Latest Publications

By Carlotta Savio

In this study we observed the effects of the entomopathogen Bacillus thuringiensis sv morrisoni biovar tenebrionis (Btt) spores and toxin on T. molitor larvae survival and growth and its persistence in larvae and in frass. Larvae of different body weight were exposed by free feeding to a range of Btt spore – crystal concentrations spiked to wheat bran (WB) for mimiking mass rearing conditions and for observing the susceptibility of to the pathogens of several larval instars. In mass-rearing conditions, the presence of the entomopathogen Bacillus thuringiensis serovar morrisoni biovar tenebrionis affects T. molitor performance. Moreover, the study highlights the direct correlation between the weight class of the larvae and the susceptibility to Btt. Responses to Btt infection in terms of FCR and weight gain showed lower performance in presence of the pathogen. Btt dynamics in T. molitor larvae along the infection show the ability of Btt to persist in the alive larva. This may suggest a role of the mealworm gut microbiota in the protection against Btt bacteria and Cry toxin, when sub-lethal doses are applied. In addition, it indicates a certain level of persistence of Btt and therefore a risk for infection of more susceptible larval weight classes, suggesting the need to monitor the detection of Btt in the T. molitor rearing setup.

Figure 1. Phase-contrast light microscopy image of Btt, bacilli and spore (orange arrow), toxin crystal (blue arrow) and Tm larvae in the cup used for the assay.

Read the full-length article here:
https://doi.10.1163/23524588-00001028

or follow us on LinkedIn for updates about our research projects: www.linkedin.com/in/carlotta-savio-48930a140


By Carlotta Savio

In this publication we offer an overview on microbial symbionts dynamics in yellow mealworm larvae fed with diet differring in protein content, added with two bacterial probiotic species and challenged with pathogens.

The provision of probiotic bacteria and higher protein content in the diet increased the survivability of the larvae challenged with fungal and bacterial entomopathogens. The bacterial strain acting as probiotic was originally a gut symbiont of the yellow mealworm population. The other probiotic bacteria not isolated from the insect did not presented beneficial activities, highligting the importance of the origins of the probiotic strains for observing protective results and improved fitness on insect population.

Moreover, the dynamics of the microbiota composition indicated the inability of both the added pathogens and probiotics to persist or increase in abundance in the larvae after their provision ended, indicating the importance of the microbial community homeostasis in insect health. Overall, probiotic bacteria could be applied in insect mass-rearing facilities as preventive treatment to reduce the risk of entomopathogens infection.

Read the full-length article here: https://doi.org/10.3389/finsc.2024.133452610.3389/finsc.2024.1334526

or follow us on LinkedIn for updates about our research projects: www.linkedin.com/in/carlotta-savio-48930a140


By Luis Henrandez Pelegrin

In this publication, we provide valuable insights into the viral tropism and transmission of RNA viruses in the medfly. The presence of covert viral infections in insects has been extensively reported. These infections can be transmitted in insect populations via two main routes: vertical from parents to offspring, or horizontal between nonrelated individuals. In the agricultural pest Ceratitis capitata, also known as the Mediterranean fruit fly or medfly, thirteen covert RNA viruses have been described to date. Despite most of these viruses are correlated with covert infections with no obvious symptoms, infection with Ceratitis capitata nora virus is known to impair medfly development, highlighting the potential of RNA viruses for the control of medfly pests.

Viral RNA detected by fluorescence in situ hybridization (FISH)
on medfly ovaries and testes.

To better understand the virus-host interactions, we uncovered which tissues are infected with covert RNA viruses in the medfly and which is the preferred transmission route of these viruses. Altogether, our results indicated that vertical and horizontal transmission can occur simultaneously, although each virus is transmitted more efficiently following one of these routes. As might be expected, our results indicated an association between the tropism of the RNA virus and the preferred route of transmission. Overall, the results presented in our manuscript set the basis for understanding how viruses are established and maintained in medfly populations.

Read the full-length article here: https://doi.org/10.1128/jvi.00108-24 or follow us on LinkedIn for updates about our research projects: Luis Hernández Pelegrín | LinkedIn


By Jirka Manuel Petersen

In our recent publication, “Nudiviruses in Free-living and Parasitic Arthropods: Evolutionary Taxonomy,” we review the latest discoveries within the virus family Nudiviridae. Utilizing a data-driven virus discovery approach, we identified multiple nudiviral elements and complete genomes in publicly available Next Generation Sequencing (NGS) datasets. Notably, we recovered full genomes of novel nudiviruses from the sequencing data of ectoparasitic insects, such as fleas and lice, which were previously unassociated with nudivirus infections. The newly obtained molecular information from our data-mining approach, combined with recently deposited data from other sources, necessitated an updated taxonomic and evolutionary review of this virus family. To achieve a greater understanding of the diversity and evolutionary history of the Nudiviridae, we developed a novel phylogeny. Our updated analyses led us to propose a new taxonomic structure for the Nudiviridae, suggesting two new viral genera: Zetanudivirus and Etanudivirus, which include lice-infecting members. Our evolutionary analysis indicates that significant turning points in nudivirus evolution may have occurred in ancestral lice or fleas, possibly on feathered dinosaurs (90 – 170 million years ago). Finally, we discuss the ecological role of nudiviruses, including their potential for veterinary applications to control ectoparasite infestations on avian and mammalian hosts.

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