Biology subjects

Bonizzoni, M.

Publications and source records attributed to Bonizzoni, M..

At least 19 recordsLinked to original sources

bioRxiv2026

The MosAICo ecosystem: bridging the taxonomic gap in vector surveillance with real-time entomological artificial intelligence

Mosquito-borne diseases represent an escalating global health threat, driven by climate change, urbanization, and the spread of invasive vectors into new territories. Effective surveillance is constrained by a critical taxonomic impediment: the rate of specimen collection far outpaces the capacity of expert entomologists to process and identify trap catches. To address this bottleneck we developed MosAICo, an integrated AI-powered ecosystem for automated mosquito species identification designed for real-world, national-scale entomological surveillance. The system combines a standardized benchtop imaging device with MosAICo-Net, a deep learning pipeline enabling efficient and principled open-set recognition and uncertainty quantification. Trained and evaluated on 12, 499 specimens spanning 15 species collected across Italy, the model identifies seven priority vector species while explicitly rejecting out-of-distribution specimens. On a geographically stratified held-out test set, MosAICo-Net achieved over 90% accuracy on target species, and an AUROC of 0.96 for out-of-distribution detection. Field validation across 20 Italian surveillance sites confirmed these results: 94% micro accuracy on 1, 470 field-collected target specimens and strong agreement with expert manual counts ([Formula] = 0.66). To assess cross-geographic generalizability, the system was further evaluated on 118 Aedes albopictus specimens collected at the fringe of the species invasion front in Ghana: a 97.4% accuracy with only a single specimen escalated to expert review, suggests that MosAICo is well-suited for deployment in distant and epidemiologically critical regions. The system processes up to 82 specimens per image, matching expert throughput at constant speed regardless of taxonomic complexity. By embedding uncertainty-aware AI within a standardized hardware-software pipeline, MosAICo acts as a scalable force multiplier for public health entomology, freeing expert attention for rare, invasive, or ambiguous specimens that require human validation.

ecology↗

bioRxiv2026

Evidence of thermal selection from experimental evolution in the arboviral vector Aedes albopictus

The extent to which phenotypic plasticity and adaptation are coupled during ectotherm thermal evolution is poorly understood. We carried out thermal experimental evolution for 20 generations in the arboviral vector Aedes albopictus, an efficient invasive species that has newly conquered climatically diverse regions in the past few decades. During acclimation (one generation of evolution) we saw accelerated development and increased reproduction that traded off against survival. After only another 10 generations, we saw adaptation in the form of major changes in mosquito fitness, metabolism and gene expression, revealing the consolidation of a temperature-dependent trade-off between reproduction and longevity. These shifts demonstrate that Ae. albopictuscan adapt at the pace of warming. When selection was relaxed, most of the thermally shifted phenotypes reverted to control levels, revealing the importance of plasticity after prolonged evolution. Furthermore, 250 warm evolution-altered genes did not return to control levels. These genes exhibited significant negative correlation between mean and variance in warm-evolved mosquitoes, but a two-fold variance reduction without mean change in relaxed-selection mosquitoes. Both signals are consistent with the action of selection operating on a polygenic trait architecture. Ecological modelling identified egg-to-adult viability as the primary driver of thermal reproductive success, highlighting juvenile stages as a crucial control target under continued warming.

evolutionary biology↗

bioRxiv2026

Thermal responses of an emerging temperate mosquito reshape arboviral transmission risk

Global warming is known to increase arboviral disease risk by enabling the expansion of tropical vectors such as Aedes aegypti and Aedes albopictus. However, whether climate-driven shifts in seasonal dynamics within temperate regions, such as warmer springs and shorter winters, create thermal settings favourable for additional vectors, which can reshape disease risk maps, is poorly understood. To answer this question, we used the invasive temperate mosquito species Aedes koreicus and tested its thermal developmental resilience, along with its vector competence for dengue and chikungunya viruses. We observed significant phenotypic variation in thermal tolerance across life stages, which translates into distinct thermal performance curves for life-history traits, ultimately shaping overall mosquito fitness. We further found that temperature effects are virus-specific, with differential impacts on infection and transmission between dengue and chikungunya viruses. These stage- and pathogen-specific responses generate carry-over effects across life stages, indicating that thermal responses may be constrained by life-history trade-offs rather than be defined by a single thermal optimum. Our results highlight the need to move beyond static, species-based risk assessments toward mechanistic frameworks that integrate thermal biology across life stages and vector-pathogen systems. As climate change increasingly reshapes seasonal structure rather than simply elevating mean temperatures, cold-adapted and temperate vectors such as Ae. koreicus, provide critical model systems to understand how transmission risk emerges outside mosquito classical thermal optima, calling for a broader paradigm shift in how global change and vector-borne disease risk are conceptualised.

ecology↗

bioRxiv2025

Metabolic homeostasis favors tolerance to persistent viral infection in Aedes aegypti mosquitoes

The mosquito Aedes aegypti harbors a wide range of persistent viral infections, including both medically important arboviruses and insect-specific viruses (ISVs). However, the mechanisms underpinning establishment and maintenance of persistent viral infections remain poorly understood despite them influencing viral dynamics and transmission. Differently than arboviruses, which circulate at lower frequencies, ISVs are highly prevalent in field mosquitoes, thus representing ideal models to study the mechanisms of persistence. On this basis, we followed infection of the ISV cell-fusing agent virus (CFAV) in two Ae. aegypti laboratory populations, Liverpool (LVP) and ZacPanda (ZacP), and studied their immune responses, including resistance and tolerance, along with physiological and fitness impacts of CFAV infection. Our results demonstrate that CFAV establishes life-long infections with a comparable activation of resistance mechanisms, in both LVP and ZacP mosquitoes. In contrast, ZacP mosquitoes exhibited greater tolerance to CFAV than LVP accompanied by the ability to maintain metabolic homeostasis during infection. In neither ZacP nor LVP, CFAV resulted in reproductive impairment. These findings highlight a key role for tolerance mechanisms, which through regulation of energetic resources, contribute to sustain persistent viral infections in mosquitoes. Our results have implications for viral transmission dynamics and vector control strategies.

immunology↗

bioRxiv2025

Do heatwaves impact mosquitoes? Multi-level analyses across developmental stages in Aedes albopictus

The increase in the frequency and intensity of heatwaves (HWs) under global warming is expected to have more dramatic biological impacts on insects than mean temperature increases by challenging their thermal thresholds. However, experimental evidence that quantifies the impact of HWs on insects in their ecological context is limited. Here, we measured across multiple biological scales (e.g. fitness, physiology, transcriptomic and microbiota) the stage-specific responses of the arboviral vector Aedes albopictus when experiencing an ecologically relevant HW. In arboviral vectors, only females require a blood-meal thus contributing to the transmission cycle, but males, eggs and larvae can also be the target of control strategies to reduce population size. As such the understanding of the responses to a HW during mosquito development has both biological and epidemiological relevance. We observed stage-specific responses, starting at the egg stage. We saw egg hatching decreasing and delaying after HW exposure. On the contrary, larvae showed to be resilient to HW. Larvae repurposed their energy resulting in trivial mortality, but delayed development. At the adult stage, we observed a marked sex difference, with extensive (>50%) male mortality, accompanied by a small (16) number of genes elicited following HW exposure, which indicates that males have limited coping mechanisms against hot events. In females, we observed a reduced reproductive output, but only when HW occurred after a blood-meal. Finally, we saw extensive HW-dependent changes in the microbial composition of larvae, but female microbiota remained dominated by Wolbachia regardless of the thermal challenge. Our results have relevant implications for both the understanding of mosquito biology and the implementation of vector control strategies as the climate crisis progresses.

ecology↗

bioRxiv2024

Prolonged thermal stress enhances mosquito tolerance to viral infection

How and to what extent mosquito-virus interaction is influenced by climate change is a complex question of ecological and epidemiological relevance. We worked at the intersection between thermal biology and vector immunology and studied shifts in tolerance and resistance to the cell fusing agent virus (CFAV), a prominent component of the mosquito virome know to contribute to shaping mosquito vector competence, in warm-acclimated and warm-evolved Aedes albopictus mosquitoes. We show that the length of the thermal challenge influences the outcome of the infection with warm-evolved mosquitoes being more tolerant to CFAV infection, while warm-acclimated mosquitoes being more resistant and suffering from extensive fitness costs. These results highlight the importance of considering fluctuations in vector immunity in relation to the length of a thermal challenge to understand natural variation in vector response to viruses and frame realistic transmission models.

immunology↗

bioRxiv2024

Reproductive resource allocation correlates with successful global invasion of a mosquito species

The understanding of traits favoring biological invasions has been considered an essential step to predict which species would become successful invaders. Classical approaches test for differences between invasive vs. not invasive species and emphasize reproduction as a critical phenotype for successful establishment of an invasive species. However, cross-species comparisons underestimate intraspecies differences, which may be relevant in invasive species with highly genetically diverse populations. Here we capitalize on the well-characterized invasion history of the arboviral vector Aedes albopictus, which resulted in genetically-distinct native, old and invasive populations, and compared the reproductive capacity (fertility and fecundity), development (timing of egg development, oviposition patterns and egg hatching) and physiology (blood digestion and nutrient movement during oogenesis) across populations. We observed that invasive mosquitoes optimize their nutrient investment during development and oogenesis, which leads to increased egg production with respect to native and long adapted laboratory mosquitoes. This higher fecundity results from a delay in oogenesis and is accompanied by higher fertility. We further tested inheritance of reproductive traits via reciprocal crosses, which showed a higher fertility and fecundity in hybrids with respect to parental strains and a potential contribution of males to the reproductive success of invasive mosquitoes. Our results provide evidence that resource allocation during development and oogenesis influences the reproductive capacity of Ae. albopictus and manifests in population differences that correlate with their invasion success. Significance StatementIn addition to being an essential process to ensure the survival of a species, reproduction is a key determinant for a species invasion success because it facilitates a species ability to establish in a new area. Reproduction is a complex phenotype that relies on intricate and timely interactions between genetic and physiological factors. Here we combined molecular, biochemical, and genetic approaches to show that efficient allocation of energetic resources during development and oogenesis fosters the reproductive output of Ae. albopictus mosquitoes and manifests as variation in the reproductive capacity of its geographic populations. These results are critical for predicting the invasion success of this species and tailoring effective control strategies.

evolutionary biology↗

bioRxiv2024

Aedes albopictus colonies from different geographic origins differ in their sleep and activity levels but not in the time of peak activity

Mosquitoes occupy a wide range of habitats where they experience various environmental conditions. The ability of some species, such as the tiger mosquito, Aedes albopictus, to adapt to local conditions certainly contributes to their invasive success. Among traits that remain to be examined, mosquitoes ability to time their activity with that of the local host population has been suggested to be of significant epidemiological importance. However, whether different populations display heritable differences in their chronotype has not been examined. Here, we compared laboratory strains originating from 8 populations from 3 continents, monitored their spontaneous locomotor activity patterns, and analyzed their sleep-like states. Overall, all strains showed conserved diurnal activity concentrated in the hours preceding the crepuscule. Similarly, they all showed increased sleep levels during the morning and night hours. However, we observed strain-specific differences in the activity levels at each phase of the day. We also observed differences in the fraction of time that each strain spends in a sleep-like state, explained by variations in the sleep architecture across strains. Human population density and the latitude of the site of geographic origin of the tested strain showed significant effects on sleep and activity patterns. Altogether, these results suggest that Ae. albopictus mosquitoes adapt to local environmental conditions via heritable adaptations of their chronotype.

animal behavior and cognition↗

bioRxiv2023

Aalbo1200: global genetic differentiation and variability of the mosquito Aedes albopictus

The mosquito Aedes albopictus transmits human viruses including dengue and chikungunya and is an extremely successful invasive species expanding into new regions of the world. New tools are needed to complement existing tools to help monitor and control this species. Genomic resources are improving for this species including genome reference sequences, and whole genome sequencing data will help to catalog genetic diversity in this species and further enable genetic analysis. We collected populations of Ae. albopictus from throughout its distribution and generated whole genome sequencing data from population samples. These data will be used to address a number of basic and applied questions for this species. Here, we show genetic differentiation patterns among the tropical and temperate forms, as well as finer scale genetic clustering at the regional and population scale. These data and results will be a valuable resource for further study and tool development for this species.

evolutionary biology↗

bioRxiv2023

Population-specific responses to developmental temperature in the arboviral vector : implications for climate change

The increase of environmental temperature due to current global warming is not only favoring the expansion of the distribution range of many insect species, but it is also changing their phenology. Insect phenology is tightly linked to developmental timing, which is regulated by environmental temperatures. However, the degree to which effects of developmental temperatures extend across developmental stages and their inter-stage relationships have not been thoroughly quantified in mosquitoes. Here, we used the mosquito Aedes albopictus, which is an aggressive invasive species and an arboviral vector to study how developmental temperature influences fitness across developmental stages, thermal traits, energy reserves, transcriptome, and Wolbachia prevalence in populations from either temperate or tropical regions. We show that hatchability, larval and pupal viability, and developmental speed are strongly influenced by temperature and these effects extend to wing length, body mass, longevity, content of water, protein and lipids in adults, in a population-specific manner. On the contrary, neither adult thermal preference nor heat resistance significantly change with temperature. Development at 18{degrees}C revealed to be a limiting factor for the proliferation of Wolbachia in adults and transcriptome analysis showed enrichment for functions linked to stress responses (i.e. cuticle proteins and chitin, cytochrome p450, and heat shock proteins) in mosquitoes reared at both 18{degrees}C and 32{degrees}C. Our data showed an overall reduced vector fitness performance when mosquitoes were reared at 32{degrees}C, and the absence of isomorphy in the relationship between developmental stages and temperature in the temperate population. Altogether these results have important implications for reliable model projections of the invasion potentials of Ae. albopictus and its epidemiological impact.

ecology↗

bioRxiv2023

Molecular signature of domestication in the arboviral vector Aedes aegypti

BackgroundDomestication is a complex, multi-stage and species-specific process that results in organisms living close to humans. In the arboviral vector Aedes aegypti adaptation to living in proximity with anthropogenic environments has been recognized as a major evolutionary shift, separating a generalist form, Aedes aegypti formosus (Aaf), from the domestic form Aedes aegypti aegypti (Aaa), which tends to deposit eggs artificial containers and bite humans for a blood meal. These behaviors enhance the mosquito vectorial capacity. The extent to which domestication has impacted the Ae. aegypti genome has not been thoroughly investigated yet. ResultsTaking advantage of two forms distinct and historically documented geographic distributions, we analyzed the genomes of 634 worldwide Ae. aegypti mosquitoes. Using more than 300 million high-confidence SNPs, we found a unique origin for all out-of-Africa Ae. aegypti mosquitoes, with no evidence of admixture events in Africa, apart from Kenya. A group of genes were under positive selection only in out-of-Africa mosquitoes and 236 genes had nonsynonymous mutations, occurring at statistically different frequencies in Aaa and Aaf mosquitoes. ConclusionWe identified a clear signal of genetic differentiation between Aaa and Aaf, circumscribed to a catalogue of candidate genes. These "Aaa molecular signature" genes extend beyond chemosensory genes to genes linked to neuronal and hormonal functions. This suggests that the behavioral shift to domestication may rely on the fine regulation of metabolic and neuronal functions, more than the role of a few significant genes. Our results also provide the foundation to investigate new targets for the control of Ae. aegypti populations.

evolutionary biology↗

bioRxiv2022

Virome and nrEVEome diversity of Aedes albopictus mosquitoes from La Reunion Island and China

BackgroundAedes albopictus is a public health threat for its worldwide spread and ability to transmit arboviruses. Understanding mechanisms of mosquito immunity can provide new tools to control arbovirus spread. The genomes of Aedes mosquitoes contain hundreads of nonretroviral endogenous viral elements (nrEVEs), which are enriched in piRNA clusters and produce piRNAs, with the potential to target cognate viruses. Recently, one nrEVE was shown to limit cognate viral infection through nrEVE-derived piRNAs. These findings suggest that nrEVEs constitute an archive of past viral infection and that the landscape of viral integrations may be variable across populations depending on their viral exposure. MethodsWe used bioinformatics and molecular approaches to identify known and novel (i.e. absent in the reference genome) viral integrations in the genome of wild collected Aedes albopictus mosquitoes and characterize their virome. ResultsWe showed that the landscape of viral integrations is dynamic with seven novel viral integrations being characterised, but does not correlate with the virome, which includes both viral species known and unknown to infect mosquitoes. However, the small RNA coverage profile of nrEVEs and the viral genomic contigs we identified confimed an interaction among these elements and the piRNA and siRNA pathways in mosquitoes. ConclusionsMosquitoes nrEVEs have been recently descrived as a new form of heritable, sequence-specific mechanism of antiviral immunity. Our results contribute to understanding the dynamic distribution of nrEVEs in the genomes of wild Ae. albopictus and their interaction with mosquito viruses.

genomics↗

bioRxiv2021

Computational methods for the discovery and annotation of viral integrations

The transfer of genetic material between viruses and eukaryotic cells is pervasive. Somatic integrations of DNA viruses and retroviruses have been linked to persistent viral infection and genotoxic effects. Integrations into germline cells, referred to as Endogenous Viral Elements (EVEs), can be co-opted for host functions. Besides DNA viruses and retroviruses, EVEs can also derive from nonretroviral RNA viruses, which have often been observed in piRNA clusters. Here, we describe a bioinformatic framework to annotate EVEs in a genome assembly, study their widespread occurrence and polymorphism and identify sample-specific viral integrations using whole-genome sequencing data.

bioinformatics↗

bioRxiv2020

ViR: a tool to account for intrasample variability in the detection of viral integrations

Lateral gene transfer (LT) from viruses to eukaryotic cells is a well-recognized phenomenon. Somatic integrations of viruses have been linked to persistent viral infection and genotoxic effects, including various types of cancer. As a consequence, several bioinformatic tools have been developed to identify viral sequences integrated into the human genome. Viral sequences that integrate into germline cells can be transmitted vertically, be maintained in host genomes and be co-opted for host functions. Endogenous viral elements (EVEs) have long been known, but the extent of their widespread occurrence has only been recently appreciated. Modern genomic sequencing analyses showed that eukaryotic genomes may harbor hundreds of EVEs, which derive not only from DNA viruses and retroviruses, but also from nonretroviral RNA viruses and are mostly enriched in repetitive regions of the genome. Despite being increasingly recognized as important players in different biological processes such as regulation of expression and immunity, the study of EVEs in non-model organisms has rarely gone beyond their characterization from annotated reference genomes because of the lack of computational methods suited to solve signals for EVEs in repetitive DNA. To fill this gap, we developed ViR, a pipeline which ameliorates the detection of integration sites by solving the dispersion of reads in genome assemblies that are rich of repetitive DNA. Using paired-end whole genome sequencing (WGS) data and a user-built database of viral genomes, ViR selects the best candidate couples of reads supporting an integration site by solving the dispersion of reads resulting from intrasample variability. We benchmarked ViR to work with sequencing data from both single and pooled DNA samples and show its applicability using WGS data of a non-model organism, the arboviral vector Aedes albopictus. Viral integrations predicted by ViR were molecularly validated supporting the accuracy of ViR results. Additionally, ViR can be readily adopted to detect any LT event providing ad hoc non-host sequences to interrogate.

bioinformatics↗

bioRxiv2020

Immunity to infections in arboviral vectors by integrated viral sequences: an evolutionary perspective

In the model organism Drosophila melanogaster, the PIWI-interacing RNA pathway contributes in silencing transposable elements (TEs) through smallRNAs (piRNAs), which arise from genomic loci (piRNA clusters) that contain sequences of previously-acquired TEs. As such, they are a functionally-immune archive of previous TE invasions that is passed to the offspring. In the arboviral vector Aedes aegypti, piRNA clusters contain TEs and endogenous viral elements from nonretroviral RNA viruses (nrEVEs) which produce piRNAs, supporting the hypothesis that nrEVEs are heritable immunity effectors. However, direct evidence that nrEVEs mediate adaptive immunity is lacking. Here, by using an analytic approach intersecting population genomics with molecular biology we demonstrate that the composition of piRNA clusters is modular through acquisition and absence of nrEVEs. We show that the genomes of wild-caught mosquitoes have a different set of nrEVEs than those annotated in the reference genome, including population-specific integrations. nrEVEs are not distributed in mosquito genomes only by genetic drift, but some show signs of positive selection. Moreover, by comparing natural mosquito populations expressing or lacking two newly characterised nrEVEs with high sequence complementarity to cell fusing agent virus, we show that nrEVEs confer antiviral immunity in ovaries against the cognate virus. Our results confirm that some nrEVEs have been co-opted for adaptive immunity to viral infections.

evolutionary biology↗

bioRxiv2020

Improved reference genome of the arboviral vector Aedes albopictus

The Asian tiger mosquito Aedes albopictus is globally expanding and has become the main vector for human arboviruses in Europe. Here we present AalbF2, a dramatically improved assembly of the Ae. albopictus genome that has revealed widespread viral insertions, novel microRNAs and piRNA clusters, the sex determining locus, new immunity genes, and has enabled genome-wide studies of geographically diverse Ae. albopictus populations and analyses of the developmental and stage-dependent network of expression data. Additionally, we built the first physical map for this species with 75% of the assembled genome anchored to the chromosomes. These up-to-date resources of the genome provide a foundation to improve understanding of the adaptation potential and the epidemiological relevance of this species and foster the development of innovative control measures. One Sentence SummaryLong-read and Hi-C-based de novo assembly of the arboviral vector Aedes albopictus genome fosters deeper understanding of its biological features.

genomics↗

bioRxiv2019

Polymorphism analyses and protein modelling inform on functional specialization of Piwi clade genes in the arboviral vector Aedes albopictus

Current knowledge of the piRNA pathway is based mainly on studies on the model organism Drosophila melanogaster, where three proteins of the Piwi subclade of the Argonaute family interact with PIWI-interacting RNAs to silence transposable elements in gonadal tissues. In mosquito species that transmit epidemic arboviruses such as the Dengue and Chikungunya viruses, Piwi clade genes underwent expansion, are also expressed in the soma, and code for proteins that may elicit antiviral functions and crosstalk with other proteins of recognized antiviral mechanisms. These observations underline the importance of expanding our knowledge of the piRNA pathway beyond D. melanogaster.\n\nHere we focus on the emerging arboviral vector Aedes albopictus and we couple traditional approaches of expression and adaptive evolution analyses with most current computational predictions of protein structure to study evolutionary divergence among Piwi clade proteins. Superposition of protein homology models indicate high structure similarity among all Piwi proteins, with high levels of amino acid conservation in the inner regions devoted to RNA binding. On the contrary, solvent-exposed surfaces showed low conservation, with several sites under positive selection. Expression profiles of Piwi transcripts during mosquito development and after infection with the Dengue 1 virus showed a concerted elicitation of all Piwi transcripts during viral dissemination, while the maintenance of infection primarily relied on the expression of Piwi5. In contrast, establishment of persistent infection by the Chikungunya virus is accompanied by an increased expression of all Piwi genes, particularly Piwi4 and, again, Piwi5. Overall these results are consistent with functional specialization and a general antiviral role for Piwi5. Experimental evidences of sites under positive selection in Piwi1/3, Piwi4 and Piwi6, further provide useful knowledge to design tailored functional experiments.\n\nAuthor summaryArgonautes are ancient proteins involved in many cellular processes, including innate immunity. Early in eukaryote evolution, Argonautes separated into Ago and Piwi clades, which maintain a dynamic evolutionary history with frequent duplications and losses. The use of Drosophila melanogaster as a model organism proved fundamental to understand the function of Argonautes. However, recent studies showed that the patterns and observations made in D. melanogaster, including the number of Argonautes, their expression profile and their function, are a rarity among Dipterans.\n\nIn vectors of epidemic arboviruses such as Dengue and Chikungunya viruses, Piwi genes underwent expansion, are expressed in the soma, and some of them appear to have antiviral functions. Besides being an important basic question, the identification of which (and how) Piwi genes have antiviral functions may be used for the development of novel genetic-based strategies of vector control. Here we coupled population genetics models with computational predictions of protein structure and expression analyses to investigate the evolution and function of Piwi genes of the emerging vector Aedes albopictus. Our data support a general antiviral role for Piwi5. Instead, the detection of complex expression profiles with the presence of sites under positive selection in Piwi1/3, Piwi4 and Piwi6 requires tailored functional experiments to clarify their antiviral role.

evolutionary biology↗

bioRxiv2018

Evolutionary landscape of mosquito viral integrations

The sequenced genome of the arboviral vector mosquito, Aedes albopictus, is replete with repetitive DNA and it harbors an unusually large number of endogenous viral sequences, collectively called Nonretroviral Integrated RNA Virus Sequences (NIRVS). NIRVS are enriched both within protein-coding gene exons and PIWI-interacting RNA (piRNA) clusters, where they encode piRNAs. Based on these features, NIRVS have been proposed to function as novel mosquito antiviral immune factors. However, the relative importance and contributions of different NIRVS as functional antiviral elements and their mechanisms of action remain open questions.\n\nWe apply an analytical approach that intersects computational, evolutionary and molecular methods to identify NIRVS most likely affecting mosquito immunity. Using this strategy, we show that NIRVS are a highly dynamic component of the Ae. albopictus repeatome, which nevertheless maintains a core set of seemingly the oldest NIRVS with similarity to Rhabdoviruses. Population-level polymorphism of NIRVS varies depending on whether they occur in intergenic regions, piRNA clusters or are part of gene exons. NIRVS from piRNA clusters are differentially widespread in diverse populations but conserved at the sequence level. This is consistent with the hypothesis that they act analogously to fragments of transposable elements in piRNA clusters and contribute to piRNA-based immunity. Among NIRVS from gene exons, AlbRha52 and AlbRha12 have the hallmarks of domestication as they are fixed across populations, stably expressed, and as polymorphic at the sequence level as fast-evolving genes. Overall these results support the hypothesis that NIRVS contribute to mosquito immunity, potentially through diverse modes of action.

evolutionary biology↗