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Conservation managers need to know the degree of connectivity showed by the populations to be preserved, especially when protected areas and/or species are involved. One of the conservation projects carried out by the Ordesa y Monte Perdido National Park (Central Pyrenees, Spain) is the monitoring of the protected Spanish Moon Moth, Graellsia isabellae (Lepidoptera, Saturniidae), in several sites within the actual park, buffer zone, and peripheral area. Here we studied the genetic diversity, geographical structure, and connectivity of this iconic insect in those areas with the aim of producing evidence-based recommendations that might help the National Park staff in their decision-making. For this, we non-lethally sampled 402 adult moths from 17 sites and worked at two geographic scales: Western/Central Pyrenees and the area monitored by the staff of the National Park. The multilocus genotypes obtained for nine nuclear microsatellite markers allowed us to quantify genetic variation, investigate population structure, and calculate recent migration rates. Our results revealed a large-scale (ca. 125 km) west–east cline in allele frequencies that causes low overall genetic differentiation (FST = 0.038) and similar levels of diversity among sites. Habitat connectivity revealed as an important element determining dispersal for G. isabellae, given the patchy distribution of the host plant (Pinus sylvestris) in the study area. Gene flow within and outside the National Park was proved, with a particular site of the buffer zone (Bujaruelo) acting as a source of migrants to other localities within and outside the National Park. This finding underlines the importance of considering buffer zones to preserve genetic diversity within protected areas, and that safeguarding the connectedness of pine patches is key to the conservation of this iconic moth.

BackgroundBroad-scale monitoring of arthropods is often carried out with passive traps (e.g. Malaise traps) that can collect thousands of specimens per sample. The identification of individual specimens requires time and taxonomic expertise, limiting the geographical and temporal scale of research and monitoring studies. DNA metabarcoding of bulk-sample homogenates is faster and has been found to be efficient and reliable, but is destructive and prevents a posteriori validation of species occurrences and/or relative abundances. Non-destructive DNA metabarcoding from the collection medium has been applied in a limited number of studies, but further tests of efficiency are required in a broader range of circumstances to assess the consistency of the method.MethodsWe quantified the detection rate of arthropod species when applying non-destructive DNA metabarcoding with a short (127-bp) fragment of mitochondrial COI on two types of passive traps and collection media: 1) water with monopropylene glycol (H2O–MPG) used in window-flight traps (WFT, 53 in total); 2) ethanol with monopropylene glycol (EtOH–MPG) used in Malaise traps (MT, 27 in total). We then compared our results with those obtained for the same samples using morphological identification (for WFTs) or destructive metabarcoding of bulk homogenate (for MTs). This comparison was applied as part of a larger study of arthropod species richness in silver fir (Abies alba) stands across a range of climate-induced tree dieback levels and forest management strategies.ResultsOf the 53 H2O-MPG samples from WFTs, 16 produced no metabarcoding results, while the remaining 37 samples yielded 77 arthropod MOTUs in total. None of those MOTUs were shared species with the 389 morphological taxa (343 of which were Coleoptera) obtained from the same traps. Metabarcoding of 26 EtOH–MPG samples from MTs detected more arthropod MOTUs (233) and insect orders (11) than destructive metabarcoding of homogenate (146 MOTUs, 8 orders). Arachnida and Collembola were more diverse in EtOH-MPG samples, but Hymenoptera, Coleoptera and Lepidoptera were less represented than in homogenate. Overall, MOTU richness per trap similar for EtOH–MPG (21.81 MOTUs) than for homogenate (32.4 MOTUs). Arthropod communities from EtOH–MPG and homogenate metabarcoding were relatively distinct, with 162 MOTUs (53%) unique to the collection medium and only 71 MOTUs (23%) present in both treatments. Finally, collection medium did not reveal any significant changes in arthropod richness along a disturbance gradient in silver fir forests. We conclude that DNA metabarcoding of collection medium can be used to complement homogenate metabarcoding in inventories to favour the detection of soft-bodied arthropods like spiders.

AimAccording to the Latitudinal Biotic Interaction Hypothesis (LBIH), the general increase in biodiversity towards lower latitudes can be partially explained by an increase in the intensity of biotic interactions. While LBIH received some support for plant-herbivores interactions, much less is known about how higher trophic levels may contribute to shape biotic interactions across latitudinal gradients. We hypothesized that the diversity of insectivorous birds increases towards lower latitude, leading to higher predation rates on insect herbivores.LocationEurope.TaxonInsectivorous birds and pedunculate oaks.MethodsWe deployed plasticine caterpillars in 138 oak trees in 47 sites along a 19° latitudinal gradient in Europe to quantify bird insectivory through predation attempts. In addition, we used passive acoustic monitoring to (i) characterize the acoustic diversity of surrounding soundscapes; and (ii) infer both taxonomic and functional diversity of insectivorous birds from recordings.ResultsThe functional diversity of insectivorous birds increased towards lower latitude. Bird predation increased with latitude, forest cover and bird acoustic diversity but decreased with mean annual temperature and functional richness of insectivorous birds. Contrary to our predictions, latitudinal clines in bird predation attempts were not directly mediated by changes in insectivorous bird diversity or acoustic diversity, but latitude and habitat still had independent effects on predation attempts.Main conclusionsOur study does not fully support the predictions of the LBIH of more biotic interactions southwards and advocates for better accounting for activity and abundance of insectivorous birds when studying the large-scale variation in insect-tree interactions.

Wild bees are declining, mainly due to the expansion of urban habitats that have led to land-use changes. Effects of urbanization on wild bee communities are still unclear, as shown by contrasting reports on their species and functional diversities in urban habitats. To address this current controversy, we built a large dataset, merging 16 surveys carried out in 3 countries of Western Europe during the past decades, and tested whether urbanization influences local wild bee taxonomic and functional community composition. These surveys encompassed a range of urbanization levels, that were quantified using two complementary metrics: the proportion of impervious surfaces and the human population density. Urban expansion, when measured as a proportion of impervious surfaces, but not as human population density, was significantly and negatively correlated with wild bee community species richness. Taxonomic dissimilarity of the bee community was independent of both urbanization metrics. However, occurrence rates of functional traits revealed significant differences between lightly and highly urbanized communities, for both urbanization metrics. With higher human population density, probabilities of occurrence of above-ground nesters, generalist and small species increased. With higher soil sealing, probabilities of occurrence of above-ground nesters, generalists and social bees increased as well. Overall, these results, based on a large European dataset, suggest that urbanization can have negative impacts on wild bee diversity. They further identify some traits favored in urban environments, showing that several wild bee species can thrive in cities.

The current decline of wild bees puts important ecosystem services such as pollination at risk. Both inventory and monitoring programs are needed to understand the causes of wild bee decline. Effective insect monitoring relies on both mass-trapping methods coupled with rapid and accurate identifications. Identifying wild bees using only morphology can be challenging, in particular, specimens from mass-trapped samples which are often in poor condition. We generated DNA barcodes for 2931 specimens representing 157 species (156 named and one unnamed species) and 28 genera. Automated cluster delineation reveals 172 BINs (Barcodes Index Numbers). A total of 36 species (22.93%) were found in highly urbanized areas. The majority of specimens, representing 96.17% of the species barcoded form reciprocally exclusive groups, allowing their unambiguous identification. This includes several closely related species notoriously difficult to identify. A total of 137 species (87.26%) show a “one-to-one” match between a named species and the BIN assignment. Fourteen species (8.92%) show deep conspecific lineages with no apparent morphological differentiation. Only two species pairs shared the same BIN making their identification with DNA barcodes alone uncertain. Therefore, our DNA barcoding reference library allows reliable identification by non-experts for the vast majority of wild bee species in the Loire Valley.

Wild silkmoths (Saturniidae) are one of the most emblematic and most studied families of moths. Yet, the absence of a robust phylogenetic framework based on a comprehensive taxonomic sampling impedes our understanding of their evolutionary history. We analyzed 1,024 ultraconserved elements (UCEs) and their flanking regions to infer the relationships among 338 species of Saturniidae representing all described subfamilies, tribes, and genera. We investigated systematic biases in genomic data and performed dating and historical biogeographic analyses to reconstruct the evolutionary history of wild silkmoths in space and time. Using Gene Genealogy Interrogation, we showed that saturation of nucleotide sequence data blurred our understanding of early divergences and first biogeographic events. Our analyses support a Neotropical origin of saturniids, shortly after the Cretaceous-Paleogene extinction event (ca 64.0 [stem] - 52.0 [crown] Ma), and two independent colonization events of the Old World during the Eocene, presumably through the Bering Land Bridge. Early divergences strongly shaped the distribution of extant subfamilies as they showed very limited mobility across biogeographical regions, except for Saturniinae, a subfamily now present on all continents but Antarctica. Overall, our results provide a framework for in-depth investigations into the spatial and temporal dynamics of all saturniid lineages and for the integration of their evolutionary history into further global studies of biodiversity and conservation. Rather unexpectedly for a taxonomically well-known family such as Saturniidae, the proper alignment of taxonomic divisions and ranks with our phylogenetic results leads us to propose substantial rearrangements of the family classification, including the description of one new subfamily and two new tribes.

International audience; Global insect decline has recently become a cause for major concern, particularly in the tropics where the vast majority of species occurs. Deforestation is suggested as being a major driver of this decline, but how anthropogenic changes in landscape structure affect tropical insect communities has rarely been addressed. We sampled Saturniidae and Sphingidae moths on 27 farms located in Brazilian Amazonia (Para state) and characterised by different deforestation histories. We used functional traits (forewing length, body mass, wing load, trophic niche breadth and resource use strategy), analysed by combining RLQ and null model analyses, to investigate the responses of their taxonomic and functional diversity to landscape change dynamics and current structure. We found that communities had a higher proportion of large and polyphagous species with low wing load in landscapes with low forest quality and relative cover and high land use turnover. This was mainly due to a significant response to deforestation by saturniids, whereas the more mobile sphingids showed no significant landscape-related pattern. We also observed an overall increase of species richness and functional dispersion in landscapes that have been deforested for a long time when compared with more recent agricultural settlements. Our results highlight the complex way in which landscape structure and historical dynamics interact to shape Neotropical moth communities and that saturniid moths respond clearly to the structure of the surrounding landscape, confirming their potential use as an indicator group for environmental monitoring programmes.

Three new treehoppers species, closely related to Lycoderides brulei Sakakibara, 2013, are described from French Guiana: Lycoderides carboneus Lapèze n. sp., Lycoderides elephantus Lapèze n. sp. and Lycoderides sonzognii Lapèze n. sp..The first two species are described based on adults of both sexes, their last nymphal stage is described and their host plants of the genus Clusia (Clusiaceae) are mentioned and illustrated. Lycoderides sonzognii n. sp. is described based on three females caught with a light trap. Lycoderides elephantus n. sp. has been reared, its biological cycle is presented in detail. Holotypes and some paratypes are deposited at MNHN of Paris. Additional notes about field observations, host-plants, distribution, behavior and predation are presented. These three new species, along with Lycoderides brulei, have a diagnostic character: a line of weakness at the base of the pronotum, morphological feature which is unique among Lycoderides. DNA barcoding allows to match males and females, and each species forms a clade and have been assigned unique Barcode Index Numbers (BIN).An identification key is provided for the four species of Lycoderides having a line of weakness. A revised check-list of the Lycoderides from French Guiana is presented. A discussion about Lycoderes mitratus Germar, 1935 presents how it may have been confused in the past with one of the four species illustrated here., Trois nouvelles espèces de membracides, proches de Lycoderides brulei Sakakibara, 2013, sont décrites de Guyane Française : Lycoderides carboneus Lapèze n. sp., Lycoderides elephantus Lapèze n. sp. et Lycoderides sonzognii Lapèze n. sp.. Les deux premières sont décrites sur des spécimens adultes des deux sexes, leur dernier stade larvaire est décrit et leurs plantes hôtes du genre Clusia (Clusiaceae) sont citées et illustrées. Lycoderides sonzognii n. sp. est décrite sur trois femelles capturées au piège lumineux. Lycoderides elephantus n. sp. a fait l'objet d'élevages, son cycle biologique détaillé est présenté. Les holotypes et plusieurs paratypes sont déposés au Musée National d'Histoire Naturelle de Paris. Des notes concernant la répartition, les mœurs et la prédation sont présentées. Ces trois nouvelles espèces, tout comme Lycoderides brulei, ont la particularité de présenter une ligne de pré-cassure à la base du casque, caractéristique qu'ils ne partagent pas avec les autres espèces du genre Lycoderides. Le DNA barcoding (gène mitochondrial COI) a permis de confirmer l’appariement des sexes. Chaque nouvelle espèce représente un clade avec un Barcode Index Number (BIN) unique. Une clé d'identification est donnée pour les quatre espèces de Lycoderides ayant une ligne de pré-cassure. Une liste révisée des Lycoderides de Guyane est présentée. Une discussion autour de Lycoderes mitratus Germar, 1935 présente en quoi elle a pu être confondue par le passé avec l'une des quatre espèces ici illustrées.

Context: Forest ecosystems worldwide are facing increasing drought-induced dieback, causing mortality patches across the landscape at multiple scales. This increases the supply of biological legacies and differentially affects forest insect communities.Objectives: We analysed the relative effects of local- and landscape-level dieback on local saproxylic beetle assemblages. We assessed how classic concepts in spatial ecology (e.g. habitat-amount and habitat-patch hypotheses) are involved in relationships between multi-scale spatial patterns of available resources and local communities.Methods: We sampled saproxylic beetle assemblages in commercial fir forests in the French highlands. Through automatic aerial mapping, we used dead tree crowns to assess dieback levels at several nested spatial scales. We analysed beetle taxonomic, phylogenetic and functional diversity related to differing levels of multi-scale dieback.Results: In line with the habitat-amount hypothesis, taxonomic and functional diversity, but not phylogenetic diversity, of beetle assemblages significantly benefitted from forest dieback, at both local and landscape scales. Very few single or interaction effects were detected in the multiplicative models combining local and landscape variables, though a significant positive effect of landscape-scale dieback on the abundance of cavity- and fungus-dwelling species was consistent with a spill-over effect. Increased landscape-scale dieback also caused a functional specialisation of beetle assemblages, favouring those related to large-diameter, well-decayed deadwood.Conclusions: Increasing tree mortality under benign neglect provides conservation benefits by heterogenising the forest landscape and enhancing deadwood habitats. Legacy retention practices could take advantage of unharvested, declining forest stands to promote species richness and functional diversity within conventionally managed forest landscapes.

Historical herbaria are valuable sources of data in invasion biology. Here we study the invasion history of the lime leaf-miner, Phyllonorycter issikii, by surveying over 15 thousand herbarium specimens of limes (Tilia spp.) collected in the Palearctic during last 253 years (1764–2016). The majority of herbarium specimens with the pest’s mines (89%) originated from East Asia (1859–2015), whereas remaining 11% of specimens with the mines came from Europe, European Russia and Western Siberia (1987–2015). These results support the hypothesis of a recent Ph. issikii invasion from Eastern to Western Palearctic.Single molecule real-time sequencing of the COI barcode region of 93 archival larvae and pupae (7–162 years old) dissected from the mines on historical herbaria allowed to distinguish between Ph. issikii and Ph. messaniella, a polyphagous species rarely feeding on Tilia, which mines were found in herbarium from Europe dated by 1915–1942. We discovered 25 haplotypes of Ph. issikii, of which 16 haplotypes were present solely in East Asia, and revealed wide distribution of the species in China. Six haplotypes shared between Eastern and Western Palearctic suggest the contribution of Ph. issikii populations from the Russian Far East, China and Japan to the westward invasion.

International audience; Global change challenges the adaptive potential of forests. Large-scale alterations of forest canopies have been reported across Europe, and further modifications are expected in response to the predicted changes in drought and windstorm regimes. Since forest canopies are dynamic interfaces between atmosphere and land surface, communities of canopy-dwelling insects are at the forefront of major changes in response to both direct and indirect effects of climate change. First, we briefly introduce the factors shaping arthropod communities in the canopy of temperate forests. Second, we cover the significant impacts of a forest decline on canopy structure and functioning, and more specifically its contrasted effects on insect microhabitats, trophic resources and forest microclimates. Deleterious effects may be expected for several guilds of leaf-dwelling insects. Nonetheless, a forest decline could also lead to transient or long-lasting resource pulses for other canopy-dwelling guilds, especially saproxylic species depending on deadwood substrates and tree-related microhabitats. The novel microclimates may also become more favorable for some particular groups of insects. We pinpoint current knowledge gaps and the technological locks that should be undone to improve our understanding of the canopy biotope and biodiversity in temperate forests. We highlight the need for integrative approaches to reveal the mechanisms at play. We call for cross-scale studies and long-term collaborative research efforts, involving different disciplines such as community and disturbance ecology, plant and insect ecophysiology, and thermal ecology, to better anticipate ongoing functional and conservation issues in temperate forest ecosystems.

Gracillariidae is the most taxonomically diverse cosmopolitan leaf-mining moth family, consisting of nearly 2000 named species in 105 described genera, classified into eight extant subfamilies. The majority of gracillariid species are internal plant feeders as larvae, creating mines and galls in plant tissue. Despite their diversity and ecological adaptations, their phylogenetic relationships, especially among subfamilies, remain uncertain. Genomic data (83 taxa, 589 loci) were integrated with Sanger data (130 taxa, 22 loci), to reconstruct a phylogeny of Gracillariidae. Based on analyses of both datasets combined and analyzed separately, monophyly of Gracillariidae and all its subfamilies, monophyly of the clade "LAMPO" (subfamilies: Lithocolletinae, Acrocercopinae, Marmarinae, Phyllocnistinae, and Oecophyllembiinae) and relationships of its subclade "AMO" (subfamilies: Acrocercopinae, Marmarinae, and Oecophyllembiinae) were strongly supported. A sister-group relationship of Ornixolinae to the remainder of the family, and a monophyletic leaf roller lineage (Callicercops Vari + Parornichinae) + Gracillariinae, as sister to the "LAMPO" clade were supported by the most likely tree. Dating analyses indicate a mid-Cretaceous (105.3 Ma) origin of the family, followed by a rapid diversification into the nine subfamilies predating the Cretaceous-Palaeogene extinction. We hypothesize that advanced larval behaviours, such as making keeled or tentiform blotch mines, rolling leaves and galling, allowed gracillariids to better avoid larval parasitoids allowing them to further diversify. Finally, we stabilize the classification by formally re-establishing the subfamily ranks of Marmarinae stat.rev., Oecophyllembiinae stat.rev. and Parornichinae stat.rev., and erect a new subfamily, Callicercopinae Li, Ohshima and Kawahara to accommodate the enigmatic genus Callicercops.

The lime leaf-miner, Phyllonorycter issikii is an invasive micromoth with an unusually higher number of haplotypes in the invaded area (Europe, Western Siberia) compared to its putative native region (East Asia). The origin of the genetic diversity in the neocolonized region remains unclear. We surveyed over 15 thousand herbarium specimens of lime trees (Tilia spp.) collected across the Palearctic over a period of 252 years (1764-2016) looking for preserved larvae within the archival leaf mines. We found 203 herbarium specimens with leaf mines of Ph. issikii collected in East Asia, one of them dating back to 1830, i.e. 133 years before the description of the species. In contrast, only 22 herbarium specimens collected in the West Palearctic in the last three decades (1987-2015) carried leaf mines. DNA barcoding of archival specimens revealed 32 haplotypes out of which 23 were novel (not known from modern populations) and found exclusively in East Asia. Six haplotypes are shared between both native and invaded areas and only two were responsible for the recent invasion of the Western Palearctic. The remarkable number of newly discovered haplotypes in archival populations supports East Asia as the native region and the source area of invasion.

The Gracillariidae fauna of Siberia, the region that occupies almost half of the territory of the Russian Federation, remains poorly studied. During a DNA barcoding study of Gracillariidae in Siberia, based on analysis of larvae and pupae collected from their leaf mines on woody plants, we identified 41 species. Three gracillariids were identified only to genus: Caloptilia sp. (host plant Prunus padus), Parornix sp. (Malus sp.), and Phyllonorycter sp. (Crataegus sp.), representing poorly studied or undescribed species. Six species are reported here for the first time for Siberia: Callisto insperatella (from Novosibirsk and Tomsk provinces), Caloptilia alnivorella (Buryatia), Phyllonorycter ermani (Irkutsk Province), Ph. lantanella (Novosibirsk Province), Ph. pumilae (Omsk and Irkutsk provinces), and Ph. viciae (Krasnoyarsk Territory). Parornix pfaffenzelleri, found in Khakassia, is reported as a species new to Russia. Other 15 gracillariid species previously known from Siberia were recorded in new administrative regions. The invasive lime leafminer Phyllonorycter issikii was first documented in Tomsk Province and Krasnoyarsk Territory in 2017 and 2018, respectively. Seven new gracillariid-host plant associations were found: Parectopa ononidis on Lupinaster pentaphyllus, Sauterina hofmanniella on Lathyrus gmelinii, Caloptilia stigmatella on Salix kochiana, Callisto insperatella on Prunus virginiana, Parornix scoticella on Amelanchier sp., Phyllonorycter ermani on Alnus alnobetula subsp. fruticosa, and Phyllonorycter viciae on Vicia unijuga. The Gracillariidae fauna of Siberia has 51% similarity with that of European Russia and only 38% similarity with that of the Russian Far East.

During a DNA barcoding campaign of leaf-mining Gracillariidae from the Asian part of Russia, a new species ofPhyllonorycterHübner, feeding on the Siberian pea shrub,CaraganaarborescensLam. (Fabaceae) was discovered in Siberia. Here, this taxon is described asPhyllonorycterivanisp. n.Among Fabaceae-feedingPhyllonorycter, so far onlyP.caraganella(Ermolaev) has been known to develop onCaragana.PhyllonorycterivaniandP.caraganellashow a large divergence in morphology (external and male genitalia) and barcode region of the mtDNA-COI gene (8.6%). They feed on different host plants species and have different ranges in Russia. We show that DNA barcode data weakly supports the Fabaceae-feeding species groups. In addition, we show that morphologically (strongly) and genetically (weakly),P.ivanihas affinity to thehaasispecies group, a West Palearctic group with asymmetrical male genitalia.

DNA barcoding has been succesfully used for bio-surveillance of forest and agricultural pests in temperate areas, but has few applications in the tropics and particulary in Africa.Cacosceles newmannii(Coleoptera: Cerambycidae) is a Prioninae species that is locally causing extensive damage in commercially-grown sugarcane in the KwaZulu-Natal Province in South Africa. Due to the risk of spread of this species to the rest of southern Africa and to other sugarcane growing regions, clear and easy identification of this pest is critical for monitoring and for phytosanitary services. The genusCacoscelesNewman, 1838 includes four species, most being very similar in morphology. The damaging stage of the species is the larva, which is inherently difficult to distinguish morphologically from other Cerambycidae species. A tool for rapid and reliable identification of this species was needed by plant protection and quarantine agencies to monitor its potential abundance and spread. Here, we provide newly-generated barcodes forC. newmanniithat can be used to reliably identify any life stage, even by non-trained taxonomists. In addition, we compiled a curated DNA barcoding reference library for 70 specimens of 20 named species of Afrotropical Prioninae to evaluate DNA barcoding as a valid tool to identify them. We also assessed the level of deeply conspecific mitochondrial lineages. Sequences were assigned to 42 different Barcode Index Numbers (BINs), 28 of which were new to BOLD. Out of the 20 named species barcoded, 11 (52.4%) had their own unique Barcode Index Number (BIN). Eight species (38.1%) showed multiple BINs with no morphological differentiation. Amongst them,C. newmanniishowed two highly divergent genetic clusters which co-occur sympatrically, but further investigation is required to test whether they could represent new cryptic species.

Marked decline in insect species richness, abundance and biomass have recently been quantified in Europe. We metabarcoded 224 Malaise-trap samples to investigate whether drought-induced forest dieback and subsequent salvage logging have an impact on flying insects (ca. 3000 insect species) in silver fir Pyrenean forests. We found no evidence that climate-induced forest dieback impacted species richness of flying insects but revealed compositional turnover patterns consistent with those seen during natural forest succession, given that the key covariates explaining compositional variation were canopy openness versus microhabitat diversity and deadwood amount at local and landscape scales, respectively. Importantly, most change was driven by rare species. In contrast, observed levels of salvage logging did not explain change in species richness or composition. Hence, although forest dieback appears to cause changes in species assemblages mimicking natural forest succession, it also increases the risk of catastrophic loss of rare species through homogenization of environmental conditions.

International audience; Natural disturbances are major drivers of forest dynamics. However, in the current context of anthropogenic global warming, shifts in disturbance regimes are expected. Natural disturbances usually leave biological or structural legacies which are important for early-successional species. Nevertheless, these legacies are usually eliminated by forest managers through salvage logging. Here, we investigated the consequences of forest dieback and the following salvage logging on both forest habitat conditions and saproxylic beetle communities. We conducted our study in two types of conifer-dominated highland forests: Pyrenean silver fir (Abies alba) which has suffered drought-induced dieback and Bavarian Norway spruce (Picea abies) which has suffered bark beetle-induced (Ips typographus) dieback. In both of the forest contexts, dieback provided a biological legacy through an increase in deadwood resources; however, this increase was much greater in the spruce forests. Nonetheless, despite this increase in resources, neither type of forest gained in total abundance or species richness after disturbance, compared to healthy stands. Nevertheless, the species composition of saproxylic beetle composition was significantly affected by dieback in spruce stands, but not in the silver fir forests. In the spruce plots, saproxylic beetles responded positively to the large increase in deadwood in the declining stands, including a very strong positive response from red listed species. Saproxylic beetle assemblages in spruce forests were mainly drove by canopy openness and deadwood amount. In the silver fir plots, we did not observed responses from the saproxylic beetle communities to deadwood amount increase. This lack of response may be explained by the relatively low amount of deadwood generated by the drought-induced dieback. Concerning salvage logging, it caused stronger contrasts in spruce forests than in silver fir forests, where it generally had no significant impact. For example, in spruce forests, salvage logging reduced the density of large snags by 91% and large logs by 87% compared with unharvested declining plots. Most of the significant environmental effects on biodiversity associated with dieback were no longer significant after accounting for the salvaged plots in our study data. Then, forest dieback and salvage logging induced much sharper and stronger effects on environmental and community metrics in the spruce than in the silver fir forests. The contrast between Bavaria and the French Pyrenees seems partly related to dieback severity. Finally, we invite forest managers to conserve biological and structural legacies through patches of deadwood-rich areas.

National audience

Developing methods to rear phytophagous insects is crucial to reveal the true complexity of interactions between insects and their host plants. Here we focus on leaf-mining insects, an ecological guild across four different orders (Lepidoptera, Diptera, Coleoptera, and Hymenoptera) whose larvae feed inside the leaves of their host plants, producing cavities in the leaf tissue that are known as leaf mines. Besides leaf lamina, some leaf-mining species can also mine leaf petioles and veins, and a few species make cavities in soft shoots, stems, or mine the surface of young fruits and seeds. Most leaf miners are host plant-specific and produce characteristic leaf mines that are remarkably variable among species. Some species are considered important crop, orchard, and forest pests. Despite their fascinating life history, global diversity, and ecological and economic importance, little is known about the biology of most species, in particular in the tropics. Here, we describe methods to collect, rear, and preserve samples of leaf miners with an emphasis on the smallest of Lepidoptera.

International audience; Graellsia isabellae is a protected lepidopteran both in France and Spain; however, there has been considerable debate over its conservation status. Recent literature emphasised the need of monitoring population size in the different mountain ranges where this iconic species occurs. We used mark-capture-recapture and genotypes of nine molecular microsatellite markers to estimate the census (N) and contemporary effective population size (N-e) of two Spanish populations extending over similar size areas (10-15 km(2)): Puebla (Eastern Spain) and Ordesa (Western Pyrenees). Only adult males were captured and analysed, as sampling was based on the use of the synthesised female sex pheromone. Estimates of N were rather different in the two populations: 3398 males in Puebla (95% CI = 2875-4145) and 1500 in Ordesa (95% CI = 1229-1932), although the area occupied by the populations was larger and more densely forested in Ordesa than in Puebla. Several lines of evidence pointed to a moderate-large contemporary N-e at Puebla (173-178 individuals) and a one-order of magnitude lower N-e at Ordesa (27-49). Thus, N-e/N ratios were very low (0.026 and 0.01 respectively). We recommend G. isabellae to be classified as of Least Concern under the IUCN criteria; however, the high temporal fragmentation index and the very low values of the N-e/N ratios obtained for this species, as compared with those recorded for most others, are usually taken as indicators of actual threat for their conservation. As a cautionary measure, managers should aim at maintaining gene flow by ensuring connectivity of Pinus sylvestris in these areas.

International audience; Saproxylic beetles are important bioindicators of forest health but their enormous diversity makes their identification challenging. As an example, the French fauna of saproxylic beetles alone contains 2,663 species in 72 families. Recently, DNA barcoding was proposed as a promising tool for the identification and monitoring of saproxylic beetle species. However, the rate of DNA barcode recovery from specimens of natural history collections using standard Sanger sequencing protocols remains low and challenges the construction of reference libraries. In this study, we test the potential of high-throughput sequencing (HTS) technology to reduce this shortfall by increasing sequencing success rate and lowering processing cost per specimen. Using a dual-indexing strategy for library construction and sequencing on the Illumina MiSeq platform, we successfully sequenced the DNA barcodes of 286 dry-pinned saproxylic beetles out of 521 specimens aged from 1 to 17 years and sampled in natural history collections. Age at sequencing did not affect sequence recovery and the success rate (54.9%) of our approach is comparable to that obtained using Sanger sequencing technology in another study targeting beetle specimens from natural history collections, but the cost per specimen is significantly reduced when using HTS. Finally, we shortly discuss how the newly produced DNA barcodes contribute to the existing library and we highlight a few interesting cases in which the new sequences question current species boundaries.

International audience; China has recently announced a reform of forestry policy, with a major goal being to transform from plantation to heterogeneous forests, which have higher resistance to pests and disease and house more biodiversity. One driver of reform is increased intensity and frequency of pest-induced tree-dieback events. To inform management, we ask what effects these events have on insect biodiversity in Pinus yunnanensis monocultures in Yunnan province, the province with one of the highest proportions of forest cover in China. We sampled aerial arthropods (mostly insect) biodiversity along gradients of Pinus yunnanensis dieback severity using Malaise traps and used metabarcoding to characterise the insect community. We used MS-GDM ('multi-site generalized dissimilarity modelling of zeta diversity'), zeta-decline analysis, and iNEXT ('Interpolation and extrapolation for species diversity') to assess community change as functions of forest-structure covariates. Metabarcoding of Malaisetrapped insects reveals that bark-beetle induced forest dieback does not result in detectable differences in species diversity but does result in compositional change, with the biggest turnover occurring between 0% and infested-0%-open-canopy forests and 20%-infested-20%-open-canopy forests. Zeta-decline analysis found that the insect community in low-infestation forests is characterized by a stochastic assembly, while in highinfestation forests, the community structure is consistent with niche assembly. Our results thus suggest that bark-beetle dieback mimics natural forest-gap dynamics, consistent with the interpretation of bark beetles as a keystone species in European conifer forests, where it has been proposed that forest heterogeneity can be created efficiently by allowing natural disturbances, including bark-beetle outbreaks, to proceed naturally, without being mitigated by deadwood removal and dense replanting. In Yunnan's situation, and given predicted increases in bark-beetle dieback severity and frequency, this strategy should probably be supplemented with anthropogenic treatments, such as deadwood enhancement and planting of multiple tree species, to accelerate the succession of plantations into heterogeneous forests.

Metabarcoding increases the taxonomic resolution and geographic scale at which researchers can assess the impacts of climate change on insect communities in forests

International audience; Forest diebacks are likely to increase in response to climate change, with increased frequency and intensity of droughts. In line with climate change scenarios, ecoclimatic modelling predicts a decrease in the range of silver fir, a drought-sensitive species, in its southern limit in the French Pyrenees. Diebacks are expected to induce a pulse of resources potentially favorable to certain forest species, e.g. tree-related microhabitats (TreM) for saproxylic species. The impact of forest dieback on biodiversity has nonetheless been poorly studied. As part of the international Climtree project, we set up a balanced sampling design of 56 plots crossing the intensity of local silver fir dieback and the salvage logging of weakened or dead trees. Detailed stand structure metrics and insect communities sampled by Malaise traps (insect MOTUs) or flight-interception traps (saproxylic beetles) have been measured. The structure of fir stands was affected by the level of decline, and to a lesser extent by salvage logging. We indeed observed a slight increase in CWD and in some TreM-bearing trees (crown deadwood, annual polypores , trunk rot holes) with dieback intensity, and a slight decrease in some TreM-bearing trees (crown deadwood, annual polypores) in salvaged compared with unharvested plots. However, these stand changes did not strongly affect local insect assemblages. Guilds of TreM-associated insects did not increase in abundance or richness with dieback-induced increase in resources. In conclusion, forest changes through dieback result in habitat and resource changes with still hard-to-predict impacts at the stand scale on a major reservoir of biodiversity.

The Russian Far East (RFE) is an important hotspot of biodiversity whose insect fauna remains understudied, particularly its Microlepidoptera. Here we explore the diversity of leaf-mining micromoths of the family Gracillariidae, their distribution and host plant associations in RFE using a combination of field observations and sampling, DNA barcoding, morphological analysis and literature review. We collected 91 gracillariid specimens (45 larvae, 9 pupae and 37 adults) in 12 localities across RFE and identified 34 species using a combination of DNA barcoding and morphology. We provide a genetic library of 57 DNA barcodes belonging to 37 Barcode Index Numbers (BINs), including four BINs that could potentially represent species new to science. Leaf mines and leaf shelters are described and illustrated for 32 studied species, male or female genitalia as well as forewing patterns of adults are shown, especially for those species identified based on morphology. Three species, Micrurapteryx caraganella (Hering), Callisto insperatella (Nickerl), and Phyllonorycter junoniella (Zeller) are newly recorded from RFE. Five species previously known from some regions of RFE, were found for the first time in Amurskaya Oblast: Phyllonorycter populifoliella (Treitschke), Primorskii Krai: Ph. sorbicola Kumata and Sahkalin Island: Caloptilia heringi Kumata, Ph. ermani (Kumata) and Ph. ulmifoliella (Hübner). Eight gracillariid–plant associations are novel to science: Caloptilia gloriosa Kumata on Acer pseudosieboldianum, Cameraria niphonica Kumata on A. caudatum subsp. ukurundense, Parornix ermolaevi Kuznetzov on Corylus sieboldiana, Phyllonorycter ermani (Kumata) on Betula platyphylla, Ph. nipponicella (Issiki) on Quercus mongolica, Ph. orientalis (Kumata) and Ph. pseudojezoniella Noreika on Acer saccharum, Ph. sorbicola on Prunus maakii. For the first time we documented the “green island” phenotype on Phyllonorycter cavella (Zeller) mines on Betula platyphylla. Two pestiferous species have been recorded during our surveys: Micrurapteryx caraganella on ornamental Caragana arborescens in urban plantations in Amurskaya Oblast, and the lime leafminer Phyllonorycter issikii (Kumata), a species known to be native to RFE and invasive elsewhere in Russia and in European countries. A revised checklist of RFE gracillariids has been compiled. It accounts for 135 species among which 17 species (13%) are only known to occur in RFE. The gracillariid fauna of RFE is more similar to the Japanese fauna (49%), than to the fauna of the rest of Russia (i.e European part and Siberia) (32%).