Western European Populations of the Ichneumonid Wasp Hyposoter didymator Belong to a Single Taxon

Hyposoter didymator (Hymenoptera, Ichneumonidae) is a generalist solitary endoparasitoid of noctuid larvae. In the present work, we tested whether populations of H. didymator were divided in several genetically distinct taxa as described for many other generalist parasitoid species, and whether differences in H. didymator parasitism rates were explained by the insect host species and/or by the plant on which these hosts were feeding on. The genetic analysis of natural populations collected in different regions in France and Spain on seven different insect hosts and seven different host plants (775 individuals) showed that H. didymator populations belong to a unique single taxon. However, H. didymator seems to be somewhat specialized. Indeed, in the fields it more often parasitized Helicoverpa armigera compared to the other host species collected in the present work. Also, H. didymator parasitism rates in field conditions and semi-field experimental studies were dependent on the host plants on which H. armigera larvae are feeding. Still, H. didymator can occur occasionally on non-preferred noctuid species. One hypothesis explaining the ability of H. didymator to switch hosts in natura could be related to fluctuating densities of the preferred host over the year; this strategy would allow the parasitoid to avoid seasonal population collapses

La clarification des compétences des collectivités territoriales ou l’improbable innovation

L’article discute les récentes réformes visant à augmenter l’efficience des collectivités locales, composées de trois volets spécifiques : leur représentativité, leur financement et leurs compétences. Centré sur ce dernier aspect, il explique d’abord comment, selon les différents échelons locaux, et l’héritage centralisateur de l’Etat français, les attributions de chacune semblent se distribuer aisément. Il insiste ensuite sur les agrégats observables et les incohérences induites, venant opacifier les rôles et responsabilités de chaque acteur. Il esquisse enfin les conditions de relative autonomie de certains niveaux territoriaux, face au pouvoir (supra)national et entre eux, en débordant les attributs de spécialité et d’exclusivité du concept de compétence, afin de laisser les décisions et les structures se configurer au gré des besoins.The article presents and discusses the recent reforms aiming to increase the efficiency of local authorities concerning three specific aspects: representativeness, funding and expertise. Focu­sing on the latter, it explains how, depending on the different local levels and considering the centralizing heritage of French state, each one’s attribution seems clearly defined. It then em­pha­sizes the observable aggregates and the resulting incoherences which tend to opacify the roles and responsabilities of the different entities. It then explains the relative autonomy of some territorial levels against State power and against each other, exceeding their attributes of expertise and the exclusivity of the concept of competence, leaving decisions and structures to adapt

Influence des propriétés physicochimiques d'hydroxyapatites sur le comportement cellulaire. Effect of the physicochemical characteristics of hydroxyapatite on the cell behaviour.

soumis à ITBMLes biocéramiques phosphocalciques sont utilisées comme substitut osseux depuis de nombreuses décennies. Le descellement aseptique après une arthroplastir totale est un problème majeur en chirurgie orthopédique. Les particules d'hydroxyapatite issues du biomatériau ont été identifiées comme cause majeure de l'échec de l'implantation. Pour cette raison et afin d'augmenter la longévité des implants aprés une arthroplastie, des recherches dans le domaine de ces particules relarguées sont donc nécessaires. Dans cet article, nous discutons de la réponse cellulaire (principalement des monocytes/macrophages qui sont parmi les premières cellules à coloniser le site inflammatoire) après exposition à des particules ayant des caractéristiques différentes (taille, forme, température de traitement et composition chimique). Les caractéristiques les plus importantes sont d'abord la forme puis la taille des particules. En effets, les particules sous forme d'aiguille induisent une plus grande production de médiateurs de l'inflammation et elles sont plus toxiques pour les cellules. La température de traitement semble être moins importante même si elle joue un rôle important dans les processus de dissolution/précipitation. Peu de choses sont connues sur l'effet d'ions dopant l'hydroxyapatite (comme le zinc, le strontium,...) sur la réponse cellulaire. Les premières données montrent que le dopage semble bénéfique pour les cellules

Trace element transfer from two contaminated soil series to Medicago sativa and one of its herbivores, Spodoptera exigua

Alfalfa was cultivated in two potted soil series obtained from two sandy soils contaminated by Cu (SM) and metal(loids)/PAH (CD). Shoot production was monitored for 8 weeks. Then, larvae of Spodoptera exigua were reared on alfalfa of both soil series for eight days. A biotest (using Phaseolus vulgaris) was used to assess the soil phytotoxicity. Increasing soil contamination reduced P. vulgaris growth, but alfalfa growth was only reduced on the SM soil series. Exposure to the SM soil was mirrored by shoot Cu and Cr concentrations of alfalfa (respectively, in mg kg -1 DW, Cu and Cr ranged from 11.9 and 0.4 in the CTRL soil to 98.5 and 1.2 in the SM one). Exposure to the CD soil series was mirrored by shoot Zn concentrations (i.e. 48 to 91.6 mg kg-1 DW). Internal metal(loid) concentrations of S. exigua remained generally steady across both soil series (respectively Cd 0.05-0.16, Cr 0.5-3.3, Cu 5.8-98.5, Ni 0.6-1.6, Pb 0.4-1.3 and Zn 57-337 mg kg-1 DW), and most of the associated transfer factors were lower than 1. Here, due to the excluder phenotype of alfalfa across our TE contamination gradients, S. exigua could cope with high total metal(loid) concentration in both contaminated soils

Isolation and characterization of microsatellites in the endoparasitic ichneumonid wasp carrying a polydnavirus Hyposoter didymator

The wasp Hyposoter didymator (Hymenoptera, Ichneumonidae) parasitizes several agricultural pest moths and could therefore be used in biological control. The 454 FLX Titanium pyrosequencing technology was used to define two distinct sets of multiplex combining 14 polymorphic microsatellite loci: 10 (referred to as HD) located within the genome of H. didymator and 4 (referred to as HdIV) located within the Ichnovirus genome which is integrated into the wasp genome. Genotyping of two populations collected in France on Helicoverpa armigera revealed that most of the loci are independent and at Hardy-Weinberg equilibrium

Increase in taxonomic assignment efficiency of viral reads in metagenomic studies

BGPI Cirad : équipe 7Metagenomics studies have revolutionized the field of biology by revealing the presence of many previously unisolated and uncultured micro-organisms. However, one of the main problems encountered in metagenomic studies is the high percentage of sequences that cannot be assigned taxonomically using commonly used similarity-based approaches (e.g. BLAST or HMM). These unassigned sequences are allegorically called "dark matter" in the metagenomic literature and are often referred to as being derived from new or unknown organisms. Here, based on published and original metagenomic datasets coming from virus-like particle enriched samples, we present and quantify the improvement of viral taxonomic assignment that is achievable with a new similarity-based approach. Indeed, prior to any use of similarity based taxonomic assignment methods, we propose assembling contigs from short reads as is currently routinely done in metagenomic studies, but then to further map unassembled reads to the assembled contigs. This additional mapping step increases significantly the proportions of taxonomically assignable sequence reads from a variety plant, insect and environmental (estuary, lakes, soil, feces) - of virome studies

Mutagenesis of both prophenoloxidases in the fall armyworm induces major defects in metamorphosis

International audienceUpon infection, the phenoloxidase system in arthropods is rapidly mobilized and constitutes a major defense system against invaders. The activation of the key enzymes prophenoloxidase (PPO) and their action in immunity through melanization and encapsulation of foreign bodies in hemolymph has been described in many insects. On the other hand, little is known about PPOs involvement in other essential functions related to insect development. In this paper, we investigated the function of the two PPOs of the crop pest, Spodoptera frugiperda (PPO1 and PPO2). We show that PPOs are mainly expressed in hemocytes with the PPO2 expressed at higher levels than the PPO1. In addition, these two genes are expressed in the same tissue and at the same stages of insect development. Through the generation of loss-of-function mutants by CRISPR/Cas9 method, we show that the presence of PPOs is essential for the normal development of the pupa and the survival of the insect