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[hal-02808562] DNA barcoding reveals that the reverse latitudinal gradient of Gracillariidae leaf-miners is an artifact of tropical under-sampling
[...]
ano.nymous@ccsd.cnrs.fr.invalid (Carlos Lopez-Vaamonde) 06 Jun 2020
https://hal.inrae.fr/hal-02808562v1
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[hal-02630970] DNA barcoding reveals a largely unknown fauna of Gracillariidae leaf-mining moths in the Neotropics
Higher taxa often show increasing species richness towards tropical low latitudes, a pattern known as the latitudinal biodiversity gradient (LBG). A rare reverse LBG (with greater richness towards temperate high latitudes) is exhibited by Gracillariidae leaf-mining moths, in which most described species occur in northern temperate areas. We carried out the first assessment of gracillariid species diversity in two Neotropical regions to test whether the relatively low tropical species diversity of this family is genuine or caused by insufficient sampling and a strong taxonomic impediment. Field surveys in six French Guianan and one Ecuadorian site produced 516 gracillariid specimens that were DNA barcoded to facilitate identification and to match larvae inside leaf mines with adults. Species delineation from sequence data was approximated using Automatic Barcode Gap Discovery and Refined Single Linkage Analysis through the Barcode Index Number system, and the proportion of described/undescribed species was estimated after comparison with types of 83% of described species. Locally, alpha-diversity far exceeds that of any known temperate fauna, with as many as 108 candidate species (59.3% as singletons) collected at one site, and with an estimated species richness lower bound of 240 species. Strikingly, at least 85% of the species collected as adults were found to be undescribed. Our sampling represents the most thorough survey of gracillariid species diversity in the Neotropics to date and the results from both our molecular and morphological analyses indicate that the current reverse LBG seen in this group is an artefact of insufficient sampling and a strong description deficit in the Neotropics.
ano.nymous@ccsd.cnrs.fr.invalid (David C Lees) 27 May 2020
https://hal.inrae.fr/hal-02630970v1
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[hal-02627834] Return of the moth: rethinking the effect of climate on insect outbreaks
The sudden interruption of recurring larch budmoth (LBM; Zeiraphera diniana or griseana Gn.) outbreaks across the European Alps after 1982 was surprising, because populations had regularly oscillated every 8-9 years for the past 1200 years or more. Although ecophysiological evidence was limited and underlying processes remained uncertain, climate change has been indicated as a possible driver of this disruption. An unexpected, recent return of LBM population peaks in 2017 and 2018 provides insight into this insect's climate sensitivity. Here, we combine meteorological and dendrochronological data to explore the influence of temperature variation and atmospheric circulation on cyclic LBM outbreaks since the early 1950s. Anomalous cold European winters, associated with a persistent negative phase of the North Atlantic Oscillation, coincide with four consecutive epidemics between 1953 and 1982, and any of three warming-induced mechanisms could explain the system's failure thereafter: (1) high egg mortality, (2) asynchrony between egg hatch and foliage growth, and (3) upward shifts of outbreak epicentres. In demonstrating that LBM populations continued to oscillate every 8-9 years at sub-outbreak levels, this study emphasizes the relevance of winter temperatures on trophic interactions between insects and their host trees, as well as the importance of separating natural from anthropogenic climate forcing on population behaviour.
ano.nymous@ccsd.cnrs.fr.invalid (Ulf Büntgen) 26 May 2020
https://hal.inrae.fr/hal-02627834v1
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[hal-02627982] Developing a list of invasive alien species likely to threaten biodiversity and ecosystems in the European Union
The European Union (EU) has recently published its first list of invasive alien species (IAS) of EU concern to which current legislation must apply. The list comprises species known to pose great threats to biodiversity and needs to be maintained and updated. Horizon scanning is seen as critical to identify the most threatening potential IAS that do not yet occur in Europe to be subsequently risk assessed for future listing. Accordingly, we present a systematic consensus horizon scanning procedure to derive a ranked list of potential IAS likely to arrive, establish, spread and have an impact on biodiversity in the region over the next decade. The approach is unique in the continental scale examined, the breadth of taxonomic groups and environments considered, and the methods and data sources used. International experts were brought together to address five broad thematic groups of potential IAS. For each thematic group the experts first independently assembled lists of potential IAS not yet established in the EU but potentially threatening biodiversity if introduced. Experts were asked to score the species within their thematic group for their separate likelihoods of i) arrival, ii) establishment, iii) spread, and iv) magnitude of the potential negative impact on biodiversity within the EU. Experts then convened for a 2-day workshop applying consensus methods to compile a ranked list of potential IAS. From an initial working list of 329 species, a list of 66 species not yet established in the EU that were considered to be very high (8 species), high (40 species) or medium (18 species) risk species was derived. Here, we present these species highlighting the potential negative impacts and the most likely biogeographic regions to be affected by these potential IAS.
ano.nymous@ccsd.cnrs.fr.invalid (Helen E. Roy) 26 May 2020
https://hal.inrae.fr/hal-02627982v1
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[hal-02743562] Diversity, species delimitation, and evolution of insect viruses
[...]
ano.nymous@ccsd.cnrs.fr.invalid (Elisabeth A. Herniou) 03 Jun 2020
https://hal.inrae.fr/hal-02743562v1
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[hal-02808538] Les codes-barres ADN révèlent que le gradient latitudinal de biodiversité inversé chez les mineuses de feuilles est un artefact
[...]
ano.nymous@ccsd.cnrs.fr.invalid (Carlos Lopez-Vaamonde) 06 Jun 2020
https://hal.inrae.fr/hal-02808538v1
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[hal-02650363] Genetic patterns in European geometrid moths revealed by the Barcode Index Number (BIN) system
Background: The geometrid moths of Europe are one of the best investigated insect groups in traditional taxonomy making them an ideal model group to test the accuracy of the Barcode Index Number (BIN) system of BOLD (Barcode of Life Datasystems), a method that supports automated, rapid species delineation and identification. Methodology/Principal Findings: This study provides a DNA barcode library for 219 of the 249 European geometrid moth species (88%) in five selected subfamilies. The data set includes COI sequences for 2130 specimens. Most species (93%) were found to possess diagnostic barcode sequences at the European level while only three species pairs (3%) were genetically indistinguishable in areas of sympatry. As a consequence, 97% of the European species we examined were unequivocally discriminated by barcodes within their natural areas of distribution. We found a 1:1 correspondence between BINs and traditionally recognized species for 67% of these species. Another 17% of the species (15 pairs, three triads) shared BINs, while specimens from the remaining species (18%) were divided among two or more BINs. Five of these species are mixtures, both sharing and splitting BINs. For 82% of the species with two or more BINs, the genetic splits involved allopatric populations, many of which have previously been hypothesized to represent distinct species or subspecies. Conclusions/Significance: This study confirms the effectiveness of DNA barcoding as a tool for species identification and illustrates the potential of the BIN system to characterize formal genetic units independently of an existing classification. This suggests the system can be used to efficiently assess the biodiversity of large, poorly known assemblages of organisms. For the moths examined in this study, cases of discordance between traditionally recognized species and BINs arose from several causes including overlooked species, synonymy, and cases where DNA barcodes revealed regional variation of uncertain taxonomic significance.
ano.nymous@ccsd.cnrs.fr.invalid (Axel Hausmann) 29 May 2020
https://hal.inrae.fr/hal-02650363v1
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[hal-02801284] DNA barcoding and DNA metabarcoding as tools for rapid inventory and high-throughput identification of Lepidoptera species in Amazonia
[...]
ano.nymous@ccsd.cnrs.fr.invalid (Rodolphe Rougerie) 05 Jun 2020
https://hal.inrae.fr/hal-02801284v1
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[hal-02798059] DNA barcoding reveals that the reverse latitudinal gradient of Gracillariidae leaf-miners is an artifact of tropical under-sampling
[...]
ano.nymous@ccsd.cnrs.fr.invalid (Carlos Lopez-Vaamonde) 05 Jun 2020
https://hal.inrae.fr/hal-02798059v1
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[hal-02640423] Species-Level Para- and Polyphyly in DNA Barcode Gene Trees: Strong Operational Bias in European Lepidoptera
The proliferation of DNA data is revolutionizing all fields of systematic research. DNA barcode sequences, now available for millions of specimens and several hundred thousand species, are increasingly used in algorithmic species delimitations. This is complicated by occasional incongruences between species and gene genealogies, as indicated by situations where conspecific individuals do not form a monophyletic cluster in a gene tree. In two previous reviews, non-monophyly has been reported as being common in mitochondrial DNA gene trees. We developed a novel web service “Monophylizer” to detect non-monophyly in phylogenetic trees and used it to ascertain the incidence of species non-monophyly in COI (a.k.a. cox1) barcode sequence data from 4977 species and 41,583 specimens of European Lepidoptera, the largest data set of DNA barcodes analyzed from this regard. Particular attention was paid to accurate species identification to ensure data integrity. We investigated the effects of tree-building method, sampling effort, and other methodological issues, all of which can influence estimates of non-monophyly. We found a 12% incidence of non-monophyly, a value significantly lower than that observed in previous studies. Neighbor joining (NJ) and maximum likelihood (ML) methods yielded almost equal numbers of non-monophyletic species, but 24.1% of these cases of non-monophyly were only found by one of these methods. Non-monophyletic species tend to show either low genetic distances to their nearest neighbors or exceptionally high levels of intraspecific variability. Cases of polyphyly in COI trees arising as a result of deep intraspecific divergence are negligible, as the detected cases reflected misidentifications or methodological errors. Taking into consideration variation in sampling effort, we estimate that the true incidence of non-monophyly is ∼23%, but with operational factors still being included. Within the operational factors, we separately assessed the frequency of taxonomic limitations (presence of overlooked cryptic and oversplit species) and identification uncertainties. We observed that operational factors are potentially present in more than half (58.6%) of the detected cases of non-monophyly. Furthermore, we observed that in about 20% of non-monophyletic species and entangled species, the lineages involved are either allopatric or parapatric—conditions where species delimitation is inherently subjective and particularly dependent on the species concept that has been adopted. These observations suggest that species-level non-monophyly in COI gene trees is less common than previously supposed, with many cases reflecting misidentifications, the subjectivity of species delimitation or other operational factors.
ano.nymous@ccsd.cnrs.fr.invalid (Marko Mutanen) 28 May 2020
https://hal.inrae.fr/hal-02640423v1
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[hal-01190252] A list of methods to detect arthropod quarantine pests in Europe
A total of 177 species of quarantine arthropods in Europe have been analysed for detection methods that are used in surveillance. This paper provides a link to a list where the methods most frequently used, either alone or in combination, are given for each species. Inspection remains the most common method of detection (108 species). Volatile compounds produced by either insects or host plants, or those released from food attractants are used for 85 species, while light trapping accounts for 28 species. Semiochemicals are known for 73 species, but are commercially available for only 43 species.
ano.nymous@ccsd.cnrs.fr.invalid (Sylvie Augustin) 01 Sep 2015
https://hal.science/hal-01190252v1
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[mnhn-05431499] À propos de Cilix hispanica : présence en Indre-et-Loire et façon de le reconnaître plus facilement sur le terrain (Lepidoptera Drepanidae Drepaninae)
La présence de Cilix hispanica est signalée pour la première fois dans le département de l’Indre-et-Loire. En outre, les auteurs dévoilent un caractère morphologique inédit permettant de différencier de manière certaine hispanica des formes claires de glaucata sans avoir recours à l’examen des genitalia ni des codes-barres ADN. Par ailleurs, l’holotype et les deux paratypes de Cilix algirica sont figurés.
ano.nymous@ccsd.cnrs.fr.invalid (Antoine Lévêque) 25 Dec 2025
https://mnhn.hal.science/mnhn-05431499v1
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[hal-03206694] Climate-induced forest dieback drives compositional change in insect communities that is concentrated amongst rare 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.
ano.nymous@ccsd.cnrs.fr.invalid (Lucas Sire) 23 Apr 2021
https://univ-tours.hal.science/hal-03206694v1
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[hal-02638263] Crossing frontiers in tackling pathways of biological Invasions
Substantial progress has been made in understanding how pathways underlie and mediate biological invasions. However, key features of their role in invasions remain poorly understood, available knowledge is widely scattered, and major frontiers in research and management are insufficiently characterized. We review the state of the art, highlight recent advances, identify pitfalls and constraints, and discuss major challenges in four broad fields of pathway research and management: pathway classification, application of pathway information, management response, and management impact. We present approaches to describe and quantify pathway attributes (e.g., spatiotemporal changes, proxies of introduction effort, environmental and socioeconomic contexts) and how they interact with species traits and regional characteristics. We also provide recommendations for a research agenda with particular focus on emerging (or neglected) research questions and present new analytical tools in the context of pathway research and management.
ano.nymous@ccsd.cnrs.fr.invalid (Franz Essl) 28 May 2020
https://hal.inrae.fr/hal-02638263v1
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[hal-02804116] Tracking origins of invasive leaf-mining moths using herbaria and minibarcodes
[...]
ano.nymous@ccsd.cnrs.fr.invalid (David C Lees) 06 Jun 2020
https://hal.inrae.fr/hal-02804116v1
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[hal-02651670] Tracking origins of invasive herbivores through herbaria and archival DNA: the case of the horse-chestnut leaf miner
Determining the native geographic range or origin of alien invasive species is crucial to developing invasive species management strategies. However, the necessary historical dimension is often lacking. The origin of the highly invasive horse-chestnut leaf-mining moth Cameraria ohridella has been controversial since the insect was first described in 1986 in Europe. Here, we reveal that herbarium collections across Europe indicate a Balkan origin for C ohridella. We successfully amplified nuclear DNA and mitochondrial DNA barcode fragments from larvae pressed within leaves of herbarium samples collected as early as 1879. These archival sequences confirm an identity of C ohridella and set back its history in Europe by more than a century. The herbarium samples uncovered previously unknown mitochondrial haplotypes and locally undocumented alleles, showing local outbreaks of C ohridella back to at least 1961 and dynamic frequency changes that may be associated with road development. This case history demonstrates that herbaria are greatly underutilized in studies of insect–plant interactions, herbivore biodiversity, and invasive species' origins.
ano.nymous@ccsd.cnrs.fr.invalid (David Lees) 29 May 2020
https://hal.inrae.fr/hal-02651670v1
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[hal-03750402] DNA metabarcoding of passive trap collection media for forest insect biomonitoring
Insect decline has been increasingly reported in the past years due to global change. Large-scale biomonitoring has thus become necessary to better understand the dynamics of insect communities and to preserve their essential role in ecosystem functioning. In that sense, coupling high-throughput sequencing and DNA metabarcoding has exponentially increased our potentiality to monitor insect communities over wider geographic regions and time scales. However, biomonitoring of entomofauna using molecular tools often results in destructive DNA extraction through voucher grinding, impeding primordial morphological backup. Here, we filter unprocessed collection medium to assess insect communities through environmental DNA metabarcoding. We demonstrate that recovered communities are different yet complementary and that insect response to environmental changes remains similar to homogenate bulk metabarcoding. We also show that insect orders-by their contrasting sclerotization ratio-, and collection medium type, are unequal in yielding metabarcoding results. Overall, we believe it as an efficient alternative for biomonitoring insect response to ecological changes while preserving insect vouchers for identification and description, especially in tropical regions were singletons or undescribed species can be very common in trap samples.
ano.nymous@ccsd.cnrs.fr.invalid (Lucas Sire) 12 Aug 2022
https://hal.inrae.fr/hal-03750402v1
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[hal-01607783] No saturation in the accumulation of alien species worldwide
Although research on human-mediated exchanges of species has substantially intensified during the last centuries, we know surprisingly little about temporal dynamics of alien species accumulations across regions and taxa. Using a novel database of 45,813 first records of 16,926 established alien species, we show that the annual rate of first records worldwide has increased during the last 200 years, with 37% of all first records reported most recently (1970-2014). Inter-continental and inter-taxonomic variation can be largely attributed to the diaspora of European settlers in the nineteenth century and to the acceleration in trade in the twentieth century. For all taxonomic groups, the increase in numbers of alien species does not show any sign of saturation and most taxa even show increases in the rate of first records over time. This highlights that past efforts to mitigate invasions have not been effective enough to keep up with increasing globalization.
ano.nymous@ccsd.cnrs.fr.invalid (Hanno Seebens) 27 May 2020
https://hal.science/hal-01607783v1
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[hal-02629243] Global rise in emerging alien species results from increased accessibility of new source pools
Our ability to predict the identity of future invasive alien species is largely based upon knowledge of prior invasion history. Emerging alien species-those never encountered as aliens before-therefore pose a significant challenge to biosecurity interventions worldwide. Understanding their temporal trends, origins, and the drivers of their spread is pivotal to improving prevention and risk assessment tools. Here, we use a database of 45,984 first records of 16,019 established alien species to investigate the temporal dynamics of occurrences of emerging alien species worldwide. Even after many centuries of invasions the rate of emergence of new alien species is still high: Onequarter of first records during 2000-2005 were of species that had not been previously recorded anywhere as alien, though with large variation across taxa. Model results show that the high proportion of emerging alien species cannot be solely explained by increases in well-known drivers such as the amount of imported commodities from historically important source regions. Instead, these dynamics reflect the incorporation of new regions into the pool of potential alien species, likely as a consequence of expanding trade networks and environmental change. This process compensates for the depletion of the historically important source species pool through successive invasions. We estimate that 1-16% of all species on Earth, depending on the taxonomic group, qualify as potential alien species. These results suggest that there remains a high proportion of emerging alien species we have yet to encounter, with future impacts that are difficult to predict.
ano.nymous@ccsd.cnrs.fr.invalid (Hanno Seebens) 27 May 2020
https://hal.inrae.fr/hal-02629243v1
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[hal-02613360] Understanding the impacts of widespread forest die-offs across France, Germany, and China
Metabarcoding increases the taxonomic resolution and geographic scale at which researchers can assess the impacts of climate change on insect communities in forests
ano.nymous@ccsd.cnrs.fr.invalid (Lucas Sire) 20 May 2020
https://hal.inrae.fr/hal-02613360v1
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[hal-04385991] Persisting roadblocks in arthropod monitoring using non-destructive metabarcoding from collection media of passive traps
Background Broad-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 has been found to be faster, efficient and reliable, but the destruction of samples prevents a posteriori validation of species occurrences and relative abundances. Non-destructive metabarcoding of DNA extracted from collection medium has been applied in a limited number of studies, but further tests of efficiency are required with different trap types and collection media to assess the consistency of the method. Methods We quantified the detection rate of arthropod species when applying non-destructive DNA metabarcoding with a short (127-bp) fragment of mitochondrial COI on two combinations of passive traps and collection media: (1) water with monopropylene glycol (H 2 O–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 Mill., 1759) stands across a range of climate-induced tree dieback levels and forest management strategies. Results Of the 53 H 2 O-MPG samples from WFTs, 16 produced no metabarcoding results, while the remaining 37 samples yielded 77 arthropod MOTUs in total, of which none matched any of the 343 beetle species morphologically identified from the same traps. Metabarcoding of 26 EtOH–MPG samples from MTs detected more arthropod MOTUs (233) than destructive metabarcoding of homogenate (146 MOTUs, 8 orders), of which 71 were shared MOTUs, though MOTU richness per trap was similar between treatments. While we acknowledge the failure of metabarcoding from WFT-derived collection medium (H 2 O–MPG), the treatment of EtOH-based Malaise trapping medium remains promising. We conclude however that DNA metabarcoding from collection medium still requires further methodological developments and cannot replace homogenate metabarcoding as an approach for arthropod monitoring. It can be used nonetheless as a complementary treatment when enhancing the detection of soft-bodied arthropods like spiders and Diptera.
ano.nymous@ccsd.cnrs.fr.invalid (Lucas Sire) 12 Jan 2024
https://hal.inrae.fr/hal-04385991v1
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[hal-01602700] Troubling travellers: are ecologically harmful alien species associated with particular introduction pathways?
Prioritization of introduction pathways is seen as an important component of the management of biological invasions. We address whether established alien plants, mammals, freshwater fish and terrestrial invertebrates with known ecological impacts are associated with particular introduction pathways (release, escape, contaminant, stowaway, corridor and unaided). We used the information from the European alien species database DAISIE (www.europe-aliens.org) supplemented by the EASIN catalogue (European Alien Species Information Network), and expert knowledge. Plants introduced by the pathways release, corridor and unaided were disproportionately more likely to have ecological impacts than those introduced as contaminants. In contrast, impacts were not associated with particular introduction pathways for invertebrates, mammals or fish. Thus, while for plants management strategies should be targeted towards the appropriate pathways, for animals, management should focus on reducing the total number of taxa introduced, targeting those pathways responsible for high numbers of introductions. However, regardless of taxonomic group, having multiple introduction pathways increases the likelihood of the species having an ecological impact. This may simply reflect that species introduced by multiple pathways have high propagule pressure and so have a high probability of establishment. Clearly, patterns of invasion are determined by many interacting factors and management strategies should reflect this complexity.
ano.nymous@ccsd.cnrs.fr.invalid (Jan Pergl) 26 May 2020
https://hal.science/hal-01602700v1
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[hal-02627472] Consistency of impact assessment protocols for non-native species
Standardized tools are needed to identify and prioritize the most harmful non-native species (NNS). A plethora of assessment protocols have been developed to evaluate the current and potential impacts of non-native species, but consistency among them has received limited attention. To estimate the consistency across impact assessment protocols, 89 specialists in biological invasions used 11 protocols to screen 57 NNS (2614 assessments). We tested if the consistency in the impact scoring across assessors, quantified as the coefficient of variation (CV), was dependent on the characteristics of the protocol, the taxonomic group and the expertise of the assessor. Mean CV across assessors was 40%, with a maximum of 223%. CV was lower for protocols with a low number of score levels, which demanded high levels of expertise, and when the assessors had greater expertise on the assessed species. The similarity among protocols with respect to the final scores was higher when the protocols considered the same impact types. We conclude that all protocols led to considerable inconsistency among assessors. In order to improve consistency, we highlight the importance of selecting assessors with high expertise, providing clear guidelines and adequate training but also deriving final decisions collaboratively by consensus.
ano.nymous@ccsd.cnrs.fr.invalid (Pablo Gonzalez-Moreno) 26 May 2020
https://hal.inrae.fr/hal-02627472v1
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[hal-02744907] Tracking origins of the highly invasive horse-chestnut leafminer using herbaria and minibarcodes
[...]
ano.nymous@ccsd.cnrs.fr.invalid (David C Lees) 03 Jun 2020
https://hal.inrae.fr/hal-02744907v1
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[hal-02662536] The role of Allee effects in gypsy moth (Lymantria dispar (L.),invasions
Allee effects have been applied historically in efforts to understand the low-density population dynamics of rare and endangered species. Many biological invasions likewise experience the phenomenon of decreasing population growth rates at low population densities because most founding populations of introduced nonnative species occur at low densities. In range expansion of established species, the initial colonizers of habitat beyond the organism’s current range are usually at low density, and thus could be subject to Allee dynamics. There has been consistent empirical and theoretical evidence demonstrating, and in some cases quantifying, the role of Allee dynamics in the gypsy moth, Lymantria dispar (L.), invasion of North America. In this review, we examine the potential causes of the Allee effect in the gypsy moth and highlight the importance of mate-finding failure as a primary mechanism behind an Allee effect, while the degree to which generalist predators induce an Allee effect remains unclear. We then explore the role of Allee effects in the establishment and spread dynamics of the gypsy moth system, which conceptually could serve as a model system for understanding how Allee effects manifest themselves in the dynamics of biological invasions.
ano.nymous@ccsd.cnrs.fr.invalid (Patrick Tobin) 31 May 2020
https://hal.inrae.fr/hal-02662536v1
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[hal-03149644] Evaluating DNA Barcoding for Species Identification and Discovery in European Gracillariid Moths
Gracillariidae is the most species-rich leaf-mining moth family with over 2,000 described species worldwide. In Europe, there are 263 valid named species recognized, many of which are difficult to identify using morphology only. Here we explore the use of DNA barcodes as a tool for identification and species discovery in European gracillariids. We present a barcode library including 6,791 COI sequences representing 242 of the 263 (92%) resident species. Our results indicate high congruence between morphology and barcodes with 91.3% (221/242) of European species forming monophyletic clades that can be identified accurately using barcodes alone. The remaining 8.7% represent cases of non-monophyly making their identification uncertain using barcodes. Species discrimination based on the Barcode Index Number system (BIN) was successful for 93% of species with 7% of species sharing BINs. We discovered as many as 21 undescribed candidate species, of which six were confirmed from an integrative approach; the other 15 require additional material and study to confirm preliminary evidence. Most of these new candidate species are found in mountainous regions of Mediterranean countries, the South-Eastern Alps and the Balkans, with nine candidate species found only on islands. In addition, 13 species were classified as deep conspecific lineages, comprising a total of 27 BINs with no intraspecific morphological differences found, and no known ecological differentiation. Double-digest restriction-site associated DNA sequencing (ddRAD) analysis showed strong mitonuclear discrepancy in four out of five species studied. This discordance is not explained by Wolbachia-mediated genetic sweeps. Finally, 26 species were classified as “unassessed species splits” containing 71 BINs and some involving geographical isolation or ecological specialization that will require further study to test whether they represent new cryptic species.
ano.nymous@ccsd.cnrs.fr.invalid (Carlos Lopez-Vaamonde) 23 Feb 2021
https://hal.sorbonne-universite.fr/hal-03149644v1
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[hal-02820959] Spatial dynamics of gypsy moth outbreaks in North America
[...]
ano.nymous@ccsd.cnrs.fr.invalid (Andrew Liebhold) 06 Jun 2020
https://hal.inrae.fr/hal-02820959v1
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[hal-02820908] Spatial synchrony in forest insect outbreaks: Why is it so ubiquitous?
[...]
ano.nymous@ccsd.cnrs.fr.invalid (Andrew Liebhold) 06 Jun 2020
https://hal.inrae.fr/hal-02820908v1
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[hal-02663129] Geographic variation in North American gypsy moth cycles: subharmonics, generalist predators, and spatial coupling
Many defoliating forest lepidopterans cause predictable periodic deforestation. Several of these species exhibit geographical variation in both the strength of periodic behavior and the frequency of cycles. The mathematical models used to describe the population dynamics of such species commonly predict that gradual variation in the underlying ecological mechanisms may lead to punctuated (subharmonic) variation in outbreak cycles through period-doubling cascades. Gypsy moth, Lymantria dispar, in its recently established range in the northeastern United States may represent an unusually clear natural manifestation of this phenomenon. In this study we introduce a new statistical spatial-smoothing method for estimating outbreak periodicity from space–time defoliation data collected with spatial error. The method statistically confirms the existence of subharmonic variation in cyclicity among different forest types. Some xeric forest types exhibit a statistical 4–5 year period in outbreak dynamics, some mesic forest types a 9–10 year period, and some intermediate forest types a dominant 9–10 year period with a 4–5 year subdominant superharmonic. We then use a theoretical model involving gypsy moth, pathogens, and predators to investigate the possible role of geographical variation in generalist predator populations as the cause of this variation n dynamics. The model predicts that the period of gypsy moth oscillations should be positively associated with predator carrying capacity and that variation in the carrying capacity provides a parsimonious explanation of previous reports of geographical variation in gypsy moth periodicity. Furthermore, a two-patch spatial extension of the model shows that, in the presence of spatial coupling, subharmonic attractors can coexist whereas nonharmonic attractors (i.e., where the cycle lengths are not integer multiples of one another) cannot.
ano.nymous@ccsd.cnrs.fr.invalid (Ottar Bjørnstad) 31 May 2020
https://hal.inrae.fr/hal-02663129v1
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[hal-03293179] Outbreaking forest insect drives phase synchrony among sympatric folivores: Exploring potential mechanisms
We explore a common feature of insect population dynamics, interspecific synchrony, which refers to synchrony in population dynamics among sympatric populations of different species. Such synchrony can arise via several possible mechanisms, including shared environmental effects and shared trophic interactions, but distinguishing the relative importance among different mechanisms can be challenging. We analyze interannual time series of population densities of the larch budmoth,Zeiraphera griseana(Lepidoptera: Tortricidae), along with six sympatric larch-feeding folivores from a site in the European Alps 1952-1979. These species include five lepidopterans,Exapate duratella,Ptycholomoides aeriferana,Spilonota laricana,Epirrita autumnataandTeleiodes saltuum, and one hymenopteran sawflyPristiphora laricis. We document that the highly regular oscillatory behavior (period 9-10 years) ofZ.griseanapopulations is similarly evident in the dynamics of most of the sympatric folivores. We also find that all of the sympatric species are phase synchronized withZ.griseanapopulations with half of the sympatric species exhibiting nonlagged phase synchrony and three of the species exhibiting 2-5 year lags behindZ.griseanapopulations. We adapt a previously developed tritrophic model ofZ.griseanadynamics to explore possible mechanisms responsible for observed phase synchronization. Results suggest that either shared stochastic influences (e.g., weather) or shared parasitoid impacts are likely causes of nonlagged phase synchronization. The model further indicates that observed patterns of lagged phase synchronization are most likely caused by either shared delayed induced host plant defenses or direct density-dependent effects shared withZ.griseana.
ano.nymous@ccsd.cnrs.fr.invalid (Andrew Liebhold) 20 Jul 2021
https://hal.inrae.fr/hal-03293179v1
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[anses-04415035] Analyse des risques sanitaires liés à l’exposition aux chenilles émettrices de poils urticants et élaboration de recommandations de gestion
Les chenilles de Lépidoptères tels que les processionnaires du pin (Thaumetopoea pityocampa Denis et Schiffermüller 1775) et du chêne (Thaumetopoea processionea L. 1758), le bombyx cul-brun (Euproctis chrysorrhoea L. 1758) et la Lithosie quadrille (Lithosia quadra L. 1758), produisent des poils urticants qui, par contact direct cutané ou par inhalation, peuvent entraîner des réactions urticariennes ou allergiques chez l’espèce humaine avec un impact sanitaire significatif en cas de pullulation. Ces espèces peuvent, de plus, avoir des impacts sur certains végétaux (chêne, pin, etc.) et animaux (chien, chat, animaux d’élevage, etc.).Plusieurs espèces de ces Lépidoptères semblent accroître d’année en année leur airede répartition sur le territoire national, telle que la processionnaire du pin dont la présence était limitée historiquement au sud de la Loire et qui remonte graduellement vers le nord et en altitude à la faveur du dérèglement climatique. Le dérèglement climatique pourrait également avoir un impact sur l’évolution de l’aire de répartition et la phénologie des autres espèces de Lépidoptères à chenilles urticantes. Les chenilles émettrices de poils urticants constituent ainsi un enjeu de santé globale (en France hexagonale et ultramarine) dans les zones où elles sont déjà présentes ou dans des zones indemnes qu’elles pourraient coloniser dans un avenir proche.
ano.nymous@ccsd.cnrs.fr.invalid (Nicolas Desneux) 24 Jan 2024
https://anses.hal.science/anses-04415035v1
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[hal-05168055] Human contributions to global soundscapes are less predictable than the acoustic rhythms of wildlife
Across the world, human (anthropophonic) sounds add to sounds of biological (biophonic) and geophysical (geophonic) origin, with human contributions including both speech and technophony (sounds of technological devices). To characterize society’s contribution to the global soundscapes, we used passive acoustic recorders at 139 sites across 6 continents, sampling both urban green spaces and nearby pristine sites continuously for 3 years in a paired design. Recordings were characterized by bird species richness and by 14 complementary acoustic indices. By relating each index to seasonal, diurnal, climatic and anthropogenic factors, we show here that latitude, time of day and day of year each predict a substantial proportion of variation in key metrics of biophony—whereas anthropophony (speech and traffic) show less predictable patterns. Compared to pristine sites, the soundscape of urban green spaces is more dominated by technophony and less diverse in terms of acoustic energy across frequencies and time steps, with less instances of quiet. We conclude that the global soundscape is formed from a highly predictable rhythm in biophony, with added noise from geophony and anthropophony. At urban sites, animals experience an increasingly noisy background of sound, which poses challenges to efficient communication.
ano.nymous@ccsd.cnrs.fr.invalid (Panu Somervuo) 09 Oct 2025
https://univ-rennes.hal.science/hal-05168055v1
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[hal-02790639] Using population genetics and genomic approaches to decipher the recent history of forest pest insects and improve management strategies
In the last decades, population genetics has proved to be a powerful tool to study differentiation and divergence of species at different spatial and temporal scales. Classical molecular markers, mostly mitochondrial sequences and microsatellite loci, were successfully used to characterize the natural structure of populations, to identify the environmental factors favouring or impeding gene flow, and to understand the driving forces of genetic differentiation. In the context of current global changes, population genetics was also used to disentangle the demographic processes during invasions and expansions and to characterize dispersion patterns. These approaches have often highlighted the complexity and the sometimes counterintuitive nature of the on-going scenarios. The development of new model-based methods, such as approximate Bayesian computation (ABC), allows quantitative inferences and the explicit comparison of alternative scenarios. The recent advent of Next Generation Sequencing (NGS) technologies has revolutionized the field of population genetics, and now allows the development of genome-wide approaches even in non-model organisms. These major improvements provide most powerful tools to analyse the evolution of both neutral and adaptive genetic diversity. Taking the pine processionary moth as a case example, we will illustrate how population genetics and genomics can be used in forest entomology and bring valuable answers regarding invasion and expansion processes. In particular, we could identify signs of both diffusive dispersal and long-range movements during the expansion of this species in France, which suggests man-aided movements possibly linked to host plant trade. We will also show how genomic markers (RAD-seq) were developed and allowed to deeply explore a case of recent allochronic differentiation in Portugal, which resulted in the occurrence of a phenologically-shifted and highly divergent population for which specific management strategies must be applied.
ano.nymous@ccsd.cnrs.fr.invalid (Carole Kerdelhue) 05 Jun 2020
https://hal.inrae.fr/hal-02790639v1
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[hal-02799903] Natural history of the Processionary Moths (Thaumetopoea spp.): New insights in relation to climate change
It is difficult to find a genus of Lepidoptera showing the high variability of life history traits observed in Thaumetopoea. There are typical summer feeding close to winter feeding species, and in one special case a recent switch has been detected even within one species, the pine processionary moth, indicating that the natural history traits are constantly evolving at a fast rate. There are species adapted to cold conditions of high mountains and high latitude close to truly Mediterranean and sub-desert region species. All species have gregarious behaviour as larva and are protected against vertebrate predators by urticating setae.
ano.nymous@ccsd.cnrs.fr.invalid (Andrea Battisti) 05 Jun 2020
https://hal.inrae.fr/hal-02799903v1
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[hal-03366792] Preventing invasions of Asian longhorn beetle and citrus longhorn beetle: are we on the right track?
Two Asian longhorn beetles, Anoplophora glabripennis and Anoplophora chinensis, are among the most serious alien invasive species attacking forest and urban trees, both in North America and Europe. Major efforts have been put into preventing further entry and establishment of the two species as well as promoting their successful eradication. Here, we review these efforts, their progress and outcome, and scientific advancements in monitoring and control methods. The combined international activities and harmonizing legislative changes in detection and eradication methods have proven worthwhile, with more than 45% of eradication programmes successful in the last 12 years. Some countries were able to completely eradicate all populations and others managed to reduce the area affected. Although the costs of the eradication programmes can be very high, the benefits outweigh inaction. Attempts to eradicate A. chinensis have been more challenging in comparison with those targeting A. glabripennis. For both species, efforts are hampered by the ongoing arrival of new beetles, both from their native regions in Asia and from other invaded regions via bridgehead effects. The methods used for eradication have not changed much during the last decade, and host removal is still the method most commonly used. On the other hand, detection methods have diversified during the last decade with advances in semiochemical research and use of detection dogs. The next decade will determine if eradications continue to be successful, particularly in the case of A. chinensis, which has been targeted in some countries for containment instead of eradication. Key Message: • Anoplophora glabripennis and Anoplophora chinensis are invasive wood borers native to Asia • Both species are serious pests in their invaded range, attacking healthy forest and urban trees • We analyse data from 2008–2020, regarding interceptions, establishments and eradications • In Europe and North America more than 45% of eradication programmes were successful • Innovations on management strategies and recent scientific achievements are reviewed
ano.nymous@ccsd.cnrs.fr.invalid (Sofia Branco) 05 Oct 2021
https://hal.inrae.fr/hal-03366792v1
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[hal-04160992] Management options for non-native forest pests along their invasion pathways
Editorial of a special issue of Neobiota on "Conceptual and technical innovations to better manage invasions of alien pests and pathogens in forests
ano.nymous@ccsd.cnrs.fr.invalid (Hervé Jactel) 13 Jul 2023
https://hal.inrae.fr/hal-04160992v1
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[hal-05087095] Ravageurs sur eucalyptus
[...]
ano.nymous@ccsd.cnrs.fr.invalid (François-Xavier Saintonge) 27 May 2025
https://hal.inrae.fr/hal-05087095v1
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[hal-02626247] Is Leptoglossus occidentalis entirely responsible for the high damage observed on cones and seeds of Pinus pinea? Results from a fertirrigation trial in Portugal
The uncertainty surrounding the part played by an invasive North American seed bug, Leptoglossus occidentalis, in the observed decrease in seed production of the Mediterranean pine, Pinus pinea, is a limiting factor for its management. Furthermore, the possibility of increasing cone production through irrigation and fertilization regimes is gaining interest among landowners, but its effects on insect pests are still unknown. Using bagged branches in the field, we aimed at evaluating the impact of L. occidentalis on young and mature cones of stone pine trees submitted to fertirrigation (FR) compared to trees with no treatment (C). For two consecutive years (2015 and 2016), we carried out both an insect-exclusion trial and an insect-bagged trial. In the first one, polyester-covered branches, excluding insects, were compared to branches exposed to natural insect infestation. In the second trial, bags included either two adult bugs or 3-4 third-instar nymphs, placed there for one month during mid-summer, or were kept without insects. Branch protection resulted in a significant decrease in the mortality of second-year conelets which dropped to 6% compared to 30% in exposed branches. Seed damage also decreased from 60% on exposed branches to 10% on protected ones. The presence of nymphs in the bags resulted in a mortality of second-year conelets 63% higher than in exclusion bags, whereas adults had no effect. In contrast, bags with adults presented the highest seed damage. The partial damage of the kernel can be a signature of L. occidentalis feeding since such damage was not observed in exclusion bags. Additionally, another type of seed damage, showing a wholly shrunken and dry embryo without remaining endosperm, and a reduction in the number of extractable seeds may also be attributed to this seed bug. Overall, seed damage per mature cone reached up to 12% in bags with two adult bugs enclosed for a month, i.e., twice the seed damage in protected cones. Overall, FR trees were more susceptible to both conelet mortality and seed damage. In the particular case of L. occidentalis, FR regime influenced the consumption positively by the nymphs but not by adults.
ano.nymous@ccsd.cnrs.fr.invalid (Ana Cristina Oliveira Farinha) 26 May 2020
https://hal.inrae.fr/hal-02626247v1
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[hal-02621251] The stone pine, Pinus pinea L., a new highly rewarding host for the invasive Leptoglossus occidentalis
The invasive seed bug Leptoglossus occidentalis, a species native to Western North America, is of major concern for the producers of stone pine seeds in the Mediterranean countries. The large size of these edible seeds and their nutritive content may represent a pull factor for the seed bug. Cone and seed traits of three main Mediterranean pine species: P. pinea, P. pinaster, and P. halepensis, were evaluated. Preference trials with cone-bearing branches, individual cones and seeds were conducted to test host preference among the three host species. Considering the kernel size, stone pine seeds provide 4 to 13 times more reward than P. pinaster and P. halepensis seeds, respectively, but also needed a greater effort to be reached as measured by coat thickness. Still, the benefit/cost ratio was higher on P. pinea. Individual seeds and cones of P. pinea were 2 to 3 times more consumed than those of the two other pine species. However, branch preference trials did not reveal any difference in hug visits. Moreover, adults manifested strong group behaviour on branches, frequently dissociating into two persisting groups. The implications of these results for P. pinea producing areas are discussed.
ano.nymous@ccsd.cnrs.fr.invalid (Ana O. Farinha) 26 May 2020
https://hal.inrae.fr/hal-02621251v1
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[hal-01603928] Recent and fast invasion in Europe: The case of the Western conifer seed bug Leptoglossus occidentalis.
Recent and fast invasion in Europe: The case of the Western conifer seed bug Leptoglossus occidentalis. . ICE 2016; XXV International Congress of Entomology
ano.nymous@ccsd.cnrs.fr.invalid (Marie-Anne Auger-Rozenberg) 03 Jun 2020
https://hal.science/hal-01603928v1
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[hal-02800929] Mechanisms of Host Tree Selection by the Pine Processionary Moth
The pine processionary moth is, by far, the most important insect defoliator of pine forests in Southern Europe and North Africa, both in terms of its temporal occurrence, geographic range and socioeconomic impact. Monitoring and pest management actions are therefore required on a regular basis, to ensure the detection, evaluation and mitigation of potential risks to forest and public health. However, we still lack some of the basic knowledge required for relevant analyses of the risk posed by the pine processionary moth. Pest risk is defined as a combination of three components: (1) pest occurrence, which depends on the spatiotemporal dynamics of populations; (2) plant vulnerability to the pest, resulting in a certain amount of damage; and (3) the socioeconomic impact of damage, depending on the potential value of the plants damaged (Jactel et al. 2012). The population dynamics of the processionary moth has been extensively studied, in particular within the context of climate change (see Battisti et al. 2014, Chap. 2, this volume). Several studies have recently addressed the question of tree and forest vulnerability to pine processionary attacks but a comprehensive review of evidence was missing. This is the first objective of this chapter. In particular we were interested in a better understanding of the ecological mechanisms responsible for the host tree selection, at both the species and individual tree levels. In a second part we show that pine susceptibility to the pine processionary moth could be reduced by improving forest diversity at different spatial scales. In the last part of this chapter we provide quantitative estimate of the growth losses caused by defoliations of the pine processionary moth. Altogether this information paves the way for quantitative risk analyses on pine processionary moth infestations based on forest growth models.
ano.nymous@ccsd.cnrs.fr.invalid (Maria Rosa Paiva) 05 Jun 2020
https://hal.inrae.fr/hal-02800929v1
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[hal-03604168] Modelling the flight trajectories of Monochamus galloprovincialis in heterogeneous landscapes
Potential spread of the pine wood nematode (PWN), Bursaphelenchus xylophilus, is driven by both insect vector and human-mediated dispersal. At local scale, dispersal capacity of the vector may explain the failure of eradication measures such as host tree removal. In Europe, the PWN is transported by the pine sawyer beetle, Monochamus galloprovincialis. Although the insect is known to disperse at short distances following mark-release-recapture experiments, the insect is able to fly rather long distances on a flight mill (cumulated distance of 16 km on average and up to 63 km). A first dispersal model was developed to describe the flight trajectory of M. galloprovincialis in non-fragmented pine forests. The shape of the dispersal kernel was fitted to the data recorded in the flight mill experiment to capture the proportion of long-distance flights compared to short-distance flights. Then, the dispersal model was refined to flight distances recorded in the field using data from the mark-recapture experiments conducted in a pine forest. Here, we will present how this model was adapted to simulate the dispersal of the insect vector in heterogeneous landscapes, e.g. a mosaic of pines, broadleaf trees, and open areas. This model was fitted to recent data from other mark-release-recapture experiments in such diverse landscapes.
ano.nymous@ccsd.cnrs.fr.invalid (Christelle Robinet) 16 Mar 2022
https://hal.science/hal-03604168v1
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[hal-02799280] Climate Warming and Past and Present Distribution of the Processionary Moths (Thaumetopoea spp.) in Europe, Asia Minor and North Africa
Pine processionary moth, Thaumetopea pityocampa, is a model insect indicator of global warming, the northwards and upwards range expansion of this Mediterranean species being directly associated with the recent warming up. The knowledge about the drivers of moth expansion is synthesized. A first standardized mapping of the northern expansion edge, from Western Europe to Turkey, is presented, then detailed for 20 countries of Europe, Asia Minor and North Africa, including future trends. Additional data about the responses of the other Thaumetopoea species are given. Finally, the chapter points out the importance of the man-mediated introductions in the expansion process.
ano.nymous@ccsd.cnrs.fr.invalid (Alain Roques) 05 Jun 2020
https://hal.inrae.fr/hal-02799280v1
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[hal-04169153] Latitudinal gradient in avian insectivory: complementary effects of climate, habitat and bird diversity
According 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. Location Europe. Taxon Insectivorous birds and pedunculate oaks. Methods We 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. Results The 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 conclusions Our 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.
ano.nymous@ccsd.cnrs.fr.invalid (Laura Schillé) 24 Jul 2023
https://hal.inrae.fr/hal-04169153v1
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[hal-02800748] Natural History of the Pine Processionary Moth,Thaumetopoea pityocampa
[...]
ano.nymous@ccsd.cnrs.fr.invalid (Dimitrios N. Avtzis) 05 Jun 2020
https://hal.inrae.fr/hal-02800748v1
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[hal-02639635] Phylogeography of the ladybird Iberorhyzobius rondensis, a potential biological control agent of the invasive alien pine bast scale Matsucoccus feytaudi
Understanding the genetic structure of natural enemies is an important step to develop efficient biocontrol programs. The ladybird Iberorhyzobius rondensis Eizaguirre (Coleoptera: Coccinellidae) from the Iberian Peninsula, is a specialized predator and potential biological control of Matsucoccus feytaudi Ducasse (Hemiptera: Matsucoccidae), an invasive alien species in Southeastern France and Italy. M. feytaudi is specialized on Pinus pinaster Aiton. The beetle is also restricted to this habitat. Genetic structure of I. rondensis populations was analysed with the barcode region (COI). It revealed two main refugia areas for the beetle in Iberian Peninsula. Comparative phylogeography of the three trophic levels, plant-herbivore-predator, is discussed. Similar population structure was found for the prey and to some extent for the pine. Indications are given on where to collect the beetles for their use in biocontrol of M. feytaudi, in order to obtain the highest genetic diversity and match with the origin of the invasive prey.
ano.nymous@ccsd.cnrs.fr.invalid (Catarina Tavares) 28 May 2020
https://hal.inrae.fr/hal-02639635v1
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[hal-04160903] Modelling the invasion dynamics of the African citrus psyllid: The role of human-mediated dispersal and urban and peri-urban citrus trees
The African citrus psyllid, Trioza erytreae (Del Guercio) (Hemiptera, Triozidae), is native to tropical Africa and invasive species in North America and Europe. The main host plants are citrus, displaying a preference for lemon trees. This psyllid was recently detected in the northwest region of the Iberian Peninsula, both in Spain and Portugal. Here, we used a model combining a reaction-diffusion model to a stochastic long-distance dispersal model to simulate the invasion dynamics of T. erytreae in Portugal. The psyllid spread in Portugal was simulated between 2015 and 2021 for different combinations of model parameters: two fecundity levels; spread with and without stochastic long-distance dispersal; single or two introductions of T. erytreae ; and considering or not the urban and peri-urban citrus trees, besides citrus orchards, estimated using Google Street view imagery. The incorporation of long-distance human mediated dispersal significantly improved the F1-score in the model validation using the official reports as the observed data. Concomitantly, the dispersal rate of T. erytreae in Portugal was on average about 66 km/year, whereas removing long-distance dispersal events, the observed mean was 7.8 ± 0.3 km/year. The dispersal was mainly towards the south along the coastline, where human population is concentrated. The inclusion of the estimated citrus trees outside orchards areas significantly increased the F1-score in the model validation, revealing the importance these isolated host plants hold as stepping stones for the species current invasion and possibly for other species alike.
ano.nymous@ccsd.cnrs.fr.invalid (Pedro Nunes) 06 Sep 2023
https://hal.inrae.fr/hal-04160903v1
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[hal-04171539] Worldwide tests of generic attractants, a promising tool for early detection of non-native cerambycid species
A large proportion of the insects which have invaded new regions and countries are emerging species, being found for the first time outside their native range. Being able to detect such species upon arrival at ports of entry before they establish in non-native countries is an urgent challenge. The deployment of traps baited with broad-spectrum semiochemical lures at ports-of-entry and other high-risk sites could be one such early detection tool. Rapid progress in the identification of semiochemicals for cerambycid beetles during the last 15 years has revealed that aggregation-sex pheromones and sex pheromones are often conserved at global levels for genera, tribes or subfamilies of the Cerambycidae. This possibly allows the development of generic attractants which attract multiple species simultaneously, especially when such pheromones are combined into blends. Here, we present the results of a worldwide field trial programme conducted during 2018–2021, using traps baited with a standardised 8-pheromone blend, usually complemented with plant volatiles. A total of 1308 traps were deployed at 302 sites covering simultaneously or sequentially 13 European countries, 10 Chinese provinces and some regions of the USA, Canada, Australia, Russia (Siberia) and the Caribbean (Martinique). We intended to test the following hypotheses: 1) if a species is regularly trapped in significant numbers by the blend on a continent, it increases the probability that it can be detected when it arrives in other countries/continents and 2) if the blend exerts an effective, generic attraction to multiple species, it is likely that previously unknown and unexpected species can be captured due to the high degree of conservation of pheromone structures within related taxa. A total of 78,321 longhorned beetles were trapped, representing 376 species from eight subfamilies, with 84 species captured in numbers greater than 50 individuals. Captures comprised 60 tribes, with 10 tribes including more than nine species trapped on different continents. Some invasive species were captured in both the native and invaded continents. This demonstrates the potential of multipheromone lures as effective tools for the detection of ‘unexpected’ cerambycid invaders, accidentally translocated outside their native ranges. Adding new pheromones with analogous well-conserved motifs is discussed, as well as the limitations of using such blends, especially for some cerambycid taxa which may be more attracted by the trap colour or other characteristics rather than to the chemical blend.
ano.nymous@ccsd.cnrs.fr.invalid (Alain Roques) 27 Jul 2023
https://hal.inrae.fr/hal-04171539v1
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[hal-02907131] Pathologists and entomologists must join forces against forest pest and pathogen invasions
The world’s forests have never been more threatened by invasions of exotic pests and pathogens, whose causes and impacts are reinforced by global change. However, forest entomologists and pathologists have, for too long, worked independently, used different concepts and proposed specific management methods without recognising parallels and synergies between their respective fields. Instead, we advocate increased collaboration between these two scientific communities to improve the long-term health of forests. Our arguments are that the pathways of entry of exotic pests and pathogens are often the same and that insects and fungi often coexist in the same affected trees. Innovative methods for preventing invasions, early detection and identification of non-native species, modelling of their impact and spread and prevention of damage by increasing the resistance of ecosystems can be shared for the management of both pests and diseases. We, therefore, make recommendations to foster this convergence, proposing in particular the development of interdisciplinary research programmes, the development of generic tools or methods for pest and pathogen management and capacity building for the education and training of students, managers, decision-makers and citizens concerned with forest health.
ano.nymous@ccsd.cnrs.fr.invalid (Hervé Jactel) 27 Jul 2020
https://hal.inrae.fr/hal-02907131v1
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[hal-02669037] Genetic isolation through time: allochronic differentiation of a phenologically atypical population of the pine processionary moth
Allochronic speciation refers to a mode of sympatric speciation in which the differentiation of populations is primarily due to a phenological shift without habitat or host change. However, it has been so far rarely documented. The present paper reports on a plausible case of allochronic differentiation between sympatric populations of the pine processionary moth ( PPM), Thaumetopoea pityocampa. The PPM is a Mediterranean insect with winter larval development. A phenologically atypical population with early adult activity and summer larval development was detected 10 years ago in Portugal. Mitochondrial and nuclear sequences strongly suggest that the 'summer' individuals are closely related to the sympatric winter population, while microsatellite data show a reduction in allelic richness, a distortion of allelic frequencies and significant genetic differentiation. Moreover, monitoring of adult flights suggests that reproductive activity does not overlap between the summer and winter populations. We postulate that the summer population appeared after a sudden phenological shift of some individuals of the sympatric winter population, leading to a founder effect and complete reproductive isolation. Given that the individuals showing this new phenology are subject to different selection pressures, the observed allochronic differentiation may rapidly lead to deeper divergence.
ano.nymous@ccsd.cnrs.fr.invalid (Helena Santos) 31 May 2020
https://hal.inrae.fr/hal-02669037v1
