the B. xylophilus genome project, 216 were unambiguous and significantly differentially regulated in the studied populations. Comparisons of their pairwise ratio were statistically treated and supported in order to convert them into discrete character states, suggesting that 141 proteins were not informative as population specific markers. Application of the Character Compatibility methodology on the remaining 75 proteins (belonging to families with different biological functions) excludes 27 which are incompatible among them. Considering only the compatible proteins, the method selects a subset of 30 specific unique protein markers which allowed the compared classification of the Iberian isolates. This approach makes it easier search for diagnostic tools and phylogenetic inference within species and populations of a pathogen exhibiting a high level of genetic diversity.

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Aims: Changing behaviour to reduce stroke risk is a difficult prospect made particularly complex because of psychological factors. This study examined predictors of intentions and behaviours to reduce stroke risk in a sample of at-risk individuals, seeking to find how knowledge and health beliefs influenced both intention and actual behaviour to reduce stroke risk. Methods: A repeated measures design was used to assess behavioural intentions at time 1 (T1) and subsequent behaviour (T2). One hundred and twenty six respondents completed an online survey at T1, and behavioural follow-up data were collected from approximately 70 participants 1 month later. Predictors were stroke knowledge, demographic variables, and beliefs about stroke that were derived from an expanded health belief model. Dependent measures were: exercise and weight loss, and intention to engage in these behaviours to reduce stroke risk. Findings: Multiple hierarchical regression analyses showed that, for exercise and weight loss respectively, different health beliefs predicted intention to control stroke risk. The most important exercise-related health beliefs were benefits, susceptibility, and self-efficacy; for weight loss, the most important beliefs were barriers, and to a lesser degree, susceptibility and subjective norm. Conclusions: Health beliefs may play an important role in stroke prevention, particularly beliefs about susceptibility because these emerged for both behaviours. Stroke education and prevention programmes that selectively target the health beliefs relevant to specific behaviours may prove most efficacious.