Aphids are highly sensitive to temperature changes and play a crucial role in transmitting plant viruses, accounting for the transmission of more than 50% of viruses that cause disease in crops. Among them, Myzus persicae is a major global pest, affecting over 400 plant species and transmitting more than 100 plant viruses, including potato virus Y (PVY), which poses a severe threat to potato crops. This study examines how temperature influences the life-history traits of M. persicae and its efficiency in transmitting PVY. Our research revealed that temperature significantly affects developmental duration, survival, and fecundity of M. persicae. The aphids exhibited the longest lifespan at 10 °C and the shortest at 30 °C. Similarly, fecundity declined from 29.81 offspring per female at 10 °C to 14.25 at 30 °C. PVY transmission efficiency was highest at 20 °C. We also mapped potential PVY transmission regions and identified tropical and subtropical areas as high-risk due to their favourable temperatures and predicted abundance of aphids. Regional temperature differences significantly influence aphid development and PVY spread, necessitating localized management strategies. Our findings emphasize the importance of integrating climatological, ecological, and epidemiological data to develop robust pest/disease management strategies that mitigate the impact of M. persicae and PVY on potato production, thereby enhancing global food security.

The emergence and global expansion of Aedes aegypti puts more than half of all humans at risk of arbovirus infection, but the origin of this mosquito and the impact of contemporary gene flow on arbovirus control are unclear. We sequenced 1206 genomes from 73 globally distributed locations. After evolving a preference for humans in Sahelian West Africa, the invasive subspecies Ae. aegypti aegypti (Aaa) emerged in the Americas after the Atlantic slave trade era and expanded globally. Recent back-to-Africa Aaa migration introduced insecticide resistance and anthropophily into regions with recent dengue outbreaks, raising concern that Aaa movement could increase arbovirus risk in urban Africa. These data underscore developing complexity in the fight against dengue, Zika, and chikungunya and provide a platform to further study this important mosquito vector.

Herein, we determine life-history consequences of selection on blood feeding in a polymorphic population of the pitcher-plant mosquito, Wyeomyia smithii Coq. (Diptera: Culicidae). All populations of W. smithii produce an initial batch of eggs without ever taking a blood meal (biting); southern populations require a blood meal for the second and subsequent batches of eggs, but are polymorphic for propensity to bite. To determine correlated life-history responses to direct selection on blood feeding, we compared fecundity, adult longevity, and reproductive allocation between a line selected specifically for increased blood feeding and its unselected, control line maintained in parallel for 11 generations. Previous studies have focused on the fitness benefits of blood feeding in terms of overall fecundity. Herein, we evaluate a novel fitness benefit of blood feeding that reduces the risk of reproductive failure by spreading that risk across multiple reproductive events in a population confronted with an unpredictably variable larval environment. We propose that "spreading the risk" reinforces selection on blood feeding in other arthropods in which the separation of fecundity from reproductive allocation in time or space has previously been neglected. Importantly, heritable variation for "spreading the risk" should enhance vectorial capacity and make more difficult vector control through larval source reduction.

The Asian tiger mosquito, Aedes albopictus, is currently the most widespread invasive mosquito species in the world. It poses a significant threat to human health, as it is a vector for several arboviruses. We used a SNP chip to genotype 748 Ae. albopictus mosquitoes from 41 localities across Europe, 28 localities in the native range in Asia, and 4 in the Americas. Using multiple algorithms, we examined population genetic structure and differentiation within Europe and across our global dataset to gain insight into the origin of the invasive European populations. We also compared results from our SNP data to those obtained using genotypes from 11 microsatellite loci (N = 637 mosquitoes from 25 European localities) to explore how sampling effort and the type of genetic marker used may influence conclusions about Ae. albopictus population structure. While some analyses detected more than 20 clusters worldwide, we found mosquitoes could be grouped into 7 distinct genetic clusters, with most European populations originating in East Asia (Japan or China). Interestingly, some populations in Eastern Europe did not share genetic ancestry with any populations from the native range or Americas, indicating that these populations originated from areas not sampled in this study. The SNP and microsatellite datasets found similar patterns of genetic differentiation in Europe, but the microsatellite dataset could not detect the more subtle genetic structure revealed using SNPs. Overall, data from the SNP chip offered a higher resolution for detecting the genetic structure and the potential origins of invasions.

Climate change will profoundly affect mosquito distributions and their ability to serve as vectors for disease, specifically with the anticipated increase in heat waves. The rising temperature and frequent heat waves can accelerate mosquito life cycles, facilitating higher disease transmission. Conversely, higher temperatures could increase mosquito mortality as a negative consequence. Warmer temperatures are associated with urbanized areas, suggesting a need for anthropophilic mosquitoes to adapt to be more hardy to heat stress. Mosquito eggs provide an opportunity to study the biological impact of climate warming as this stage is stationary and must tolerate temperatures at the site of female oviposition. As such, egg thermotolerance is critical for survival in a specific habitat. In nature, Aedes mosquitoes exhibit different behavioral phenotypes, where specific populations prefer depositing eggs in tree holes and prefer feeding non-human vertebrates. In contrast, others, particularly human-biting specialists, favor laying eggs in artificial containers near human dwellings. This study examined the thermotolerance of eggs, along with larval and adult stages, for Aedes aegypti lineages associated with known ancestry and shifts in their host preferences. Mosquitoes collected from areas with high human density showed increased egg viability following high-temperature stress, and a similar, yet more muted effect was noted in larvae. Unlike eggs and larvae, thermal tolerance among adults showed no significant correlation based on the area of collection or human-association. This study underscores that urbanization is a major driver of egg thermotolerance, highlighting the egg stage is likely critical to mosquito survival when associated with humans and needs to be accounted for when predicting future mosquito distribution.

The distribution of container mosquitoes in relation to distances from forests was studied in temperate Japan. Mosquito larvae were collected between May and September in 4 years from tree holes, bamboo stumps, riverine rock pools, and artificial containers; sampling ranged spatially from the mountain forest across the deforested plain developed as agriculture and urban areas to the seacoast. Although tree holes, bamboo stumps, and artificial containers existed throughout the deforested plain area, 10 container species of 6 genera were found virtually only within 5 km from the nearest forest edge. Worldwide invasive Aedes albopictus (Skuse) and Aedes japonicus (Theobald) of Asian origin showed unique occurrence patterns different from other container species and from each other. Ae. japonicus was dominant in artificial containers in and near the forest but minor in forest natural containers and only occurred within 5 km from the forest. Ae. albopictus was minor in the forest irrespective of container types but not bound to the forest and dominant in natural and artificial containers throughout rural and urban areas. The 5-km range was designated as the circum-forest zone for container mosquitoes (except Ae. albopictus) in Japan, and an expanded concept, circum-boundary zone, is proposed. The widths of these zones primarily depend on the dispersal traits of mosquitoes. Whether the relation of Ae. albopictus and Ae. japonicus to forests we observed are common in the native and invasive ranges is discussed. The study of across-ecosystem dispersal is important for mosquito management under anthropogenically changing environments due to either deforestation or green restoration.

RNA interference (RNAi) is a conserved cellular pathway found in nearly all eukaryotes that leads to the silencing of target mRNAs. Using RNAi as a mechanism to knockdown specific genes has enabled functional and reverse genetics studies in a wide range of eukaryotes. Previous work suggests that RNAi is inhibited at lower temperatures, potentially limiting the possibility to perform knockdown studies on ecologically relevant phenotypes that are only expressed at low temperatures. To determine whether RNAi is inhibited at low temperatures in Aedes albopictus (Skuse), we injected mosquitoes reared at 20 ± 1 °C, with dsRNA targeting yellow-g2 and compared knockdown efficacy to mosquitoes injected at 26.5 ± 1 °C. Our results demonstrate efficient knockdown at both temperatures, thereby establishing the feasibility of RNAi for functional genetic studies in A. albopictus at low temperatures.

Climate change poses significant challenges to agriculture and food security, particularly through its effects on insect vector populations and the pathogens they transmit. Aphids are one of the biggest group of ectotherms that transmit viruses to plants; more than 200 species have been identified as pathogen vectors. These aphids are responsible for transmitting over 300 viruses. The life-history traits of aphids such as fecundity and survival respond strongly and non-linearly to temperature and therefore to global warming. In this study, we elaborate the thermal responses for the main life-history traits (i.e, development and mortality rate) for aphid species for which data were available or generated. Also, thermal responses for virus transmission rates were elaborated to describe plant host to vector and vector to plant host dynamics. With these data, we elaborated thermal suitability models which were used to map current and projected scenarios for the transmission of viruses by aphids. Data was only available/generated for 19 aphid species, many of which only have data either at the lower or upper thermal limits. For virus transmission rates, from host plant to vector and from vector to plant data was only available/generated for potato virus Y (PVY), potato virus A (PVA), and potato leaf roll virus (PLRV) transmitted by the aphid Myzus persicae . Projections show that virus transmission by aphids will shift to northern latitudes. Understanding the thermal biology of aphids is crucial for developing effective measures to safeguard agriculture, especially staple crops, and food security in the context of climate change. ### Competing Interest Statement The authors have declared no competing interest.

The number of dengue cases worldwide has increased ten-fold over the past decade as Aedes aegypti , the primary vector of this disease, thrives and expands its distribution, revealing limitations to current control methods. To better understand how Ae. aegypti evolved from a forest dwelling, generalist species to a highly anthropophilic urban species and the impact of contemporary gene flow on the future of dengue control, we sequenced 1,206 genomes from mosquitoes collected at 74 locations around the globe. Here we show that after evolving a preference for humans in the Sahel region of West Africa, the origin of the fully domesticated, anthropophilic subspecies Ae. aegypti aegypti ( Aaa ) occurred in the Americas during the Atlantic Slave Trade era and was followed by its explosive expansion around the globe. In recent decades, Aaa has invaded coastal Africa, the ancestral home range, introducing insecticide resistance mutations and an affinity for human hosts. Evidence of back-to-Africa migration is found in regions with recent dengue outbreaks, raising concern that global movement of Aaa could increase transmission risk of arboviruses including dengue in urban Africa. These data provide a platform to further study this important mosquito vector species and underscore developing complexity in the fight to limit the spread of dengue, Zika, and chikungunya diseases. ### Competing Interest Statement JEC and BJW report employment and equity ownership at Verily Life Sciences, a for-profit company developing new technologies for mosquito control.

We evaluated miRNA and mRNA expression differences in head tissues between avid-biting vs. reluctant-biting Aedes albopictus (Skuse) females from a single population over a 20-min timescale. We found no differences in miRNA expression between avid vs. reluctant biters, indicating that translational modulation of blood-feeding behavior occurs on a longer timescale than mRNA transcription. In contrast, we detected 19 differentially expressed mRNAs. Of the 19 differentially expressed genes at the mRNA level between avid-biting vs. reluctant-biting A. albopictus, 9 are implicated in olfaction, consistent with the well-documented role of olfaction in mosquito host-seeking. Additionally, several of the genes that we identified as differentially expressed in association with phenotypic variation in biting behavior share similar functions with or are inferred orthologues of, genes associated with evolutionary variation in biting behaviors of Wyeomyia smithii (Coq.) and Culex pipiens (Lin.). A future goal is to determine whether these genes are involved in the evolutionary transition from a biting to a non-biting life history.

Background Although whole-genome sequencing (WGS) is the preferred genotyping method for most genomic analyses, limitations are often experienced when studying genomes characterized by a high percentage of repetitive elements, high linkage, and recombination deserts. The Asian tiger mosquito ( Aedes albopictus ), for example, has a genome comprising up to 72% repetitive elements, and therefore we set out to develop a single-nucleotide polymorphism (SNP) chip to be more cost-effective. Aedes albopictus is an invasive species originating from Southeast Asia that has recently spread around the world and is a vector for many human diseases. Developing an accessible genotyping platform is essential in advancing biological control methods and understanding the population dynamics of this pest species, with significant implications for public health. Methods We designed a SNP chip for Ae. albopictus (Aealbo chip) based on approximately 2.7 million SNPs identified using WGS data from 819 worldwide samples. We validated the chip using laboratory single-pair crosses, comparing technical replicates, and comparing genotypes of samples genotyped by WGS and the SNP chip. We then used the chip for a population genomic analysis of 237 samples from 28 sites in the native range to evaluate its usefulness in describing patterns of genomic variation and tracing the origins of invasions. Results Probes on the Aealbo chip targeted 175,396 SNPs in coding and non-coding regions across all three chromosomes, with a density of 102 SNPs per 1 Mb window, and at least one SNP in each of the 17,461 protein-coding genes. Overall, 70% of the probes captured the genetic variation. Segregation analysis found that 98% of the SNPs followed expectations of single-copy Mendelian genes. Comparisons with WGS indicated that sites with genotype disagreements were mostly heterozygotes at loci with WGS read depth < 20, while there was near complete agreement with WGS read depths > 20, indicating that the chip more accurately detects heterozygotes than low-coverage WGS. Sample sizes did not affect the accuracy of the SNP chip genotype calls. Ancestry analyses identified four to five genetic clusters in the native range with various levels of admixture. Conclusions The Aealbo chip is highly accurate, is concordant with genotypes from WGS with high sequence coverage, and may be more accurate than low-coverage WGS. Graphical Abstract

Understanding the molecular and physiological processes underlying biting behavior in vector mosquitoes has important implications for developing novel strategies to suppress disease transmission. Here, we conduct small-RNA sequencing and qRT-PCR to identify differentially expressed microRNAs (miRNAs) in the head tissues of two subspecies of Culex pipiens that differ in biting behavior and the ability to produce eggs without blood feeding. We identified eight differentially expressed miRNAs between biting C. pipiens pipiens (Pipiens) and non-biting C. pipiens molestus (Molestus); six of these miRNAs have validated functions or predicted targets related to energy utilization (miR8-5-p, miR-283, miR-2952-3p, miR-1891), reproduction (miR-1891), and immunity (miR-2934-3p, miR-92a, miR8-5-p). Although miRNAs regulating physiological processes associated with blood feeding have previously been shown to be differentially expressed in response to a blood meal, our results are the first to demonstrate differential miRNA expression in anticipation of a blood meal before blood is actually imbibed. We compare our current miRNA results to three previous studies of differential messenger RNA expression in the head tissues of mosquitoes. Taken together, the combined results consistently show that biting mosquitoes commit to specific physiological processes in anticipation of a blood meal, while non-biting mosquitoes mitigate these anticipatory costs.

Climate change is expected to dramatically alter autumnal and winter conditions in many temperate regions. However, limited data is available to accurately predict how these changes will impact species’ overwinter survival and post-winter fitness. Here, we determine how a longer, warmer fall period and winter heatwaves affect overwintering fitness and post-winter performance of the invasive mosquito vector, Aedes albopictus. We found that a longer, warmer fall period representative of early entry into diapause did not affect overwinter survival but did lead to reduced post-winter performance for multiple traits. Specifically, larvae that experienced longer, warmer fall conditions as diapause embryos exhibited reduced post-diapause larval starvation tolerance, increased post-diapause larval mortality, and longer post-diapause larval development compared to individuals from the short-fall treatments. These negative post-diapause fitness effects likely resulted from the greater energetic demands and/or damage incurred during the warmer, longer fall period. In contrast, exposure to winter heatwaves increased overwinter survival, possibly by allowing diapausing embryos to escape or repair cold injury. Finally, fall treatment and winter heatwaves had an interactive effect on male development time, while neither treatment impacted pupal mass in either sex. Overall, our results highlight that experiments that fail to measure post-diapause fitness are likely to substantially under-estimate the impacts of climate change on post-winter performance. Additionally, our results emphasize that it is crucial to consider the potentially conflicting effects of different aspects of climate change on a species’ overall overwintering success.

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.

STEM PhDs increasingly contribute to commercial science, such as patenting. We analyze faculty’s role in training STEM PhD students as new inventors on patents at leading research universities, emphasizing the drivers of gender differences. We ...STEM PhDs are a critical source of human capital in the economy, contributing to commercial as well as academic science. We examine whether STEM PhD students become new inventors (file their first patent) during their doctoral training at the top 25 U.S. ...

Creating transgenic insects is a key technology in insect genetics and molecular biology. A widely used instrument in insect transgenesis is the piggyBac transposase, resulting in essentially random genomic integrations. In contrast, site-specific recombinases allow the targeted integration of the transgene construct into a specific genomic target site. Both strategies, however, often face limitations due to low transgenesis efficiencies. We aimed to enhance transgenesis efficiencies by utilizing capped mRNA as a source of transposase or recombinase instead of a helper plasmid. A systematic comparison of transgenesis efficiencies in Aedes mosquitoes, as models for hard-to-transform insects, showed that suppling piggyBac transposase as mRNA increased the average transformation efficiency in Aedes aegypti from less than 5% with the plasmid source to about 50% with mRNA. Similar high activity was observed in Ae. albopictus with pBac mRNA. No efficiency differences between plasmid and mRNA were observed in recombination experiments. Furthermore, a hyperactive version of piggyBac transposase delivered as a plasmid did not improve the transformation efficiency in Ae. aegypti or the agricultural pest Drosophila suzukii. We believe that the use of mRNA has strong potential for enhancing piggyBac transformation efficiencies in other mosquitoes and important agricultural pests, such as tephritids.

An innovative isotopic labelling strategy shows that malaria mosquitoes in the West-African Sahel region survive in dormancy over the prolonged dry season. These results have implications for efforts to suppress malaria transmission in Africa.

Mosquitoes transmit a wide variety of devastating pathogens when they bite vertebrate hosts and feed on their blood. However, three entire mosquito genera and many individual species in other genera have evolved a nonbiting life history in which blood is not required to produce eggs. Our long‐term goal is to develop novel interventions that reduce or eliminate the biting behavior in vector mosquitoes. A previous study used biting and nonbiting populations of a nonvector mosquito, Wyeomyia smithii, as a model to uncover the transcriptional basis of the evolutionary transition from a biting to a nonbiting life history. Herein, we ask whether the molecular pathways that were differentially expressed due to differences in biting behavior in W. smithii are also differentially expressed between subspecies of Culex pipiens that are obligate biting (Culex pipiens pipiens) and facultatively nonbiting (Culex pipiens molestus). Results from RNAseq of adult heads show dramatic upregulation of transcripts in the ribosomal protein pathway in biting C. pipiens, recapitulating the results in W. smithii, and implicating the ancient and highly conserved ribosome as the intersection to understanding the evolutionary and physiological basis of blood feeding in mosquitoes. Biting Culex also strongly upregulate energy production pathways, including oxidative phosphorylation and the citric acid (TCA) cycle relative to nonbiters, a distinction that was not observed in W. smithii. Amino acid metabolism pathways were enriched for differentially expressed genes in biting versus nonbiting Culex. Relative to biters, nonbiting Culex upregulated sugar metabolism and transcripts contributing to reproductive allocation (vitellogenin and cathepsins). These results provide a foundation for developing strategies to determine the natural evolutionary transition between a biting and nonbiting life history in vector mosquitoes.