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The overall objective of the 2018 survey campaign of contaminants of emerging concern in surface waters (continental and coastal) and sediments known as EMNAT 2018, is to provide monitoring data for the emerging contaminants prioritization exercise, which will allow the update of the list of relevant substances to be monitored (SPAS), as part of the future Water Framework Directive (WFD) monitoring programmes (2022). This campaign collected nearly 14,000 data regarding 49 contaminants of emerging concern (32 biocides and 17 surfactants) in surface waters and sediments on 98 sites in mainland France and in the French overseas regions. Linear Alkylbenzene Sulfonic acids (LAS) were the most frequently quantified surfactants and at the highest median concentrations in water and sediment samples, in metropolitan France and in the overseas regions. Fipronil was the most frequently quantified biocide in water samples in metropolitan France and in the overseas regions, but at lower median concentrations than other biocides. Methyl nonyl ketone was the most frequently quantified biocide and at high median concentrations in sediment samples from mainland France and in overseas regions. Based on the available predicted no effect concentrations (PNEC), several contaminants were identified as highly and moderately critical regarding the PNEC exceedance, and will be considered to be included in the SPAS list for the next WFD cycle.

Access to high‐quality food is a main driver of population dynamics. For herbivores, protein and carbohydrates are key nutrients that are notoriously variable in plants and are affected by land use. However, few studies have linked foraging decisions and performance in the laboratory to the nutritional landscape available in the field. Oedaleus senegalensis is a non‐model locust, a grass‐feeder, and the main pest of millet, a subsistence crop in the Sahel. In this study, we examined dietary preference and locust performance across a range of protein:carbohydrate ratios using the Geometric Framework methodology. We then applied a fitness landscape approach to visualize these results with the plant nutrient contents available across four land‐use types: millet, groundnut, fallow, and grazed fields. Finally, we contrasted our results with locust distribution in the field. Several locust species (O. senegalensis included) exhibit density‐dependent colour polymorphism; thus, we also reported individual coloration (brown or green). We found that O. senegalensis preferred moderately carbohydrate‐biased food 1:1.6 protein:carbohydrate ratio. All traits recorded (mass gain, development time, growth rate, moult success and performance index) were best near that ratio and declined on either side presenting a ‘hump‐shape’. Fallow fields contained more plants, particularly grasses, that were both abundant and closer to the optimal protein:carbohydrate ratio recorded from the laboratory experiments. When we surveyed O. senegalensis abundance and proportion, we found that they were more numerous in the fallow fields. Brown morph individuals, the ones associated with high density, were proportionally more abundant in fallow fields than green individuals. Our study provides evidence that variation in nutritional landscapes – relative to an herbivore's optimal nutrient balance – is a key driver of herbivore population distribution and abundance, and can be used to predict bottom‐up effects on herbivore species.

Animal populations must be able to acquire an adequate amount of nutrients to persist regardless of what environment they are in. In highly variable environments, such as drylands where food sources are limited, this potential mismatch between physiological demands and what is available in the environment is accentuated. For herbivores, the balance of macronutrients (protein and carbohydrate) is particularly important and both nutrients are highly variable in plants both spatially and temporally. Whereas it is known that many herbivores will forage multiple plants to achieve an optimal nutritional ratio (termed the intake target), it is less known how herbivores with different life history strategies address this in variable environments. In this study, we measured the intake targets of three grasshopper species with differing life history strategies, two migratory and one non‐migratory, at three locations in New South Wales, Australia. We measured nutrient variation in plants spatially and temporally by sampling three different locations and repeated the measurement twice for one of these locations. At all three locations and both times, host plant protein differed substantially but carbohydrate content remained constant. The non‐migratory grasshopper species shifted their intake target, presumably to redress nutrient imbalances. On the other hand, the two migratory grasshopper species largely maintained the same intake target, even when in a nutritionally suboptimal environment. These results suggest that non‐migratory species are likely more limited in their capacity to forage for optimal diets and may rely more on digestion to survive in nutritionally suboptimal locations. In contrast, migratory grasshoppers may migrate to obtain the nutrients they need instead of redressing imbalances locally. Therefore, a strong metapopulation structure may aid in the persistence of migratory species at larger spatial scales. Since herbivores, especially insects, are important from nutrient cycling to food chains, understanding how populations persist in nutritionally variable environments is important to the overall ecosystem functioning. Further research should consider how nutritional demands drive population dynamics and how it changes with life history strategies.

La prevention et le traitement des escarres passe par l’utilisation de supports de redistribution des pressions pour decharger ou augmenter la surface d’appui et diminuer l’intensite des pressions. Le choix du support depend de la mobilite et du risque d’escarre du patient. Des recommandations existent pour aider au choix de la categorie de support, mais les etudes cliniques manquent pour appuyer scientifiquement l’utilisation d’un support plutot qu’un autre.

Terrestrial molluscs are some of the most important herbivores in temperate habitats. They tend to be generalists and can be serious pests in agricultural fields, particularly no-till fields used for field and forage crops; however, farmers have access to few commercially available solutions, and the existing ones present many disadvantages (e.g. reliability, cost, environmental concerns). In this paper, we review these current management options with a focus on agronomic crops, as well as the biotic factors that influence mollusc feeding, such as natural enemies, plant nutritional content, and chemical defences. These biotic factors all have important direct consequences on mollusc fitness and can be manipulated in agricultural settings. We then review evidence from the latest research in the field of nutritional ecology to propose the use of the Geometric Framework, a well-established nutritional approach, to measure nutrient regulation and performance of terrestrial molluscs and develop ecologically based management programs that also relies on susceptibility to natural enemies. To illustrate our point, we detail a specific strategy being used by farmers in the Mid-Atlantic US to manage slug populations; in this system, farmers are using cover crops terminated after the cash crop is planted (also called “planting green”) and this approach appears to harness slug nutritional preferences and natural enemies to manage slug populations.

Nitrogen limitation theory predicts that terrestrial plants should benefit from nitrogen inputs and that herbivores should benefit from subsequent higher plant protein contents. While this pattern has generally been supported, some herbivorous insects have shown preference and higher performance on low protein (p), high carbohydrate (c) diets as juveniles. However, little is known about the effects on reproduction in adults. Using nitrogen fertilizer, we demonstrate that high plant p:c has negative effects on Senegalese locust (Orthoptera: Oedaeleus senegalensis) reproduction and survival in an agroecological setting. For this, we measured p:c in millet plants Pennisetum glaucum that received two levels of fertilizer (high and moderate) and a control, then we caged locusts on these plants for 2 weeks. In the laboratory, we gave locusts the choice between untreated millet leaves and leaves that received one of the two fertilization treatment. We found that fertilization increased p:c ratio in a concentration-dependent fashion. We counted the number of locusts alive over the course of 2 weeks and showed that fewer females survived on fertilized plants than on control plants. Females that ate plants from the high fertilization treatment laid lighter eggs. Finally, we showed that female locusts prefer unfertilized plants to plants with a high p:c. We hypothesize that this pattern will apply broadly to species that have extensive carbohydrate needs, such as long-distance migrators. Because many ecological studies focus primarily on nitrogen or protein, and fail to consider carbohydrates, this study has important implications for how ecologists consider nutrient limitation of primary consumers in ecosystems globally.

The rheological properties of dough have an essential role in processing handling and quality of baked products. Understanding how measurement parameters impact dough strain hardening behaviour and how dough microstructure changes during the extensional deformation measurements is important for the evaluation of dough rheological properties. Four wheat flour samples were used in this study. They had either a low (9%) or high (13%) protein content and a glutenin-to-gliadin ratio of 0.35:1 or 0.7:1. The uniaxial extensional measurements were performed at three different extension speeds of 60, 120 or 600 mm/min, respectively. A typical characteristic of viscoelastic materials was obtained, showing that the maximum extension (Emax) and maximum resistance (Rmax) were dependent on the measurement speed, whereas the strain hardening indices were found to be independent on the speed. The differences in glutenin-to-gliadin ratios did not show a significant influence on Emax and strain hardening behaviour of dough but they affected the strength and extensibility of rehydrated gluten. The confocal microscopic in situ tensile experiments show that starch granules became aligned within the gluten network in the direction of extensional force. This indicates that both the re-arrangement of gluten network and starch granules contribute to the extensional rheological properties of dough.

Agriculture is a major factor in landscape fragmentation, altering nutrient cycling and animal and plant populations through increasing habitat edge density. Most research on insect herbivores in agroecosystems has focused on the top-down effects of predators moving throughout the habitat mosaic. Few studies have focused on the top-down and bottom-up factors modulating the distribution of insect herbivore populations between natural and agricultural patches. For example, despite an understanding that Australian plague locusts (Chortoicetes terminifera) avoid tree patches, the underlying mechanisms remain unknown. Here, we explored how wooded remnants within pastures affect locust density and the potential top-down and bottom-up mechanistic explanations. We tested three hypotheses: 1) grasses near wooded areas are nutritionally suboptimal, 2) predator density is higher near wooded areas, and 3) temperatures are cooler underneath trees. We measured locust density, grass nutrient content, predator abundance, temperature, and ground cover along 50 m transects from wooded areas to open grassy areas. We ran those transects in three fields and had four transects per field. We confirmed locust avoidance for trees at a 20 m periphery, however none of the variables tested independently explained this trend. Grass nutrient content was similar underneath wooded areas and in open patches. Predator abundance did not differ between the two habitats. The ground was warmer under wooded areas than in grassy areas potentially due to woody vegetation negating windchill. Further, we found that locust density was negatively correlated with plant protein content and was highest in areas with approximately 20 % bare ground cover. Both plant protein and ground cover are important for grasshopper performance and reproduction. It is likely a complex interaction between these variables and others that drive the distribution of this species and other insect herbivores in agroecosystems. The small-scale mechanisms driving the response of insect herbivores to landscape changes is critical to understanding and predicting population dynamics at large-scales.

International audience

International audience; Soil erosion is one of the main factors influencing land degradation and water quality at the global scale. Identifying the main sediment sources is therefore essential for the implementation of appropriate soil erosion mitigation measures. Accordingly, caesium-137 (137Cs) concentrations were used to determine the relative contribution of surface and subsurface erosion sources in a lowland drained catchment in France. As 137Cs concentrations are often dependent on particle size, specific surface area (SSA) and novel thorium (Th) based particle size corrections were applied. Surface and subsurface samples were collected to characterize the radionuclide properties of potential sources. Sediment samples were collected during one hydrological year and a sediment core was sampled to represent sediment accumulated over a longer temporal period. Additionally, sediment from tile drains was sampled to determine the radionuclide properties of sediment exported from the drainage network. A distribution modelling approach was used to quantify the relative sediment contributions from surface and subsurface sources. The results highlight a substantial enrichment in fine particles and associated 137Cs concentrations between the sources and the sediment. The application of both correction factors reduced this difference, with the Th correction providing a more accurate comparison of source and sediment samples than the SSA correction. Modelling results clearly indicate the dominance of surface sources during the flood events and in the sediment core. Sediment exported from the drainage network was modelled to originate predominantly from surface sources. This study demonstrates the potential of Th to correct for 137Cs particle size enrichment. More importantly, this research indicates that drainage networks may significantly increase the connectivity of surface sources to stream networks. Managing sediment transferred through drainage networks may reduce the deleterious effects of suspended sediment loads on riverine systems in similar lowland drained agricultural catchments.

International audience; Soil erosion in agricultural catchments leads to the accelerate supply of sediment to rivers. Here, we determine the sources contributing to the siltation of a pond in the Louroux catchment (24 km², French Loire River basin), representative of lowland agricultural environments of Northwestern Europe. Strontium isotopic ratios were determined in potential sources and sediment core samples collected in the Louroux pond, at the outlet of the catchment. These ratios were shown to provide good discrimination between different sediment sources (soil, suspended particulate matter, calcareous rock samples), and their respective contributions were calculated using mass balance equations. These results should be used to guide the implementation of soil conservation measures to limit sediment supply to the Louroux River.

International audience; Soil erosion is recognized as one of the main processes triggering the physical and chemical degradation of water bodies. Although erosive dynamics have been widely described in morphogenic areas, much less is known about this process in lowland agricultural catchments.To address this issue, a multidisciplinary study was carried out at the scale of a small agricultural lowland catchment (Louroux catchment, France, 25 km (2)) to reconstruct the evolution of the soil erosion rates and sources, from the hillslopes to the deposition areas in the water bodies. This study's goal is specifically to understand the impact of changes in land use and agricultural practices after 1950 (field re-design, ditch creation, drainage) on sediment dynamics For this purpose, sediment cores were collected in a medieval pond (870AD) located at the outlet of the catchment. These cores have been dated and used to reconstruct the temporal variations in sediment fluxes over time (from 1954 to 2013). In addition, sediment sources were identified using fallout radionuclide measurements (cesium-137 and beryllium7 / excess lead-210 ratios). These results will contribute to the implementation of effective management measures to reduce the transfer of sediments from the hillslopes to the hydrosystems.; 14 15 L'érosion des sols est reconnue comme étant l'un des principaux processus à l'origine de la dégradation physico-16 chimique des masses d'eau. Les phénomènes érosifs, largement décrits en contexte morphogène, restent pourtant 17 peu étudiés en contexte de plaine. 18 Pour combler ce manque, une étude pluridisciplinaire a été menée à l'échelle d'un petit bassin versant (25 km²) 19 de plaine agricole drainée pour reconstruire l'évolution des taux et des sources d'érosion, depuis les zones 20 d'accumulation de matière jusqu'aux zones sources. Cette étude vise ainsi à comprendre l'impact des 21 aménagements intervenus dans le bassin après 1950 (remembrements, création de fossés, drainage) sur la 22 dynamique sédimentaire actuelle et passée. 23 À cette fin, des carottages ont été réalisés dans un étang médiéval (870AD) localisé à l'exutoire du bassin versant 24 du Louroux (France). Les carottes ont été datées et ont permis de reconstruire les variations temporelles du flux 25 sédimentaire (de 1954 à 2013), mais aussi de les associer avec les changements d'usage des sols. Par ailleurs, les 26 sources de sédiments ont été identifiées à partir de mesures de radionucléides (césium 137 et rapport béryllium 27 7/plomb 210 en excès). Ces résultats vont permettre de guider la mise en place d'aménagements pour lutter contre 28 le départ de matière sur les versants. 29 MOTS CLEFS : érosion, sédiment, colmatage, archive sédimentaire, traçage 30 31 Increase of erosion source contributions to rivers and lakes (1950-2010): 32 the case of the Louroux Pond (Central France) 33 Soil erosion is recognized as one of the main processes triggering the physical and chemical degradation of water 34 bodies. Although erosive dynamics have been widely described in morphogenic areas, much less is known about 35 this process in lowland agricultural catchments. 36 To address this issue, a multidisciplinary study was carried out at the scale of a small agricultural lowland 37 catchment (Louroux catchment, France, 25 km²) to reconstruct the evolution of the soil erosion rates and sources, 38 from the hillslopes to the deposition areas in the water bodies. This study's goal is specifically to understand the 39 impact of changes in land use and agricultural practices after 1950 (field redesign , ditch creation, drainage) on 40 sediment dynamics 41 For this purpose, sediment cores were collected in a medieval pond (870AD) located at the outlet of the 42 catchment. These cores have been dated and used to reconstruct the temporal variations in sediment fluxes over 43 time (from 1954 to 2013). In addition, sediment sources were identified using fallout radionuclide measurements 44 (cesium-137 and beryllium7 / excess lead-210 ratios). These results will contribute to the implementation of 45 effective management measures to reduce the transfer of sediments from the hillslopes to the hydrosystems. 46 KEY WORDS: erosion, sediment, siltation, lake deposits, sediment fingerprinting 47 48 49

International audience; 18 Cropland cultivated under no-tillage has dramatically increased in Brazil during the last three 19 decades. However, soil degradation by water erosion remains excessive in the country. 20 Furthermore, the impact of inappropriate agricultural practices on soil erosion is often neglected 21 by farmers. Therefore, the contribution of potential sources of sediment should be quantified in 22 order to raise awareness among rural communities on the need to improve land management for 23 protecting soil and water resources. This study quantified the contribution of potential sources to 24 sediment transiting the Guaporé River, draining a 2032-km² cultivated catchment, in Southern 25 Brazil. Potential sediment source types were surface of cropland soils (n = 159), unpaved roads 26 (n = 58), and stream channel banks (n = 46). A total of 175 suspended sediment samples were 27 collected following different sampling strategies (including sampling of river water during 28 floods, installation of time-integrated suspended sediment samplers, and collection of bed 29 sediment) in 10 sub-catchments, from January 2011 to March 2014. Discriminant properties 30 were selected among the concentrations in 22 geochemical elements and total organic carbon. 31 Results showed that sediment source contributions were similar for the different sediment 32 sampling strategies. Although, the contributions of sediment sources varied in space across 33 Guaporé catchment, they were dominated by cropland (91±15%), while stream channels (5±2%) 34 and unpaved roads (4±10%) were sources of minor importance. Cropland contribution increased 35 with the drained cropland surface area. The unambiguous dominance of cropland as the main 36 source supplying sediment to the Guaporé River justifies the urgent need to better plan land use 37 and to promote the adoption of appropriate conservation farming practices in similar areas of 38 Southern Brazil. Soil losses in cropland could be reduced by implementing crop rotation, 39 mechanical runoff control strategies, and by avoiding the construction of unpaved roads in 40 thalwegs. 41 42

International audience; Soil erosion is recognized as one of the main processes of land degradation in agricultural areas. High suspended sediment loads, often generated from eroding agricultural landscapes, are known to degrade downstream environments. Accordingly, there is a need to identify suspended sediment sources and to investigate their dynamics. Here, soil and sediment strontium isotopic ratios were used to examine suspended sediment sources and dynamics in a lowland drained catchment in France. Suspended sediment (n=14) was collected in stream and at tile drain (n=4) outlets during three flood events between December 2013 and February 2014. Potential source soils (n=28) representative of the carbonate and silicate substrates found in the catchment were sampled and analyzed. Strontium isotopic ratios (87 Sr/ 86 Sr) were measured in different particle size fractions (

Protein and carbohydrates are important nutrients driving the growth of herbivores; however, their content in plants is highly variable. Multiple studies have explored their effect on herbivores, but only one other study (using a caterpillar) has provided a comprehensive overview that includes a simultaneous evaluation of their ratios and concentrations. In the present work, we ran two experiments using nymphs of the generalist grasshopper Melanoplus differentialis. Grasshoppers and caterpillars differ in a number of important ways, which might affect their feeding and physiological responses to foods with variable content of protein and carbohydrates. First, in a choice experiment, we measured performance and related this to the self-selected intake of nutrients. No differences were found for duration of development across treatments, but gain in mass was lower on a diet of low macronutrient concentration. Consumption of protein was always tightly regulated, but intake of carbohydrate was significantly reduced when consuming diluted food. In the second experiment, insects were constrained to one of nine diets and we plotted performance and consumption using a fitness-landscape approach that mimics the natural variation of nutrients in plants. We found significant effects of protein and carbohydrate content on gain in mass and in duration of development. The concentration of macronutrients in the food had more pronounced effects than did the protein-to-carbohydrate ratio. The protein-carbohydrate content also significantly affected the intake of food and energy (calories), production of frass, and digestive efficiency. On foods with low macronutrient concentration consumption was high, but digestive efficiency was low. Our results suggest that insects will favor protein-biased foods when the total macronutrient content of available foods is low, and that in the short-term compensatory feeding responses can overcome nutritional deficits and/or imbalances. However, over the long term, insect herbivores might pay substantial costs when eating foods that are nutritionally suboptimal.

International audience; Soil erosion often supplies high sediment loads to rivers, degrading water quality and contributing to the siltation of reservoirs and lowland river channels. These impacts are exacerbated in agricultural catchments where modifications in land management and agricultural practices were shown to accelerate sediment supply. In this study, sediment sources were identified with a novel tracing approach combining cesium (137Cs) and strontium isotopes (87Sr/86Sr) in the Louroux pond, at the outlet of a lowland cultivated catchment (24 km2, Loire River basin, France) representative of drained agricultural areas of Northwestern Europe.Surface soil (n = 36) and subsurface channel bank (n = 17) samples were collected to characterize potential sources. Deposited sediment (n = 41) was sampled across the entire surface of the pond to examine spatial variation in sediment deposits. In addition, a 1.10 m sediment core was sampled in the middle of the pond to reconstruct source variations throughout time. 137Cs was used to discriminate between surface and subsurface sources, whereas 87Sr/86Sr ratios discriminated between lithological sources. A distribution modeling approach quantified the relative contribution of these sources to the sampled sediment.Results indicate that surface sources contributed to the majority of pond (μ 82%, σ 1%) and core (μ 88%, σ 2%) sediment with elevated subsurface contributions modeled near specific sites close to the banks of the Louroux pond. Contributions of the lithological sources were well mixed in surface sediment across the pond (i.e., carbonate sediment contribution, μ 48%, σ 1% and non-carbonate sediment contribution, μ 52%, σ 3%) although there were significant variations of these source contributions modeled for the sediment core between 1955 and 2013. These fluctuations reflect both the progressive implementation of land consolidation schemes in the catchment and the eutrophication of the pond.This original sediment fingerprinting study demonstrates the potential of combining radionuclide and strontium isotopic geochemistry measurements to quantify sediment sources in cultivated catchments.

International audience; Rural landscapes have been extensively modified by human activities in Western Europe since the beginning of the 20th century in order to intensify agricultural production. Cultivated areas often expanded at the expense of grassland and wetlands located in lowland areas (de Groot et al., 2002). Therefore, large modifications were made to the agricultural landscapes: stream redesign, land consolidation, removal of hedges, and installation of tile drainage networks to drain the hydromorphic soils. These changes modified sediment processes and resulted in large morphological alterations (e.g. channel bed incision, deposition of fine sediment, channel bank erosion). Accordingly, these alterations threaten water quality and prevent to meet the requirements of the European directives. Improving water quality requires a clear understanding of the hydrosedimentary dynamics in these lowland cultivated catchments. However, few studies were conducted in drained environments. To fill this research gap, a pilot study was started in cultivated catchment of the Loire River basin, France, where tile drain densities are very high (> 1.5 km/km²). Six hydro-sedimentary monitoring stations were installed in the Louroux catchment (24 km²). One of them was specifically dedicated to measuring water/sediment fluxes from tile drains. Water level and turbidity were continuously monitored and sediments were sampled during floods and low stage periods. Samples were measured for particle size distribution, and sediment tracing studies are currently being developed to quantify the contribution of potential sources (e.g. surface vs subsurface, lithologies) to river sediment. Hydro-sedimentary fluxes were quantified and modelled for some selected events. The catchment hydrosedimentary fluxes and their properties were shown to be impacted by tile drain sediment transport, especially regarding particle size distribution, with the dominant export of very fine particles (< 2 µm) from tile drains. This study demonstrates that tile drain transport should be included when developing and running hydro-sedimentary models in catchments, and particularly in lowland/wetland environments.

International audience; Rural landscapes have been extensively modified by human activities in Western Europe since the beginning of the 20th century in order to intensify agricultural production. Cultivated areas often expanded at the expense of grassland and wetlands located in lowland areas (de Groot et al., 2002). Therefore, large modifications were made to the agricultural landscapes: stream redesign, land consolidation, removal of hedges, and installation of tile drainage networks to drain the hydromorphic soils. These changes modified sediment processes and resulted in large morphological alterations (e.g. channel bed incision, deposition of fine sediment, channel bank erosion). Accordingly, these alterations threaten water quality and prevent to meet the requirements of the European directives. Improving water quality requires a clear understanding of the hydrosedimentary dynamics in these lowland cultivated catchments. However, few studies were conducted in drained environments. To fill this research gap, a pilot study was started in cultivated catchment of the Loire River basin, France, where tile drain densities are very high (> 1.5 km/km$^2$). Six hydro-sedimentary monitoring stations were installed in the Louroux catchment (24 km 2). One of them was specifically dedicated to measuring water/sediment fluxes from tile drains. Water level and turbidity were continuously monitored and sediments were sampled during floods and low stage periods. Samples were measured for particle size distribution, and sediment tracing studies are currently being developed to quantify the contribution of potential sources (e.g. surface vs subsurface, lithologies) to river sediment. Hydro-sedimentary fluxes were quantified and modelled for some selected events. The catchment hydrosedimen-tary fluxes and their properties were shown to be impacted by tile drain sediment transport, especially regarding particle size distribution, with the dominant export of very fine particles (< 2 $\mu$m) from tile drains. This study demonstrates that tile drain transport should be included when developing and running hydro-sedimentary models in catchments, and particularly in lowland/wetland environments.

International audience; The variation of dissolved and particulate metal(loid) concentrations was investigated during a Mediterranean flood in a former mining watershed, the Gardon River (SE France), using high-temporal resolution sampling. Dissolved antimony originating from the Upper Gardon River watershed underwent dilution during flood. Conversely, dissolved As and particulate As, Pb, Zn, Cd and Tl concentrations exhibited increased values during rising flood compared to low and receding flow conditions, with a double-peak shape. As, Pb, Cd and Tl concentration data in suspended particulate matter from this double-peak were distributed along two different correlation lines, showing the successive mobilization of two groups of particles highly enriched with As and Cd or Pb and Tl, both inherited from ancient Pb/Zn mines. Metal(loid) loads during the monitored 24h-flood event were: 0.5kg for Cd, 19.4kg for Sb and 204kg for As in the dissolved phase and 24kg for Cd, 38kg for Tl, 94kg for Sb, 1915kg for As, 2860kg for Pb and 5214kg for Zn in the particulate phase. Altogether, these results highlighted the importance of floods in the mobilization of metals and metalloids from ancient mining sites in Mediterranean regions, showing the need for high-temporal resolution monitoring of flood events to accurately assess the long-term contribution of mining activity to metal(loid) loads of downstream watershed.

Negative effects of parasites on their hosts are well documented, but the proximate mechanisms by which parasites reduce their host’s fitness are poorly understood. For example, it has been suggested that parasites might be energetically demanding. However, a recent meta-analysis suggests that they have statistically insignificant effects on host resting metabolic rate (RMR). It is possible, though, that energetic costs associated with parasites are only manifested during and/or following periods of activity. Here, we measured CO2 production (a surrogate for metabolism) in Mediterranean geckos (Hemidactylus turcicus) infected with a lung parasite, the pentastome Raillietiella indica, under two physiological conditions: rested and recently active. In rested geckos, there was a negative, but non-significant association between the number of pentastomes (i.e., infection intensity) and CO2 production. In recently active geckos (chased for 3 minutes), we recorded CO2 production from its maximum value until it declined to a stationary phase. We analyzed this decline as a 3 phase function (initial decline, secondary decline, stationary). Geckos that were recently active showed, in the secondary phase, a significant decrease in CO2 production as pentastome intensity increased. Moreover, duration of the secondary phase showed a significant positive association with the number of pentastomes. These results suggest that the intensity of pentastome load exerts a weak effect on the metabolism of resting geckos, but a strong physiological effect on geckos that have recently been active; we speculate this occurs via mechanical constraints on breathing. Our results provide a potential mechanism by which pentastomes can reduce gecko fitness.

SummaryUsing triatomine bugs (Hemiptera: Reduvidae) red-eyed mutants, we tested the hypothesis of an alternative function of insect screening pigments against oxidative stress. To tests our hypothesis, we studied the morphological and physiological changes associated with the mutation. We found that wild-type eyes possess great amount of brown and red screening pigment inside the primary and secondary pigment cells as well as in the retinular cells. Red-eyed mutants, however, have only some scarce red granules inside the pigmentary cells. We then compared red-eyed mutants and wild-types visual sensitivity by measuring photonegative responses of insects reared in light/dark cycles (LD 12:12) or constant darkness (DD). Finally, we analyzed both the impact of oxidative stress associated with blood ingestion and photodamage of UV light on the eye retina. We found that red-eyed mutants reared in DD conditions were the most sensitive to the light intensities tested. Retinae of LD reared mutants were gradually damaged over the life cycle while for DD reared insects retinae were conserved intact. No retinal damages were observed on non-fed mutants exposed to UV lights for two weeks while insects fed on blood prior to UV exposition showed clear signs of retinal damage. Wild-type insects exposed to UV-light showed a marked increase in the amount and density of screening pigments.