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Geographic variation in floral scent reinforces local pollinator attraction in the fig–fig wasp mutualism
No full textInternational audienceBackgroundVolatile organic compounds (VOCs) emitted during floral receptivity are crucial for attracting pollinators, especially in brood-site pollination systems. Geographic variation in floral scent can alter host recognition cues, potentially shaping pollinator behavior in obligate mutualisms such as the fig–fig wasp system. Understanding whether and how such variation affects pollinator responses is essential for assessing the stability of these interactions. Here, we investigated geographic variation in floral scent and pollinator responses in Ficus hispida, a dioecious species widely distributed in tropical Asia.Using dynamic headspace sampling and GC-MS, we characterized receptive fig VOCs from populations in South China, Southwest China, and South Thailand. Behavioral assays tested the responses of Ceratosolen marchali wasps from the South China Botanical Garden (SCBG) and Xishuangbanna Tropical Botanical Garden (XTBG) to local versus non-local fig odors.ResultsScent profiles differed significantly among regions, forming three distinct clusters. Although C. marchali was present at both sites, Y-tube experiments revealed that wasps responded only to odors from their local population.ConclusionsThis local scent specificity may reinforce population-level mutualisms and restrict long-distance pollinator movement. While such divergence could promote reproductive isolation among closely related wasp lineages, the mechanisms allowing cryptic species to coexist on the same host remain unclear. Overall, our results highlight the key role of chemical cues in shaping plant–pollinator interactions across different populations
High-frequency fluorescence monitoring in karst aquifers: A multivariate approach for early detection of anthropogenic contamination of water resources
No full textInternational audienceKarst aquifers play an essential role in drinking water supply, but their vulnerability to anthropogenic pollution, particularly during rainfall events, requires adapted monitoring methods. In this study, we developed an approach combining high-frequency in situ measurements and laboratory analyses to characterise the intensity and occurrence of organic matter fluorescence peaks, in particular Tryptophan-Like Fluorescence (TLF) peaks, associated with faecal contamination. We adapted a background noise correction method based on multiple regression applied to multispectral signals from field fluorometers. A specific calibration in TLF equivalents of the signals from an optical sensor measuring fluorescence at 285 nm is used to quantify contamination peaks. This method was tested on a dataset including 95 samples analysed in the laboratory and high-frequency data spanning 2015–2025 at 15-minute intervals from the Lez karst spring (France), showing its effectiveness in correcting optical interferences and detecting low pollution episodes. The analysis of time series underlined the importance of high-frequency monitoring to capture rapid water flow dynamics, while confirming the indispensable complementarity of laboratory analyses to better discriminate the fluorophores controlling the intensity of high-frequency in situ signals. The results highlight critical contamination periods, particularly in autumn and spring, and confirms the suitability of TLF for Early Warning System (EWS) applications. This approach broadens the methods used for water quality management in karst environments and proposes a methodological framework transferable to other sites
Réduction des émissions de méthane entérique chez les ruminants : enjeux, solutions et perspectives à l’échelle de l’animal et des systèmes d’élevage
No full textInternational audienceReducing enteric methane emissions from ruminant livestock is a common goal of many countries to limit global warming. While direct measurements of enteric methane emissions are limited to a small number of animals, indirect predictive methods based on milk or feces can now be used to assess emissions from large numbers of animals in a variety of contexts. These approaches allow the development of genetic selection models and management practices associated with lower methane emissions for small and large ruminants. A better understanding of the relationships between rumen microbial diversity and the ruminant (host) will help to identify new solutions for modulating rumen microbial populations and hydrogen fluxes, with the aim of reducing methane emissions while maintaining animal production and health. Ruminant diets and herd management are important ways to reduce enteric methane emissions, but the practices are not always suitable for the different pedoclimatic contexts, particularly in hot regions. Trade-off must be evaluated to identify combinations of levers that can reduce enteric methane emissions without compromising the health of animals and the ecosystem services associated with ruminant livestock systems.La réduction des émissions de méthane entérique associées aux systèmes d’élevage de ruminants est l’un des objectifs de lutte contre le changement climatique pour de nombreux pays. Si les mesures directes des émissions de méthane entérique sont limitées dans leur déploiement à un petit nombre d’animaux, des méthodes indirectes de prédiction via le lait ou les fèces peuvent être appliquées à un grand nombre d’animaux dans des contextes variés. Ces approches permettent de développer de nouveaux modèles de sélection génétique ou de conduites d’élevage des petits et gros ruminants associées à des niveaux d’émissions de méthane entériques plus faibles. Les recherches pour comprendre les relations entre la diversité microbienne du rumen et les phénotypes des ruminants contribuent à l’identification de nouveaux leviers pour moduler les populations microbiennes et les flux d’hydrogène dans le rumen, avec l’ambition de réduire les émis-sions de méthane tout en préservant la production et la santé de l’animal. L’alimentation et la conduite des troupeaux constituent aussi des leviers d’intérêt, mais leurs effets sur la réduction des émissions de méthane entérique sont variables selon les contextes pédoclimatiques, notamment en régions chaudes. Des stratégies combinant différents leviers doivent être identifiées pour réduire efficacement les émissions de méthane sans compromettre la santé de l’animal et les services écosystémiques rendus par leurs systèmes d’élevage
Spatio-temporal generation of precipitation using a Hidden Markov Model, extended extreme distributions and conditional Gaussian fields
No full textCurrent weather generators struggle to capture large-scale spatio-temporal variability in rainfall occurrence and intensity. To address this challenge, this study develops a spatio-temporal weather generator for daily precipitation across multiple stations by extending the classical multivariate hidden Markov model to a spatial framework. Both occurrence and intensity processes are driven by spatio-temporal latent fields with distinct covariance structures, allowing for different dynamical behaviours. The rainfall intensity process is simulated conditionally on the occurrence process, ensuring continuity between dry and wet conditions in both time and space. Model inference relies on a novel hybrid Expectation-Maximisation algorithm designed to address the intractability of the complete likelihood, while achieving substantial computational gains compared to compositelikelihood EM approaches. The generator is applied to 51 years of daily precipitation data from 37 weather stations across France. Four interpretable hidden states are identified, whose most probable temporal sequence is consistent with known meteorological patterns. The generator is assessed through several model-agnostic metrics, targeting marginal, pairwise, spatial, and spatiotemporal properties. Results demonstrate that the proposed generator accurately reproduces rainfall statistics across a wide range of spatial and temporal scales, including droughts and extreme precipitation events, validating its relevance for climate impact assessment
Spatio‐temporal patterns and risk factors of wild boar–pig farm contact across Europe
No full textInternational audienceAbstract Diseases circulating at the wild–domestic animal interface are increasingly difficult to control due to human encroachment into wildlife habitats. Understanding the factors driving wild animals to visit livestock farms is crucial for reducing the risk of disease outbreaks with severe economic and social consequences. In this study, we quantified the contact rate at the wild boar–domestic pig interface across Europe using a large‐scale dataset of wild boar GPS tracking and domestic pig farm geolocations. We estimated wild boar contact rate with pig farms at hourly and monthly scales and analysed the influence of environmental, wild boar‐ and farm‐related variables. Across 187 tracked wild boars and 457 pig farms, we detected 3322 contact events, with a highly skewed contact distribution: only 5% of wild boars and 1% of farms accounted for 50% of all events. On average, each wild boar had 1.59 contacts per month with a given farm (95% CI: 1.33–1.85) and 2.58 contacts per month when considering all farms located within its monthly home range (95% CI: 1.62–3.53). Seasonal variation differed between sexes, with a bimodal distribution for males with contact rates peaking in March and August–September, and a slight increase in contact rate throughout winter for females. Monthly contact rate increased with forest cover, human footprint, wild boar population density and individual proximity to pig farms. Farms with more built infrastructure faced fewer contacts, and larger farms had higher contact rates. Contacts occurred mostly after sunset and around sunrise. Synthesis and applications . Our results highlight the need to incorporate wild boar spatio‐temporal behaviour and farm context into strategies aimed at reducing contact at the wild–domestic pig interface. While physical barriers and avoiding unintentional feeding remain essential, targeted measures during high‐risk periods, such as night‐time surveillance in summer and autumn, especially around large farms in wooded landscapes or areas with high wild boar density, could help reduce contact occurrence
New species of Endaeus Schoenherr, 1826 (Curculionidae: Curculioninae: Ochyromerini) associated with Annonaceae and Clusiaceae
No full textInternational audienceRepresentatives of the weevil tribe Ochyromerini (Coleoptera: Curculionidae: Curculioninae) have been increasingly reported as specialized pollinators of Annonaceae Juss., with some species in the genus Endaeus Schoenherr, 1826 engaging in brood-site pollination with their host. Recent investigations into the poorly documented life history of these pollinators have led to the discovery of new species in the genus Endaeus and provided details of their life histories. The following species are herein described: E. canangae Haran sp. nov. from Southeast Asia, associated with Cananga odorata (Lam.) Hook.f. and Thomson (Annonaceae); E. lenticulatus Haran sp. nov. from Central Africa, associated with Uvariodendron molundense (Diels) R.E.Fr. (Annonaceae); E. xylopiae Haran and Zelvelder sp. nov., E. jaculifer Haran and Zelvelder sp. nov. and E. convexiculus Haran and Zelvelder sp. nov. from Central Africa, associated with Xylopia aethiopica (Dunal) A.Rich. (Annonaceae) and E. staminicola Haran sp. nov. also from Central Africa, associated with Allanblackia floribunda Oliv. (Clusiaceae Lindl.). Pictures of habitus and terminalia of adults, molecular and morphological diagnostic tools along with life history data are provided for each species. These new associations are discussed in light of the general patterns of specialized brood-site pollination mutualism between plants and weevils
Agronomic management and soil properties dominate the production of pulses in China
No full textInternational audienceContextPlanting pulses can ensure food security and sustainable agriculture through increasing soil fertility, diversification of cropping systems, and nitrogen fixation. However, increasing the yield of pulses is an unresolved challenge due to the lack of understanding of the driving factors affecting it.Research questionsTo address this issue, a comprehensive analysis of the critical yield-limiting factors influencing pulse productivity is necessary. We synthesized national dataset of 304 observations across a north-south gradient of China to illustrate how climate (mean annual precipitation and temperature), soil properties (total carbon, total nitrogen, ammonium nitrogen, nitrate nitrogen, total phosphorus, Olsen-phosphorus, pH, electrical conductivity and soil texture) and management (fertilization, mulching film, cropping system, irrigation, selection of pulse species) affect yield of five main pulses: cowpea, faba bean, mung bean, pea and adzuki bean.ResultsThe average yield of cowpea, faba bean, mung bean, pea and adzuki bean were 1.31, 3.35, 1.39, 2.65, 1.81 t ha−1, respectively. The average yield change of pulses at the site level compared to the country-level is 33 % (ranging from −74–190 %). Management, soil properties and their interaction explained 94 % of the yield variation while the contribution of climate factors was minimal in the whole dataset. The contribution of key factors to yield depends on the selection of pulse species. Farmers should select pulse species suited best to local conditions, adopt mulching, optimize irrigation and fertilization to increase the yield of pulses.ConclusionsOverall, this analysis emphasized that proper agronomic management and soil properties are crucial for maximizing pulse production, offering practical guidance to raise productivity and support global food security
Les futurs de la bioéconomie urbaine - Quelle place pour la bioéconomie et les bioressources dans les villes françaises à l’horizon 2050 ?
No full textEco‐Evolutionary Drivers of Body Size Variation in Arthropods, With a Focus on Spiders
No full textInternational audienceAim Body size has been used thoroughly in arthropod ecology as a reliable trait to assess fitness responses to changes in environmental factors. We aim to assess general patterns of intraspecific body size variation along macroecological gradients in arthropods. We more specifically discuss these patterns in spiders, as they represent a large and diverse group, colonising most terrestrial habitats. Location: Global. Time Period: 1982–2024. Major Taxa Studied: Arthropods. Methods We propose a systematic review and a meta‐analysis of 146 studies on intraspecific body size variation in arthropods over two main macroecological spatial gradients—latitude and elevation—both of high interest in a global warming context. Results We found that more species with direct than with indirect development present a converse Bergmann cline along both gradients. Main Conclusions We propose that life history traits such as voltinism, mobility and brood care influence intraspecific body size patterns—potentially hiding large‐scale patterns. This review gathers empirical data about body size variation along elevational and latitudinal gradients in arthropods, providing a step forward to a better understanding of the underlying mechanisms driving body size variation
