An horizon scan of biogeography

The opportunity to reflect broadly on the accomplishments, prospects, and reach of a field may present itself relatively infrequently. Each biennial meeting of the International Biogeography Society showcases ideas solicited and developed largely during the preceding year, by individuals or teams from across the breadth of the discipline. Here, we highlight challenges, developments, and opportunities in biogeography that were summarized at or emerge from that biennial synthesis. We note the realized and potential impact of rapid data accumulation in several fields, a Renaissance for inter-disciplinary research, the importance of recognizing the evolution-ecology continuum across spatial and temporal scales and at different taxonomic, phylogenetic and functional levels, and re-exploration of classical assumptions and hypotheses using new tools. However, advances are taxonomically and geographically biased, key theoretical frameworks await development of tools for handling, or strategies for simplifying, the biological complexity seen in empirical systems. Current threats to biodiversity require unprecedented integration of knowledge and development of predictive capacity which may enable biogeography to unite its descriptive and hypothetico-deductive arms and establish a greater role within and outside academia

Case complexity and clinical outcome in diabetes mellitus. A prospective study using the INTERMED.

The aim of this study was to assess a population of patients with diabetes mellitus by means of the INTERMED, a classification system for case complexity integrating biological, psychosocial and health care related aspects of disease. The main hypothesis was that the INTERMED would identify distinct clusters of patients with different degrees of case complexity and different clinical outcomes. Patients (n=61) referred to a tertiary reference care centre were evaluated with the INTERMED and followed 9 months for HbA1c values and 6 months for health care utilisation. Cluster analysis revealed two clusters: cluster 1 (62%) consisting of complex patients with high INTERMED scores and cluster 2 (38%) consisting of less complex patients with lower INTERMED. Cluster 1 patients showed significantly higher HbA1c values and a tendency for increased health care utilisation. Total INTERMED scores were significantly related to HbA1c and explained 21% of its variance. In conclusion, different clusters of patients with different degrees of case complexity were identified by the INTERMED, allowing the detection of highly complex patients at risk for poor diabetes control. The INTERMED therefore provides an objective basis for clinical and scientific progress in diabetes mellitus. Ongoing intervention studies will have to confirm these preliminary data and to evaluate if management strategies based on the INTERMED profiles will improve outcomes.

Behavioural types and ecological effects in a natural population of the cooperative cichlid Neolamprologus pulcher

The ecological relevance of behavioural syndromes is little studied in cooperative breeding systems where it is assumed that the behavioural type might influence individual decisions on helping and dispersal (e.g. shy, nonaggressive and nonexplorative individuals remain philopatric and helpful, whereas bold, aggressive, explorative individuals compete for vacancies outside their group and disperse). We measured the behavioural type of 19 subordinates in the cooperatively breeding cichlid fish Neolamprologus pulcher in their natural environment by quantifying six behavioural traits up to four times ('trials') in three different contexts, by presenting them with a conspecific intruder, a predator or nothing inside a tube. We found only moderate within-context repeatability (intraclass correlation coefficients) of the focal individual's behaviour, except for attacking either the conspecific or the predator inside the tube. The focal individual's attack rate of the tube was also positively affected by its group size. Averaging traits per context removed the between-trial variation, and consequently the across-context repeatability was very high for all six traits, except for territory maintenance. Trait values depended significantly on the context, except for territory defence. Consequently, individuals could be classified into different behavioural types based on their reaction towards the tube, but surprisingly, and opposite to laboratory studies in this species, ranging propensity and territory maintenance were not included in this behavioural syndrome. We suggest that more studies are needed to compare standardized focal personality tests (e.g. exploration propensity) with actual behaviour observed in nature (e.g. ranging and dispersal).

Evolutionary and ecological significance of non-shivering thermogenesis in the common vole

La production endogène à long terme de chaleur, même au repos, est une adaptation que l'on retrouve chez les animaux à sang chaud (les oiseaux et les mammifères). Cette production de chaleur a comme but le maintien d'une température constante du corps indépendamment de la température extérieure. A cette fin, les mammifères ont développé une forme de tissu spécialisé nommé tissu adipeux brun (BAT). Ce tissu est responsable de la conversion de nourriture en chaleur, procédé appelé thermogenèse sans frisson (NST = non-shivering thermogenesis). Durant ce procédé la uncoupling protein 1 (UCP1) convertit, au sein des mitochondries, la nourriture en chaleur au lieu de produire de l'ATP, molécule utilisée comme énergie cellulaire. On suppose que cette inefficacité de la conversion de la nourriture en ATP dans le BAT influence l'homéostasie de l'énergie, l'allocation des ressources ainsi que la régulation de processus gourmant en énergie comme la croissance et la reproduction. Afin de maintenir une température du corps constante, les mammifères doivent ajuster leur NST en fonction de la température ambiante. La NST devrait être donc plus importante que la croissance et la reproduction durant l'hiver que lors l'été/à haute altitude qu'à basse altitude. En effet, plusieurs études ont déjà démontré la dépendance de la NST aux divers paramètres environnementaux. Par contre, l'héritabilité de la NST ainsi que sa relation avec d'autres traits de caractère, ne sont que très peu connus, ceci malgré l'importance d'une telle information afin de pouvoir comprendre son potentiel évolutif. L'étude de l'importance évolutive et écologique sur la NST chez les campagnols des champs (Microtus arvalis) fut donc le but cette thèse de doctorat. Grâce aux informations collectées sur 4 générations de campagnols (chapitre 1), une dépendance saisonnière et journalière de la NST a été démontrée: elle augmente lors des périodes froides et diminue lors de la lactation. On a démontré que bien qu'étant plastique, la variation de la NST a une composante génétique significative. Elle est corrélée avec le taux d'activité métabolique au repos indiquant des contraintes intrinsèques. A l'aide d'une expérience de jardin commune, on a pu démontrer dans le chapitre 2 que les campagnols habitant en altitude ont une capacité génétique de thermogenèse sans frisson plus haute que celles de basse altitude. Ils produisent des portées plus petites et leur descendance grandit moins vite, surtout à partir du 10ème jour ce qui coïncide avec le début de la production de chaleur endogène. En choisissant artificiellement des campagnols avec une NST faible ou grande, on a pu démontrer une relation entre la NST et la développement de la masse corporelle. Les campagnols avec une haute NST grandissent plus lentement et sont plus légères à l'âge adulte que celles ayant une basse NST. A l'aide d'un croisement interligne entre les campagnols sélectionnés (avec basse et haute NST), on a pu montrer dans le chapitre 3 des effets « parent-of-origin >> du développement massique de la descendance, indiquant une empreinte génétique parentale. Cela veut dire que l'expression d'un allele dépend de l'origine parentale. De plus, des effets « parent-of-origin » des taux de base de norépinephrine et d'irisine ont pu être trouvés. Ces hormones sont connues pour influencer non seulement la TSF mais aussi d'autres caractéristiques. Ces influences ouvrent la voie à de nouvelles études sur la relation entre la TSF et l'histoire de vie. Dans le chapitre 4 on a démontré des effets à long terme de l'allocation des ressources en manipulant la taille des portées qui ont abouti à des différences dans l'investissement dans la reproduction et de la croissance de la descendance à la fois dans le cas de la reproduction manipulé et aussi dans le non - manipulée entre les femelles avec portées agrandies et réduites. Ensemble, ces résultats mettent en évidence le rôle central de la NST dans l'allocation des ressources sur la base d'un compromis entre le maintien et la croissance et ainsi transforme l'histoire de vie des mammifères. Ces études montrent comment les mammifères peuvent répondre rapidement à court et à long terme (c'est-à-dire par des réponses génétiques ou plastiques) à un changement rapide du climat. On montre aussi qu'il y a probablement une corrélation entre l'histoire de vie et des changements du comportement. Finalement mes résultats ont montré un lien étroit entre la NST et la croissance et les dimensions du corps. Ces résultats indiquent que le tissu adipeux brun et la NST pourraient être une cible thérapeutique intéressante pour traiter l'obésité.

Symbiotic effectiveness and ecological characterization of indigenous Rhizobium loti populations in Uruguay

The objectives of this work were to describe the distribution, density and seasonal variation of the indigenous populations of Rhizobium loti in different Uruguayan soils and to determine the symbiotic effectiveness and stress tolerance factors of different isolates, both with the aim of obtaining selected strains to re-introduce as inoculants in Lotus pastures. R. loti was present in ten soils studied and their densities varied from year to year and within each soil. All the isolates nodulated Lotus corniculatus effectively. The nodules in Lotus pedunculatus and Lotus subbiflorus were small, red on the surface and ineffective in nitrogen fixation. The study of 50 isolates from the ten soils showed high variability in their symbiotic efficiency and tolerance to pH. The indigenous population was acid tolerant in culture medium (pH 4.5), 83% of them could grow at pH 4.5 in 3 days. This work showed that there was a great diversity between the strains of R. loti isolated from Uruguayan soils and supports the importance of selecting among them the most efficient and resistant strains to be included in the inoculants.

Modelling hydrodynamics in the Rio Parana, Argentina : an evaluation and inter-comparison of reduced-complexity and physics based models applied to a large sand-bed river

Depth-averaged velocities and unit discharges within a 30 km reach of one of the world's largest rivers, the Rio Parana, Argentina, were simulated using three hydrodynamic models with different process representations: a reduced complexity (RC) model that neglects most of the physics governing fluid flow, a two-dimensional model based on the shallow water equations, and a three-dimensional model based on the Reynolds-averaged Navier-Stokes equations. Row characteristics simulated using all three models were compared with data obtained by acoustic Doppler current profiler surveys at four cross sections within the study reach. This analysis demonstrates that, surprisingly, the performance of the RC model is generally equal to, and in some instances better than, that of the physics based models in terms of the statistical agreement between simulated and measured flow properties. In addition, in contrast to previous applications of RC models, the present study demonstrates that the RC model can successfully predict measured flow velocities. The strong performance of the RC model reflects, in part, the simplicity of the depth-averaged mean flow patterns within the study reach and the dominant role of channel-scale topographic features in controlling the flow dynamics. Moreover, the very low water surface slopes that typify large sand-bed rivers enable flow depths to be estimated reliably in the RC model using a simple fixed-lid planar water surface approximation. This approach overcomes a major problem encountered in the application of RC models in environments characterised by shallow flows and steep bed gradients. The RC model is four orders of magnitude faster than the physics based models when performing steady-state hydrodynamic calculations. However, the iterative nature of the RC model calculations implies a reduction in computational efficiency relative to some other RC models. A further implication of this is that, if used to simulate channel morphodynamics, the present RC model may offer only a marginal advantage in terms of computational efficiency over approaches based on the shallow water equations. These observations illustrate the trade off between model realism and efficiency that is a key consideration in RC modelling. Moreover, this outcome highlights a need to rethink the use of RC morphodynamic models in fluvial geomorphology and to move away from existing grid-based approaches, such as the popular cellular automata (CA) models, that remain essentially reductionist in nature. In the case of the world's largest sand-bed rivers, this might be achieved by implementing the RC model outlined here as one element within a hierarchical modelling framework that would enable computationally efficient simulation of the morphodynamics of large rivers over millennial time scales. (C) 2012 Elsevier B.V. All rights reserved.

Training referential communicative skills to individuals with autism spectrum disorder: a pilot study

Summary. The present study reports the effects of referential communication training in individuals formally diagnosed with autism spectrum disorder (ASD). Participants were 20 children with ASD (M age = 14.3 yr., SD = 4.2; 6 girls, 14 boys) in the role of speakers and 20 control children, who acted as listeners. They were all enrolled in mainstream compulsory education. Inclusion/exclusion criteria were defined according to the clinical diagnosis of ASD, the presence or absence of additional or associated disability, previous training in referential communication, and any drug treatment. Speakers were randomly assigned to one of two groups (trained vs untrained). Linguistic age, cognitive level, and autistic symptoms were analyzed, respectively, with the Peabody Picture Vocabulary Test (PPVT), the Wechsler Intelligence Scale (WISCR or WAISIII), and the Autistic Behavior Checklist (ABC). Communicative abilities were analyzed through two indexes related to message complexity and self-regulation. The trained group was trained in referential communication tasks (task analysis, role taking, and task evaluation), while the untrained group took part in a communicative game but without any specific communicative training. The results showed that the complexity of emitted messages had improved statistically significantly in the trained group as an effect of training. Ecological referential communication is shown to be an appropriate paradigm for studying the communicative process and its products and could be used to develop and implement a training program focused on those skills in which individuals with ASD are most deficient.

Cellular source and mechanisms of high transcriptome complexity in the Mammalian testis.

Understanding the extent of genomic transcription and its functional relevance is a central goal in genomics research. However, detailed genome-wide investigations of transcriptome complexity in major mammalian organs have been scarce. Here, using extensive RNA-seq data, we show that transcription of the genome is substantially more widespread in the testis than in other organs across representative mammals. Furthermore, we reveal that meiotic spermatocytes and especially postmeiotic round spermatids have remarkably diverse transcriptomes, which explains the high transcriptome complexity of the testis as a whole. The widespread transcriptional activity in spermatocytes and spermatids encompasses protein-coding and long noncoding RNA genes but also poorly conserves intergenic sequences, suggesting that it may not be of immediate functional relevance. Rather, our analyses of genome-wide epigenetic data suggest that this prevalent transcription, which most likely promoted the birth of new genes during evolution, is facilitated by an overall permissive chromatin in these germ cells that results from extensive chromatin remodeling.

Dissecting the role of low-complexity regions in the evolution of vertebrate proteins

Low-complexity regions (LCRs) in proteins are tracts that are highly enriched in one or a few aminoacids. Given their high abundance, and their capacity to expand in relatively short periods of time through replication slippage, they can greatly contribute to increase protein sequence space and generate novel protein functions. However, little is known about the global impact of LCRs on protein evolution. We have traced back the evolutionary history of 2,802 LCRs from a large set of homologous protein families from H.sapiens, M.musculus, G.gallus, D.rerio and C.intestinalis. Transcriptional factors and other regulatory functions are overrepresented in proteins containing LCRs. We have found that the gain of novel LCRs is frequently associated with repeat expansion whereas the loss of LCRs is more often due to accumulation of amino acid substitutions as opposed to deletions. This dichotomy results in net protein sequence gain over time. We have detected a significant increase in the rate of accumulation of novel LCRs in the ancestral Amniota and mammalian branches, and a reduction in the chicken branch. Alanine and/or glycine-rich LCRs are overrepresented in recently emerged LCR sets from all branches, suggesting that their expansion is better tolerated than for other LCR types. LCRs enriched in positively charged amino acids show the contrary pattern, indicating an important effect of purifying selection in their maintenance. We have performed the first large-scale study on the evolutionary dynamics of LCRs in protein families. The study has shown that the composition of an LCR is an important determinant of its evolutionary pattern.

Ecological niche overlap in sister species: how do oil-collecting bees Macropis europaea and M. fulvipes (Hymenoptera: Melittidae) avoid competition and hybridization?

Oil-collecting bees are found worldwide and always in association with particular oil-producing flowers. In the Western Palearctic, three oil-collecting bee species within the genus Macropis (Hymenoptera, Melittidae) interact in a tight pollination mutualism with species of the only European oil-producing plant genus Lysimachia L. (Myrsinaceae). Two of these oil-collecting bees (Macropis europaea and Macropis fulvipes) show overlapping geographic distributions, comparable morphologies, and similar ecological characteristics (e.g., habitat type, floral preferences). In view of these similarities, we presume that hybridization should occur between the two species unless potential variation among the species' ecological niches prevents it, simultaneously decreasing competition for resources. Using modern genetic analyses and ecological niche modeling on a large bee sampling throughout Europe, we discuss new perspectives on the ecology and evolutionary history of this mutualism.

Rethinking study and management of agricultural systems for policy design

There is a concern that agriculture will no longer be able to meet, on a global scale, the growing demand for food. Facing such a challenge requires new patterns of thinking in the context of complexity and sustainability sciences. This paper, focused on the social dimension of the study and management of agricultural systems, suggests that rethinking the study of agricultural systems entails analyzing them as complex socio-ecological systems, as well as considering the differing thinking patterns of diverse stakeholders. The intersubjective nature of knowledge, as studied by different philosophical schools, needs to be better integrated into the study and management of agricultural systems than it is done so far, forcing us to accept that there are no simplistic solutions, and to seek a better understanding of the social dimension of agriculture. Different agriculture related problems require different policy and institutional approaches. Finally, the intersubjective nature of knowledge asks for the visualization of different framings and the power relations taking place in the decision-making process. Rethinking management of agricultural systems implies that policy making should be shaped by different principles: learning, flexibility, adaptation, scale-matching, participation, diversity enhancement and precaution hold the promise to significantly improve current standard management procedures.