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Revisiting the systematics of Brevipalpus flat mites (Tenuipalpidae): phylogeny, species groups and cryptic diversity
No full textPeer reviewed and recommended by PCI Zoology, https://doi.org/10.24072/pci.zool.100359.Supplementary figures and tables are available online (https://hal.science/hal-04907421v3; de Mendonça et al., 2025a).Data are available online (https://doi.org/10.5281/zenodo.14722287; de Mendonça et al., 2025b).International audiencePhytophagous mites in the genus Brevipalpus (Tenuipalpidae) can be major pests, causing direct damage to their host plants or vectoring viruses. However, a phylogeny-based classification to understand their evolution and predict their bioecological aspects is lacking. Accurate species identification is crucial for studying pathosystem interactions, implementing quarantine measures, and developing control strategies. This study revisited the classification of Brevipalpus based on phylogenetic relationships, identifying cryptic species and determining genetic distance boundaries. A multi-tool exploration of DNA datasets, including mitochondrial (two COI regions) and nuclear (ITS2 and D1-D3) data combined with a detailed morphological study using light and scanning microscopy, was performed. Specimens were collected from 20 host plant families from South America, Europe, and the Middle East. Species were discriminated using three different approaches, namely, Automatic Barcode Gap Discovery (ABGD), Assemble Species by Automatic Partition (ASAP), and a local regression to establish consistent genetic distance thresholds. Results indicate that the current species-group classification only partially matches that based on genetic lineages. Some species currently classified as belonging to the phoenicis and cuneatus species groups were found to be polyphyletic and related to species placed in other species groups. A rearrangement of the species groups to align with the observed genetic lineages is proposed, and phylogenetically informative morphological traits are defined. Cryptic diversity in certain taxa was consistently confirmed by various methods. Nuclear and mitochondrial markers were essential for identifying candidate lineages when morphology alone was insufficient. Nuclear markers detected host-associated lineages within certain species. Inconsistencies between markers and methods suggest the presence of ongoing speciation processes, and hypotheses about speciation events were explored. Intra- and interspecific genetic distances and threshold values were determined for the four studied genomic fragments and can be used for routine taxonomic identification and uncovering cryptic lineages. Further research should combine genetic data, carefully selected markers, and thorough morphological analyses before proposing new species
Out‐of‐Africa: Origin of the Disjunct Distribution of Paleotropical Eneopterinae Crickets (Gryllidae, Xenogryllini)
No full textInternational audienceMany groups of terrestrial plants and animals display a disjunct distribution pattern in the Paleotropics, being found almost exclusively in tropical Africa and Asia. The origin of such a pattern may be manifold, particularly for older lineages where plate tectonics potentially played an important role. Several potential colonisation routes may have been involved in dispersal events between the Afrotropics and tropical Asia, not to mention long-distance dispersal events through island hopping. To advance in the understanding of disjunct Paleotropical distributions, we focus on a tribe of Paleotropical crickets, the Xenogryllini. They supposedly originated in the Early Eocene, thus experiencing multiple past geological and environmental changes during their diversification. Resolving the evolutionary history of Xenogryllini is thus expected to shed light on the biogeographic processes that generated disjunct Paleotropical distributions. To tackle this, we assembled a multi-marker molecular dataset for the tribe encompassing all species. We carried out phylogenetic, molecular dating, and historical biogeography analyses. Our results provide a highly supported phylogenetic hypothesis for the tribe and suggest an out-of-Africa origin with several independent dispersal events towards Asia, likely involving distinct colonisation routes in the Neogene
Doping feruloylated arabinoxylan covalent hydrogels with cellulose nanocrystals
No full textInternational audienceAlthough quite abundant, feruloylated arabinoxylans are poorly valued today. They are water soluble and lead to covalent hydrogels simply by oxidation of the ferulic moieties 1. These macroporous hydrogels, with mesh sizes ranging from 40 to 400 nm, are stable whatever the pH and ionic strength, and can absorb up to 150 grams of water per gram of polymer. While their structure and swelling capacity make them good candidates as encapsulation matrices 2, their mechanical strength (elastic modulus of the order of 100 Pa) needs to be improved to extend their use as materials.The study investigates the enhancement of viscoelastic properties in feruloylated arabinoxylan (F-WEAX) hydrogels by incorporating cellulose nanocrystals (CNC). F-WEAX, a cereal cell wall polysaccharide, was crosslinked using laccase in the presence of CNC, with CNC/F-WEAX weight ratios ranging from 0 to 1.5. The addition of CNC significantly increased gel stiffness, with the elastic modulus scaling as [CNC]³. CNC also influenced relaxation behavior, enhancing the loss factor at low frequencies.Quartz crystal microbalance with dissipation (QCM-D) measurements showed that F-WEAX adsorbed irreversibly onto CNC, similar to non-feruloylated arabinoxylans. In the presence of CNC, laccase action led to twice as many elastically active oxidation products, namely dimer and trimer forms of ferulic acid (FA). Consequently, the swelling capacity of F-WEAX-CNC gels decreased but less than expected from the increase in shear modulus. This synergistic enhancement of elasticity while maintaining swelling capacity is attributed to the formation of high-functionality junctions through the irreversible adsorption of F-WEAX onto CNC.The study concludes that the introduction of CNC prior to F-WEAX gelation significantly improves elastic properties more effectively than increasing F-WEAX concentration alone. This is due to the high affinity of F-WEAX for CNC, increased cross-link density, and the formation of multi-armed junctions. The findings highlight the potential of CNC in enhancing the mechanical properties of biopolymer hydrogels, which can be achieved through simple mixing. (1) Izydorczyk, M.; Biliaderis, C.; Bushuk, W. Journal of Cereal Science 1990, 11 (2), 153-169.(2) Paz‐Samaniego, R.; Rascón‐Chu, A.; Brown‐Bojorquez, F.; Carvajal‐Millan, E.; Pedroza‐Montero, M.; Silva‐Campa, E.; Sotelo‐Cruz, N.; López‐Franco, Y. L.; Lizardi‐Mendoza, J. Journal of Applied Polymer Science 2018, 135 (26)
Improving rice-fish farming systems: complexity, heterogeneity, and the promise of co-design solutions
No full textInternational audienceIn Guinea and Madagascar, rice cultivation plays a central role in the country's food security. 80% of farms in these countries produce rice, and Guineans and Malagasy consume 110 and 120 kg of rice per capita per year, respectively. Fish is also the main protein consumed in Guinea, at 24 kg per capita per year, whereas fish is a rare food in Madagascar. Indeed, on this island, the population can consume only 4 kg of fish per inhabitant per year, compared with a world average of 10 kg per inhabitant.Rice-fish farming is an Asian model that can improve both rice and fish production and two notable initiatives seem to be spreading in Madagascar. The complexity of this system creates challenges for testing and identifying innovations that could improve its efficiency. One of the obstacles to optimizing the rice-fish system lies in understanding how it operate, which makes it difficult to optimize through conventional agricultural interventions. In light of this context, the study explores the internal mechanisms of these systems: their biological, technical or spatial complexity, and the inter- and intra-regional variability in agricultural performance. The results are discussed in terms of the usefulness of mobilizing farmer experimentation and co-design in the search for agroecological intensification of rice-fish farming systems.Our research indicates greater emphasis on co-designing agrifood systems research in South Asia is required to increase the resilience and sustainability of smallholder production systems, and the effectiveness of investments by donors and governments and increase. Smallholder farmers must be supported to incorporate new management practices to ensure these are scaled effectively and rapidly, thus maximizing the value of research and the investments underpinning it. This approach has important learnings for researchers, donors and policymakers, particularly across South Asia where methods of effectively scaling interventions have not been sufficiently widely incorporated into domestic and international research agendas
Multicriteria assessment of cropping systems performances in Madagascar highlands reveals trade-offs between agroecology principles
No full textInternational audienceThe context of family farming in Madagascar's highlands calls for tailored criteria to inform farmers and decision-makers about the strengths and limitations of agroecological practices. Here we suggest a set of 11 indicators considered relevant for assessing the sustainability of these cropping systems, essentially focused on subsistence. These indicators aim to assess the relevance of cropping systems in terms of food production, maintenance of soil fertility, connection with livestock systems, profitability, and labor productivity. They were selected to evaluate sustainability aspects at the field level, while also addressing issues from a systemic perspective: at farm (fodder availability, labor)and territory levels (biomass use). We have applied these indicators to two contrasting systems: rice monocropping and rotation of rice-fish farming and potato, with differentfertilization methods.Farming systems sustainability can hardly be assessed based on field scale evaluation, as there are many trade-offs and synergies between sustainability components emerging at farm scale. Based on this diagnosis of cropping systems, a farm model will be mobilized to evaluate the feasibility of these cropping systems at farm scale, i.e. taking into account resource availability at the household level. In addition to this contextualization of cropping systems, the modeling process will allow exploring different scenarios of agroecological innovation at farm scale
Development of a “hydro-reporter” to unravel the early phases of water deficit in plants
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Exploration du rôle des objets du paysage agricole dans la visualisation des systèmes Socio-techniques
No full textInternational audienceThis study explores agricultural landscape objects' role in visualizing socio-technical systems through a scoping review of scientific literature. Agricultural landscape objects are spatially discernible elements shaped by the interactions between natural processes and human activities, particularly farming practices. A systematic review of 62 studies—selected out of 1066 documents (1988–2025)—retrieved from the Web of Science database allowed us to identify four primary roles of these objects: (i) interfaces between technical and social systems, (ii) enablers for the spatialization of changes and processes, (iii) supports for ecosystem services, and (iv) mediators between perceptions and biophysical reality. These objects, including cultivated fields, livestock facilities, and terraces, facilitate understanding of how social practices and spatial elements mutually design agricultural landscapes. The results can help to inform future agent-based model development for farming system modeling and landscape management strategies
Comparison of two participatory approaches for agroecological design: consultative vs collaborative
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Unveiling lipid and oxylipin composition in the coffee leaves throughout coffee cherry maturation
No full textInternational audienceThis study investigates the evolution of lipids, oxylipins (phytoprostanes (PhytoPs) and phytofurans (PhytoFs)), and alkaloids in Mexican Coffea arabica leaves as coffee cherries mature. The impact of drying methods on leaf composition was also examined. Lipid extraction was performed using a binary MTBE/MeOH mixture. Fatty acid profiling was conducted by GC-FID. HPTLC was used to identify lipids (free fatty acids, acylglycerols, sterols, sterol esters, glycolipids, phospholipids, tocopherol), diterpenes (cafestol and kahweol), and alkaloids (caffeine and theobromine). A micro-HPLC-QTRAP analysis was used to identify and quantify oxylipins. The drying method influenced the leaves total lipid extraction. Freeze-dried leaves (HL) had higher lipid content than vacuum oven-dried leaves (HS). Total lipids decreased and oxylipin content varied with cherry maturity. The predominant fatty acid in coffee leaves was C18:3. This study reveals coffee leaves as a significant source of PhytoPs and PhytoFs for the first time
Individual, Collective, or Both ? Payment Mechanisms and Adoption of Sustainable Land-Use Systems
No full textThe adoption of sustainable land-use systems (SLUS) remains low among smallholder farmers in Sub-Saharan Africa, mainly due to immediate costs and risks outweighing short-term benefits. This study examines how different payments for environmental services (PES) mechanisms can incentivize SLUS adoption among smallholder farmers in Zimbabwe, assuming a critical mass adoption would enhance environmental services. Using a framed lab-in-the-field experiment with 588 farmers, we modeled SLUS adoption as a threshold public good game and compared three PES mechanisms: individual payments unconditional on reaching an adoption threshold, collective payments conditional on reaching adoption threshold, and a combined approach incorporating both payment types. We also investigated policy framing effects on adoption decisions and explored prosocial and risk preferences' role in decision-making. Results show only the combined payment scheme successfully achieved the SLUS adoption threshold. When the same payment structure was implemented without explicit explanation of the additional payment, contributions dropped to control group levels, highlighting policy framing's crucial role. Social preferences and risk attitudes showed minimal correlation with adoption decisions, although farmers exhibiting other-regarding preferences in the dictator game contributed more to the threshold public good game. These findings advance our understanding of PES design by demonstrating that combining individual and collective payments can overcome coordination challenges in SLUS adoption, while emphasizing clear communication in program implementation