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The exponential increase in the human population in tandem with increased food demand has caused agriculture to be the global‐dominant form of land use. Afrotropical drylands are currently facing the loss of natural savannah habitats and agricultural intensification with largely unknown consequences for bees. Here we investigate the effects of agricultural intensification on bee assemblages in the Afrotropical drylands of northern Tanzania. We disentangled the direct effects of agricultural intensification and temperature on bee richness from indirect effects mediated by changes in floral resources. We collected data from 24 study sites representing three levels of management intensity (natural savannah, moderate intensive and highly intensive agriculture) spanning an extensive gradient of mean annual temperature (MAT) in northern Tanzania. We used ordinary linear models and path analysis to test the effects of agricultural intensity and MAT on bee species richness, bee species composition and body‐size variation of bee communities. We found that bee species richness increased with agricultural intensity and with increasing temperature. The effects of agricultural intensity and temperature on bee species richness were mediated by the positive effects of agriculture and temperature on the richness of floral resources used by bees. During the off‐growing season, agricultural land was characterized by an extensive period of fallow land holding a very high density of flowering plants with unique bee species composition. The increase in bee diversity in agricultural habitats paralleled an increasing variation of bee body sizes with agricultural intensification that, however, diminished in environments with higher temperatures. Synthesis and applications. Our study reveals that bee assemblages in Afrotropical drylands benefit from agricultural intensification in the way it is currently practiced. However, further land‐use intensification, including year‐round irrigated crop monocultures and excessive use of agrochemicals, is likely to exert a negative impact on bee diversity and pollination services, as reported in temperate regions. Moreover, several bee species were restricted to natural savannah habitats. To conserve bee communities and guarantee pollination services in the region, a mixture of savannah and agriculture, with long periods of fallow land should be maintained.

Natural history collections (NHCs) are a cornerstone of entomology, and the conservation of specimens is the essential prerequisite for the development of research into systematics, biogeography, ecology, evolution and other disciplines. Yet, specimens collected during decades of entomological research conducted in less developed countries across Sub-Saharan Africa on pests, beneficial insects and insect biodiversity in general have largely been exported to be permanently preserved in developed countries, primarily in South Africa, Europe and the United States of America.This is particularly true for the Democratic Republic of the Congo’s (DRC) diverse wild bee fauna, which has been investigated throughout the colonial period by visiting or resident entomologists and missionaries who have then transferred their collected material primarily to Belgium as part of a wider legacy of scientific exploration and colonialism. Digitizing NHC is one way to mitigate this current bias, by making samples accessible to researchers from the target post-colonial countries as well as to the wider international scientific community.In this study, we compiled and digitized 6,490 specimens records relevant to 195 wild bee species grouped in 18 genera within the biodiverse family Megachilidae, essentially from the colonial era (i.e., mostly between 1905-1960, with additional records up to 1978), and curated at the Royal Museum for Central Africa (RMCA) in Belgium. We provide a detailed catalogue of all records with updated locality and province names, including 26 species only available as type specimens. We also explore the historical patterns of diversity and distribution across DRC, and we provide a list of the research entomologists involved. This study is an important first step that uses digital technologies to democratize and repatriate important aspects of DRC’s natural heritage of insect biodiversity, to stimulate more contemporary field surveys, as well as to identify and characterize research gaps and biodiversity shortfalls in little-explored regions of Sub-Saharan Africa.

Maintaining the diversity of wild bees is a priority for preserving ecosystem function and promoting stability and productivity of agroecosystems. However, wild bee communities face many threats and beekeeping could be one of them, because honey bees may have a strong potential to outcompete wild pollinators when placed at high densities. Yet, we still know little about how beekeeping intensity affects wild bee diversity and their pollinator interactions. Here, we explore how honey bee density relates to wild bee diversity and the structure of their pollination networks in 41 sites on 13 Cycladic Islands (Greece) with similar landscapes but differing in beekeeping intensity. Our large-scale study shows that increasing honey bee visitation rate had a negative effect on wild bee species richness and abundance, although the latter effect was relatively weak compared to the effect of other landscape variables. Competition for flowering resources (as indicated by a resource sharing index) increased with the abundance of honey bees, but the effect was more moderate for wild bees in family Apidae than for bees in other families, suggesting a stronger niche segregation in Apidae in response to honey bees. Honey bees also influenced the structure of wild bee pollination networks indirectly, through changes in wild bee richness. Low richness of wild bees in sites with high honey bee abundance resulted in wild bee networks with fewer links and lower linkage density. Our results warn against beekeeping intensification in these islands and similar hotspots of bee diversity, and shed light on how benefits to pollination services of introducing honey bees may be counterbalanced by detriments to wild bees and their ecosystem services., Ecography, 44 (9), ISSN:0906-7590, ISSN:1600-0587

Two Chinese species of the genus

info:eu-repo/semantics/published

The study of wild bees has markedly increased in recent years due to their importance as pollinators of crops and wild plants, and this interest has been accentuated by increasing evidence of global declines in their abundance and species richness. Though best studied in Europe and North America, knowledge on the current state of wild bees is scarce in regions where they are particularly diversified, such as the Mediterranean basin. The eastern Mediterranean country of Lebanon, located at the heart of the Levant in a biodiversity hotspot, is particularly poorly studied. The aim of this paper is to produce a first annotated checklist of the wild bees of Lebanon from new and museum collections, literature records, and verified occurrences from online databases. The present list totals 573 species for Lebanon of which 289 are reported for the first time, but the estimated diversity is likely to be closer to 700. Preliminary information on local distributions and flower records are also presented. The local species assemblages indicate affinities with montane habitats of the Mediterranean and Anatolia and the semi-arid habitats of the Levant and north Africa. This study also encourages further research on local wild bee faunas and the use of this knowledge for conservation purposes.

Urbanisation is often put forward as an important driver of biodiversity loss, including for pollinators such as wild bees. However, recent evidence shows that the mosaics of urban green spaces, and in particular certain categories of informal urban green spaces (IGS), can play an important role to help native wild bees thrive in cities.Here, we describe the results of five years of citizen science and standardised field surveys of wild bees conducted at the Friche Josaphat, a 24-ha urban wasteland in the Brussels-Capital Region (Belgium). These field surveys were initiated following the planned restructuring and partial destruction of this site by the regional authorities.We recorded a total of 2,507 specimens belonging to 127 species of wild bees, i.e. 60.5% of the 210 species recorded regionally, including nine that are threatened with extinction at national or European scales. The Friche Josaphat encompasses a significant share of the functional and phylogenetic diversity of wild bees known from the Brussels-Capital Region and is one of the most species-rich localities known to date for wild bees in Belgium.Collectively, our results highlight the strong complementarity of citizen science and academic approaches in biodiversity surveys, and they reaffirm that wastelands are essential components of urban biodiversity. Our study stresses the need to provide biodiverse IGS with a formal status within the mosaic of urban green spaces, but also to acknowledge and safeguard their natural capital and the multiple ecosystem services they provide.

Morocco is a well known hot-spot of biodiversity in the Mediterranean basin. While some taxa like vascular plants are relatively well recorded, important groups of pollinators like bees are still understudied. This article presents an updated checklist of the bee species of Morocco and includes a summary of global and regional distribution of each species. A total of 961 species belonging to six bee families and 68 genera are recorded: Andrenidae (8 genera, 217 species); Apidae (15 genera, 241 species); Colletidae (2 genera, 74 species), Halictidae (12 genera, 144 species), Megachilidae (28 genera, 271 species) and Melittidae (3 genera, 14 species). Among them, 67 species are recorded for the first time in Morocco. Around 70% of the bee fauna of Morocco consists of widespread Palaearctic species. Only 18% of Moroccan species recorded are restricted to North Africa and 8% are Moroccan single-country endemics (81 species). Afrotropical elements in the Moroccan fauna are few, with only 3% of Morocco species co-occuring in that region. This checklist is intended to stimulate new regional research on bees including their taxonomy and biogeography. As many groups of bees have been understudied, discovery of new species for science and new records for the country can be expected. Additional research including inventorying, monitoring, and integrative taxonomic studies are needed to develop a comprehensive strategy for bee conservation in Morocco.

Recent studies have reported on dramatic cases of aerial insect population declines by focusing on the measure of the total biomass of caught insects. However, there is currently no consensus about how biomass patterns among sites and habitats might consistently capture the subtleties of changes in aerial insect community structure. Here, we investigated the relationship between the total biomass of wild bees collected using pan traps in urban, agricultural, and semi-natural habitats on one hand, and a spectrum of biodiversity metrics on the other hand, particularly species richness (SR), alpha diversity, functional diversity (FD) and three different forms of phylogenetic diversity (PD). Our results indicate that although biomass is significantly and highly correlated with the abundance of wild bees, it is generally significantly but only moderately and non-linearly correlated to the various facets of wild bee diversity among habitats. By contrast, we also found that all three measures of PD used are consistent across habitats, suggesting that a taxonomic hierarchy based on Linnaean classification could be used as a proxy for the measurement of PD in wild bees, particularly in other well-studied areas such as Western Europe where a multi-gene molecular phylogeny is unavailable as yet. Collectively, our results illustrate the clear limitations of biodiversity monitoring through measures of trapped insects biomass. We advocate for more robust measures of biodiversity trends in wild bees, requiring both standardized surveys, and the identification of caught specimens down to the species level to capture the subtleties of species, traits-based and phylogeny-based community changes across habitats or time. Scaling out this approach is an essential prerequisite for more global conservation planning tailored to the ecological requirements of the targeted insect species.

This work aims to develop stable and reliable sensor films based on polyaniline (PANI) composites able to detect ammonia in a humid environment. For the preparation, PANI is hosted in poly(methyl methacrylate)(PMMA)/polystyrene (PS) blends matrix and to optimize the electrical properties, multi-walled carbon nanotubes (MWCNTs) are added into the matrix. The preparation method alternating heating and ultrasonic treatment leads to good dispersion and ensure stable films. The materials are characterized by infrared (IR) spectroscopy, scanning electron microscopy (SEM) and electrical characterizations. The temperature-dependent electrical measurement showed that PANI governed the electrical properties in the composites. The resistive sensors based on such composites are tested for ammonia detection and the composite based especially on PANI/PMMA/PS/MWCNTs shows the best sensor performances, with a linear sensitivity in the 5–20 ppm range, a limit of detection (LOD) averaging 830 ppb and response and recovery time estimated to 270 and 630 s, respectively. Furthermore, it presents repeatable responses and very good stability in a humid environment as well as long-term stability. The preparation way is an essential point to reach these performances that result from a synergetic contribution of all elements.

Summarizing individual gene trees to species phylogenies using two-step coalescent methods is now a standard strategy in the field of phylogenomics. However, practical implementations of summary methods suffer from gene tree estimation error, which is caused by various biological and analytical factors. Greatly understudied is the choice of gene tree inference method and downstream effects on species tree estimation for empirical data sets. To better understand the impact of this method choice on gene and species tree accuracy, we compare gene trees estimated through four widely used programs under different model-selection criteria: PhyloBayes, MrBayes, IQ-Tree, and RAxML. We study their performance in the phylogenomic framework of $>$800 ultraconserved elements from the bee subfamily Nomiinae (Halictidae). Our taxon sampling focuses on the genus Pseudapis, a distinct lineage with diverse morphological features, but contentious morphology-based taxonomic classifications and no molecular phylogenetic guidance. We approximate topological accuracy of gene trees by assessing their ability to recover two uncontroversial, monophyletic groups, and compare branch lengths of individual trees using the stemminess metric (the relative length of internal branches). We further examine different strategies of removing uninformative loci and the collapsing of weakly supported nodes into polytomies. We then summarize gene trees with ASTRAL and compare resulting species phylogenies, including comparisons to concatenation-based estimates. Gene trees obtained with the reversible jump model search in MrBayes were most concordant on average and all Bayesian methods yielded gene trees with better stemminess values. The only gene tree estimation approach whose ASTRAL summary trees consistently produced the most likely correct topology, however, was IQ-Tree with automated model designation (ModelFinder program). We discuss these findings and provide practical advice on gene tree estimation for summary methods. Lastly, we establish the first phylogeny-informed classification for Pseudapis s. l. and map the distribution of distinct morphological features of the group. [ASTRAL; Bees; concordance; gene tree estimation error; IQ-Tree; MrBayes, Nomiinae; PhyloBayes; RAxML; phylogenomics; stemminess]

Herein we focus on gas sensor responses of both organic macrocycles (MCs) and carbon nanotubes (CNTs) functionalized with MCs (CNTs/MCs) to understand the interaction mechanisms of these materials exposed to aromatics volatile organic compounds (VOCs) such as benzene, toluene and xylene (BTX). The MCs-functionalized CNTs are prepared by non-covalent functionalization using phthalocyanines and porphyrins derivatives. We focus our analysis on the peripheral groups of both the MCs (tert-butyl, phenyl, ethyl) and BTX (methyl) by means of the analyses of both the desorption kinetics and surface interactions. A cross-analysis between the physisorption phenomena and kinetics of the responses is found to be relevant for understanding the interactions. The analysis of the sensing performances at room temperature (25 °C) for the MCs-based QCM sensors revealed that the nature of the peripheral moieties (aryl or alkyl of the MCs alone) dictates the kinetics and the desorption profile whatever the VOC. The similar analysis conducted on the sensing performances of the CNTs/MCs-based QCM sensors shows that, methyl groups of the BTX are the dominant parameter that modulate the response profile whatever the hybrid materials. A focus on dispersion interactions and desorption kinetics allows to evidence that the interaction between the VOCs and MCs or CNTs/MCs is reinforced or weakened depending on the peripheral moieties from the MCs or BTX. From this study, it is clearer that substituents of the VOCs are more important for kinetics of desorption than the functional groups of the CNTs/MCs.

Globally, pollinators are threatened by land-use changes, including habitat degradation. East African rangelands are under pressure due to livestock population increase and overutilization, which lead to degradation of vegetation and soils. While traditional grazing management is widely used to restore vegetation, little is known how this affects insect pollinators. We investigated whether differently managed rangeland areas harbor different insect pollinator abundance, richness and diversity in Simanjiro, Tanzania. We established twelve blocks in four grazing areas under different management categories (private and communal enclosures, wet and dry season grazing lands) and used pan traps and sweep nets to collect insect pollinators. We collected a total of 1977 insects, representing 44 families and 239 species. Beetles were most frequently trapped, with 646 (33%) individuals, followed by 522 bees (26%). Pollinator abundance was twice as high in the private enclosure compared to the communal dry grazing area (χ2 = 27.63, P

Taxonomy of bees (Hymenoptera: Anthophila) of the Socotra Archipelago is evaluated based on historical and newly available specimens. Four new species of Halictidae are described from the Socotra Island: Austronomia socotrana Pauly & Straka sp. nov., Lasioglossum (Hemihalictus) boswelliae Pauly & Straka sp. nov., Lasioglossum (Sphecodogastra) dioscoridis Pauly & Straka sp. nov., and Lasioglossum (Ctenonomia) dracaenae Pauly & Straka sp. nov. The correct original spelling of Eucera wfkirbyi Kohl, 1906 is restored, Eucera kirbyi Friese, 1909 being its unjustified emendation and junior objective synonym. Identity of both Socotran species of Xylocopa Latreille, 1802 is clarified. Lasioglossum (Evylaeus) kowitense (Cockerell, 1937), Nomioides facilis (Smith, 1853), and Nomioides rotundiceps Handlirsch, 1888 are removed from the list of bees of Socotra. In total, 28 species in 16 genera are reported from the archipelago, of which nearly two thirds are considered endemic at the species level. Biogeographic origin of Socotran bees is analysed and proposed. Host associations with beetle parasites of the families Meloidae and Ripiphoridae (Coleoptera) and cleptoparasitic bees are evaluated for the Socotran bee fauna. Obligate bee parasitoid Ripiphorus arabiafelix arabiafelix Batelka, 2009 (Coleoptera: Ripiphoridae) is reported from the archipelago (Socotra Island) for the first time.

SummaryThe present study is an update to the first Red List of European Bees published in 2014. The additional records are based on (i) comprehensive review of literature; (ii) new data provided by bee specialists in response to the publication of the first Red List; (iii) new developments in taxonomy of European bees including description of new cryptic species; (iv) new specimens from recent field collections. While the first Red List included a list of 1965 wild bee species with 75 genera, we found 86 additional species, while two more genera have been erected (Seladonia and Vestitohalictus), giving an updated total of 2051 species and 77 genera. The authors discuss the artificial framework of the study considered by International Union for Conservation of Nature (IUCN) to produce the first Red List and they propose the more meaningful West Palaearctic biogeographical region. For this whole region, a first estimation gives 3408 wild bee species in 105 genera. The next taxa have been erected from subspe...

Morphological and allozyme analyses suggested the occurrence of a pseudocryptic species in the Lasioglossum villosulum (Kirby, 1802) species complex (Hymenoptera: Halictidae). We analysed the morphology of more than 1500 specimens and the DNA barcode fragment of the cytochrome c oxidase subunit I (COI) of 102 specimens of this species complex from several Palaearctic countries. Our phylogenetic tree reconstructions, based on maximum likelihood and Bayesian inference revealed one clade corresponding to all specimens morphologically identified as Lasioglossum medinai (Vachal, 1895) and one divergent specimen morphologically identified as Lasioglossum berberum (Benoist, 1941). The other specimens, morphologically identified as L. villosulum , aggregated into at least three other lineages in our phylogenetic trees. The tree-based species delineations methods based on the Generalized Mixed Yule Coalescent (GMYC) model and the Bayesian Poisson Tree Process (bPTP) identified five to ten candidate species within the L. villosulum species complex, with L. medinai and L. berberum consistently recognized as separated from all other candidate species. Diagnostic morphological differences were found among L. medinai , L. berberum and the remaining specimens identified as L. villosulum . No diagnostic morphological differences were found to distinguish the different phylogenetic candidate species or lineages found within L. villosulum and L. medinai . Thus, both genetic and morphological approaches support the existence of L. medinai and L. berberum as distinct species from L. villosulum .

Two previously unknown species of the genus Pseudapis Kirby, 1900 are described and illustrated: Pseudapis neumayeri Bossert & Pauly, sp. nov. (♂, ♀, Kenya, Tanzania), and P. crassivertex Bossert & Pauly, sp. nov. (♂, ♀, Mali, Mauritania, Niger, Senegal). We provide diagnoses for the new species and report all currently available records. Lastly, we present a revised identification key for the African species of the genus.

International audience; AbstractThe parallel sequencing of targeted amplicons is a scalable application of next-generation sequencing (NGS) that can advantageously replace Sanger sequencing in certain DNA barcoding studies. It can be used to sequence different PCR products simultaneously, including co-amplified products. Here, we explore this approach by simultaneously sequencing five markers (including the DNA barcode and a diagnostic marker of Wolbachia) in 12 species of Halictidae that were previously DNA barcoded using Sanger sequencing. Consensus sequences were obtained from fresh bees with success rates of 74–100% depending on the DNA fragment. They improved the phylogeny of the group, detected Wolbachia infections (in 8/21 specimens) and characterised haplotype variants. Sequencing cost per marker and per specimen (11.43 €) was estimated to decrease (

Herein we present gas sensor responses of functionalized carbon nanotubes (CNTs) toward benzene and xylene vapors. The functional moieties are phthalocyanine and porphyrin derivatives which possess a central part delimited by the macroring and different peripheral groups (aryl or alkyls) surrounding the macroring. The sensor devices based on QCM (quartz crystal microbalance) and resistive transducers are performed simultaneously to elucidate the sensing mechanism. The sensing performance from the two transducers recorded at room temperature revealed different behavior but complementary to understand the mechanism. Our findings show that if the aromatic VOCs bear methyl groups (xylene), the desorption profile is slow and the response time too long, while in the absence of a methyl group (benzene) the desorption profile is very rapid with a shorter response time. This illustrates that the whole gas response is driven by an interplay between the π–π interaction and the π–alkyl or alkyl–alkyl interactions, i....

Review DOI: 10.3390/s17020391 URL: http://www.mdpi.com/1424-8220/17/2/391 Filiació URV: SI Memòria This paper presents a focused review on the nanomaterials and associated transduction schemes that have been developed for the selective detection of hydrogen sulfide. It presents a quite comprehensive overview of the latest developments, briefly discusses the hydrogen sulfide detection mechanisms, identifying the reasons for the selectivity (or lack of) observed experimentally. It critically reviews performance, shortcomings, and identifies missing or overlooked important aspects. It identifies the most mature/promising materials and approaches for achieving inexpensive hydrogen sulfide sensors that could be employed in widespread, miniaturized, and inexpensive detectors and, suggests what research should be undertaken for ensuring that requirements are met.

This work presents the development of a microwave gas sensor at room temperature. The design of the sensor includes a coplanar grounded wave guide where is deposited a molecular gas sensing material. In this study, the sensitive material is a thin layer of cobalt phthalocyanine (CoPc), sensitive to ammonia and toluene. Submitted to an electromagnetic incident wave in the microwave range, the sensor response is a reflected wave. In the presence of pollutant, the reflected wave shape is specific to the species concentrations. The results interpretation is led at each frequency by the evaluation of the reflected coefficient, which traduces the ratio between the reflected wave over the incident wave. This study deals with the influence of molecular sensitive materials on the sensor response in the presence of ammonia (or toluene) in an argon flow. All the measurements are carried out at room temperature.

The flower-visiting records for the 43 species of bees considered to be native to New Caledonia show that females of 21 species visited 116 native species of plants in 69 genera and 41 families, and the bees were documented to carry pollen from 64 species and possibly four more. The plant families with the greatest number of species documented for visits by female bees were, in descending order: Myrtaceae (21), Dilleniaceae (10), Cunoniaceae (nine), Araliaceae (seven), Fabaceae (seven, encompassing the Caesalpinioideae, Mimosoideae, and Papilionoideae), Goodeniaceae (five), Proteaceae (five), Apocynaceae (four), Sapindaceae (four), and remaining families with one to three species. Females of six and possibly one more species carried pollen from each of Dilleniaceae and Myrtaceae, six carried pollen from Araliaceae, five from Goodeniaceae, four and possibly one more from Cunoniaceae, four from each of Fabaceae and Sapindaceae, and none to three from the remaining 34 families observed. For introduc...

Resume Huit especes de Lasioglossum sont inventoriees de Nouvelle-Caledonie. Un nouveau sous-genre cleptoparasite endemique, avec une nouvelle espece, Lasioglossum (Parachilalictus n. subg. ) neocaledonicum n. sp., est decrit. Les especes endemiques suivantes du sous-genre Chilalictus sont nouvelles : Lasioglossum (Chilalictus) alticola n. sp., L. (C.) tchambae n. sp. et L. (C.) webbi n. sp. Une nouvelle sous-espece, Lasioglossum (Chilalictus) polygoni austrocaledonicum n. ssp., est decrite de Nouvelle-Caledonie et d'Australie. Les especes australiennes L. (Chilalictus) lanarium (Smith 1853) et L. (C.) instabilis (Cockerell 1914) sont decouvertes pour la premiere fois en Nouvelle-Caledonie. Lasioglossum (Parasphecodes) sulthicum (Smith 1853) est la premiere espece de ce sous-genre australien signale en Nouvelle-Caledonie. L’emergence du parasitisme et la speciation en condition insulaire font l'objet d'une discussion. Le cleptoparasitisme du nouveau sous-genre Parachilalictus n. subg. peut etre etabli en ...

In order to achieve the selective detection of NO2 in the environment, a chemical filter is added to a semiconductor gas sensor that is very sensitive to oxidizing gases in the gas flow. The aim is to remove ozone (O3), the main interfering oxidizing gas for NO2 detection before its measurement by a phthalocyanine sensor. The first parameter for the carbon material as a filter is the specific surface area (SSA), which should be high enough to ensure interaction with O3 and low enough to avoid interaction with NO2. The key role of surface oxygenated groups and dangling bonds was underlined by NEXAFS and EPR, respectively. A mixture of nanocones/nanodiscs (20/70% w/w) with SSA of 30 m2 g−1 with both structural and electronic defects is found to be the most efficient filter and was used upstream of a phthalocyanine sensor. The lifetime of the chemical filter was investigated and a strategy to increase it is described. Raman spectroscopy, EPR and NEXAFS allow the reactivity of the carbon with NO2 and O3 in the 10–1000 ppb concentration range to be studied.

Contribution to the inventory of wild bees from Aveyron department (France) (Hymenoptera, Apoidea). Inventory of wild bees from Aveyron currently stands at 199 species, including 67 Apidae (31 Bombus, 21 Anthophorini, 9 Xylocopini, 4 Melectini, 2 Nomadini), 47 Halictidae, 38 Megachilidae, 40 Andrenidae, 7 Colletidae and 2 Dasypodaidae. Fifty-seven new species for Aveyron were surveyed over the past decade. Ninety species were not inventoried again in recent surveys. For each species not frequently collected, an inventory showing the locations, dates or periods of observations, plants visited, number and sex of individuals collected, is given. Comparison of the fauna of wild bees in the Aveyron with available studies in West Palearctic region reveals the presence of relatively high species diversity in this department. A decrease in the diversity of bumblebees is however observed on the study area., L’inventaire des Abeilles sauvages du département de l’Aveyron s’élève actuellement à 199 espèces, dont 67 Apidae (31 Bombus, 21 Anthophorini, 9 Xylocopini, 4 Melectini, 2 Nomadini), 47 Halictidae, 38 Megachilidae, 40 Andrenidae, 7 Colletidae et 2 Dasypodaidae. Cinquante-sept espèces nouvelles pour ce département ont été inventoriées au cours de la dernière décennie. Quatre-vingt-dix espèces n’ont pas été réinventoriées lors des récentes prospections. Pour chaque espèce peu fréquemment collectée, un inventaire reprenant les localités d’observations, les dates ou périodes de récoltes, les plantes visitées, le nombre et le sexe des individus collectés, a été rédigé. La comparaison de la faune des Abeilles sauvages de l’Aveyron à celle des études disponibles en région Ouest-Paléarctique révèle la présence d’une certaine richesse spécifique dans ce département. Une diminution de la diversité des Bourdons est cependant constatée sur la zone étudiée., Baliteau Lucas, Iserbyt Stéphanie, Mahé Gilles, Rasmont Pierre, Le Goff Gérard, Pauly Alain, Scheuchl Erwin. Contribution à l’inventaire des Abeilles sauvages du département de l’Aveyron (France) (Hymenoptera, Apoidea). In: Bulletin de la Société entomologique de France, volume 118 (3),2013. pp. 343-362.

International audience; Here, we report on the use of electrochemical methods for the detection of volatiles fatty acids (VFAs), namely acetic acid. We used tetra-tert-butyl phthalocyanine (PcH 2-tBu) as the sensing material and investigated its electroanalytical properties by means of cyclic voltammetry (CV) and square wave voltammetry (SWV). To realize the electrochemical sensing system, the PcH 2-tBu has been dropcast-deposited on carbon (C) orgold (Au)screen-printed electrodes (SPEs) and characterized by cyclic voltammetry and scanning electron microscopy (SEM). The SEM analysis reveals that the PcH 2-tBu forms mainly aggregates on the SPEs. The modified electrodes are used for the detection of acetic acid and present a linear current increase when the acetic acid concentration increases. The Cmodified electrode presents a limit of detection (LOD) of 25.77 mM in the range of 100 mM-400 mM, while the Aumodified electrode presents an LOD averaging 40.89 mM in the range of 50 mM-300 mM. When the experiment is realized in a buffered condition, theCmodified electrode presents a lower LOD, which averagesthe 7.76 mM. A pronounced signal decay attributed to an electrode alteration is observed in the case of the gold electrode. This electrode alteration severely affects the coating stability. This alteration is less perceptible in the case of the carbon electrode.

The sensing properties of various metallophthalocyanines layered on Quartz Crystal Microbalance (QCM) transducers towards toluene vapor were investigated. Structural and morphological properties of thermally evaporated thin films of substituted and unsubstituted phthalocyanines were firstly characterized by Infrared spectroscopy, X-ray Diffraction and Scanning Electron Microscopy. The sensing characteristics were then determined from QCM responses to toluene at room temperature and correlated to physical and chemical properties of thin films. Effects of molecular composition of phthalocyanine, especially the nature of metal atom in the central cavity and peripheral grafted substituents, on sensor metrological characteristics were established. No significant effect because of change of the central metal atom (Cu, Zn, Fe, Co) in monomeric phthalocyanines was observed on toluene sensitivity. In contrast, strong effects of substituents particularly tert-butyl group at the periphery of the phthalocyanine ring on sensor response were highlighted. The sensing behavior of metallophthalocyanines towards toluene has been interpreted in correlation with the chemical nature of the materials (nature of metal atom and peripheral grafting groups), the physical properties of the sensitive films (structure, morphology and thickness) and the involved molecular interactions forces.

An original organic semiconductor gas sensor devoted to the selective monitoring of nitrogen dioxide in air has been successfully developed. This device combines the great sensitivity and the partial selectivity toward oxidizing gases of a molecular organic semiconductor, copper phthalocyanine, with the O3 filtering selectivity of an organic material, indigo. Experimental measurements highlight filtering yield of indigo close to 100% toward O3 and lower than 10% for NO2. Nanometric indigo layers were realized for the first time by thermal evaporation and characterized by FT-IR spectroscopy. Such all-organic device exhibits a high NO2 sensitivity for low concentrations, a resolution better than 20 ppb, a threshold of detection to few ppb and a high level of selectivity. The influence of filtering layer thickness and the optimization for real-time measurements are also discussed. Beyond sensor development, such nanostructured indigo layers are relevant as protective element of electronic components against adverse ozone effects.

Several new synthesis methods of fluorinated carbon nanofibres, such as controlled fluorination using fluorinating agent (TbF4 or XeF 2), or assisted fluorination under UV and gamma irradiation, are reviewed and compared with the direct fluorination using undiluted fluorine gas. The results highlight the different fluorinationmechanisms for the direct fluorination and the new methods. The other advantage of those alternative fluorination routes is the possibility to provide fine tuning of the fluorination level, i.e. from F/C atomic ratio close to zero, as a functionalization, to the unity (CF1) according to the required application, electrochemical or tribological. Two applications are described in this paper as a function of the fluorine content: protection against ozonation and use as solid lubricants. © 2010 Elsevier B.V. All rights reserved.

Pauly, Alain, Villemant, Claire (2009): Hyménoptères Apoidea (Insecta) de l'archipel du Vanuatu. Zoosystema 31 (3): 719-730, DOI: 10.5252/z2009n3a16, URL: http://www.bioone.org/doi/abs/10.5252/z2009n3a16

In a metal/p-InP Schottky diode, interface states existing at the surface of the semiconductor are responsible for Fermi level pinning. The value of the Schottky barrier height contact is thus limited by this phenomenon. In gas sensor application, the sensitivity varies according to the Schottky barrier height. In order to reduce the effect of Fermi level pinning, we have developed pseudo-Schottky junctions on p-InP. The rectifying contact on p-InP using Ge-based metallization followed by moderate annealing temperatures is studied. Diffusion of Ge atoms at the metal–semiconductor interface creates a thin n + -InP layer. Pseudo-Schottky junctions are obtained with a significant barrier height enhancement, typically by 0.06 eV for Pd diodes and 0.12–0.14 eV for Au diodes. The metallization process involved throughout the present work leads to high-quality Schottky diodes within a rather simple procedure similar to those used in general to obtain good ohmic contacts. The behavior of pseudo-Schottky devices is thoroughly analyzed as a function of the annealing procedure. The best performances are obtained by applying cumulative annealing sequences, increasing the temperature while decreasing the time of thermal treatment. Comparisons of electrical characteristics between Au and Pd pseudo-Schottky diodes are realized.

This article is devoted to the optimization of the electrical parameters of p-InP-based Schottky diodes realized with gold metal, in order to enhance their NO2 gas sensitivity. In the structures based on p-InP, the interface states that exist at the surface of the semiconductor are responsible for the undesirable Fermi level pinning, and the value of the Schottky barrier height (ΦB) thus becomes limited by this phenomenon. In gas sensor application, the sensitivity varies as the Schottky barrier height varies. Therefore, to reduce the effect of the Fermi level pinning, one solution is to realize a pseudo-Schottky junction: a thin opposite doping layer to that of the bulk is created between the metal and the p-InP. This can be realized by introducing a germanium (Ge) layer during the evaporation of the metal, followed by an annealing process. The mechanisms of the electrical conduction of these structures are analyzed at different temperatures. The influence of the electrical properties, namely barrier height (ΦB) and n (ideality factor) on these devices sensitivities towards NO2 are demonstrated. Through the values of the ideality factor, we investigate its influence on the conduction mechanism and on the sensitivity of the gas sensor.