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19 Pág., Microgeographical adaptation occurs when the effects of directional selection persist despite gene flow. Traits and genetic loci under selection can then show adaptive divergence, against the backdrop of little differentiation at other traits or loci. How common such events are and how strong the selection is that underlies them remain open questions. Here, we discovered and analysed microgeographical patterns of genomic divergence in four European and Mediterranean conifers with widely differing life-history traits and ecological requirements (Abies alba MIll., Cedrus atlantica [Endl.] Manetti, Pinus halepensis Mill. and Pinus pinaster Aiton) by screening pairs from geographically close forest stands sampled along steep ecological gradients. We inferred patterns of genomic divergence by applying a combination of divergence outlier detection methods, demographic modelling, Approximate Bayesian Computation inferences and genomic annotation to genomic data. Surprisingly for such small geographical scales, we showed that selection is strong in all species but generally affects different loci in each. A clear signature of selection was systematically detected on a fraction of the genome, of the order of 0.1%-1% of the loci depending on the species. The novel modelling method we designed for estimating selection coefficients showed that the microgeographical selection coefficient scaled by population size (Ns) was 2-30. Our results convincingly suggest that selection maintains within-population diversity at microgeographical scales in spatially heterogeneous environments. Such genetic diversity is likely to be a major reservoir of adaptive potential, helping populations to adapt under fluctuating environmental conditions., Agence Nationale de la Recherche, Grant/ Award Number: FLAG project (ANR-12- ADAP-0007-01); European Commission, Grant/Award Number: TOPWOOD project (MSCA-RISE-2014-645654- TOPWOOD) and grant agreement No. 676876 (GenTree); Ministère de l'Écologie, du Développement Durable et de l'Énergie, Grant/Award Number: GRAAL project (10-MCGOT-GICC-8-CVS-139)

International audience; Tropical rainforests are one of the most diverse ecosystems worldwide, yet the mechanisms driving the spatial distribution of their biodiversity remain poorly understood. Here, we tested the effects of elevation, sampling method and their interaction on alpha and beta diversities of spider assemblages between two close elevations in one tropical forest of French Guiana. Through a standardized protocol, both ground- and vegetation-dwelling (up to 2.5-m high) assemblages were sampled at medium and high elevations, during day and night using 3 complementary methods (beating, sweeping, and nocturnal hand collecting). Despite a lower total number of species at high elevation, we found no significant effect of elevation on mean species richness. However, elevation had a significant effect on species composition, notably with less web builders and more ground hunters at higher elevations. In addition, we found a significant effect of sampling methods on both estimated species richness and composition. These results suggest that even slight elevation shape spider assemblages of tropical forests, which probably contributes to the high turn-over and amazing gamma diversity of these ecosystems.

A critical hurdle in ant venom proteomic investigations is the lack of databases to comprehensively and specifically identify the sequence and function of venom proteins and peptides. To resolve this, we used venom gland transcriptomics to generate a sequence database that was used to assign the tandem mass spectrometry (MS) fragmentation spectra of venom peptides and proteins to specific transcripts. This was performed alongside a shotgun liquid chromatography&ndash, mass spectrometry (LC-MS/MS) analysis of the venom to confirm that these assigned transcripts were expressed as proteins. Through the combined transcriptomic and proteomic investigation of Paraponera clavata venom, we identified four times the number of proteins previously identified using 2D-PAGE alone. In addition to this, by mining the transcriptomic data, we identified several novel peptide sequences for future pharmacological investigations, some of which conform with inhibitor cysteine knot motifs. These types of peptides have the potential to be developed into pharmaceutical or bioinsecticide peptides.

International audience; Adaptation is a major stake of forest management in the climate change context The genetic diversity of forest trees confers them a huge – yet not boundless – adaptive potential Taking evolutionary mechanisms into account in adaptive forest management practices will reinforce the capacity of managed forests to respond to climate-induced changes and hazards By laying the emphasis on forests under natural regeneration conditions,we propose a general conceptual framework that includes knowledge on these mechanisms in decision- making processes, in a silvicultural approach through and for evolution This general framework will encompass diverse and complex local situations by relying on knowledge of local contexts from forest managers. We developed a simple analysis grid based on a small number of parameters characterising evolutionary mechanisms to understand the impact of silvicultural practices on the genetic diversity dynamics and the maintenance of the evolutionary potential of forest tree populations After recalling the current state of knowledge on the evolutionary mechanisms of forest trees, we examined the expected effects of current or innovative silvicultural practices on these mechanisms To illustrate the complexity of these interacting mechanisms, we further studied the evolutionary consequences of biotic interactions and of interactions in a highly heterogeneous environment Silviculture through and for evolution can contribute to the adaptation of forests to climate change This will require combining short-term and long-term objectives We further propose lines ofresearch and experimentation to support this approach.; L’adaptation est un enjeu majeur de la gestion forestière dans le contexte du changement climatique La diversité génétique qui caractérise les arbres forestiers leur confère un potentiel adaptatif très important mais pas illimité Prendre en compte les mécanismes de l’évolution dans les pratiques de gestion forestière adaptative renforcera la capacité des forêts gérées à répondre aux changements et aux aléas induits par le climat. En mettant l’accent sur le cas des forêts en régénération naturelle, nous proposons un cadre conceptuel général permettant d’intégrer la connaissance de ces mécanismes dans la prise de décision, dans une démarche de sylviculture par et pour l’évolution Ce cadre général pourra être décliné dans des situations locales diverses et complexes en s’appuyant sur la connaissance du contexte qu’ont les gestionnaires forestiers Nous développonsune grille d’analyse simple, basée sur un petit nombre de paramètres caractérisant les mécanismes de l’évolution, pour comprendre l’impact des pratiques sylvicoles sur la dynamique de la diversité génétique et le maintien du potentiel d’évolution des populations d’arbres forestiers Après avoir rappelé l’état des connaissances sur les mécanismes de l’évolution chez les arbres forestiers, nous examinons les effets attendus de pratiques forestières actuelles ou innovantes sur ces mécanismes Pour illustrer la complexité des mécanismes en interaction, nous développons plus en détail les conséquences évolutives des interactions biotiques et celles d’un environnement fortement hétérogène La sylviculture par et pour l’évolution peut contribuer à l’adaptation des forêts au changement climatique Elle nécessite de combiner des objectifs à court et à long terme Nous proposons des pistes de recherche et d’expérimentation pour accompagner cette démarche.

Rivers of French Guiana are still little invaded by non-native fish, but several fish introductions were recently recorded through the development of aquarium fish trade and fish farms. Here we report records of 11 non-native fish species. Among them, four (Cichla monoculus, Heros efasciatus, Mesonauta guyanae and Poecilia reticulata) are established and one of them (Heros efasciatus) is rapidly increasing its spatial range. Two species (Hyphessobrycon eques and Pterophyllum scalare) were not retrieved in recent records and are probably extinct from French Guiana. The establishment status of the five other species (Arapaima gigas, Colossoma macropomum, Cyprinus carpio, Oreochromis mossambicus and Osteoglossum bicirrhosum) is uncertain and only a few specimens were observed in the wild. Nevertheless, these species, intensively reared in nearby countries, belong to highly invasive species able to cause detrimental impacts on recipient ecosystems. Those first occurrences of invasive fish species in French Guiana should therefore act as an early warning for both researchers and environmental managers.

The evolutionary potential of long-lived species, such as forest trees, is fundamental for their local persistence under climate change (CC). Genome–environment association (GEA) analyses reveal if species in heterogeneous environments at the regional scale are under differential selection resulting in populations with potential preadaptation to CC within this area. In 79 natural [i]Fagus sylvatica[/i] populations, neutral genetic patterns were characterized using 12 simple sequence repeat (SSR) markers, and genomic variation (144 single nucleotide polymorphisms (SNPs) out of 52 candidate genes) was related to 87 environmental predictors in the latent factor mixed model, logistic regressions and isolation by distance/environmental (IBD/IBE) tests. SSR diversity revealed relatedness at up to 150m intertree distance but an absence of large-scale spatial genetic structure and IBE. In the GEA analyses, 16 SNPs in 10 genes responded to one or several environmental predictors and IBE, corrected for IBD, was confirmed. The GEA often reflected the proposed gene functions, including indications for adaptation to water availability and temperature. Genomic divergence and the lack of large-scale neutral genetic patterns suggest that gene flow allows the spread of advantageous alleles in adaptive genes. Thereby, adaptation processes are likely to take place in species occurring in heterogeneous environments, which might reduce their regional extinction risk under CC

Devil's gardens are one of the most remarkable mutualistic associations between ants and plants. Myrmelachista ants eliminate all vegetation from around their host plants, resulting in wide forest clearings which have intrigued scientists from the start. Despite their noticeability, here we report the discovery of devil's gardens in remote highland cloud forests of the Eastern Amazon, more than 2000 km away from their nearest known analogues in Western Amazonia. We describe the ecological characteristics of these gardens and consider what factors could have produced the geographic isolation of Eastern Amazonian devil's gardens. Three hypotheses are investigated: (1) the host plant distribution restricts the distribution of the mutualism, (2) the ecological tolerances of Myrmelachista explain the isolation, and (3) the devil's gardens of the Eastern Amazon constitute relicts from ancient forest refugia. The distribution of the possible associated myrmecophytes and previously described ecological ranges of devil's gardens cannot explain their ecological restriction to cloud forests in Eastern Amazonia, but our discovery is consistent with the biogeographic refuge hypothesis (i.e. highlands along the Amazon Basin constitute refugia for humid forests that spread during the Cenozoic). Our finding opens exciting perspectives for comparative studies of the origin, ecology and evolutionary history of this ant–plant mutualism.

International audience; No abstract available

International audience; & Context Managing forests under climate change requires adaptation. The adaptive capacity of forest tree populations is huge but not limitless. Integrating evolutionary consider-ations into adaptive forestry practice will enhance the ca-pacity of managed forests to respond to climate-driven changes. & Aims Focusing on natural regeneration systems, we pro-pose a general framework that can be used in various and complex local situations by forest managers, in combination with their own expertise, to integrate evolutionary consid-erations into decision making for the emergence of an evolution-oriented forestry. & Methods We develop a simple process-based analytical grid, using few processes and parameters, to analyse the impact of forestry practice on the evolution and evolvability of tree populations. & Results We review qualitative and, whenever possible, quantitative expectations on the intensity of evolutionary drivers in forest trees. Then, we review the effects of actual and potential forestry practice on the evolutionary processes. We illustrate the complexity of interactions in two study cases: the evolutionary consequences for forest trees of biotic in-teractions and of highly heterogeneous environment. & Conclusion Evolution-oriented forestry may contribute adapting forests to climate change. It requires combining short-term and long-term objectives. We propose future lines of research and experimentation.