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In the parasitoid genus Sclerodermus, multiple foundresses produce and care for communal broods on large hosts, which can lead to greater reproductive success for group members than attempting to reproduce alone. We explore the consequences of foundress group size on the benefits of cooperative brooding and on brood sex ratios by providing groups of 10-55 foundresses with a single host and no alternative reproductive options. Within this range, increasing foundress group size leads to increasingly common failure in brood production and diminished per capita success. Group production of adult offspring declines once foundress number reaches around 25. Brood failure is usually at the early developmental stages, and current evidence suggests that there may be competition among foundresses for oviposition sites, possibly involving reproductive dominance and ovicide, which also delays initial brood production. Once broods become established, their rate of development is enhanced by large foundress numbers. The sex ratios of broods are very strongly female biased, irrespective of the foundress number. As this bias is not easily explained by standard models of local mate competition or by a recent model of local resource enhancement, we suggest an explanation based on control of sex allocation by a minority of dominant foundresses, which monopolise the production of adult males.

Understanding the responses of insect herbivores to plant chemical defences is pivotal for the management of crops and pests. However, the mechanisms of interaction are not entirely understood. In this study, we compared the whole transcriptome gene expression of the aphid Macrosiphum euphorbiae grown on two different varieties of tomato that differ in their inducible chemical defences. We used two isogenic lines of tomato with a shared genetic background that only differ in the presence of type IV glandular trichomes and their associated acylsucrose excretions. This works also reports a de novo transcriptome of the aphid M. euphorbiae. Subsequently, we identified a unique and distinct gene expression profile for the first time corresponding to aphid´s exposure to type IV glandular trichomes and acylsugars. The analysis of the aphid transcriptome shows that tomato glandular trichomes and their associated secretions are highly efficient in triggering stress-related responses in the aphid, and demonstrating that their role in plant defence goes beyond the physical impediment of herbivore activity. Some of the differentially expressed genes were associated with carbohydrate, lipid and xenobiotic metabolisms, immune system, oxidative stress response and hormone biosynthesis pathways. Also, the observed responses are compatible with a starvation syndrome. The transcriptome analysis puts forward a wide range of genes involved in the synthesis and regulation of detoxification enzymes that reveal important underlying mechanisms in the interaction of the aphid with its host plant and provides a valuable genomic resource for future study of biological processes at the molecular level using this aphid.

Butterflies of the genus Zerynthia often have different host plants in the genus Aristolochia in the different parts of their distribution range. In Mediterranean France the Southern Festoon reaches its North Western distribution limit, where it generally lays eggs on A. rotunda in either coastal wet meadows or riparian and garrigue habitats in the backcountry. In the study area (Hérault and Gard departments), its distribution range overlaps with that of the Spanish Festoon Zerynthia rumina at its north-eastern limits. The Spanish Festoon lays its eggs on A. pistolochia plants growing in dry garrigues in the backcountry. Three types of field observations were conducted to determine : (1) whether habitat variation influences the rates of egg deposition by the Southern Festoon, (2) the extent to which A. rotunda is the preferential host plant and (3) if both Southern and Spanish Festoons are specialised if they co-occur with both their host plants in proximity. We found that A. rotunda is the main host plant of the Southern Festoon in both habitats where it grows in Mediterranean France although egg laying was observed on A. clematitis and more rarely on A. paucinervis in coastal sites. Finally, in parapatry, Southern and Spanish Festoons exchange their host plants but remain both more specialised on a different host. Despite their protection status, destruction of their habitats by urbanisation and infrastructures are a major threat to these specialised butterflies., Dans leurs différentes aires de distribution, les papillons du genre Zerynthia présentent des plantes-hôtes diverses au sein du genre Aristolochia. En France méditerranéenne, où Z. polyxena, la Diane, est en limite nord-ouest de distribution, elle pond généralement sur A. rotunda qui pousse à la fois dans les prairies humides littorales et certaines garrigues d’arrière-pays. Dans la zone d’étude (départements de l’Hérault et du Gard), son aire de distribution chevauche celle de Z. rumina, la Proserpine, dans sa limite orientale. Cette dernière pond sur A. pistolochia qui pousse dans les garrigues sèches d’arrière-pays. Trois axes d’observations de terrain ont été définis afin de voir (1) si la fréquence de ponte de Z. polyxena varie dans ses différents habitats, (2) dans quelle mesure A. rotunda est réellement la plantehôte préférentielle de Z. polyxena et (3) si Z. polyxena et Z. rumina demeurent spécialistes lorsqu’elles partagent le même habitat avec leurs deux plantes-hôtes en mélange ou en étroite proximité. L’ensemble de ces travaux a bien conforté qu’A. rotunda est l’hôte privilégié de Z. polyxena dans ses deux grands habitats de France méditerranéenne bien que des pontes puissent être observées sur A. clematitis et plus rarement sur A. paucinervis sur les sites littoraux. En parapatrie, Z. polyxena et Z. rumina peuvent ponctuellement changer de plante-hôte même si elles conservent une préférence pour la leur. Malgré leur statut de protection, ces papillons spécialistes sont principalement menacés par la destruction de leurs habitats par l’urbanisation et l’implantation d’infrastructures., Gauthier Perrine, Manincor Natasha de, Picquenot Manon, Pons Virginie, Schumpp Ugo, Thompson John D. Spécificité et flexibilité dans la ponte de Zerynthia polyxena sur différentes espèces du genre Aristolochia en région méditerranéenne française / Specificity and flexibility of egg laying by Zerynthia polyxena on different species of Aristolochia in Mediterranean France. In: Ecologia mediterranea, tome 46 n°2, 2020. pp. 47-63.

The relationship between plants and insects is one of the greatest evolutionary stories in the history of life on earth. Their importance in global terrestrial ecosystem functioning is self evident, as both represent the most abundant life on the planet. While plant-insect interactions have received much attention and are easily manipulated in experimental investigations, there have been few broad-scale phylogenetic studies for circumscribed herbivorous groups. As a result, the evolutionary role of interspecific interactions in promoting herbivorous insect diversification, at both the global and local scales, remains unclear. Remarkably, one of the largest gaps in our evolutionary and ecological understanding includes the sap-feeding insects in the Auchenorrhyncha suborder (Hemiptera), which contain some of the largest, terrestrially dominant host-plant restricted insect groups known (e.g., Cicadas, planthoppers, and leafhoppers). The evolutionary success of Auchenorrhyncha is due, at least in part, to ancient associations with a consortium obligate bacterial endosymbionts that have persisted for over 260 million years. However, like their insect hosts, the diversity and evolutionary relationships of endosymbiont associations remain relatively unknown for most aucchenorrhynchan groups.The leafhoppers (Cicadomorpha: Cicadellidae) remain one of the largest, yet poorly understood insect families. Of the 22,000 currently described species, thousands remain to be described with an overall unknown diversity (some estimates suggest as many as 90% of tropical Cicadomorpha remain to be described). This is surprising, since they offer excellent models to understand ecological and biogeographic mechanisms of species diversification due to their strict host-plant specificity, limited dispersal, and high rates of local endemism. The cicadellid subfamily, Deltocephalinae, represents the largest leafhopper groups, yet their patterns of species diversification, host-plant use, and endosymbiont associations remain almost entirely unknown. This study used the Hawaiian Archipelago as a model system to investigate the roles of ecology, biogeography, and endosymbiont interactions in the diversification of the native Hawaiian leafhopper genus, Nesophrosyne (Cicadellidae: Deltocephalinae). The Hawaiian Islands offer a tractable natural laboratory to circumscribe and study plant-insect evolution due to their isolated, discrete and replicated nature, and high levels of endemism. Nesophrosyne represents one of the most diverse and ecologically dominant herbivore radiations on Hawai`i, but has eluded scientific attention for over 60 years. Species are obligate phloem feeders and are highly host-plant specific. Moreover, Nesophrosyne exhibits the quintessential characteristics of an adaptive radiation, including dramatic morphological adaptations to the endemic Hawaiian flora and adaptive diversification across the archipelago to fill habitat types from coastal to sub-alpine regions. The specific goals of this study were to 1) update the current taxonomic status of Nesophrosyne, 2) determine the diversity and phylogenetic relationships of species in the genus, 3) infer the roles of ecology and geology in the adaptive radiation, historical biogeography, and species diversification dynamics of Nesophrosyne, and 4) to reconstruct the global relationships of the dual obligate bacterial endosymbionts of Nesophrosyne and their rates of evolution.In the first chapter, the taxonomic history and status of Nesophrosyne was reviewed. The genus was redescribed, and the subgenus Nesoreias was synonymized with Nesophrosyne. Eight new species associated with the widespread host-plant species, Broussaisia arguta (Hydrangeaceae), were described. Results reveal morphologically cryptic diversity according to individual Hawaiian Islands and volcanoes within this group. A model usage of morphological and molecular characters was developed for future delimitation of species in Nesophrosyne. The second chapter reconstructed a comprehensive phylogeny for Nesophrosyne in order to determine the origins, species diversity, and host-plant use of the native Hawaiian leafhoppers. Results support a monophyletic Nesophrosyne, originating from the Western Pacific basin, with a sister-group relationship to the genus Orosius. Nesophrosyne species are characterized by high levels of morphologically cryptic diversity and local endemicity, comprising > 200 species. Species demonstrate four dominant patterns of host-plant specialization that shape species diversity: 1) diversification through host switching; 2) specialization on widespread hosts with allopatric speciation; 3) repeated, independent shifts to the same hosts; and, 4) absence or low abundance on some hosts, suggesting herbivore interactions may limit ecological opportunity.The third chapter inferred the roles of ecology and geology in the adaptive radiation, historical biogeography, and species diversification dynamics of Nesophrosyne. The molecular age of Nesophrosyne indicates a split from Orosius 4.5 million years ago (Ma), with a basal divergence on Hawai`i 3.2 Ma. The genus originated on Kaua`i and subsequently colonized younger islands as they formed. Ancestral host-plant reconstructions reveal that the plant families, Urticaceae and Rubiaceae, played important roles in the early diversification of Nesophrosyne. Results indicate that island geography have imposed significant barriers to continued gene flow, leading to extensive allopatric speciation and intra-island diversification. Finally, Nesophrosyne diversification dynamics show an initial burst in speciation rates, with a subsequent diversity-dependent decline, corresponding to island formation. Finally, chapter four examined the global relationships of Nesophrosyne's dual obligate, bacteriome restricted bacterial endosymbionts, `Candidatus Sulcia muelleri' and a novel β-proteobacterium in the `Ca. Nasuia' genus. A global bacterial phylogeny was reconstructed, revealing a shared origin for the β-proteobacterial lineages throughout Deltocephalinae genera, and potentially throughout Auchenorrhyncha. The bacteriome association and transovarial transmission of Nesophrosyne's endosymbionts were confirmed using Fluorescent in situ Hybridization techniques. Finally, inference of absolute molecular rates demonstrates highly elevated rates of molecular evolution - the fastest so far recorded. We propose a second species in the genus Nasuia to describe the novel β-proteobacterium in Nesophrosyne.Hawai`i has long been held as a model system to understand adaptive radiation and evolutionary biology, however my study is one of the first to test these patterns directly for a hyper-diverse endemic insect radiation, and for the suborder Auchenorrhyncha. The presented results illustrate that, in diverse herbivorous groups, multiple evolutionary processes play fundamental roles in species diversification, including associations with bacterial endosymbionts, host-plant specialization, insect-insect interactions, and the geologic formation of islands. These results develop both an understanding of how ecological and geological controls shape adaptive diversification in insects, and a general model for contextualizing species diversification in herbivorous insects.

Gall-inducing insects cause the development of specialised plant tissues (galls) that provide them with nutrition and some measure of protection from physical and biotic stresses. Their interaction with the plant is the most intimate metabolically of any herbivore group and is often associated with high host specificity. We survey the gall inducers that have become invasive pests of forest trees, most of which belong to just four insect families in three orders: Hemiptera (Adelgidae), Diptera (Cecidomyiidae) and Hymenoptera (Cynipidae and Eulophidae). Most are associated with introduction of plants on which they are specialists, but some have also shifted from introduced to native plant hosts. No formal comparative analysis of traits associated with success of establishment and subsequent range expansion has yet been made, and it is often hard to identify why one species has become a major range-expanding pest, while closely related and biologically very similar species have not. We provide an overview of biological traits likely to facilitate gall inducer range expansion, and highlight the importance of natural enemies in community impacts and biological control. Increasing global trade is likely to result in further range expansions by economically damaging species. The effects of climate change on the direction, frequency, and impact of gall inducer range expansions are likely to be complex and probably species-specific.

The indirect defence compounds termed herbivore induced plant volatiles (HIPVs), which are used to attract beneficial fauna, are one of the most effective biological control tools for the aggregation of natural enemies of key pests. The aim of this study was to test the attraction of three aphid predators of the Chrysopidae, Coccinellidae and Syrphidae families using synthetic formulations of four main HIPVs [methyl salicylate (MeSa), benzaldehyde (B), linalool (L) and farnesene (F)] alone and in binary combinations (MeSa + B; MeSa + F; MeSa + L; F + B; B + L; F + L) in an apple orchard in the Bursa province of Turkey. This study was the first demonstration of the attraction of these aphid predators to single and binary combinations of synthetic HIPVs in an apple orchard. A larger number of coccinellids were captured using single treatments of both B and F than with other HIPV combinations. Furthermore, the chrysopid individuals studied were significantly attracted to traps baited with single HIPVs. In addition, the binary combination of MeSa + L significantly attracted more Syrphids than in both single treatments and control traps. Thus, some of the HIPV's tested were found to have potential value for the congregation of aphid predators in apple orchards. University of Bursa Uludag, Scientific Research Unit, Bursa, Turkey [UAP (Z) -2010/45] This study was supported by University of Bursa Uludag, Scientific Research Unit, Bursa, Turkey, Grant Project No: UAP (Z) -2010/45.

© 2019 Wong, Lutz, Natera, Wang, Ng, Grigoriev, Martin, Roessner, Anderson and Plett. Plant roots co-inhabit the soil with a diverse consortium of microbes of which a number attempt to enter symbiosis with the plant. These microbes may be pathogenic, mutualistic, or commensal. Hence, the health and survival of plants is heavily reliant on their ability to perceive different microbial lifestyles and respond appropriately. Emerging research suggests that there is a pivotal role for plant root secondary metabolites in responding to microbial colonization. However, it is largely unknown if plants are able to differentiate between microbes of different lifestyles and respond differently during the earliest stages of pre-symbiosis (i.e., prior to physical contact). In studying plant responses to a range of microbial isolates, we questioned: (1) if individual microbes of different lifestyles and species caused alterations to the plant root metabolome during pre-symbiosis, and (2) if these early metabolite responses correlate with the outcome of the symbiotic interaction in later phases of colonization. We compared the changes of the root tip metabolite profile of the model tree Eucalyptus grandis during pre-symbiosis with two isolates of a pathogenic fungus (Armillaria luteobubalina), one isolate of a pathogenic oomycete (Phytophthora cinnamomi), two isolates of an incompatible mutualistic fungus (Suillus granulatus), and six isolates of a compatible mutualistic fungus (Pisolithus microcarpus). Untargeted metabolite profiling revealed predominantly positive root metabolite responses at the pre-symbiosis stage, prior to any observable phenotypical changes of the root tips. Metabolite responses in the host tissue that were specific to each microbial species were identified. A deeper analysis of the root metabolomic profiles during pre-symbiotic contact with six strains of P. microcarpus showed a connection between these early metabolite responses in the root with later colonization success. Further investigation using isotopic tracing revealed a portion of metabolites found in root tips originated from the fungus. RNA-sequencing also showed that the plant roots undergo complementary transcriptomic reprogramming in response to the fungal stimuli. Taken together, our results demonstrate that the early metabolite responses of plant roots are partially selective toward the lifestyle of the interacting microbe, and that these responses can be crucial in determining the outcome of the interaction.

The predator-prey system Phytoseiulus persimilis Athias-Henriot (Acari: Phytoseiidae) and Tetranychus urticae (Koch) (Acari: Tetranychidae) represents the most studied and the most known system among the Acari. Because of the agronomical importance of the two mite species, a wealth of modelling studies investigated the interactions of the two species at the individual level. However, regional or global level works on this system are lacking, which is impeding the investigation of climate change effects on biological control effectiveness. Here we compile and geo-locate worldwide occurrences for the two species considered, based on literature, collection and field survey data. The datasets presented in this document gather most of the literature records of both species for which locality data were available for geo-referencing (1,037 for T. urticae and 126 for P. persimilis). Geo-located data from collections and field surveys including host-plants are also presented for the first time (322 for T. urticae and 65 for P. persimilis). Phytoseiulus persimilis is also reported for the first time from Kenya and La Martinique., Acarologia, 59, 301-307

Every interaction between two organisms is a force driving the adaptation of one to the other and vice versa. This force of adaptation becomes more important as the number of interacting organisms and interaction levels increases. In this study we investigate the impact of withanolides, which are a group of plant secondary metabolites synthesized by Physalis plants, on the microbiota of two insect species in order to shed light on the mechanisms of insect-plant coevolution mediated by endosymbionts. We used the model system composed of the generalist lepidopteran moth Heliothis virescens and its close relative Heliothis subflexa, which is a specialist feeder of Physalis plants. We showed by means of bacterial 16S rRNA gene sequencing that H. subflexa has a more diversified gut microflora than H. virescens. Both gut bacterial communities were largely dominated by the genus Enterococcus. Withanolide supplementation to diet given to larvae had no significant effect on the diversity and richness of gut symbionts. In addition, we assessed the temporal expression levels of two antimicrobial peptides - i-type-lysozyme and attatcin-1 - under withanolide treatments on third instar larvae. We showed that the expression of attacin-1 was not affected by any of the treatments; however, i-type-lysozyme was upregulated after 24 hours.; Un des thèmes phares de la biologie de l’évolution est l’étude des interactions entre deux organismes et comment ces interactions deviennent des moteurs d’adaptation, ou plus précisément de coadaptation. Un exemple célèbre et largement étudié est celui des interactions entre les insectes et les plantes. Cette coévolution, souvent appelée « course aux armements », promeut plus souvent la spécialisation des insectes à un nombre réduit de quelques espèces de plantes phylogénétiquement proches qu’à l’expansion de la gamme d’hôte à un grand nombre de plantes (Ehrlich et Raven, 1964, Fox, 1981, Jaenike, 1990).Les plantes ont développé des mécanismes de défense pour se protéger contre les herbivores au moyen, entre autres, de composés appelés « métabolites secondaires de plantes » (MSP). Les insectes quant à eux ont évolué des moyens pour détoxifier leur nourriture, devenir tolérant voire même séquestrer les toxines végétales pour servir leurs propres intérêts (Heckel, 2014). Outre la gestion des toxines de plantes, les insectes doivent également résister aux attaques d’un grand nombre de pathogènes (Lacey et al., 2001).Cependant, comme pour la plupart des animaux, les insectes ne sont pas seuls pour y faire face. Ils sont accompagnés de microorganismes qu’ils portent dans leur intestins, et qui leur procure une grande variété de bienfaits (Frago et coll., 2012, Janson et coll., 2008, McFall-Ngai et coll., 2013). Les études montrant l'importance des microbes intestinaux sur ce sujet se sont multipliées au cours de la dernière décennie. Les symbiotes intestinaux sont connus pour dégrader les matières végétales indigestes, détoxifier l’organisme des MSP, et protéger l’hôte contre les agents pathogènes. Ils sont ainsi considérés comme une potentielle force évolutive capable de provoquer des changements de gamme hôtes chez les insectes. Dans certains cas, le microbiote intestinal de l'insecte serait même impliqué dans le développement de résistances aux insecticides (Pietri et Liang, 2018).Cette présente étude porte sur le système Heliothis subflexa et son espèce soeur Heliothis virescens. H. subflexa est un lépidoptère spécialiste des Physalis (Solanaceae) qui produisent des withanolides pour se défendre, alors que H. virescens peut se nourrir sur plus d’une dizaine de famille de plantes différentes excepté des Physalis (Brazzel, 1953; Cho et al., 2008). Les withanolides sont des lactones stéroïdiennes avec un ergonstane pour structure centrale (Misico et al., 2011). Ces molécules sont reconnues comme étant des antiappétants efficaces (Ascher et al., 1980), des antagonistes des ecdystéroïdes (Dinan et al., 1996), des immunosuppresseurs (Garcia et al., 2006) et pour présenter une activité antimicrobienne (Kurup, 1956). Ils sont répulsifs ou nocifs pour une grande quantité d'organismes. Une étude récente menée par Barthel et al. (2016) a montré dans des expériences d’alimentation que les withanolides bénéficiait à H. subflexa. Celui voyait en effet sa prise de poids relatif augmenter lorsque il en consommait. D’autre part, la consommation de withanolides avait un effet négatif sur H. virescens qui se traduisait par une perte de poids relatif en comparaison du contrôle. Les effets des withanolides portaient également sur l’immunité des deux insectes, l’activité phenoloxidase (PO) était augmentée chez H. subflexa alors qu’elle restait inchangée chez H. virescens. De plus l’apport de withanolides à leurs régimes alimentaires provoqua chez H. subflexa une augmentation non significative de l’expression de la plupart des gènes de l’immunité alors que ces mêmes gènes étaient réprimés chez H. virescens. Ces résultats ont inspiré la présente étude qui s’organise autour de deux questions : les microorganismes intestinaux d’H. subflexa interviennent-ils dans son adaptation aux Physalis ? Il y a-t-il un changement de composition de la microflore intestinale de ce dernier qui puisse expliquer la capacité de cet insecte à se nourrir de Physalis ? Et deuxièmement, cette étude s’intéresse à l’aspect temporel de la réponse immunitaire de cet insecte aux withanolides. Cette réponse est-elle rapide ou bien s’inscrit elle dans la durée ? Et quelle en est l’ampleur en terme que quantification de la surexpression des gènes de l’immunité ?Pour répondre à ces deux problématiques deux expériences de nutrition comprenant deux conditions de traitements ont été établies. Le premier traitement consistait en un extrait purifié de withanolide provenant de Physalis peruviana tandis que le second était du withaferin A, un withanolide disponible dans le commerce. Le traitement control était le méthanol, solvant dans lequel ces composés étaient dissouts. La première expérience consistait à appliquer les traitements de withanolides sur un régime alimentaire artificiel et de permettre à des larves de H. subflexa et H. virescens de s’en nourrir pour une durée de 48h. À l’issue de ce temps d’exposition les intestins des larves ont été disséqués et l’ADN génomique extrait. Les échantillons ont ensuite été envoyés à séquencer pour le gène bactérien ribosomal 16S. Les données brutes ont été traitées dans QIIME2 par le Dr. Shantanu Shukla qui a produit un tableau répertoriant le nombre de comptage obtenu par échantillon pour une séquence donnée. La seconde expérience consistait à exposer les larves à ces mêmes traitements sur des durées de une, six 12 et 24 heures, à l’issue desquelles l’ARN total a été extrait des larves entières, converti en ADN complémentaire et utilisé dans des réactions de PCR quantitatives en temps réel. Cela a permis de suivre au cours du temps l’expression relative de deux gènes de l’immunité : le peptide antimicrobien (AMP) attacine-1 et le lysozyme 1 de type i en réponse aux traitements.Les résultats de l’analyse métagénomique des intestins a montré que H. subflexa a une microflore intestinale plus diversifiée que celle de H. virescens, comprenant 70 familles bactériennes différentes contre seulement cinq chez H. virescens. Cependant le nombre total de séquences quantifiées dans les échantillons de H. subflexa variaient grandement. Certain échantillons comprenant seulement 388 ou 423 séquences lorsque tous les échantillons de H. virescens en avaient plus de 22687. Les deux communautés bactériennes intestinales étaient largement dominées par le genre bactérien Enterococcus. Ce dernier prévalait à 99,89% chez H. virescens et à 84,57% chez son espèce soeur. Ces observations ne sont pas inhabituelles pour des populations d’insectes de laboratoires. L’ajout de withanolides au régime alimentaire administré aux larves n'a pas eu d'effet significatif sur la diversité et la richesse intraspécifique de leurs symbiotes intestinaux. Seul la proportion relative a été impactée chez H. subflexa où l’ordre des Bacillales composait seulement 0,27% de la communauté totale sur le contrôle mais représentaient 4% et 31% lorsque les larves étaient exposées à l’extrait de withanolide et au withaferin A respectivement. Ces résultats suggèrent que H. subflexa n’a pas de communauté bactérienne résidente mais plutôt transitoire. Il a ensuite été montré que l'expression du gène de l'attacine-1 n'était pas affectée par les traitements alors le gène du lysozyme 1 de type i était surexprimé de manière significative après 24 heures chez les deux espèces comparé au temps zéro. Cependant, l’expression des deux gènes de l’immunité ne différait pas dans les conditions de traitement par rapport au contrôle, et ce pour tous les temps étudiés.

Hyalesthes obsoletus, vektor biljnog patogena 'Candidatus (Ca.) Phytoplasma solani', smatra se polifagnom štetočinom od ekonomskog značaja u centralnoj Evropi i Mediteranu. Istraživanjima sprovedenim u jugoistočnoj Evropi, koja gravitira centru arela vrste i gde je zabeležen značajan broj 'Ca. P. solani'- uslovljenih biljnih bolesti, utvrđeno je postojanje četiri asocijacije vektora sa biljkama dualnim domaćinima: Convolvulus arvensis (Ca), Urtica dioica (Ud), Vitex agnus-castus (Vac) i Crepis foetida (Cf). Populaciono-genetičkim analizama mitohondrijskih i nuklearnih markera (mikrosatelita) utvrđena je kriptična diferencijacija simpatričkih (uključujući sintopske) i geografski udaljenih H. obsoletus populacija na tri filogenetičke linije uslovljene biljkom domaćinom: (1) Ca-Ud, (2) Vac i (3) Cf. Pored jasne diferencijacije na mitohondrijskim genima (1.1% - 1.5%) i mikrosatelita koji potvrđuju izdvajanje populacija u jedan od tri klastera prema biljci domaćinu (pripadnost >90%), podršku za izdizanje genetičke divergencije H. obsoletus sensu lato na nivo kriptične specijacije daje registrovana distanca u odnosu na morfološki najsrodniju vrstu - Hyalesthes thracicus (2.1% - 3.3%). Posledice specijalizacije i diferencijacije H. obsoletus sensu lato prema biljkama domaćinima na epidemiologiju 'Ca. P. solani' procenjene su multigenskom karakterizacijom izolata fitoplazme detektovanih (1) in situ u prirodnim epidemiološkim sistemima mediteranskih vinograda i (2) eksperimentima unakrsne inokulacije biljaka putem prirodno inficiranih populacija vektora. Potvrđena je osnovna epidemiološka divergencija 'Ca. P. solani' na tuf-a/-ab i tuf-b cikluse vezane za Ud i Ca uz ukrštanje sa Vac-uzrokovanom tuf-b epidemiologijom i utvrđena kompleksnost tuf-b epidemiologije u kojoj učestvuje i treća genetička linija vektora, H. obsoletus ex Cf, kao i sama biljka dualni domaćin - C. foetida. The cixiid planthopper Hyalesthes obsoletus is generally considered as a polyphagous vector of 'Candidatus (Ca.) P. solani' associated with numerous wild and cultivated plants in central Europe and Mediterranean. Research conducted in southeastern Europe, the distribution centre of H. obsoletus and the area of most 'Ca. P. solani'-inflicted crop diseases, points toward specific dual host-plant associations with: Convolvulus arvensis (Ca), Urtica dioica (Ud), Vitex agnus-castus (Vac) and Crepis foetida (Cf). Population-genetic analysis of mitochondrial and nuclear genetic markers (microsatellites) have revealed cryptic differentiation between sympatric (including syntopic) and geographically distant H. obsoletus populations into three phylogenetic lineages delineated by host-plant preference: 1) Ca-Ud, 2) Vac i 3) Cf. Cryptic species diversification within H. obsoletus sensu lato is supported by the genetic divergence of mitochondrial genes (1.1% - 1.5%), microsatellites that confirm population clustering into three genetic groups associated with specific host-plant (average assignment >90%) and genetic distances among host-associated H. obsoletus metapopulations comparable to the most closely related, morphologically distinguishable species - Hyalesthes thracicus (2.1% - 3.3%). Consequences of the H. obsoletus sensu lato differentiation on the epidemiology of 'Ca. P. solani' are assessed by multilocus genotyping of the phytoplasma isolates detected (1) in situ in natural epidemiological systems of the Mediterranean vineyards and (2) plant inoculation experiments using naturally infected vector populations. Basic 'Ca. P. solani' epidemiological divergence into tuf-a/-ab and tuf-b cycles, each associated with Ud and Ca, respectively, is confirmed with evidences of intermixing Vac-induced tuf-b epidemiology, while complexity of the tuf-b epidemiology is further evidenced through influence of the third genetic lineage of the vector H. obsoletus ex C. foetida and its dual host-plant.

Nutritional symbioses play a central role in the ability of insects to thrive on unbalanced diets and in ensuring their evolutionary success. A genomic model for nutritional symbiosis comprises the hemipteran Acyrthosiphon pisum, and the gamma-3-proteobacterium, Buchnera aphidicola, with genomes encoding highly integrated metabolic pathways. A. pisum feeds exclusively on plant phloem sap, a nutritionally unbalanced diet highly variable in composition, thus raising the question of how this symbiotic system responds to nutritional stress. We addressed this by combining transcriptomic, phenotypic and life history trait analyses to determine the organismal impact of deprivation of tyrosine and phenylalanine. These two aromatic amino acids are essential for aphid development, are synthesized in a metabolic pathway for which the aphid host and the endosymbiont are interdependent, and their concentration can be highly variable in plant phloem sap. We found that this nutritional challenge does not have major phenotypic effects on the pea aphid, except for a limited weight reduction and a 2-day delay in onset of nymph laying. Transcriptomic analyses through aphid development showed a prominent response in bacteriocytes (the core symbiotic tissue which houses the symbionts), but not in gut, thus highlighting the role of bacteriocytes as major modulators of this homeostasis. This response does not involve a direct regulation of tyrosine and phenylalanine biosynthetic pathway and transporter genes. Instead, we observed an extensive transcriptional reprogramming of the bacteriocyte with a rapid down-regulation of genes encoding sugar transporters and genes required for sugar metabolism. Consistently, we observed continued overexpression of the A. pisum homolog of RRAD, a small GTPase implicated in repressing aerobic glycolysis. In addition, we found increased transcription of genes involved in proliferation, cell size control and signaling. We experimentally confirmed the significance of these gene expression changes detecting an increase in bacteriocyte number and cell size in vivo under tyrosine and phenylalanine depletion. Our results support a central role of bacteriocytes in the aphid response to amino acid deprivation: their transcriptional and cellular responses fine-tune host physiology providing the host insect with an effective way to cope with the challenges posed by the variability in composition of phloem sap. ispartof: FRONTIERS IN PHYSIOLOGY vol:9 issue:OCT ispartof: location:Switzerland status: published

First record of the crape myrtle aphid Sarucallis kahawaluokalani (Kirkaldy) and its natural enemies in Guadeloupe (Hemiptera, Aphididae). The aphid Sarucallis kahawaluokalani (Kirkaldy) is recorded for the first time from Guadeloupe and several predator species associated with it are mentioned. All the identified species are illustrated., Le puceron Sarucallis kahawaluokalani (Kirkaldy) est signalé pour la première fois de Guadeloupe et plusieurs espèces de prédateurs qui lui sont associées sont mentionnées. Toutes les espèces identifiées sont illustrées., Étienne Jean, Michel Bruno, Grapin Cyril. Premier signalement du puceron Sarucallis kahawaluokalani (Kirkaldy, 1907) et de ses ennemis naturels en Guadeloupe (Hemiptera, Aphididae). In: Bulletin de la Société entomologique de France, volume 123 (4),2018. pp. 447-450.

Brassicogethes salvan (Audisio et al. Insect Systematics and Evolution, 34, 121) is certainly among the most important and unexpected recent discoveries in the European beetle fauna. The species was initially described from a couple of unidentified specimens collected in 1912 on the Maritime Alps (NW Italy). Despite a long series of attempts to recollect the species at the type locality (Rovina Lake, Mount Argentera Massif, Cuneo Province, Piedmont, NW Italy) and several neighbouring areas of the SW Alps between 2002 and 2016, no specimens of this species were found. We re-discovered B. salvan in a small high valley of the Regional Natural Park of the Maritime Alps, a few dozen kilometers from the type locality. The previously unknown larval host-plant as Descurainia tanacetifolia (L.) Rchb., Brassicaceae was determined. Some unusual life history traits were also observed. In an effort to yield a suitable taxonomic placement for this species, we present a partial preliminary molecular phylogeny for this species and related taxa. A discussion regarding some issues about its actual and potential geographic distribution in southern France and northwestern Italy is also provided. We propose an EN (Endangered) classification for this species following the IUCN criteria, and discuss aspects of its rather problematic conservation biology.

Hyalesthes obsoletus, vektor biljnog patogena 'Candidatus (Ca.) Phytoplasmasolani', smatra se polifagnom štetočinom od ekonomskog značaja u centralnojEvropi i Mediteranu. Istraživanjima sprovedenim u jugoistočnoj Evropi, kojagravitira centru arela vrste i gde je zabeležen značajan broj 'Ca. P. solani'-uslovljenih biljnih bolesti, utvrđeno je postojanje četiri asocijacije vektora sabiljkama dualnim domaćinima: Convolvulus arvensis (Ca), Urtica dioica (Ud), Vitexagnus-castus (Vac) i Crepis foetida (Cf). Populaciono-genetičkim analizamamitohondrijskih i nuklearnih markera (mikrosatelita) utvrđena je kriptičnadiferencijacija simpatričkih (uključujući sintopske) i geografski udaljenih H.obsoletus populacija na tri filogenetičke linije uslovljene biljkom domaćinom: (1)Ca-Ud, (2) Vac i (3) Cf. Pored jasne diferencijacije na mitohondrijskim genima(1.1% - 1.5%) i mikrosatelita koji potvrđuju izdvajanje populacija u jedan od triklastera prema biljci domaćinu (pripadnost >90%), podršku za izdizanje genetičkedivergencije H. obsoletus sensu lato na nivo kriptične specijacije daje registrovanadistanca u odnosu na morfološki najsrodniju vrstu - Hyalesthes thracicus (2.1% -3.3%). Posledice specijalizacije i diferencijacije H. obsoletus sensu lato premabiljkama domaćinima na epidemiologiju 'Ca. P. solani' procenjene su multigenskomkarakterizacijom izolata fitoplazme detektovanih (1) in situ u prirodnimepidemiološkim sistemima mediteranskih vinograda i (2) eksperimentimaunakrsne inokulacije biljaka putem prirodno inficiranih populacija vektora.Potvrđena je osnovna epidemiološka divergencija 'Ca. P. solani' na tuf-a/-ab i tuf-bcikluse vezane za Ud i Ca uz ukrštanje sa Vac-uzrokovanom tuf-b epidemiologijom iutvrđena kompleksnost tuf-b epidemiologije u kojoj učestvuje i treća genetičkalinija vektora, H. obsoletus ex Cf, kao i sama biljka dualni domaćin - C. foetida. The cixiid planthopper Hyalesthes obsoletus is generally considered as apolyphagous vector of 'Candidatus (Ca.) P. solani' associated with numerous wildand cultivated plants in central Europe and Mediterranean. Research conducted insoutheastern Europe, the distribution centre of H. obsoletus and the area of most'Ca. P. solani'-inflicted crop diseases, points toward specific dual host-plantassociations with: Convolvulus arvensis (Ca), Urtica dioica (Ud), Vitex agnus-castus(Vac) and Crepis foetida (Cf). Population-genetic analysis of mitochondrial andnuclear genetic markers (microsatellites) have revealed cryptic differentiationbetween sympatric (including syntopic) and geographically distant H. obsoletuspopulations into three phylogenetic lineages delineated by host-plant preference:1) Ca-Ud, 2) Vac i 3) Cf. Cryptic species diversification within H. obsoletus sensu latois supported by the genetic divergence of mitochondrial genes (1.1% - 1.5%),microsatellites that confirm population clustering into three genetic groupsassociated with specific host-plant (average assignment >90%) and geneticdistances among host-associated H. obsoletus metapopulations comparable to themost closely related, morphologically distinguishable species - Hyalesthes thracicus(2.1% - 3.3%). Consequences of the H. obsoletus sensu lato differentiation on theepidemiology of 'Ca. P. solani' are assessed by multilocus genotyping of thephytoplasma isolates detected (1) in situ in natural epidemiological systems of theMediterranean vineyards and (2) plant inoculation experiments using naturallyinfected vector populations. Basic 'Ca. P. solani' epidemiological divergence intotuf-a/-ab and tuf-b cycles, each associated with Ud and Ca, respectively, isconfirmed with evidences of intermixing Vac-induced tuf-b epidemiology, whilecomplexity of the tuf-b epidemiology is further evidenced through influence of thethird genetic lineage of the vector H. obsoletus ex C. foetida and its dual host-plant.