Biology subjects

Montarsi, F.

Publications and source records attributed to Montarsi, F..

4 recordsLinked to original sources

bioRxiv2021

dynamAedes: a unified modelling framework for invasive Aedes mosquitoes

O_LIMosquito species belonging to the genus Aedes have attracted the interest of scientists and public health officers for their invasive species traits and efficient capacity of transmitting viruses affecting humans. Some of these species were brought outside their native range by human activities such as trade and tourism, and colonised new regions thanks to a unique combination of eco-physiological traits. C_LIO_LIConsidering mosquito physiological and behavioural traits to understand and predict the spatial and temporal population dynamics is thus a crucial step to develop strategies to mitigate the local densities of invasive Aedes populations. C_LIO_LIHere, we synthesised the life cycle of four invasive Aedes species (Ae. aegypti, Ae. albopictus, Ae. japonicus and Ae. koreicus) in a single multi-scale stochastic modelling framework which we coded in the R package dynamAedes. We designed a stage-based and time-discrete stochastic model driven by temperature, photo-period and inter-specific larval competition that can be applied to three different spatial scales: punctual, local and regional. These spatial scales consider different degrees of spatial complexity and data availability, by accounting for both active and passive dispersal of mosquito species as well as for the heterogeneity of the input temperature data. C_LIO_LIOur overarching aim was to provide a flexible, open-source and user-friendly tool rooted in the most updated knowledge on species biology which could be applied to the management of invasive Aedes populations as well as for more theoretical ecological inquiries. C_LI

ecology↗

bioRxiv2021

Aedes koreicus, a vector on the rise: pan-European genetic patterns, mitochondrial and draft genome sequencing

BackgroundThe mosquito Aedes koreicus (Edwards, 1917) is a recent invader on the European continent that was introduced to several new places since its first detection in 2008. Compared to other exotic Aedes mosquitoes with public health significance that invaded Europe during the last decades, this species biology, behavior, and dispersal patterns were poorly investigated to date. Methodology/Principal FindingsTo understand the species population relationships and dispersal patterns within Europe, a fragment of the COI gene was sequenced from 130 mosquitoes, collected from five countries where the species has been introduced and/or established. Oxford Nanopore and Illumina sequencing techniques were combined to generate the first complete nuclear and mitochondrial genomic sequences of Ae. koreicus from the European region. The complete genome of Ae. koreicus is 879 Mb. COI haplotype analyses identified five major groups (altogether 31 different haplotypes) and revealed a large-scale dispersal pattern between European Ae. koreicus populations. Continuous admixture of populations from Belgium, Italy, and Hungary was highlighted, additionally, haplotype diversity and clustering clearly indicate a separation of German sequences from other populations, pointing to an independent introduction of Ae. koreicus to Europe. Finally, a genetic expansion signal was identified, suggesting the species might be present in more locations than currently detected. Conclusions/SignificanceOur results highlight the importance of genetic research of invasive mosquitoes to understand general dispersal patterns, reveal main dispersal routes and form the baseline of future mitigation actions. The first complete genomic sequence also provides a significant leap in the general understanding of this species, opening the possibility for future genome-related studies, such as the detection of Single Nucleotide Polymorphism markers. Considering its public health importance, it is crucial to further investigate the species population genetic dynamic, including a larger sampling and additional genomic markers. Author SummaryIn the present context of globalization and changing environment, the rapid spread of Invasive Mosquito Species (IMS) across Europe represents a serious public health threat because some species are competent vectors for several pathogens. A better knowledge of the IMS population relationships, demographic trends, and dispersal patterns can help the relevant authorities mitigating further spread. Aedes koreicus is an IMS that invaded the continent and has been expanding its geographic range over the last decade. In the present study, one of the most popular DNA marker (COI) was used to investigate the pan-European haplotype diversity and phylogenetic relatedness within and between Ae. koreicus populations. Also, the first complete mitochondrial genome and draft nuclear genome of Ae. koreicus were generated using combined high-throughput sequencing techniques (Oxford Nanopore, Illumina). This provides a significant leap in the general understanding of this species and opens the possibility for future genomic studies.

genetics↗

bioRxiv2020

Mosquitoes of the Maculipennis complex in Northern Italy

The correct identification of mosquito vectors is often hampered by the presence of morphologically indiscernible sibling species. The Maculipennis complex is one of these groups which include both malaria vectors of primary importance and species of low/negligible epidemiological relevance, of which distribution data in Italy are outdated. Our study was aimed at providing an updated distribution of Maculipennis complex in Northern Italy through the sampling and morphological/molecular identification of specimens from five regions. The most abundant species was Anopheles messeae s.l. (2032), followed by Anopheles maculipennis s.s. (418), Anopheles atroparvus (28) and Anopheles melanoon (13). The distribution of species was characterized by Ecological Niche Models (ENMs), fed by recorded points of presence. ENMs provided clues on the ecological preferences of the detected species, with An. messeae s.l. linked to stable breeding sites and An. maculipennis s.s. more associated to ephemeral breeding sites. We demonstrate that historical Anopheles malaria vectors are still widespread in Northern Italy.

ecology↗

bioRxiv2020

Phylogenomics reveals that Asaia symbionts from insects underwent convergent genome reduction, preserving an insecticide-degrading gene

The mosquito microbiota is composed by several lineages of microorganisms whose ecological roles and evolutionary histories have yet to be investigated in depth. Among these microorganisms, Asaia bacteria play a prominent role, given its abundance in the gut, reproductive organs and salivary glands of different mosquito species, while its presence has also been reported in several other insects. Notably, Asaia has great potential as a tool for the control of mosquito-borne diseases. Here, we present a wide phylogenomic analysis of Asaia strains isolated from different species of mosquito vectors and from different populations of the Mediterranean fruit fly (medfly) Ceratitis capitata, an insect pest of worldwide economic importance. We show that phylogenetically distant lineages of Asaia experienced independent genome reductions, despite following a common pattern, characterized by the early loss of genes involved in genome stability. This result highlights the role of specific metabolic pathways in the symbiotic relationship between Asaia and the insect host. Finally, we discovered that all but one of the Asaia strains included in the study possess the pyrethroid hydrolase gene. Phylogenetic analysis revealed that this gene is ancestral in Asaia, strongly suggesting that it played a role in the establishment of the symbiotic association between these bacteria and the mosquito hosts. We propose that this gene from the symbiont contributed to initial pyrethroid resistance in insects harboring Asaia, also considering the widespread production of pyrethrins by several plants. ImportanceWe have studied genome reduction within several strains of the insect symbiont Asaia, isolated from different species/strains of mosquito and medfly. Phylogenetically distant strains of Asaia, despite following a common pattern involving the loss of genes related to genome stability, have undergone independent genome reductions, highlighting the peculiar role of specific metabolic pathways in the symbiotic relationship between Asaia and its host. We also show that the pyrethroid hydrolase gene is present in all the Asaia strains isolated except for the South American malaria vector An. darlingi, for which resistance to pyrethroids has never been reported, suggesting a possible involvement of Asaia in determining the resistance to insecticides.

microbiology↗