Biology subjects

Herniou, E. A.

Publications and source records attributed to Herniou, E. A..

6 recordsLinked to original sources

bioRxiv2025

A solinvivirus induces cellular antiviral response and reduces the lifespan of adult Hermetia illucens (black soldier flies)

Viral pathogens pose an emerging threat to the sustainability of insect mass-rearing systems, yet remain understudied in key species like the black soldier fly (BSF, Hermetia illucens). Although multiple viral sequences have been reported in BSF, their role in disease has not been established until now. Here, we provide the first in vivo characterisation of Hermetia illucens solinvivirus (HiSvV), confirming its role as a viral entomopathogen of BSF. Metatranscriptomic analysis of a diseased colony revealed a high viral load attributable to HiSvV. We successfully isolated the virus and developed injection- and oral-based infection assays to investigate replication, tissue tropism, transmission and risk of mortality. HiSvV replicated in inoculated adults, induced premature mortality in flies, and was transmitted both horizontally and vertically. Infected flies also mounted a broad antiviral response, supporting active pathogenesis. These findings establish HiSvV as the first confirmed viral pathogen of BSF and underscore the urgent need for viral surveillance and experimental tools to safeguard industrial insect rearing.

microbiology↗

bioRxiv2024

Optimization of screening methods leads to the discovery of new viruses in black soldier flies (Hermetia illucens)

Virus discovery in mass-reared insects is a growing topic of interest due to outbreak risks and for insect welfare concerns. In the case of black soldier flies (BSF), pioneering bioinformatic studies have uncovered exogenous viruses from the orders Ghabrivirales and Bunyavirales, as well as endogenous viral elements from five virus families. This prompted further virome investigation of BSF metagenomes and metatranscriptomes, including from BSF individuals displaying signs and symptoms of disease. In this study, we describe five newly discovered viruses from the families Dicistroviridae, Iflaviridae, Rhabdoviridae, Solinviviridae, and Inseviridae. These viruses were detected in BSF from multiple origins, outlining a diversity of naturally occurring viruses associated with BSF. This viral community may also include BSF pathogens. The growing list of viruses found in BSF allowed the development of molecular detection tools which could be used for viral surveillance, both in mass-reared and wild populations of BSF.

microbiology↗

bioRxiv2023

Polinton-like Viruses Associated with Entomopoxviruses Provide Insight into Replicon Evolution

Polinton-like viruses (PLVs) are a diverse group of small integrative dsDNA viruses that infect diverse eukaryotic hosts. Many PLVs are hypothesized to parasitize viruses in the phylum Nucleocytoviricota for their own propagation and spread. Here we analyze the genomes of novel PLVs associated with the occlusion bodies of entomopoxvirus (EV) infections of two separate lepidopteran hosts. The presence of these elements within EV occlusion bodies suggests that they are the first known hyperparasites of poxviruses. We find that these PLVs belong to two distinct lineages that are highly diverged from known PLVs. These PLVs possess mosaic genomes, and some essential genes share homology with mobile genes within EVs. Based on this homology and observed PLV mosaicism, we propose a mechanism to explain the turnover of PLV replication and integration genes.

genomics↗

bioRxiv2023

Non-destructive DNA metabarcoding of arthropods using collection medium from passive traps

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

molecular biology↗

bioRxiv2021

Climate-induced forest dieback drives compositional change in insect communities that is concentrated amongst rare species

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

ecology↗

bioRxiv2017

Genomic divergence footprints in the bracovirus of Cotesia sesamiae identified by targeted re-sequencing approach

The African parasitoid wasp Cotesia sesamiae is structured in contrasted populations showing differences in host range and the recent discovery of a specialist related species, C. typhae, provide a good framework to study the mechanisms that link the parasitoid and their host range. To investigate the genomic bases of divergence between these populations, we used a targeted sequencing approach on 24 samples. We targeted a specific genomic region encoding the bracovirus, which is deeply involved in the interaction with the host. High sequencing coverage was obtained for all samples allowing the study of genetic variations between wasp populations and species. Combining population genetic estimations, the diversity ({pi}), the relative differentiation (FST) and the absolute differentiation (dxy), and branch-site dN/dS measures, we identified six divergent genes impacted by positive selection belonging to different gene families. These genes are potentially involved in host adaptation and in the specialization process. Fine scale analyses of the genetic variations also revealed deleterious mutations and large deletions on certain genes inducing pseudogenization and loss of function. These results highlight the crucial role of the bracovirus in the molecular interactions between the wasp and its hosts and in the evolutionary processes of specialization.

evolutionary biology↗