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National audience; Les pesticides biologiques ou biopesticides sont de plus en plus utilisés pour lutter contre les nuisibles et les plantes adventices. Parmi ceux-ci figurent les bioinsecticides Btk. Or, une utilisation accrue de ces bioinsecticides pourrait avoir, sur le long terme, des conséquences sur la faune (l’environnement) et la santé publique (pathologies du tube digestif), malgré des doses relativement faibles retrouvées dans le biotope. Il est donc nécessaire d’analyser les risques environnementaux et sanitaires liés à l’ingestion chronique de Btk : ici, à partir du modèle Drosophila melanogaster ou mouche du vinaigre.

Un coffre sculpté en bois a été récemment confié a l'université de Lincoln pour un traitement de conservation. Ce coffre contient quatre tiroirs avec une collection de Lépidoptères et de Rhopalocères (papillons de jour et de nuit) qui a été sérieusement endommagée par des insectes nuisibles. Après consultation, il a été décidé que les spécimens de Lépidoptères seraient aussi restaurés, sans modification ou intervention importante. Ceci a été décidé après une recherche sur les réparations historiques de collections de Lépidoptères et des entretiens avec des entomologistes. Cette enquête inclut l'examen de réparations effectuées au 18ème siècle sur des papillons de la collection du Hunterian Museum. Un des tiroirs contenant des papillons de nuit a été restauré. Le traitement de conservation a été aussi appliqué sur le coffre en bois. A carved wooden chest was recently given to the University of Lincoln for conservation treatment. The chest holds four drawers with a Lepidoptera (Butterflies and Moths) collection badly damaged by pests. After consultation, it has been decided that the Lepidoptera specimens will be restored, without modification or serious intervention. This was achieved after investigations were carried out on historic repairs on Lepidoptera collections, and consultation with entomologists as well. The research involved the examination of repairs carried out in the 18th century on butterflies at the Hunterian Museum’s collection. One drawer holding moths was treated and restored. Conservation treatment was also applied on the wooden chest.

L'inventaire des Lépidoptères de la tourbière de la source du ruisseau des Dauges (Haute-Vienne) a débuté en 1983. La liste qui en découle (308 espèces), permet de mettre en évidence la diversité de ce site., The Lepidoptera survey of peat-bog Dauges began in 1983. The present list (308 species) point out the high diversity of this site., Annales Scientifiques du Limousin, HS | 1998

International audience; We studied host selection and exploitation, two crucial aspects of parasite ecology, in Achrysocharoides parasitoid wasps, which show remarkable host specificity and unusual offspring sex allocation. We estimated a molecular phylogeny of 15 Achrysocharoides species and compared this with host (plant and insect) phylogenies. This tri-trophic phylogenetic comparison provides no evidence for cospeciation, but parasitoids do show phylogenetic conservation of the use of plant genera. Patterns of sequence divergence also suggest that the parasitoids radiated more recently (or evolved much faster) than their insect hosts. Three main categories of brood production occur in parasitoids: (1) solitary offspring, (2) mixed sex broods and (3) separate (split) sex broods. Split sex broods are very rare and virtually restricted to Achrysocharoides, while the other types occur very widely. Our phylogeny suggests that split sex broods have evolved twice and provides evidence for a transition from solitary to mixed sex broods, via split sex broods, as predicted by theory.

Interspecific hybridization is more and more studied these last years and its consequences on species evolution are diverse. The literature especially points out its potential impact on new species emergence and the number of hybrid speciation cases is increasing. My work aims at understanding how interspecific crosses can initiate the rise of a new hybrid lineage and stimulate the diversification of living organisms.Reviewing the examples of animals hybrid species described in the literature allows me, in the first part of this work, to identify the main patterns associated with the process of hybrid speciation. I observe in particular that, if the recombination of parental characteristics is always the main driver of hybrid speciation, it leads to various patterns in hybrid species establishment. I also discuss methodological issues concerning the identification of hybrid species, which limit our capacity to estimate the prevalence of such process in species evolution dynamic.In the second part of this work I investigate the process of hybrid speciation in a complex of closely related butterfly species of the genus Coenonympha. I show that among the four lineages composing the complex, two originated through hybridization events. Their genetic, ecological and morphological characteristics allow us to better understand how their recombinant phenotype led to their emergence and their isolation from parental species.The evolutionary history of these butterflies is discussed in detail in the last part of this work. The results obtained in this particular case are compared with other examples of hybrid species and with theoretical expectations from literature. This example adds its specificities to the current knowledges about hybrid speciation and evolutionary impacts of hybridization., L’hybridation interspécifique est un phénomène très étudié ces dernières années et les conséquences qui lui sont attribuées dans l’évolution des espèces sont diverses. Une littérature de plus en plus fournie met notamment en évidence le rôle que peut avoir l’hybridation sur l’émergence de nouveaux taxons. Mon travail de thèse s’attache à comprendre comment des croisements entre espèces peuvent impacter le processus de spéciation d’une nouvelle lignée évolutive et stimuler ainsi la diversification des organismes vivants.Une revue des différents cas d’espèces hybrides animales proposés dans la littérature a permis, dans la première partie de cette thèse, d’identifier les patrons associés de façon redondante au processus de spéciation hybride. Nous observons par exemple que, si l’apport premier de l’hybridation à la spéciation reste toujours la recombinaison de caractéristiques parentales divergentes, cela peut se traduire de manière différente lors de l’émergence de la lignée hybride. Cette synthèse a aussi été l’occasion de discuter des difficultés méthodologiques qui limitent une réelle estimation de la prévalence de ce phénomène dans l’évolution des espèces.Dans la seconde partie de ma thèse j’explore le processus de spéciation hybride chez un complexe d’espèces proches de papillons du genre Coenonympha. Je montre que, parmi les quatre lignées identifiées dans le complexe, deux sont issues de l’hybridation. Leurs caractéristiques génétiques, écologiques et morphologiques permettent de comprendre, en partie, comment leur phénotype recombinant a favorisé leur établissement en tant qu’espèces à part entière et leur isolement vis-à-vis de leurs espèces parentales.L’histoire évolutive de ces papillons est discutée en détail dans la dernière partie de mon travail de thèse. Les résultats obtenus pour ce cas particulier y sont confrontés aux autres exemples de spéciation hybride ainsi qu’aux attendus théoriques associés à ce phénomène. Les spécificités de ce système d’étude viennent ainsi enrichir les connaissances actuelles sur le processus de spéciation hybride et sur les impacts évolutifs de l’hybridation.

A two-choice bioassay was developed to evaluate the role of host-plant berry compounds on the oviposition site acceptance of the generalist moth Lobesia botrana (Denis & Shiffermüller). A key feature was the lining of the bioassay arena with felt which focused oviposition on the test substrates. Initial experiments comparing substrates with different physical features indicated that smooth textures and spherical shapes with interstices favour oviposition. Artificial oviposition substrates were thus constructed with glass spheres in order to test the behavioural activity of grapevine berry extracts. Only polar extracts obtained by soaking berries in methanol or water stimulated oviposition (more eggs were laid on the extract-treated substrate than on the control substrate), whereas more apolar ones obtained with chloroform or hexane had no significant effect. The prior removal of epicuticular waxes from grape berries before extraction did not enhance the stimulatory activity of the methanol extract. The oviposition response to this extract was dose-dependent. It is concluded that polar compounds present on grape berries act as oviposition stimulants for L. botrana.

Chez les insectes phytophages, l’adaptation à la plante hôte peut correspondre à l’une des premières étapes de la spéciation. Dans ce contexte, ce manuscrit s’intéresse à Spodoptera frugiperda (Lepidoptera : Noctuidae), un ravageur responsable de dommages importants sur de nombreuses cultures en Amérique et dans les Caraïbes. Spodoptera frugiperda présente deux variants, l’un adapté au riz et l’autre au maïs, et constitue un modèle biologique pertinent pour étudier ce mécanisme. En effet, les deux variants sont morphologiquement identiques, mais ils sont génétiquement différenciés et présentent des différences écologiques et comportementales. L’ensemble de ces caractéristiques suggèrent la présence d’un isolement reproducteur entre les deux variants, qui pourraient alors correspondre à deux espèces différentes. Cependant la présence d’hybrides dans la nature ainsi que des résultats controversés sur le succès d’accouplement entre les deux variants, rendent ambiguë le statut d’espèce de S. frugiperda. L’objectif de ce travail est donc de mieux estimer, à travers une étude intégrative, le niveau de différenciation génétique présent entre les deux variants de S. frugiperda. Grâce à un premier niveau d’analyse, menées à partir de population naturelles, il a été possible de mettre en évidence un niveau de différenciation génétique élevé entre les deux variants, qui est compatible à celui attendu entre deux espèces. Le deuxième niveau d’étude réalisé à partir de population de laboratoire nous a permis de mettre en évidence la présence d’un isolement reproducteur entre les deux variants, se traduisant notamment par une distorsion de ségrégation méiotique des marqueurs moléculaires chez les hybrides. L’ensemble de ces résultats supportent l’hypothèse selon laquelle le variant riz et maïs de Spodoptera frugiperdaseraientdes entités situées à une étape avancée dans le continuum de la spéciation., In phytophagous insects, adaptation to host plant could be the first step leading to speciation. In this context, this document focus on moth Spodoptera frugiperda (Lepidoptera: Noctuidae), a pest responsible for serious damages in several crops in the Western hemisphere. Spodoptera frugiperda consists of two host-plant strains, one adapted to rice and the other adapted to maize, which made it a relevant model to study this mechanism. Though the two variants are morphologically identical, they are nonetheless genetically distinguishable and present some ecological and behavioral differences. The species status of S. frugiperda is also highly controversial because hybrids naturally occur in the wild, not to mention the fact of the discrepancies among published results concerning mating success between the two strains. The aim of this thesis is thus to better estimate, through an integrative approach, the level of genetic differentiation between the two variants of S. frugiperda. Starting with natural populations, various phylogenetic methods allowed us to highlight a high level of genetic differentiation between the two variants, compatible with what is expected between distinct species. Furthermore, studies on laboratory populations, including crossing experiments, showed a significant unidirectional bias in inter-strain mating success and the presence of meiotic segregation distortion of molecular markers in hybrid progenies. These results as a whole support the assumption that the two strains of S. frugiperda are well-advanced in the continuum of speciation.

Background Spodoptera frugiperda (Noctuidae) is a major agricultural pest throughout the American continent. The highly polyphagous larvae are frequently devastating crops of importance such as corn, sorghum, cotton and grass. In addition, the Sf9 cell line, widely used in biochemistry for in vitro protein production, is derived from S. frugiperda tissues. Many research groups are using S. frugiperda as a model organism to investigate questions such as plant adaptation, pest behavior or resistance to pesticides. Results In this study, we constructed a reference transcriptome assembly (Sf_TR2012b) of RNA sequences obtained from more than 35 S. frugiperda developmental time-points and tissue samples. We assessed the quality of this reference transcriptome by annotating a ubiquitous gene family - ribosomal proteins - as well as gene families that have a more constrained spatio-temporal expression and are involved in development, immunity and olfaction. We also provide a time-course of expression that we used to characterize the transcriptional regulation of the gene families studied. Conclusion We conclude that the Sf_TR2012b transcriptome is a valid reference transcriptome. While its reliability decreases for the detection and annotation of genes under strong transcriptional constraint we still recover a fair percentage of tissue-specific transcripts. That allowed us to explore the spatial and temporal expression of genes and to observe that some olfactory receptors are expressed in antennae and palps but also in other non related tissues such as fat bodies. Similarly, we observed an interesting interplay of gene families involved in immunity between fat bodies and antennae. Electronic supplementary material The online version of this article (doi:10.1186/1471-2164-15-704) contains supplementary material, which is available to authorized users.

The genus Xenorhabdus consists of the specific bacterial symbionts of the entomopathogenic nematodes of the family Steinernematidae (40) and was separated from the genus Photorhabdus (11), which contains the symbionts of the entomopathogenic nematodes of the family Heterorhabditidae. Both genera are entomopathogenic gram-negative bacteria belonging to the Enterobacteriaceae. The nematodes carry their bacterial symbionts monoxenically in a special vesicle of the infective stage (L3 juveniles) in Steinernematidae (8) and throughout the whole intestine of Heterorhabditidae (20). These bacteria are transported by their nematode hosts into the hemocoel of the insect prey, which is killed, probably via a combination of toxin action and septicemia. The bacterial symbionts also contribute to the symbiotic relationship by establishing and maintaining suitable conditions for nematode reproduction (31). Recently, isolation of some Photorhabdus strains from infected humans in Australia and the United States was reported (21, 30), and the strains from the United States were classified as Photorhabdus asymbiotica (23). The form of the bacterium that is normally isolated from symbiotic infective-stage nematodes is referred to as phase I. Like many pathogenic bacteria, Xenorhabdus and Photorhabdus strains spontaneously produce colonial variants which have been called phase II variants (10). The two variants of the bacteria have generally been shown to be equally pathogenic for the larvae of the greater wax moth, Galleria mellonella (3). However, Volgyi et al. (42) described for the first time a phase II variant that showed reduced virulence in the tobacco hornworm, Manduca sexta. Xenorhabdus nematophila and Photorhabdus luminescens are highly pathogenic to insects, and 50% insect mortality has been reported with direct infection with fewer than 20 bacteria per larva (5). The bacterial factors involved in killing of the insect or in overcoming the insect immune reactions are still under investigation. Following invasion of the insect host by the nematodes, both bacteria produce potential virulence factors, including lipase, protease, lecithinase, and lipopolysaccharides (LPSs), in the hemocoel (for a review, see reference 24). It was shown that purified LPS, Photorhabdus protease fractions, or Xenorhabdus lecithinase isomers showed no toxic effect following injection into insect hemocoel (12, 16, 39). Recently, a novel toxin complex with both oral and injectable activities against a wide range of insects was identified in a supernatant of P. luminescens (13). Purified toxin complex a (Tca) has specific effects on the midgut epithelium of the insect (9). In order to study Xenorhabdus and Photorhabdus virulence in insects, a genetic approach was also used. Avirulent mutants of X. nematophila have been isolated by transposon mutagenesis (Tn5). These mutants were pleiotropic, but all five mutants that tested as avirulent in G. mellonella were nonmotile and partially impaired in blood hemolysis (43). It was also shown that a homoserine lactone autoinducer restored virulence to one avirulent X. nematophila strain and stimulated the level of bacterial lipase activity (17). Recently we reported that flhDC, the flagellar master operon of X. nematophila, controls flagellin expression. Furthermore we revealed that lipolytic and extracellular hemolysin activity is flhD dependent. We also showed that the flhD null mutant displayed an attenuated virulence phenotype in the common cutworm, Spodoptera littoralis, compared to the wild-type strain (25). The recently published partial genome sequence of P. luminescens (22) revealed a diverse array of genes that putatively encodes potential virulence factors. These factors include exoenzymes (proteases, lipases, and chitinases), a type III secretion system (Yop homolog), and several classes of toxins (insecticidal toxin complex, Rtx-like toxins, and hemolysin and cytotoxin homologs) (22). Until now, studies examining hemolytic activity of both genera have not been reported. Cytolysins are proteins which cause lysis of red blood cells (RBC) as well as nucleated cell types by hydrolysis (lipases, phospholipases, or proteases) or by forming pores in the plasma membrane. Surfactants may also cause cytolysis by solubilization of the target cell membrane. Bacterial cytolysins are usually recognized as hemolysin on blood agar where a transparent zone appears around colonies. The production by a few strains of Xenorhabdus and Photorhabdus of hemolysin has been detected on agar supplemented with sheep blood (6, 21, 25). Apart from their phoretic location inside infective juvenile nematodes, these bacteria are only observed in insect hemolymph, where they enter their growth cycle. Here the bacteria are in contact with hemocytes which achieve defense reactions in insects. Some of these cells are immunocompetent cells able to engulf (phagocytosis) or to isolate and kill (nodule formation) bacteria. We hypothesize that hemolytic activities could target the immunocompetent cells in insect hemolymph. In this study, we report that different cytolytic activities were found in supernatants of Xenorhabdus whereas none was detected in supernatants of various strains of Photorhabdus. We have studied the kinetics of the production of cytolytic activities over the course of in vitro bacterial growth. We also provide evidence on the characteristics and on the specificity of each of these cytolytic activities against mammalian RBC and insect hemocyte types.

International audience; A cDNA encoding the prohormone of the pheromone biosynthesis activating neuropeptide (PBAN) in the moth Agrotis ipsilon was isolated. The cDNA contains 834 nucleotides, coding for a 193-amino acid protein that exhibits 89% identity with PBAN prohormones of other moths. The prohormone contains five potential peptides belonging to the FXPRL family. The peptide corresponding to the Bombyx mori diapause hormone exhibits an extra residue, and the C-terminal leucine is replaced by an isoleucine, introducing a new type of variability in this family of peptides. Northern blot analysis revealed expression in suboesophagal ganglion complexes. Constitutive heterologous expression of Agi-PBAN cDNA in yeast, using three different antibodies, did not produce PBAN-immunoreactive material.

Eucosma balatonana (Osthelder, 1937), a new boreo-alpine species from the mountains of Jura (Lepidoptera Tortricidae). Eucosma balatonana (Osthelder, 1937) is a species infrequently cited from France (only from the Southern Alps and Lorraine). Two recent observations in the Jura department are consistent with its boreo-alpine distribution in Europe., Eucosma balatonana (Osthelder, 1937) est une espèce peu citée en France (uniquement des Alpes méridionales et de Lorraine). Deux observations récentes dans le département du Jura sont cohérentes avec sa répartition en Europe de type boréo-alpine., Delmas Sylvain. Eucosma balatonana (Osthelder ; 1937), espèce boréo-alpine nouvelle pour la chaîne jurassienne (Lepidoptera Tortricidae). In: Bulletin mensuel de la Société linnéenne de Lyon, 77ᵉ année, n°1-2, Janvier-février 2008. pp. 26-28.

International audience; In vineyards, larvae of Lobesia botrana (Denis and Schiffermuller) (Lepidoptera: Tortricidae) and Botrytis cinerea (Persoon: Fries) often occur together This study was carried out to establish whether first instar larvae are attracted by the fungus. Olfactory and gustatory responses of larvae to the fungus were investigated on grape berry clusters (Vitis vinifera) and in two types of olfactometer. In clusters infected partly by B. cinerea, 82% of first instar larvae settled where berries had been infected. In the olfactometers, first instar larvae detected and discriminated between two tested foods. They significantly preferred synthetic media or grape berries (cv., 'Alphonse Lavallee' or 'Cabernet Sauvignon') infected with B. cinerea to non-infected controls. The olfactory response led to 62.2% to 72.6% of the first instar larvae attracted by the fungus and the association of olfactory with gustatory responses resulted in similar rates (64.1% to 81.6%). So, the larvae were most attracted by synthetic media or grape berries infected by the fungus as compared to the controls. Olfaction appears to be the main sense involved in this attraction process.

Nine nonlinear models (degree-day with a 10°C base, degree-day model, polynomial, normal distribution, Stinner model, Sharpe and DeMichele model, Logan model with or without a base, Hilbert and Logan model) were tested to describe the relationship between development rate and temperature for the European com borer, Ostrinia nubilalis Hubner. These models were calibrated with laboratory experiments based on destructive sampling under sinusoidal temperatures from 9 to 42°C. They were then evaluated and compared with field experiments, at temperatures from 4 to 37°C, carried out as artificial infestations in various areas. Laboratory development models with the smallest time shifts between predicted and observed molts were the Sharpe and DeMichele model, polynomial model, normal distribution, and Stinner model. A classification with an adjusted coefficient of determination (taking into account the number of parameters in the model) slightly modified the results and the best models were the polynomial and the normal distribution, followed by the Stinner model and the degree-day model with a 10°C base. The classification was almost reversed under field conditions. Large shifts occurred in all models in some experiments, thereby demonstrating that temperature was not the only factor involved. Models showing the smallest shifts under field conditions were the degree-day model and the Logan model. The experiments that showed the greater shifts corresponded to infestations on early or on late phenological stages of corn. Results confirmed that the experimental design and calibration method were adequate. The laboratory experiments provided a means of calibrating the models and of predicting results under field conditions from laboratory experiments. Future studies will focus on a precise quantitative analysis of factors affecting development other than temperature, notably infestation date, climatic factors, and phenological stage of corn.

International audience; The existence of L. botrana genotypes more suitable to mating in synthetic pheromone permeated air in olfactometer was investigated by artificial selection through two consecutive generations. The major compound of the female pheromone blend (7E, 9Z)-7, 9-dodecadienyl acetate 7E, 9Z DDA was used, the only one commercialized at present both for monitoring and for mating disruption. The adults mated in a mating disruption atmosphere in the parental generation (G1) were reared separately to make up the selected filial generation (G2). Trial was carried out at the doses of 0 (control), 0.5 and 1 μg of 7E, 9Z DDA. In G1 83.33% (50/60 pairs), 18.87% (50/265) and 8.62% (31/360) mated respectively. In the selected generation (G2) 76.67% (46/60), 20.91% (69/330) and 14.38% (64/445) mated respectively. Thus, control mating percentages in both generations were similar. Nevertheless, after selection the increase in mating was significant at 1 μg dose (G = 6.53; d.f. = 1; P < 0.05) but not at 0.5 μg (G = 0.38; d.f. = 1; P > 0.05). On the other hand, selection for increasing mating ability in sex pheromone permeated air at the doses tested, was not linked with a decrease in the dusk time elapsed before mating (mean: 24–30 min). With regard to the controls without pheromone (mean: 10–12 min), matings were significantly delayed (F(5,04) = 18.52; P < 0.01). The differences in response to selection between pheromone doses show the possible effect of the genetic homeostasis. These preliminary results suggest a genetic basis for mating ability and are a complementary hypothesis to explain the lack of an absolute efficiency in control by mating disruption. Finally, the possible factors that could interact and counteract the studied selection pressure are discussed, since resistance to the mating disruption method has not been observed at this time in field conditions.

International audience; Disruption experiments were carried out under vineyard conditions and in the laboratory. Males from laboratory cultures were conditioned in an atmosphere permeated with pheromone (E7 Z9-12Ac), marked externally with fluorescent powder, and released in the middle of vine plots. They were then trapped in a series of traps baited with virgin females or dispensers loaded with various amounts of pheromone. Over 10,000 males were released in these experiments between 19 May and 22 July. Electroantennography tests were used for studying olfactory sensitivity in pheromone-permeated air by measuring the EAG responses of male antennae in constant pheromone air-flows. The conclusion is that both sensory adaptation and central nervous system habituation mechanisms acted simultaneously in air laden with pheromone, but they are probably not relevant when concentrations are of the same order of magnitude as those obtained under field conditions in which mating disruption methods are used for controlling the European grape moth.

National audience; The pine processionary moth is known for its stinging caterpillars, moving in single file, and feeding on conifer needles until weakening significantly the trees. Their strong stinging character can cause severe allergic reactions in humans and animals. To prevent health hazard and to control this pest, solution are being developed with the goal of reducing the use of insecticides. Both for small busy areas where the "zero risk" is targeted, or for large and less crowded forest areas where their presence is tolerated, solutions and innovative experiments are under study at INRA in the experimental Unit, Entomology and Mediterranean Forest (UEFM).; La processionnaire du pin est un lépidoptère connu pour ses chenilles urticantes, se déplaçant en file indienne, et se nourrissant des aiguilles de conifères jusqu’à provoquer un affaiblissement important des arbres. Leur fort caractère urticant peut provoquer d'importantes réactions allergiques chez l’homme et l’animal. Pour réguler ce ravageur, et surtout, pour prévenir les risques sanitaires, des solutions répondant au plan Ecophyto 2018, sont développées, afin de réduire l’utilisation d’insecticides. Que ce soit pour de petites surfaces très fréquentées, où le risque « zéro » est visé, ou que ce soit pour de grandes surfaces en forêt moins fréquentées où leur présence est tolérée, des solutions existent et des expérimentations innovantes sont en cours d’étude à l’INRA, au sein de l’UEFM.

National audience; The pine processionary moth is known for its stinging caterpillars, moving in single file, and feeding on conifer needles until weakening significantly the trees. Their strong stinging character can cause severe allergic reactions in humans and animals. To prevent health hazard and to control this pest, solution are being developed with the goal of reducing the use of insecticides. Both for small busy areas where the "zero risk" is targeted, or for large and less crowded forest areas where their presence is tolerated, solutions and innovative experiments are under study at INRA in the experimental Unit, Entomology and Mediterranean Forest (UEFM).; La processionnaire du pin est un lépidoptère connu pour ses chenilles urticantes, se déplaçant en file indienne, et se nourrissant des aiguilles de conifères jusqu’à provoquer un affaiblissement important des arbres. Leur fort caractère urticant peut provoquer d'importantes réactions allergiques chez l’homme et l’animal. Pour réguler ce ravageur, et surtout, pour prévenir les risques sanitaires, des solutions répondant au plan Ecophyto 2018, sont développées, afin de réduire l’utilisation d’insecticides. Que ce soit pour de petites surfaces très fréquentées, où le risque « zéro » est visé, ou que ce soit pour de grandes surfaces en forêt moins fréquentées où leur présence est tolérée, des solutions existent et des expérimentations innovantes sont en cours d’étude à l’INRA, au sein de l’UEFM.

This study, implemented in the framework of ITTECOP project, is the result of a follow-up of three taxa (flora, reptile and lepidoptera) in order to better understand the impacts of twinning railway (LGV-Est) and highway (A4) on biodiversity. The surveys were conducted in three kinds of configurations: outside the railway, inside small isolates between the two infrastructures and inside wider isolates. Through this study, several results have been highlighted. Concerning the flora, plant communities differ in their Grime's strategy depending on their proximity to the highway. There are more species of CR type further away from the highway (ISOL and LGV stations). This work also shows that lepidopteras do not seem affected by the transport infrastructures. Concerning reptiles, this study did not draw conclusions about the impact of the twinning on the populations of reptiles due to the small number of observations. Nevertheless, we can affirm that isolates offer potential habitat for reptiles. Finally, this study did not determine whether the populations in isolates come from migrations or were present before the match. A long-term monitoring would be useful, particularly in terms of population genetics in the isolates to determine whether there is a risk of inbreeding. The impacts of the twinning in this study are limited and the matching seems to be a good compromise between mobility and biodiversity.; Cette étude, mise en oeuvre dans le cadre du projet ITTECOP, est le résultat d'un suivi de trois taxons (flore, reptile et lépidoptère), afin de mieux cerner les impacts du jumelage de la LGV-Est et de l'autoroute A4 sur la biodiversité. Les inventaires ont été effectués dans trois types de configurations : à l'extérieur de la LGV et dans les isolats (isolats et isolats larges) entre les deux infrastructures. Grâce à cette étude, plusieurs résultats ont pu être mis en évidence. Pour la flore, les communautés végétales diffèrent par leur stratégie de Grime, en fonction de la proximité de l'autoroute. Il y aurait plus d'espèces de type CR plus on s'éloigne de l'autoroute (stations ISOL et LGV). Ce travail montre également, que les lépidoptères ne semblent pas impactés par les infrastructures de transport. Concernant les reptiles, cette étude n'a pas permis de tirer de conclusions sur les impacts du jumelage sur les populations de reptiles à cause du faible nombre d'observations. Néanmoins, nous pouvons affirmer que les isolats offrent des habitats potentiels aux reptiles. Enfin, cette étude n'a pas permis de déterminer si les populations présente dans les isolats sont issues de migrations ou si celles-ci étaient présentes avant le jumelage. Un suivi à long terme serait judicieux, notamment au niveau de la génétique des populations dans les isolats, afin de savoir s'il y a un risque de consanguinité. Les impacts du jumelage dans cette étude sont donc limités et le jumelage semble être un bon compromis entre mobilité et biodiversité.

La processionnaire du pin est un lépidoptère connu pour ses chenilles urticantes, se déplaçant en file indienne, et se nourrissant des aiguilles de conifères jusqu’à provoquer un affaiblissement important des arbres. Leur fort caractère urticant peut provoquer d'importantes réactions allergiques chez l’homme et l’animal. Pour réguler ce ravageur, et surtout, pour prévenir les risques sanitaires, des solutions répondant au plan Ecophyto 2018, sont développées, afin de réduire l’utilisation d’insecticides. Que ce soit pour de petites surfaces très fréquentées, où le risque « zéro » est visé, ou que ce soit pour de grandes surfaces en forêt moins fréquentées où leur présence est tolérée, des solutions existent et des expérimentations innovantes sont en cours d’étude à l’INRA, au sein de l’UEFM., The pine processionary moth is known for its stinging caterpillars, moving in single file, and feeding on conifer needles until weakening significantly the trees. Their strong stinging character can cause severe allergic reactions in humans and animals. To prevent health hazard and to control this pest, solution are being developed with the goal of reducing the use of insecticides. Both for small busy areas where the "zero risk" is targeted, or for large and less crowded forest areas where their presence is tolerated, solutions and innovative experiments are under study at INRA in the experimental Unit, Entomology and Mediterranean Forest (UEFM).

Impact of 3 control methods on larval European corn borer, Ostrinia nubilalis Hubner, dynamics on com, Zea mays (L.), was evaluated under field conditions at Versailles, France. The control methods studied were a chemical insecticide, Beauveria bassiana Vuillemin (Deuteromycotina: Hyphomycete), and a transgenic corn hybrid. The experimental study showed that B. bassiana control was similar to chemical control. The transgenic hybrid control was always very high throughout the corn cycle studied. A substantial decrease of B. bassiana and chemical control efficacy was observed with an increase in the delay between treatment and infestation. The complementary studies of B. bassiana persistence, control impact, and pathogen contact showed control-larval behavior interactions, which could explain this decrease in efficacy. To take into account the main factors that condition control efficacy, a modular and mechanistic model was proposed to describe larval dynamic and control impact. The proposed control model made it possible to integrate O. nubilalis dynamics, and thus to describe the time response of control.

An immunoblotting technique used to visualize pheromone-biosynthesis-activating-neuropeptide (PBAN)-like peptides in insect tissues is described. This technique involves a tricine-SDS-PAGE system and a chemiluminescent revelation of the antigens. Using this technique, PBAN-like immunoreactive peptides were found in the brain-subesophageal ganglion complex of various lepidopteran species, including moths: Heliothis zea, Mamestra brassicae, Spodoptera littoralis, S. latifascia and S. descoinsi (Noctuidae), Eldana saccharina (Pyralidae), and a butterfly: Pieris brassicae (Pieridae). PBAN-like peptides were detected in both sexes of the species studied, and even in a butterfly species that does not use pheromone to mate. This suggests that those peptides are widely distributed among Lepidoptera and confirms that they could be involved in functions other than regulation of sex pheromone production.

Infestation rate of Dioryctria sylvestrella was studied for the following three categories of maritime pine: (i) those trees that had been selected for pruning and pruned; (ii) those trees that had been selected for pruning but not pruned; and those trees that had neither been selected nor pruned. In comparing 10 diameter classes and 4 dates of pruning, the percentage of trees attacked was recorded. In both pruned and unpruned trees, the level of attack increased with tree diameter, according to a logistic curve. Pruned trees were significantly more infested than unpruned trees. Selection for pruning did not result in a significant higher rate of attack in unpruned trees. The percentage of pruned trees attacked did not differ significantly according to the date of pruning. The interaction between tree diameter and tree type did not induce any significant difference in infestation rate. The model of tree infestation, involving primary attraction for the female moth, was strengthened. Volatile attractants, originating in the constitutive oleoresin, might allow the selection of susceptible trees. Tree pruning, creating bark wounds, and tree vigour, increasing bark cracking, could similarly, though independently, increase constitutive resin flow, thus enhancing tree attractiveness.

The main consequence of mating disruption in the European grape moth is a decrease of female active space. Two experiments were done in a vineyard in order to evaluate the effect of population density and initial distance between insects on female detection by males. In the first experiment, two population densities corresponding to 10 and 20% infestation levels during the previous generation, were carried out in regard to two types of distribution of the population: low and high aggregates. Within these limits, population density had no influence on later attacks if the distribution was homogeneous, while, if the distribution was not homogeneous, attacks were more important. In the second experiment, colored males were released in areas with dispensers (1 and 500 mg of pheromone) and traps baited with one virgin female in a small cage. It was confirmed that the number of males trapped by females decreased when the dose of pheromone increased. Without pheromone, males scattered and may be captured at all distances. With pheromone, the nearest female only may be located by a male. Resume Etude des mecanismes de la confusion sexuelle chez l'Eudemis de la vigne, Lobesia botrana Den et Schiff (Lep., Tortricidae). II - Roles respectifs de la densite de population et de la distance entre les insectes pour la detection des femelles par les mâles en atmosphere impregnee de pheromone Chez L. botrana, la confusion sexuelle a pour consequence majeure la diminution de l'espace actif de la femelle. Dans ce travail, deux experimentations ont ete realisees en vignoble en vue d'evaluer l'effet de la densite de population et de la distance initiale entre les insectes sur la detection des femelles par les mâles. Dans la premiere experience, deux densites de population, correspondant a des attaques de 10 et 20% des grappes lors de la generation precedente ont ete realisees selon deux types de repartition en vignoble (agregats faibles et agreggats forts). Dans ces limites, la densite n'intervient pas sur les attaques ulterieures si la population est bien repartie, alors que, dans le case contraire, les attaques sont nettement plus abondantes. Dans la deuxieme experience, des lâchers de mâles d'elevage colores etaient effectues en differents points des zones ou etaient disposes des diffuseurs charges de 1 ou 500 mg, face a des pieges englues appâtes d'une femelle vierge encagee. Il est confirme que la proportion des mâles captures par les femelles diminue quand la dose de pheromone augmente. En absence de confusion, les mâles se dispersent et peuvent etre captures a toutes les distances. En confusion, seule la femelle la plus proche peut etre reperee par le mâle.

International audience; A process of adaptive divergence for tolerance to high temperatures was identified using a rare model system, consisting of two sympatric populations of a Lepidoptera (Thaumetopoea pityocampa) with different life cycle timings, a ‘mutant’ population with summer larval development, Leiria SP, and the founder natural population, having winter larval development, Leiria WP. A third, allopatric population (Bordeaux WP) was also studied. First and second instar larvae were experimentally exposed to daily-cycles of heat treatment reaching maximum values of 36, 38, 40 and 42 °C; control groups placed at 25 °C. A lethal temperature effect was only significant at 42 °C, for Leiria SP, whereas all temperatures tested had a significant negative effect upon Leiria WP, thus indicating an upper threshold of survival c.a. 6 °C above that of the WP. Cox regression model, for pooled heat treatments, predicted mortality hazard to increase for Leiria WP (+108%) and Bordeaux WP (+78%) in contrast to Leiria SP; to increase by 24% for each additional °C; and to decrease by 53% from first to second instar larvae. High variability among individuals was observed, a population characteristic that may favour selection and consequent adaptation. Present findings provide an example of ecological differentiation, following a process of allochronic divergence. Results further contribute to a better understanding of the implications of climate change for ecological genetics.

International audience; This book provides the first comprehensive review of the fauna of alien terrestrial arthropods that have colonized the European continent and its associated islands. Directly ensuing from the DAISIE proiect, this is the result of the joint work of 89 authors from 27 different European countries. The book summarizes present knowledge of the arthropod invasion process, from temporal trends and biogeographic patterns, to pathways and vectors, invaded habitats, and ecological and economical impacts. A total of 1590 species alien to Europe, including crustaceans, myriapods, mites, spiders, and insects, are listed in two volumes and 21 separate chapters that detail the different taxonomic groups. For each species, all key information - feeding regime, date and country of first record in Europe, invaded countries, invaded habitats, plant or animal host - is supplied. More detailed factsheets are provided for the 80 species considered to be most representative of the different pathways of introduction and of the diversity of impacts on ecosystems, economic activities and human and animal health.

In the south-west of France the protected butterfly Euphydryas aurinia occurs mainly in two habitat types: humid herbaceous vegetations and dry grasslands, where it is supposed to use Succisa pratensis and Scabiosa columbaria respectively as larval host-plants. Our observations from 2005 to 2009 in the western part of the Gironde department showed the frequent use of another host-plant: Lonicera periclymenum. This part of the Gironde is covered by evenaged maritime pine stands. Larval nests were mainly observed in Molinia caerulea dominated clearcuttings and firebreaks, and at pine stand edges., Dans le Sud-Ouest de la France, Euphydryas aurinia, un papillon de jour protégé, colonise principalement deux types d’habitats : des milieux herbacés humides et des pelouses sèches. Les plantes-hôtes généralement admises pour les chenilles sont respectivement Succisa pratensis pour le premier type d’habitat et Scabiosa columbaria pour le second. Nos observations, réalisées entre 2005 et 2009 dans la partie ouest du département de la Gironde, ont montré l’utilisation fréquente d’une autre plante-hôte : Lonicera periclymenum. Cette partie de la Gironde est principalement occupée par des plantations de pins maritimes et les nids de chenilles ont été observés dans des coupes rases et des pare-feux dominés par la Molinie et en bordure des peuplements de pins.

Les guides des sylvicultures des chênaies intègrent à tous les niveaux les grands principes favorables à la biodiversité, en l'état actuel des connaissances. À l'échelle régionale ou du paysage, par exemple, la multiplicité des traitements et des itinéraires proposés contribue à l'expression de la diversité. Les critères de choix du traitement font cependant la plus large part à la futaie régulière et bon nombre de peuplements issus de taillis-sous-futaie seront convertis. Comment les communautés d'espèces réagissent-elles à ce changement de régime ? Les résultats des études du Cemagref en forêt de Montargis sont plutôt rassurants.

International audience; Plant chemistry can strongly influence interactions between herbivores and their natural enemies, either by providing volatile compounds that serve as foraging cues for parasitoids or predators, or by affecting the quality of herbivores as hosts or prey. Through these effects plants may influence parasitoid population genetic structure. We tested for a possible specialization on specific crop plants in Chelonus insularis and Campoletis sonorensis, two primary parasitoids of the fall armyworm, Spodoptera frugiperda. Throughout Mexico, S. frugiperda larvae were collected from their main host plants, maize and sorghum and parasitoids that emerged from the larvae were used for subsequent comparison by molecular analysis. Genetic variation at eight and 11 microsatellites were respectively assayed for C. insularis and C. sonorensis to examine isolation by distance, host plant and regional effects. Kinship analyses were also performed to assess female migration among host-plants. The analyses showed considerable within population variation and revealed a significant regional effect. No effect of host plant on population structure of either of the two parasitoid species was found. Isolation by distance was observed at the individual level, but not at the population level. Kinship analyses revealed significantly more genetically related-or kin-individuals on the same plant species than on different plant species, suggesting that locally, mothers preferentially stay on the same plant species. Although the standard population genetics parameters showed no effect of plant species on population structure, the kinship analyses revealed that mothers exhibit plant species fidelity, which may speed up divergence if adaptation were to occur.

Article Open Access Correspondance auteur: J.M. Escoubas E-mail: Jean-Michel.Escoubas@univ-montp2.fr; International audience; Background: X-tox proteins are a family of immune-related proteins only found in Lepidoptera and characterized by imperfectly conserved tandem repeats of several defensin-like motifs. Previous phylogenetic analysis of X-tox genes supported the hypothesis that X-tox have evolved from defensins in a lineage-specific gene evolution restricted to Lepidoptera. In this paper, we performed a protein study in which we asked whether X-tox proteins have conserved the antimicrobial functions of their ancestral defensins and have evolved as defensin reservoirs. Methodology/Principal Findings: We followed the outcome of Spod-11-tox, an X-tox protein characterized in Spodoptera frugiperda, in bacteria-challenged larvae using both immunochemistry and antimicrobial assays. Three hours post infection, the Spod-11-tox protein was expressed in 80% of the two main classes of circulating hemocytes (granulocytes and plasmatocytes). Located in secretory granules of hemocytes, Spod-11-tox was never observed in contact with microorganisms entrapped within phagolyzosomes showing that Spod-11-tox is not involved in intracellular pathogen killing. In fact, the Spod-11-tox protein was found to be secreted into the hemolymph of experimentally challenged larvae. In order to determine antimicrobial properties of the Spod-11-tox protein, it was consequently fractionated according to a protocol frequently used for antimicrobial peptide purification. Over the course of purification, the anti-Spod-11-tox immunoreactivity was found to be dissociated from the antimicrobial activity. This indicates that Spod-11-tox is not processed into bioactive defensins in response to a microbial challenge. Conclusions/Significance: Altogether, our results show that X-tox proteins have not evolved as defensin reservoirs and have lost the antimicrobial properties of the ancestral insect defensins. The lepidopteran X-tox protein family will provide a valuable and tractable model to improve our knowledge on the molecular evolution of defensins, a class of innate immune effectors largely distributed over the three eukaryotic kingdoms

Par leur immense diversité, leur rôle écologique majeur et le caractère bio-indicateur de certains, la prise en compte des insectes dans la gestion et la conservation des espaces naturels est croissante depuis une dizaine d'années. Cependant, l'étude de ce groupe souffre d'un manque de ressources professionnelles (entomologistes professionnels, formation) et d'une connaissance encore trop lacunaire de la part des gestionnaires, pourtant fortement intéressés par ce vaste groupe. Du simple état des lieux (inventaire) à l'étude de l'effet d'un type de gestion (étude comparative) en passant par des suivis, l'approche de la diversité entomologique passe par des méthodes et des techniques d'échantillonnage particulières. Les gestionnaires d'espaces forestiers ont depuis longtemps mené des études entomologiques avec des divergences fréquentes, d'un site à un autre, dans les protocoles d'échantillonnage et les groupes taxonomiques abordés. Ces approches quasi- indépendantes de la part d'un gestionnaire à un autre conduisent à une comparaison des résultats entre sites difficile. En 2001, à la demande d'organismes gestionnaires, un groupe de travail dénommé Inv.Ent.For. (Inventaires Entomologiques en Forêt) s'est constitué pour mener une réflexion sur la prise en compte de la faune entomologique dans les espaces naturels forestiers. Composé d'entomologistes professionnels (chercheurs, chargés d'étude de bureaux d'étude ou d'associations, etc.) et de gestionnaires d'espaces naturels (ONF, Réserves Naturelles de France), le groupe a eu pour objectifs de faire des propositions concrètes sur un cadre technique minimal et standardisé concernant les groupes à prendre à compte dans les études entomologiques et les méthodes permettant de les échantillonner. Le présent document présente ces propositions en cinq chapitres. Le premier chapitre reprend des éléments conceptuels et pratiques sur la réalisation d'un inventaire ou d'un échantillonnage. Il fait le point sur les étapes incontournables d'une étude scientifique et sur l'importance de quelques grands principes à respecter. Le deuxième chapitre dresse la liste de l'ensemble des méthodes et techniques permettant d'échantillonner les insectes, aussi bien dans les milieux terrestres, forestiers ou non, que dans les milieux aquatiques. Puis il détaille avec des conseils pratiques, quatre méthodes proposées par le groupe de travail Inv.Ent.For. pouvant être utilisées en forêt tempérée : le piège à fosse, les pièges à vitres, le piège Malaise et les pièges lumineux. Quelques groupes entomologiques pouvant être appréhendés pour des inventaires en milieux forestiers tropicaux sont également abordés avec leurs méthodes spécifiques dans le troisième chapitre. Face à l'impossibilité d'appréhender la colossale diversité des insectes, les membres d'Inv.Ent.For. ont dégagé cinq groupes d'insectes méritant une prise en compte systématique en forêt : les Coléoptères Carabidae et saproxyliques, les Diptères Syrphidae, les Lépidoptères diurnes et nocturnes et les Fourmis rousses (Hyménoptères). Ceux-ci sont présentés un par un dans le quatrième chapitre avec quelques généralités, l'intérêt de leur étude et les méthodes permettant de les échantillonner en fonction des objectifs assignés par le gestionnaire. Enfin, le dernier chapitre donne des conseils pratiques sur la gestion des récoltes d'insectes, depuis le conditionnement après la récolte jusqu'à la valorisation des données d'inventaires en passant par la préparation des individus. / Due to their high diversity, their crucial ecological roles and their use as bio-indicators, insects have been increasingly taken into account into the management of natural areas for ten years. However, the study of insects currently suffers from a lack of professional resources (entomologists, diplomas) and from insufficient background knowledge among land managers, despite an increasing interest. Insect studies include not only rough inventories but also monitoring designs or studies comparing the environmental effects of management practices. All these approaches require particular sampling methods. Even though forest managers have been leading entomological studies for a long time, sampling protocols and study groups often differ between study sites. The comparison of results is therefore quite misleading. In 2001, upon request of several land managers, a working group called Inv.Ent.For. emerged. This group, composed of professional and non-professional entomologists, aimed at defining a technical and standardized framework for forest insect sampling; i.e. key insect groups and common sampling techniques. Proposals are detailed in five chapters of this report. Chapter 1 includes conceptual and practical information about the basic principles and steps of sampling designs. Chapter 2 gives a detailed list of techniques to sample insects in terrestrial (not only forest)ecosystems as well as landwaters. Four families of methods are precisely described, with a practical perspective in temperate forests: pitfall traps, window-flight traps, Malaise traps and light traps. Insect groups and related techniques in tropical forests are highlighted in Chapter 3. Since it is really difficult to encompass the huge diversity of forest insects, the Inv.Ent.For. group suggests to focus insect studies on 5 representative insect groups: ground beetles, saproxylic beetles, Hoverflies, Butterflies and moths, and Formica ants. The interests of these 5 groups, as well as their sampling techniques, are discussed in Chapter 4. The last chapter points out some practical tips to maintain and preserve insect samples, from sampling to packaging, mounting and data management.

Junonia coenia densovirus (JcDNV) is an ambisense insect parvovirus highly pathogenic for lepidopteran pests at larval stages. The potential use of DNVs as biological control agents prompted us to reinvestigate the host range and cellular mechanisms of infection. In order to understand the early events of infection, we set up a functional infection assay in a cell line of the pest Lymantria dispar to determine the intracellular pathway undertaken by JcDNV to infect a permissive lepidopteran cell line. Our results show that JcDNV particles are rapidly internalized into clathrin-coated vesicles and slowly traffic within early and late endocytic compartments. Blocking late-endocytic trafficking or neutralizing the pH with drugs inhibited infection. During internalization, disruption of the cytoskeleton, and inhibition of phosphatidylinositol 3-kinase blocked the movement of vesicles containing the virus to the nucleus and impaired infection. In summary, our results define for the first time the early endocytic steps required for a productive DNV infection.

Udgivelsesdato: 2009-Jun Male moths use sex pheromones to find their mating partners. In the moth, Agrotis ipsilon, the behavioral response and the neuron sensitivity within the primary olfactory centre, the antennal lobe (AL), to sex pheromone increase with age and juvenile hormone (JH) biosynthesis. By manipulating the JH level, we previously showed that JH controls this age-dependent neuronal plasticity, and that its effects are slow (within 2 days). We hypothesized that the hormonal effect might be indirect, and one neuromodulator candidate, which might serve as a mediator, is octopamine (OA). Here, we studied the effects of OA and an OA receptor antagonist, mianserin, on behavioral and AL neuron responses of mature and immature males during stimulation with sex pheromone. Our results indicate that, although OA injections enhanced the behavioral pheromone response in mature males, OA had no significant effect on behavior in immature males. However, mianserin injections decreased the behavioral response in mature males. AL neuron sensitivity increased after OA treatment in immature males, and decreased after mianserin treatment in mature males. Determination of OA levels in ALs of immature and mature males did not reveal any difference. To study the possible interactive effects of JH and OA, the behavioral pheromone response was analyzed in JH-deprived mature males injected with OA, and in immature males injected with fenoxycarb, a JH agonist, and mianserin. Results show that both JH and OA are necessary to elicit a behavioral response of A. ipsilon males to sex pheromone.

Par leur immense diversité, leur rôle écologique majeur et le caractère bio-indicateur de certains, la prise en compte des insectes dans la gestion et la conservation des espaces naturels est croissante depuis une dizaine d'années. Cependant, l'étude de ce groupe souffre d'un manque de ressources professionnelles (entomologistes professionnels, formation) et d'une connaissance encore trop lacunaire de la part des gestionnaires, pourtant fortement intéressés par ce vaste groupe. Du simple état des lieux (inventaire) à l'étude de l'effet d'un type de gestion (étude comparative) en passant par des suivis, l'approche de la diversité entomologique passe par des méthodes et des techniques d'échantillonnage particulières. Les gestionnaires d'espaces forestiers ont depuis longtemps mené des études entomologiques avec des divergences fréquentes, d'un site à un autre, dans les protocoles d'échantillonnage et les groupes taxonomiques abordés. Ces approches quasi- indépendantes de la part d'un gestionnaire à un autre conduisent à une comparaison des résultats entre sites difficile. En 2001, à la demande d'organismes gestionnaires, un groupe de travail dénommé Inv.Ent.For. (Inventaires Entomologiques en Forêt) s'est constitué pour mener une réflexion sur la prise en compte de la faune entomologique dans les espaces naturels forestiers. Composé d'entomologistes professionnels (chercheurs, chargés d'étude de bureaux d'étude ou d'associations, etc.) et de gestionnaires d'espaces naturels (ONF, Réserves Naturelles de France), le groupe a eu pour objectifs de faire des propositions concrètes sur un cadre technique minimal et standardisé concernant les groupes à prendre à compte dans les études entomologiques et les méthodes permettant de les échantillonner. Le présent document présente ces propositions en cinq chapitres. Le premier chapitre reprend des éléments conceptuels et pratiques sur la réalisation d'un inventaire ou d'un échantillonnage. Il fait le point sur les étapes incontournables d'une étude scientifique et sur l'importance de quelques grands principes à respecter. Le deuxième chapitre dresse la liste de l'ensemble des méthodes et techniques permettant d'échantillonner les insectes, aussi bien dans les milieux terrestres, forestiers ou non, que dans les milieux aquatiques. Puis il détaille avec des conseils pratiques, quatre méthodes proposées par le groupe de travail Inv.Ent.For. pouvant être utilisées en forêt tempérée : le piège à fosse, les pièges à vitres, le piège Malaise et les pièges lumineux. Quelques groupes entomologiques pouvant être appréhendés pour des inventaires en milieux forestiers tropicaux sont également abordés avec leurs méthodes spécifiques dans le troisième chapitre. Face à l'impossibilité d'appréhender la colossale diversité des insectes, les membres d'Inv.Ent.For. ont dégagé cinq groupes d'insectes méritant une prise en compte systématique en forêt : les Coléoptères Carabidae et saproxyliques, les Diptères Syrphidae, les Lépidoptères diurnes et nocturnes et les Fourmis rousses (Hyménoptères). Ceux-ci sont présentés un par un dans le quatrième chapitre avec quelques généralités, l'intérêt de leur étude et les méthodes permettant de les échantillonner en fonction des objectifs assignés par le gestionnaire. Enfin, le dernier chapitre donne des conseils pratiques sur la gestion des récoltes d'insectes, depuis le conditionnement après la récolte jusqu'à la valorisation des données d'inventaires en passant par la préparation des individus. / Due to their enormous diversity, crucial ecological role and, in some cases, their use as bio-indicators, insects have been increasingly taken into account in the management and conservation of natural areas over the last decade or so. However, the study of insects is currently suffering from a lack of professional resources (professional entomologists, training) and insufficient background knowledge among land managers, despite their strong interest in this vast group. Ranging from rough inventories to the examination of the effects of a given management approach (comparative studies) including monitoring, any approach to entomological diversity will involve specific sampling methods and techniques. Despite the fact that forest managers have long conducted entomological studies, sampling protocols and study groups often differ from one site to the next. Such virtually independent approaches between managers lead to difficulties in comparing the results from different sites. In 2001, at the request of land management bodies, a working group entitled, Inv.Ent.For.', was set up to reflect upon how consideration could be given to entomological fauna within forest areas. This group, composed of professional entomologists (researchers, research managers in consultancies and not profit associations, etc.) and management bodies for natural areas (e.g. ONF, Réserves Naturelles de France), aimed to define a minimum technical and standardised framework for the insect groups to be targeted in entomological studies and the methods for their sampling. These proposals are detailed in the five chapters of this report. Chapter 1 contains conceptual and practical information on conducting inventories and sampling. It sets out the imperative stages any scientific study must go through and the importance of a small number of broad principles to be followed. Chapter 2 provides a detailed list of techniques for insect sampling in terrestrial (not only forest) ecosystems as well as aquatic environments. It goes on to detail, with accompanying practical advice, four methods proposed by the working group for use in temperate forests: pitfall traps, window flight traps, Malaise traps and light traps. Chapter 3 describes a small number of insect groups that can be captured for tropical forest inventories, along with the specific techniques required. Given the impossibility of encompassing the huge diversity of forest insects, the members of Inv.Ent.For. have defined five insect groups that merit systematic attention in the forest context: ground beetles, saproxylic beetles, hoverflies, butterflies and moths, and red ants. Each of these is discussed in turn in Chapter 4, addressing the benefits to be gained from studying them, and the methods whereby they can be sampled in accordance with the objectives defined by forest managers. The final chapter contains some practical advice on the management of those insect samples that have been collected, from packaging after sampling, to the use of the data and including the mounting of individual insects.

SCOPUS: ar.j, FLWIN, info:eu-repo/semantics/published

International audience; The primary olfactory centres share striking similarities across the animal kingdom. The most conspicuous is their subdivision into glomeruli, which are spherical neuropil masses in which synaptic contacts between sensory and central neurons occur. Glomeruli have both an anatomical identity (being invariant in location, size and shape) and a functional identity (each glomerulus receiving afferents from olfactory receptor neurons that express the same olfactory receptor). Identified glomeruli offer a favourable system for analysing quantitatively the constancy and variability of the neuronal circuits, an important issue for understanding their function, development and evolution. The noctuid moth Spodoptera littoralis with its well-studied pheromone communication system has become a model species for olfaction research. We analyse here its glomerular organisation based on ethyl-gallate-stained and synapsin-stained preparations. Although we have confirmed that the majority of glomeruli can be individually identified in various antennal lobes, we have recognised several types of biological variability. Some glomeruli are absent, possibly indicating the lack of the corresponding receptor neuron type or its misrouting during development. The antennal lobes vary in global shape and, consequently, the spatial location of the glomerular changes. Although they do not prevent glomerulus identification when quantitative analysis methods are used, these variations place limits on the straightforward identification of glomeruli in functional studies, e.g. calcium-imaging or single-cell staining, when using conventional three-dimensional maps of individual antennal lobes

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