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The uptake, accumulation, and ontogenetic transfer of microplastics (MPs) in bloodsucking mosquitoes of the genus Anopheles, vectors of helminth and protozoa parasites in humans and animals, were studied under laboratory conditions. In the experiment, 2‐μm‐diameter fluorescent polystyrene spheres were counted in mosquitoes of all stages, from larvae to adults. Larvae from a natural population readily ingested MPs with food, accumulating on average 3.9 × 106 particles per larva within 3 days. The concentration of MPs decreased significantly in mosquitoes during their transition from stage to stage. The average number of detected MPs attained 110 particles per pupa and 3.0 particles per adult. MP uptake by mosquitoes did not affect their survival, whereas the rate of metamorphosis in MP‐consuming mosquitoes was slightly higher. Our data confirmed that MPs can be transferred from feeding larvae to non‐feeding pupae and adult flying Anopheles mosquitoes from natural populations in aquatic ecosystems. [ABSTRACT FROM AUTHOR]

BACKGROUND: Controlling the spread of arboviral diseases remains a considerable challenge due to the rapid development of insecticide resistance in Aedes mosquitoes. This study evaluated the effects of boric acid‐containing toxic sugar bait (TSB) on field populations of resistant Aedes aegypti mosquitoes. In addition, this study examined the flight activity and wing beat frequency and amplitude of males and the flight activity, fecundity, and insemination of females after pairing with males exposed to TSB. The population dynamics of Aedes mosquitoes under imbalanced sex ratios were examined to simulate realistic field conditions for male suppression under the effect of TSB. RESULTS: The mortality of male mosquitoes was consistently high within 24 h after exposure. By contrast, the mortality of female mosquitoes was inconsistent, with over 70% mortality observed at 168 h. The flight activity and wing beat amplitude of treated males were significantly lower than those of controls, but no significant difference in wing beat frequency was detected. The fecundity and insemination of treated female mosquitoes were lower than those of controls. A simulation study indicated that considerably low male population densities led to mating failures, triggering a mate‐finding Allee effect and resulting in persistently low population levels. CONCLUSION: Boric acid‐containing TSB could effectively complement current chemical intervention approaches to control resistant mosquito populations. TSB is effective in reducing field male populations and impairing male flight activity and female‐seeking behavior, resulting in decreased fecundity and insemination. Male suppression due to TSB potentially results in a small mosquito population. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

It is often necessary to use motorised transport to move live mosquitoes from distant field collection points into a central insectary, so that their behavioural and/or physiological phenotypes can be assessed under carefully controlled conditions. However, a survey of heritable insecticide susceptibility traits among wild‐caught Anopheles arabiensis mosquitoes, collected across an extensive study area composed largely of wilderness in southern Tanzania, necessitated that live mosquitoes were carried on foot over distances up to 25 km per day because most of the area was impassable by car, motorcycle or even bicycle during the rains. A self‐cooling, self‐humidifying carrier backpack was therefore developed that allows live adult mosquito specimens to be transported across rugged miombo woodland and floodplain terrain throughout the year. This wettable backpack was fabricated from stitched Tanzanian kitenge cotton fabric and polyvinyl chloride–coated fibreglass netting that allows easy circulation of air in and out. An outer cover flap made of cotton towelling embedded inside a kitenge envelope overhangs the fibreglass netting upper body of the bag, to protect mosquitoes from direct sunlight, and can be soaked with water to maintain low temperature and high humidity inside. Mean survival of insectary‐reared female An. arabiensis transported through nine different mobile camps inside the 509 km2 Ifakara‐Lupiro‐Mang'ula wildlife management area (ILUMA WMA), over up to 143 km and 25 days, was statistically indistinguishable from those left in the field insectary over the same period. Although considerable variance of survival was observed between different batches of mosquitoes from the insectary and between individual cups of mosquitoes, the different levels and positions inside the backpack had no influence on this outcome. Temperature and humidity inside the backpack were maintained at standard insectary conditions throughout, despite much more extreme conditions immediately outside. When the backpack was used to transport wild An. arabiensis and Anopheles quadriannulatus across a much larger study area of >4000 km2, encompassing the ILUMA WMA, some nearby villages and adjacent parts of Nyerere National Park (NNP), it achieved a mean survival rate of 58.2% (95% confidence interval 47.5–68.2). Encouragingly, no difference in survival was observed between ILUMA WMA and NNP even though transport back from NNP involves much longer distances, sometimes involving lengthy journeys by car or boat. Overall, this mosquito carrier backpack prototype appears to represent a viable and effective method for transporting live wild‐caught mosquitoes on foot across otherwise impassable terrain under challenging weather conditions with minimal detrimental impact on their survival. [ABSTRACT FROM AUTHOR]

ABSTRACT Fieldwork investigations and stratigraphic analyses in the Parnaíba Basin, northern Brazil, reveal the interaction of the uppermost part of the Triassic Sambaíba aeolian dune field (erg) system with the latest Triassic–earliest Jurassic Mosquito lava flows. The lava flows originated as part of the Central Atlantic Magmatic Province (CAMP, ~201 Ma) and covered the aeolian system, allowing almost complete preservation of large‐scale in situ aeolian bedforms, even preserving lee‐ and stoss‐side. During the emplacement, the lava flows interacted with unconsolidated aeolian sediment, generating sediment–lava deformation features that are preserved at the interface between these units. This occurrence attests to arid conditions in the low latitudes of Gondwana at the Triassic–Jurassic transition. [ABSTRACT FROM AUTHOR]

Notonecta species (Hemiptera: Notonectidae) are generalist true predators with a strong impact on the size, structure, and richness of the aquatic communities, particularly on mosquito populations. Juvenile and adult backswimmers not only prey on mosquito larvae (consumptive effect) but their presence can also deter the oviposition of gravid mosquito females (non‐consumptive effect). In this study, we selected a Western Palearctic backswimmer, Notonecta maculata Fabricius, as a predator and deterrent of the highly invasive and health‐threatening Asian tiger mosquito, Aedes albopictus (Skuse) (Diptera: Culicidae). In central Italy, N. maculata is univoltine and overwinters in the adult stage. Females lay eggs from February to the end of May, and the first new adults will emerge in late June; the complete nymphal development requires 44.5 ± 3.1 days. The number of Ae. albopictus larvae preyed on by N. maculata during its growth increases while developing, going from 0.03 ± 0.02 larvae per day for first instar nymphs to 21.38 ± 2.90 for mature adults. Furthermore, the presence of a single N. maculata adult in a mosquito ovitrap is enough to discourage the Ae. albopictus oviposition for up to 5 days. Limiting mosquito populations and, consequently, the transmission of viruses and parasites should be our main goal. Therefore, the integrated management of Ae. albopictus by the use of insecticides and a predator (such as backswimmer juveniles and adults), even if only in specific situations, may be promising and feasible. A more in‐depth knowledge of the biological cycle of N. maculata could help, consequently, to optimize its mass rearing. [ABSTRACT FROM AUTHOR]

Mosquito‐borne viruses continue to affect billions of people globally, posing a severe health risk and an economic burden. Aedes albopictus (Skuse), a highly invasive mosquito species, has repeatedly invaded and increased its presence, serving as a key vector of dengue virus, yellow fever virus (YFV), Zika virus (ZIKV), and Chikungunya virus (CHIKV), causing frequent outbreaks of related viral diseases. This study investigated the impact of larval diet quantity on larval duration and adult body size. The effect of adult mosquito body size on various aspects of Ae. albopictus was also examined, including blood‐feeding behavior, follicular development, reproductive capacity, egg retention capacity, preoviposition period, and fecundity. These diverse characteristics all have an effect on arboviruses transmission. The changes in body size (small, medium, and large) are obtained by providing different quantities of larval diet (low, average, and high). The results indicate that the quantity of larval diet directly impacts the adult body size while inversely affecting the larval duration. Furthermore, a positive correlation exists between adult body size and wing length, implying that wing length could be a reliable indicator of adult body size and rearing conditions during the developmental stages. Large females exhibited higher numbers of follicles and greater fecundity. Moreover, a significant correlation was observed between follicle number before the first blood meal and total egg number. In contrast, increasing wing length decreased the number of blood meals, egg retention, and the preoviposition period. The tendency of small females to perform multiple feedings was greater than that of large females. Small females exhibited a higher propensity for multiple feeding activities when compared to their larger counterparts. Most medium‐sized females (92.8%) deposited eggs in their ovaries, however, 7.2% retained a few. In contrast, most large females (87.4%) had complete ovary egg‐laying, whereas a minority (12.6%) retained some of their eggs. About 35.2% of small females showed ovarian egg retention, while 64.8% successfully laid all their eggs. After the first blood meal, the oviposition rate was 92% for large females, 88% for medium females, and 76% for small females. About 69.86% of the follicles in large females underwent vitellogenesis. This finding suggests that small females with low energy reserves exhibited incomplete oviposition and multiple blood feedings to increase their reproductive capacity. Research Highlights: Add more information about arbovirus epidemics and their consequences.Aedes albopictus is a global invasive species that transmit dengue virus, CHIKV, YFV, and ZIKV.A negative correlation was observed between body size, egg retention, and multiple blood feedings in Aedes albopictus.Size of the female's body was positively correlated with fecundity, while it was negatively correlated with the preoviposition period.Size‐dependent multiple blood feeding affects vector‐host contact frequency. [ABSTRACT FROM AUTHOR]

BACKGROUND: Vector mosquito control is important for preventing and controlling mosquito‐borne infectious diseases. This study designed and developed a mosquito killer (MK) with a specific light wavelength, simulated human body temperature, human odor, and a photocatalyst to stimulate CO2 based on the physiological characteristics and ecological habits of mosquitoes. We tested the trapping effect of individual and multiple mosquito‐trapping elements of the MK through two‐way selection experiments and compared them with several commercial mosquito traps. RESULTS: The 365 nm wavelength MK was significantly more effective than the 395 nm (Cx. quinquefasciatus: 62.00% vs. 34.25%; Ae. albopictus: 50.75% vs 45.00%, An. sinensis: 49.75% vs 39.00%). Mosquitoes captured by the MK with heaters at 365 nm were significantly more than those captured by the MK without heaters at 365 nm. A trap with a 365 nm wavelength, heating element, and lure showed significantly better capture effectiveness than MK with a 365 nm wavelength, heating element, but without lure (Cx. quinquefasciatus: 67.00% vs. 29.75%, Ae. albopictus: 60.25% vs 36.25%, An. sinensis: 49.75% vs 39.75%). The coated photocatalyst trap with a 365 nm wavelength, heating element, and lure showed significantly better capture effectiveness than the trap without coating (Cx. quinquefasciatus: 54.25% vs. 42.50%; Ae. albopictus: 53.50% vs 44.00%, An. sinensis: 50.00% vs 41.25%). This trap demonstrated a significantly better capture advantage for Cx. quinquefasciatus and Ae. albopictus compared to the three commercial products. CONCLUSION: The developed mosquito trap with multiple attractant factors significantly enhanced the capture effectiveness of common mosquitoes. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Issue Addressed Methods Results Conclusions So What? An important part of preventing and managing Aedes‐borne mosquito disease outbreak risk is engaging the community. Research shows that high‐income countries tend to use top‐down measures for Aedes mosquito management, favouring educational approaches to engage the community over participatory approaches that actively involve and empower the community in addressing disease risk. Little is known about the reasons behind the use of these approaches and how they could be strengthened. This research explores the community engagement approaches used in Aedes mosquito management in Cairns, Queensland, Australia and the factors influencing the choice of these approaches.A case study design was used, drawing on two qualitative methods—key informant, semi‐structured interviews (n = 25), and a document review (n = 20). Thematic analysis was used to identify, analyse and attribute meaning from the data.Various approaches were used to engage the community, including direct interaction through door‐to‐door inspections, broad outreach via mass media campaigns, and community participation in a novel mosquito replacement strategy. Factors influencing the choice of these approaches included government legislative responsibilities, research‐related ethical obligations, work norms within local government and public health units, the perceived importance of gaining community trust, constraints on workforce capacity, time and funding.There were multiple factors influencing the community engagement approaches used in this study. Resource constraints, institutional norms and prevailing attitudes and beliefs were identified as hindering the use of more empowering approaches to engaging the community. These barriers should be considered and addressed in the planning of Aedes mosquito management to better support community engagement in this setting.Community engagement is an important aspect of managing the Aedes mosquito disease threat. With the global increase in Aedes mosquito‐borne disease risk, these findings can help other at‐risk settings understand potential organisational impediments to engaging the community. This is particularly important when advocating for the inclusion of bottom‐up approaches in policy, and to ensure sufficient resources are allocated to strengthen community engagement in Aedes mosquito management. [ABSTRACT FROM AUTHOR]

Mosquitoes and sandflies exhibit a wide range of blood feeding patterns, targeting a wide range of vertebrate species, including birds, mammals, reptiles, and amphibians, for proteins vital for egg development. This broad host range increases the opportunity for them to acquire pathogens of numerous debilitating‐and‐fatal diseases from various animal reservoirs, playing a significant role in disease crossover between animals and humans, also known as zoonotic transmission. This review focuses on the intricate blood‐feeding habits of these dipteran vectors, their sensory systems and the complex dance between host and pathogen during disease transmission. We delve into the influence of blood sources on pathogen spread by examining the insect immune response and its intricate interplay with pathogens. The remarkable sense of smell guiding them towards food sources and hosts is explored, highlighting the interplay of multiple sensory cues in their navigation. Finally, we examine the challenges in mosquito control strategies and explore innovations in this field, emphasizing the need for sustainable solutions to combat this global health threat. By understanding the biology and behaviour of these insects, we can develop more effective strategies to protect ourselves and mitigate the burden of vector‐borne diseases. [ABSTRACT FROM AUTHOR]

Insects geographically separated into island and mainland populations often exhibit phenotypic variations, a phenomenon known as insular conditions. These conditions can lead to rapid evolutionary changes that affect the morphological characteristics of mosquito vectors. Nevertheless, studies that specifically examine phenotype differences between island and mainland mosquito populations have been limited. In this study, wing variation in size and shape was investigated using the geometric morphometric (GM) technique in two dominant mosquito vectors, Aedes albopictus and Armigeres subalbatus, in the Ranong and Trat archipelagos of Thailand. Significant differences in average wing centroid size (CS) were found in 6 out of 15 population pairs for Ae. albopictus (p < 0.05) and in 5 population pairs for Ar. subalbatus (p < 0.05). After removing the allometric effect, canonical variate analyses (CVA) based on wing shape analysis revealed overlap across all populations for both Ae. albopictus and Ar. subalbatus. However, the statistical analysis indicated that Ar. subalbatus exhibited wing shape differences across all populations (p < 0.05), and most Ae. albopictus populations also displayed distinct wing shapes (p < 0.05), except for the populations from Chang Island and the mainland of Ranong, which showed no significant differences (p > 0.05). These findings enhance our understanding of mosquito adaptability in island regions and provide valuable data for the surveillance and monitoring of vector evolution. [ABSTRACT FROM AUTHOR]

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 eight populations from three continents, monitored their spontaneous locomotor activity patterns and analysed 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 the 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. [ABSTRACT FROM AUTHOR]

Aedes aegypti is an important mosquito vector of human disease with a wide distribution across the globe. Climatic conditions and ecological pressure drive differences in the biology of several populations of this mosquito species, including blood‐feeding behaviour and vector competence. However, no study has compared activity and/or sleep among different populations/lineages of Ae. aegypti. Having recently established sleep‐like states in three mosquito species with observable differences in timing and amount of sleep among species, we investigated differences in activity and sleep levels among 17 Ae. aegypti lines drawn from both its native range in Africa and its invasive range across the global tropics. Activity monitoring indicates that all the lines show consistent diurnal activity, but significant differences in activity level, sleep amount, number of sleep bouts and bout duration were observed among the lines. The variation in day activity was associated with differences in host preference and ancestry for the lineages collected in Africa. This study provides evidence that the diurnal sleep and activity profiles for Ae. aegypti are consistent, but there are significant population differences for Ae. aegypti sleep and activity levels and interactions with host species may significantly impact mosquito activity. [ABSTRACT FROM AUTHOR]

Mosquito traps, historically used for surveillance and research, have gained prominence as a tool for mosquito control, amidst concern over the environmental impact and increased resistance to insecticide‐based methods. In this study, we tested the effectiveness of a mass trapping barrier design with two types of traps, Mosquito Magnet (MM) traps and BG‐Protector (BGP) traps. This experiment was conducted in three coastal camping areas in southern France between summer and autumn 2022, where the presence of floodwater mosquito species with anthropophilic preferences like Aedes caspius represents a year‐long nuisance. MM traps were set around the campsite as a barrier to interfere with mosquitoes from entering the campsites, whereas BGP traps were set within the campsites, with the aim of diverting mosquitoes away from humans at peak activity hours. Over 210,000 mosquitoes of 11 species from 4 genera were collected by both trap types across treatment campsites, with no significant differences in mosquito community samplings between BGP and MM traps. Barrier traps effectively targeted Ae. caspius, reducing total mosquito abundance in two of the three study sites by 34% and 55%. This study provides valuable insights into the efficacy and feasibility of using mass trapping barriers as a complementary control strategy for mosquito species in wetlands. [ABSTRACT FROM AUTHOR]

BACKGROUND: Spinosad consists of spinosyn A and spinosyn D that are produced by the soil‐dwelling actinomycete Saccharopolyspora spinosa. It has been used to control a wide variety of arthropod pests of economic importance. Formulations of spinosad have been used to control larval mosquitoes since approximately 2010. However, the target site‐ and metabolism‐based resistance to this neurotoxin has been reported since 2000 in agricultural pests The current studies aim to further evaluate resistance risk and develop resistance prevention tactics in the southern house mosquito Culex quinquefasciatus. RESULTS: The first comparison group involved selection at lethal concentration, 75% (LC75) of technical spinosad for 30 generations, resulting in baseline resistance ratios (RRs) of 51.1‐fold at LC50 and 45.4‐fold at LC90 in Cx. quinquefasciatus. However, under the same conditions, selection by a combination of spinosad and Bacillus thuringiensis subsp. israelensis (B.t.i.), negated resistance development to spinosad, RRs ranging 1.00–1.75‐fold at LC50 and 0.83–1.76‐fold at LC90. At the same time, the selected population remained susceptible to the combination throughout the selection process, RRs fluctuating 0.74–1.38‐fold at LC50 and 0.63–1.23‐fold at LC90. CONCLUSION: Combination of spinosad and B.t.i. negates resistance development to spinosad, as opposed to spinosad alone in Cx. quinquefasciatus. Moreover, the species tested does not develop resistance to this combination upon repeated exposures, implying the potential for further developing this combination as a viable product for larval mosquito control. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

BACKGROUND: The incompatible insect technique (IIT) has been used for Aedes mosquito population suppression to curb the transmission of dengue. However, its wide application is limited owing to the low output of male mosquitoes and the risk of population replacement from the release of fertile Wolbachia‐infected females. This study aims to improve IIT efficiency for broader adoption. RESULTS: We assessed the impact of 10% pyriproxyfen (PPF) sticky powder exposure on Wolbachia (from Culex molestus)‐transinfected Aedes albopictus Guangzhou line (GUA line) (GC) mosquitoes. We found that the exposure caused chronic toxicity in adult mosquitoes without affecting the cytoplasmic incompatibility (CI)‐inducing capability of males. The PPF‐contaminated GC females exhibited significant sterilization and the ability to disseminate lethal doses of PPF to breeding sites. Subsequently, we conducted a field trial combining PPF with IIT aiming to suppress the Ae. albopictus population. This combined approach, termed boosted IIT (BIIT), showed a notable enhancement in population suppression efficiency. The improved efficacy of BIIT was attributed to the dispersion of PPF particles in the field via the released PPF‐contaminated male mosquitoes. During the BIIT field trial, no Wolbachia wPip‐positive Ae. albopictus larvae were detected, indicating the effective elimination of the risk of Wolbachia‐induced population replacement. Additionally, the field trial of BIIT against Ae. albopictus resulted in the suppression of the nontarget mosquito species Culex quinquefasciatus. CONCLUSION: Our results highlight the remarkable efficiency and feasibility of combining IIT with PPF in suppressing mosquito populations, facilitating the widespread implementation of IIT‐based management of mosquito‐borne diseases. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Aedes albopictus is an important vector of arboviruses and prefers small containers of stagnant water as oviposition sites. One of the mechanisms mosquitoes use to search for suitable oviposition sites is relying on odor cues from prospective sites and their surroundings. The genetic and molecular bases of this behavior are not known for Ae. albopictus. Oviposition site‐searching behavior can be separated into 2 stages: container location and water detection. We applied a glue compound to the antennae and the maxillary palps of adult females to mask their ability to detect molecules that may guide them to preferred oviposition sites. Treatment of the antennae significantly reduces the location index (P < 0.001), indicating a decreased ability to find oviposition sites, whereas no significant difference was observed in mosquitoes with maxillary palps treated with the same glue compound (P > 0.05). The detection time, measured as the duration from contact with the water surface to the deposition of the first egg, was extended in mosquitoes with treated antennae or maxillary palps, supporting the conclusion that olfaction is involved in the detection of oviposition site. Transcriptomic analysis identified differentially expressed olfactory‐related genes, including obp67, obp56d‐like, obp19d‐like and obp67‐like. RNA interference (RNAi)‐mediated knockdown of obp67 and obp56d‐like significantly affected the location index and detection time, respectively. Cas9/guide RNA‐mediated knockout of obp56d‐like resulted in a prolonged detection time, compared with the wild type (P < 0.05). These findings help to elucidate aspects of the olfactory mechanisms involved in Ae. albopictus oviposition site selection, and provide a basis for the development of mosquito surveillance and control strategies. [ABSTRACT FROM AUTHOR]

Anopheles stephensi Liston, 1901 (Diptera: culicidae) is a competent vector of Plasmodium falciparum (Haemosporida: plasmodiidae) malaria, and its expansion in the African continent is of concern due to its viability in urban settings and resistance to insecticides. To enhance its genetic tractability, we determined the utility of a ~2 kb An. stephensi lipophorin (lp) promoter fragment in driving transgene expression. Lipophorin genes are involved in lipid transport in insects, and an orthologous promoter in An. gambiae (AGAP001826) was previously demonstrated to successfully express a transgene. In the present study, we qualitatively characterised the expression of a ZsYellow fluorescent marker protein, expressed by An. stephensi lp promoter fragment. Our study indicated that the lp promoter fragment was effective, generating a distinct expression pattern in comparison to the commonly utilised 3xP3 promoter. The lp:ZsYellow fluorescence was largely visible in early instar larvae and appeared more intense in later instar larvae, pupae and adults, becoming especially conspicuous in adult females after a blood meal. Different isolines showed some variation in expression pattern and intensity. Aside from general transgene expression, as the lp promoter produces a suitable fluorescent protein marker expression pattern, it may facilitate genotypic screening and aid the development of more complex genetic biocontrol systems, such as multi‐component gene drives. This study represents an expansion of the An. stephensi genetic toolbox, an important endeavour to increase the speed of An. stephensi research and reach public health milestones in combating malaria. [ABSTRACT FROM AUTHOR]

We present a rigorous mathematical analysis of a non‐convex optimal control problem for mosquito populations. The nonlinear model for the dynamics of the mosquito population takes in consideration the iterations among the immature (aquatic) subpopulation, the adult winged subpopulation, and the environment resources; the immature subpopulation is assumed to be age‐structured. Moreover, the action of certain control mechanisms on these subpopulations is also taken in account. The cost functional to be minimized is non‐convex. The proof of the existence of an optimal control is done by using fixed point arguments and a special minimizing sequence obtained with the help of Ekeland's variational principle. [ABSTRACT FROM AUTHOR]

Mosquitoes such as Aedes aegypti must consume a blood meal for the nutrients necessary for egg production. Several transcriptome and proteome changes occur post‐blood meal that likely corresponds with codon usage alterations. Transfer RNA (tRNA) is the adapter molecule that reads messenger RNA codons to add the appropriate amino acid during protein synthesis. Chemical modifications to tRNA enhance codon decoding, improving the accuracy and efficiency of protein synthesis. Here, we examined tRNA modifications and transcripts associated with the blood meal and subsequent periods of vitellogenesis in A. aegypti. More specifically, we assessed tRNA transcript abundance and modification levels in the fat body at critical times post blood‐feeding. Based on a combination of alternative codon usage and identification of particular modifications, we discovered that increased transcription of tyrosine tRNAs is likely critical during the synthesis of egg yolk proteins in the fat body following a blood meal. Altogether, changes in both the abundance and modification of tRNA are essential factors in the process of vitellogenin production after blood‐feeding in mosquitoes. [ABSTRACT FROM AUTHOR]

Recent reports have disclosed the occurrence of Wolbachia in Aedes aegypti. Our study detected Wolbachia infection in Ae. aegypti by screening wild adult mosquitoes using two Wolbachia‐specific molecular markers. Overall, 444 adult Ae. aegypti mosquitoes were collected from April 2022 to October 2022 in Jeddah, Saudi Arabia. Each individual sample was processed and screened for the presence of Wolbachia using selected markers, the Wolbachia‐specific 16S rDNA and the Wolbachia surface protein gene (wsp), under optimized polymerase chain reaction (PCR) conditions, and sequenced. In total, 39 (8.78%) and 48 (10.81%) individual mosquito samples were determined to be infected with Wolbachia using the wsp and 16S rDNA markers, respectively. By utilizing two Wolbachia‐specific molecular markers, our study demonstrated the presence of Wolbachia from individual Ae. aegypti samples. Our results showed a low rate of Wolbachia infection and inferred that the detected strain belongs to supergroup B. [ABSTRACT FROM AUTHOR]

Culex tarsalis Coquillett (Diptera: Culicidae) mosquitoes are capable of vectoring numerous pathogens affecting public and animal health. Unfortunately, the probing behaviors of mosquitoes are poorly understood because they occur in opaque tissues. Electropenetrography (EPG) has the potential to elucidate these behaviors by recording the electrical signals generated during probing. We used an AC–DC EPG with variable input resistors (Ri levels) to construct a waveform library for Cx. tarsalis feeding on human hands. Biological events associated with mosquito probing were used to characterize waveforms at four Ri levels and with two electrical current types. The optimal settings for EPG recordings of Cx. tarsalis probing on human hands was an Ri level of 107 Ohms using an applied signal of 150 millivolts alternating current. Waveforms for Cx. tarsalis included those previously observed and associated with probing behaviors in Aedes aegypti L. (Diptera: Culicidae): waveform families J (surface salivation), K (stylet penetration through the skin), L (types 1 and 2, search for a blood vessel/ingestion site), M (types 1 and 2, ingestion), N (type 1, an unknown behavior which may be a resting and digestion phase), and W (withdrawal). However, we also observed variations in the waveforms not described in Ae. aegypti, which we named types L3, M3, M4, and N2. This investigation enhances our understanding of mosquito probing behaviors. It also provides a new tool for the automated calculation of peak frequency. This work will facilitate future pathogen acquisition and transmission studies and help identify new pest and disease management targets. [ABSTRACT FROM AUTHOR]

Front cover: Female mosquitoes suck blood to mature their eggs. It has been reported that fi brinopeptide A (FPA), which is cleaved from fi brinogen α chain during blood coagulation, makes mosquitoes feel "full" and stop sucking blood (Sakuma et al. (2024) Cell Reports 43: 114354, DOI: 10.1016/j.celrep.2024.114354). The mother in this painting is trying to use a mosquito net imbued with the ability of FPA to override the child's nightmare of a bloodsucking mosquito with the image of a satiated mosquito. In addition to fi brinogen and FPA, the mother's kimono shows schematic images of fi brin that has just begun to coagulate. Designed by TRAIS Co., Ltd. (Kobe, Japan). [ABSTRACT FROM AUTHOR]

Multiple Wolbachia strains can block pathogen infection, replication and/or transmission in Aedes aegypti mosquitoes under both laboratory and field conditions. However, Wolbachia effects on pathogens can be highly variable across systems and the factors governing this variability are not well understood. It is increasingly clear that the mosquito host is not a passive player in which Wolbachia governs pathogen transmission phenotypes; rather, the genetics of the host can significantly modulate Wolbachia‐mediated pathogen blocking. Specifically, previous work linked variation in Wolbachia pathogen blocking to polymorphisms in the mosquito alpha‐mannosidase‐2 (αMan2) gene. Here we use CRISPR‐Cas9 mutagenesis to functionally test this association. We developed αMan2 knockouts and examined effects on both Wolbachia and virus levels, using dengue virus (DENV; Flaviviridae) and Mayaro virus (MAYV; Togaviridae). Wolbachia titres were significantly elevated in αMan2 knockout (KO) mosquitoes, but there were complex interactions with virus infection and replication. In Wolbachia‐uninfected mosquitoes, the αMan2 KO mutation was associated with decreased DENV titres, but in a Wolbachia‐infected background, the αMan2 KO mutation significantly increased virus titres. In contrast, the αMan2 KO mutation significantly increased MAYV replication in Wolbachia‐uninfected mosquitoes and did not affect Wolbachia‐mediated virus blocking. These results demonstrate that αMan2 modulates arbovirus infection in A. aegypti mosquitoes in a pathogen‐ and Wolbachia‐specific manner, and that Wolbachia‐mediated pathogen blocking is a complex phenotype dependent on the mosquito host genotype and the pathogen. These results have a significant impact for the design and use of Wolbachia‐based strategies to control vector‐borne pathogens. [ABSTRACT FROM AUTHOR]

BACKGROUNDS: In order to provide a long‐lasting formulation for spinosad (SP) targeting larval stages of Aedes aegypti (Linnaeus) and others alike, a SP tablet was developed based on microspheres, using polylactic acid as inside coating material. The microspheres were encapsulated using polyethylene glycol and 1‐hexadecanol to form a sustained‐release SP tablet. Micromorphology, active ingredient loading, structure identification, photolysis resistance and biological activity were evaluated in this report. RESULTS: (i) The SP microspheres had an average particle size of 6.16 ± 2.28 μm, low adhesion and good dispersion as evaluated by scanning electron microscopy and morphology. (ii) The average active ingredient loading and encapsulation of SP microspheres were 32.80 ± 0.74% and 78.41 ± 2.22%, respectively. (iii) The chemical structure of encapsulated SP was confirmed by Fourier transform infrared and 1H‐nuclear magnetic resonance. (iv) The photostability of the microspheres and the tablets were evaluated. The results showed that DT50 (time required to dissipate 50% of the mass originally present) of SP was 0.95 days in microspheres and 6.94 days in tablets. (v) The long‐term insecticidal activity of SP tablets was investigated, and the tablet had a long‐lasting activity against the mosquito larvae, showing 100% larval mortality for 63 days. CONCLUSIONS: The study provided a new long‐lasting formulation of SP, which displayed good efficacy in the control of Ae. aegypti larvae. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Wolbachia continue to be reported in species previously thought to lack them, particularly Aedes aegypti mosquitoes. The presence of Wolbachia in this arbovirus vector is considered important because releases of mosquitoes with transinfected Wolbachia are being used around the world to suppress pathogen transmission and these efforts depend on a lack of Wolbachia in natural populations of this species. We previously assessed papers reporting Wolbachia in natural populations of Ae. aegypti and found little evidence that seemed convincing. However, since our review, more and more papers are emerging on Wolbachia detections in this species. Our purpose here is to evaluate these papers within the context of criteria we previously established but also new criteria that include the absence of releases of transinfections within the local areas being sampled which has contaminated natural populations in at least one case where novel detections have been reported. We also address the broader issue of Wolbachia detection in other insects where similar issues may arise which can affect overall estimates of this endosymbiont more generally. We note continuing shortcomings in papers purporting to find natural Wolbachia in Ae. aegypti which are applicable to other insects as well. [ABSTRACT FROM AUTHOR]

BACKGROUND: Ultra‐low volume (ULV) space sprays aerosolize insecticide formulated products (FP) to contact flying mosquitoes, while barrier sprays expose mosquitoes to FP residue on vegetation and other surfaces. Centers for Disease Control and Prevention bottle bioassays used to assess insecticide resistance are based on residual active ingredient (AI) exposure and do not directly relate to FP efficacy. The current pilot study developed a novel compact wind tunnel for mosquito exposure to FP. Caged Aedes albopictus and Culex pipiens/quinquefasciatus were exposed to undiluted Biomist®3 + 15 FP (permethrin AI) or air (control) within the wind tunnel, transferred to new cages, and held in a 28 °C incubator. Separate mosquitoes were exposed to residual permethrin AI (8 μg mL−1) in bottle bioassays. Mortality was monitored 15, 30, 60, and 120 min post‐exposure. RESULTS: Chi‐square tests (P < 0.05) showed significantly higher mortality in Aedes compared to Culex populations for most time points in both bioassay and wind tunnel exposure groups. As expected, mosquitoes exposed to Biomist®3 + 15 showed higher mortality rates than bottle bioassay exposure to permethrin. Two Culex colonies resistant to permethrin in bottle bioassays were susceptible to Biomist®3 + 15 in the wind tunnel. CONCLUSION: The novel compact wind tunnel developed here may be an alternative to field trials for testing FP efficacy, avoiding factors such as weather, logistical planning, and extended personnel hours. The wind tunnel could allow programs to conveniently test efficacy of multiple FP. Comparisons of different insecticide exposure methods provide practical information to inform operational decisions. © 2024 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Aedes aegypti is a mosquito species known for transmitting several diseases, with dengue fever being of utmost importance. Controlling the spread of dengue fever remains a significant global health challenge. Other diseases transmitted by Ae. aegypti include Zika virus, chikungunya, and yellow fever. Padina boryana algae were collected from the Red Sea coast south of Jeddah to evaluate the effectiveness of its alcoholic and aqueous extracts against Ae. aegypti mosquito larvae. The algae sample was washed, dried in the shade, processed, and subjected to aqueous and alcohol extraction using a rotary evaporator. The resulting extracts were tested for their larvicidal activity against Ae. aegypti mosquito larvae using standard bioassay techniques. The larval mortality rates were recorded, and the lethal concentration (LC50 and LC90) values were calculated. The results revealed that both the aqueous and alcoholic extracts of P. boryana algae exhibited significant larvicidal activity against Ae. aegypti mosquito larvae. However, the alcoholic formulation demonstrated higher efficacy compared to the aqueous formulation. The LC50 values for the alcoholic and aqueous extracts were 194.8 and 195.7 ppm, respectively. The LC90 values for both extracts were 653.1 and 656.7 ppm, respectively. This indicates the effectiveness of Padina extracts as an effective pesticide against the larvae of the Ae. aegypti mosquito. Overall, the alcohol extract showed promising efficacy, indicating its potential as a significant component in developing effective mosquito control strategies. [ABSTRACT FROM AUTHOR]

Mosquito‐borne diseases (MBDs) annually kill nearly half a million people. Due to the lack of effective vaccines and drugs on most MBDs, disease prevention relies primarily on controlling mosquitoes. Despite huge efforts having been put into mosquito control, eco‐friendly and sustainable mosquito‐control strategies are still lacking and urgently demanded. Most mosquito‐transmitted pathogens have lost the capacity of de novo nutrition biosynthesis, and rely on their vertebrate and invertebrate hosts for sustenance during the long‐term obligate parasitism process. Therefore, a better understanding of the metabolic interactions between mosquitoes and pathogens will contribute to the discovery of novel metabolic targets or regulators that lead to reduced mosquito populations or vector competence. This review summarizes the current knowledge about the effects of mosquito metabolism on the transmission of multiple pathogens. We also discuss that research in this area remains to be explored to develop multiple biological prevention and control strategies for MBDs. [ABSTRACT FROM AUTHOR]

Mosquito‐borne viruses (MBVs) are a large class of viruses transmitted mainly through mosquito bites, including dengue virus, Zika virus, Japanese encephalitis virus, West Nile virus, and chikungunya virus, which pose a major threat to the health of people around the world. With global warming and extended human activities, the incidence of many MBVs has increased significantly. Mosquito saliva contains a variety of bioactive protein components. These not only enable blood feeding but also play a crucial role in regulating local infection at the bite site and the remote dissemination of MBVs as well as in remodeling the innate and adaptive immune responses of host vertebrates. Here, we review the physiological functions of mosquito salivary proteins (MSPs) in detail, the influence and the underlying mechanism of MSPs on the transmission of MBVs, and the current progress and issues that urgently need to be addressed in the research and development of MSP‐based MBV transmission blocking vaccines. [ABSTRACT FROM AUTHOR]

The adaptation of Anopheles malaria vectors to domestic settings is directly linked to their ability to feed on humans. The strength of this species–habitat association is unequal across the species within the genus, with the major vectors being particularly dependent on humans. However, our understanding of how blood‐feeding behavior interacts with and adapts to environmental settings, including the presence of humans, remains limited. Using a field‐based approach, we first investigated Anopheles community structure and feeding behavior patterns in domestic and sylvatic settings in La Lopé National Park in Gabon, Central Africa. We characterized the preference indices using a dual‐host choice sampling approach across mosquito species, habitats, and seasons. We then quantified the plastic biting behavior of mosquito species in each habitat. We collected individuals from 16 Anopheles species that exhibited significant differences in species composition and abundance between sylvatic and domestic settings. The host‐seeking behavior also varied among the seven most abundant species. The general attractiveness to each host, human or animal, remained relatively constant for each species, but with significant variations between habitats across species. These variations, to more generalist and to more anthropophilic behavior, were related to seasonal changes and distance from the village, respectively. Finally, we pointed out that the host choice of major malaria vectors changed in the absence of humans, revealing a plastic feeding behavior of these species. This study highlights the effect of humans on Anopheles distribution and feeding evolution. The characterization of feeding behavior in wild and domestic settings provides opportunities to better understand the interplay between genetic determinants of host preference and ecological factors. Our findings suggest that protected areas may offer alternative thriving conditions to major malaria vectors. [ABSTRACT FROM AUTHOR]

The effects of resource subsidies on a recipient ecosystem depends on a variety of factors. Firstly, increasing the supply of limiting nutrients tends to increase the accumulation of biomass across different compartments of the recipient food web. Secondly, in the case of aquatic microorganisms, this accumulation may also be contingent on inputs of energy through light, mediating interactions between heterotrophic bacteria and autotrophic algae. Thirdly, macroscopic consumers feed upon microorganisms and recycle nutrients through excretion and egestion, profoundly affecting nutrient cycling.In order to examine the context‐dependency of nutrient cycling in aquatic systems, we performed an experiment in mesocosms where we followed the responses of dissolved nutrients, microorganisms, and larvae of the cosmopolitan mosquito Culex quinquefasciatus (Diptera: Culicidae) to two terrestrial subsidies differing in carbon (C):nutrient, in combination with two light intensities.We found that the interactions amongst bacteria and algae themselves remained generally unimportant after accounting for treatment effects, and that light did mediate some of the effects of nutrient subsidies on microorganisms. We also found that the presence of mosquito larvae was associated with altered concentrations of nitrogen (N) in some treatments, ultimately benefitting algae. Finally, we found that low C:nutrient subsidies generally increased the development rate of mosquito larvae, and that increased light exposure led to higher mosquito survival.Overall, these patterns may be explained by strong nitrogen limitation in our system, causing both group of microorganisms to respond similarly to variations in nutrient supply without direct covariation, and to the key role of N recycling by mosquito larvae in sustaining algal densities in exposed treatments.The context‐dependency in our study may reflect elemental or molecular constraints other than phosphorus. Our experiment thus calls for greater synthesis amongst ecological theories. [ABSTRACT FROM AUTHOR]

Mayaro virus (MAYV; Alphavirus: Togaviridae) is an emerging pathogen in Latin America, causing fever and polyarthritis. Sporadic outbreaks of MAYV have occurred in the region, with reported human cases being imported to Europe and North America. Although primarily a risk for those residing in the Amazon basin's tropical forests, recent reports highlight that urbanization would increase the risk of MAYV transmission in Latin America. Urban emergence depends on human susceptibility and the ability of mosquitos like Aedes aegypti (Linnaeus, 1762) (Diptera: Culicidae) to transmit MAYV. Despite the absence of active MAYV transmission in Argentine, the risk of introduction is substantial due to human movement and the presence of Ae. aegypti in the region. This study aimed to evaluate the susceptibility of different Argentine Ae. aegypti populations to MAYV genotype L (MAYV‐L) using dose–response assays and determine barriers to virus infection, dissemination and transmission. Immature mosquito stages were collected in Buenos Aires, Córdoba and Rosario cities. Female Ae. aegypti (F2) were orally infected by feeding on five concentrations of MAYV‐L, ranging from 1.0 to 6.0 log10 PFU/mL. Abdomens, legs and saliva were analysed using viral plaque assays. Results revealed that MAYV‐L between infection and dissemination were associated with viral doses rather than the population origin. Infection rates varied between 3% and 65%, with a 50% infectious dose >5.5 log10 PFU/mL. Dissemination occurred at 39%, with a 50% dissemination dose of ~6.0 log10 PFU/mL. Dissemination among infected mosquitoes ranged from 60% to 86%, and transmission from disseminated mosquitoes ranged from 11% to 20%. Argentine Ae. aegypti populations exhibited a need for higher viral doses of MAYV‐L than those typically found in humans to become infected. In addition, only a small proportion of infected mosquitoes were capable of transmitting the virus. Understanding MAYV transmission in urban areas is crucial for public health interventions. [ABSTRACT FROM AUTHOR]

Microplastics (plastic particles <5 mm) permeate aquatic and terrestrial ecosystems and constitute a hazard to animal life. Although much research has been conducted on the effects of microplastics on marine and benthic organisms, less consideration has been given to insects, especially those adapted to urban environments. Here, we provide a perspective on the potential consequences of exposure to microplastics within typical larval habitat on mosquito biology. Mosquitoes represent an ideal organism in which to explore the biological effects of microplastics on terrestrial insects, not least because of their importance as an infectious disease vector. Drawing on evidence from other organisms and knowledge of the mosquito life cycle, we summarise some of the more plausible impacts of microplastics including physiological, ecotoxicological and immunological responses. We conclude that although there remains little experimental evidence demonstrating any adverse effect on mosquito biology or pathogen transmission, significant knowledge gaps remain, and there is now a need to quantify the effects that microplastic pollution could have on such an important disease vector. [ABSTRACT FROM AUTHOR]

Global climate change is predicted to cause range shifts in the mosquito species that transmit pathogens to humans and wildlife. Recent modeling studies have sought to improve our understanding of the relationship between temperature and the transmission potential of mosquito‐borne pathogens. However, the role of the vertebrate host population, including the importance of host behavioral defenses on mosquito feeding success, remains poorly understood despite ample empirical evidence of its significance to pathogen transmission. Here, we derived thermal performance curves for mosquito and parasite traits and integrated them into two models of vector–host contact to investigate how vertebrate host traits and behaviors affect two key thermal properties of mosquito‐borne parasite transmission: the thermal optimum for transmission and the thermal niche of the parasite population. We parameterized these models for five mosquito‐borne parasite transmission systems, leading to two main conclusions. First, vertebrate host availability may induce a shift in the thermal optimum of transmission. When the tolerance of the vertebrate host to biting from mosquitoes is limited, the thermal optimum of transmission may be altered by as much as 5°C, a magnitude of applied significance. Second, thresholds for sustained transmission depend nonlinearly on both vertebrate host availability and temperature. At any temperature, sustained transmission is impossible when vertebrate hosts are extremely abundant because the probability of encountering an infected individual is negligible. But when host biting tolerance is limited, sustained transmission will also not occur at low host population densities. Furthermore, our model indicates that biting tolerance should interact with vertebrate host population density to adjust the parasite population thermal niche. Together, these results suggest that vertebrate host traits and behaviors play essential roles in the thermal properties of mosquito‐borne parasite transmission. Increasing our understanding of this relationship should lead us to improved predictions about shifting global patterns of mosquito‐borne disease. [ABSTRACT FROM AUTHOR]

The mere presence of predators causes prey organisms to display predation‐avoidance strategies. Predator presence is often communicated through predator‐released chemical signals. Ovipositing female mosquitoes of several species are repelled by unknown signals released from larvivorous fish.It was previously suggested that in many cases, a predator's microbiota plays an important role in the release of these signals; however, this mechanism is still poorly understood.In this study, we looked into the effects of the microbiota originating from the larvivorous Gambusia affinis (Baird and Girard) on the oviposition behaviour of gravid female mosquitoes. We used fish with altered microbiota and bacterial isolates in a set of outdoor mesocosm experiments to address this aim.We show that interference with the fish microbiota significantly reduces fish's repellent effect. We further show that the bacterium Pantoea pleuroti, isolated from the skin of the fish, repels oviposition of Culex laticinctus Edwards and Culiseta longiareolata Macquart mosquitoes similarly to the way in which live fish repel them.Our results highlight the importance of bacteria in the interspecies interactions of their hosts. Furthermore, this finding may lead to the development of an ecologically friendly mosquito repellent, that may reduce the use of larvivorous fish for mosquito control. [ABSTRACT FROM AUTHOR]

Background and objective: No autochthonous human cases of Japanese encephalitis (JE) have been reported to date in the European Union (EU). In this study, we assess the likelihood of Japanese encephalitis virus (JEV) introduction and transmission within the EU and propose outbreak response measures. Risk assessment: Given the global geographical distribution of JEV, the probability of virus introduction into the EU is currently very low, with viremic bird migration being the most plausible pathway of introduction. However, this likelihood would significantly increase if the virus were to become established in the Middle East, Caucasus, Central Asia or Africa. Considering the environmental conditions that are expected to be conducive for virus circulation, there is a high likelihood of virus transmission within the EU after its introduction in environmentally suitable areas. The spread of the virus within the EU would likely occur through the movement of wild birds, pigs and mosquitoes. Mitigation: To mitigate or potentially contain the emergence of JE in the EU, early detection of both human and animal cases will be crucial. [ABSTRACT FROM AUTHOR]

Diapause, a form of dormancy to delay or halt the reproductive development during unfavourable seasons, has evolved in many insect species. One example is aestivation, an adult‐stage diapause enhancing malaria vectors' survival during the dry season (DS) and their re‐establishment in the next rainy season (RS). This work develops a novel genetic approach to estimate the number or proportion of individuals undergoing diapause, as well as the breeding sizes of the two seasons, using signals from temporal allele frequency dynamics. Our modelling shows the magnitude of drift is dampened at early RS when previously aestivating individuals reappear. Aestivation severely biases the temporal effective population size (Ne$$ {N}_e $$), leading to overestimation of the DS breeding size by 1/1−α2$$ 1/{\left(1‐\alpha \right)}^2 $$ across 1 year, where α$$ \alpha $$ is the aestivating proportion. We find sampling breeding individuals in three consecutive seasons starting from an RS is sufficient for parameter estimation, and perform extensive simulations to verify our derivations. This method does not require sampling individuals in the dormant state, the biggest challenge in most studies. We illustrate the method by applying it to a published data set for Anopheles coluzzii mosquitoes from Thierola, Mali. Our method and the expected evolutionary implications are applicable to any species in which a fraction of the population diapauses for more than one generation, and are difficult or impossible to sample during that stage. [ABSTRACT FROM AUTHOR]

Mosquitoes transmit many disease-relevant flaviviruses. Efficient viral transmission to mammalian hosts requires mosquito salivary factors. However, the specific salivary components facilitating viral transmission and their mechanisms of action remain largely unknown. Here, we show that a female mosquito salivary gland-specific protein, here named A. aegypti Neutrophil Recruitment Protein (AaNRP), facilitates the transmission of Zika and dengue viruses. AaNRP promotes a rapid influx of neutrophils, followed by virus-susceptible myeloid cells toward mosquito bite sites, which facilitates establishment of local infection and systemic dissemination. Mechanistically, AaNRP engages TLR1 and TLR4 of skin-resident macrophages and activates MyD88-dependent NF-κB signaling to induce the expression of neutrophil chemoattractants. Inhibition of MyD88-NF-κB signaling with the dietary phytochemical resveratrol reduces AaNRP-mediated enhancement of flavivirus transmission by mosquitoes. These findings exemplify how salivary components can aid viral transmission, and suggest a potential prophylactic target. Synopsis: Mosquito saliva contains factors that promote flavivirus infection in the animal host. This study reveals that the mosquito salivary protein AaNRP mediates cutaneous recruitment of flavivirus-susceptible myeloid cells to mosquito bite sites, thus aiding flavivirus transmission. AaNRP is a female-mosquito-specific salivary protein. AaNRP stimulates skin-resident macrophages via TLR1/4-MyD88-NF-κB signaling to release chemoattractants for neutrophils. The AaNRP-induced influx of myeloid cells promotes flaviviral cutaneous infection. Dietary supplementation with resveratrol suppresses AaNRP-promoted flavivirus transmission by mosquitoes. AaNRP is a female-specific mosquito salivary protein that promotes Zika and dengue virus infection by stimulating skin macrophage-dependent neutrophil recruitment. [ABSTRACT FROM AUTHOR]

The ability of mosquitoes to transmit a pathogen is affected, among other factors, by their survival rate, which is partly modulated by their microbiota. Mosquito microbiota is acquired during the larval phase and modified during their development and adult feeding behavior, being highly dependent on environmental factors. Pharmaceutical residues including antibiotics are widespread pollutants potentially being present in mosquito breeding waters likely affecting their microbiota. Here, we used Culex pipiens mosquitoes to assess the impact of antibiotic exposure during the larval and adult stages on the survival rate of adult mosquitoes. Wild‐collected larvae were randomly assigned to two treatments: larvae maintained in water supplemented with antibiotics and control larvae. Emerged adults were subsequently assigned to each of two treatments, fed with sugar solution with antibiotics and fed only with sugar solution (controls). Larval exposure to antibiotics significantly increased the survival rate of adult females that received a control diet. In addition, the effect of adult exposure to antibiotics on the survival rate of both male and female mosquitoes depended on the number of days that larvae fed ad libitum in the laboratory before emergence. In particular, shorter larval ad libitum feeding periods reduced the survival rate of antibiotic‐treated adult mosquitoes compared with those that emerged after a longer larval feeding period. These differences were not found in control adult mosquitoes. Our results extend the current understanding of the impact of antibiotic exposure of mosquitoes on a key component of vectorial capacity, that is the vector survival rate. [ABSTRACT FROM AUTHOR]

Mosquitoes are of great medical significance as vectors of many deadly diseases. Mitogenomes have been widely used in phylogenetic studies, but mitogenome knowledge within the family Culicidae is limited, and Culicidae phylogeny is far from resolved. In this study, we surveyed the mitogenomes of 149 Culicidae species, including 7 newly sequenced species. Comparative analysis of 149 mosquito mitogenomes shows gene composition and order to be identical to that of an ancestral insect, and the AT bias, length variation, and codon usage are all consistent with that of other reported Dipteran mitogenomes. Phylogenetic analyses based on the DNA sequences of the 13 protein‐coding genes from the 149 species robustly support the monophyly of the subfamily Anophelinae and the tribes Aedini, Culicini, Mansoniini, Sabethini, and Toxorhynchitini. To resolve ambiguous relationships between clades within the subfamily Culicinae, we performed topological tests and show that Aedini is a sister to Culicini and that Uranotaeniini is a sister to (Mansoniini + (Toxorhynchitini + Sabethini)). In addition, we estimated divergence times using a Bayesian relaxation clock based on the sequence data and 3 fossil calibration points. The results show mosquitoes diverged during the Early Jurassic with massive Culicinae radiations during the Cretaceous, coincident with the emergence of angiosperms and the burst of mammals and birds. Overall, this study, which uses the largest number of Culicidae mitogenomes sequenced to date, comprehensively reveals the mitogenome characteristics and mitogenome‐based phylogeny and divergence times of Culicidae, providing information for further studies on the mitogenome, phylogeny, evolution, and taxonomic revision of Culicidae. [ABSTRACT FROM AUTHOR]

Dengue fever is currently one of the most serious mosquito‐borne infectious disease in the world. How to effectively prevent the outbreak of dengue fever has become a matter of significant public health concern. In this work, the cytoplasmic incompatibility induced by Wolbachia is assumed to be complete. Based on this assumption, we establish an extended discrete Ricker model with overlapping generations to investigate the suppression of mosquito population in the wild by adopting two different release strategies: the constant release strategy and the proportional release strategy. We prove the nonnegativity, boundedness, and stability of equilibrium points and finally find the release threshold, denoted as r1∗$$ {r}_1&#x0005E;{\ast } $$ and k1∗$$ {k}_1&#x0005E;{\ast } $$, for the successful suppression in these two release strategies. In addition, we demonstrate that the model that adopts the constant release strategy, respectively, has a saddle node bifurcation when r=r1∗$$ r&#x0003D;{r}_1&#x0005E;{\ast } $$ and a stable period‐doubling bifurcation when r=r2∗$$ r&#x0003D;{r}_2&#x0005E;{\ast } $$. While in the case of proportional release strategy, the model exhibits a transcritical bifurcation when k=k1∗$$ k&#x0003D;{k}_1&#x0005E;{\ast } $$ and a stable period‐doubling bifurcation when k=k2∗$$ k&#x0003D;{k}_2&#x0005E;{\ast } $$. Finally, we substantiate the conclusions through numerical simulations. [ABSTRACT FROM AUTHOR]

Understanding microbial roles in ecosystem function requires integrating microscopic processes into food webs. The carnivorous pitcher plant, Sarracenia purpurea, offers a tractable study system where diverse food webs of macroinvertebrates and microbes facilitate digestion of captured insect prey, releasing nutrients supporting the food web and host plant. However, how interactions between these macroinvertebrate and microbial communities contribute to ecosystem functions remains unclear. We examined the role of the pitcher plant mosquito, Wyeomyia smithii, in top‐down control of the composition and function of pitcher plant microbial communities. Mosquito larval abundance was enriched or depleted across a natural population of S. purpurea pitchers over a 74‐day field experiment. Bacterial community composition and microbial community function were characterized by 16S rRNA amplicon sequencing and profiling of carbon substrate use, bulk metabolic rate, hydrolytic enzyme activity, and macronutrient pools. Bacterial communities changed from pitcher opening to maturation, but larvae exerted minor effects on high‐level taxonomic composition. Higher larval abundance was associated with lower diversity communities with distinct functions and elevated nitrogen availability. Treatment‐independent clustering also supported roles for larvae in curating pitcher microbial communities through shifts in community diversity and function. These results demonstrate top‐down control of microbial functions in an aquatic microecosystem. [ABSTRACT FROM AUTHOR]

BACKGROUND: The potential reappearance and/or expansion of vector‐borne diseases is one of the terrifying issues awaiting humanity in the context of climate change. The presence of competent Anopheles vectors, as well as suitable environmental circumstances, may result in the re‐emergence of autochthonous Malaria, after years of absence. In Morocco, international travel and migration movements from Malaria‐endemic areas have recently increased the number of imported cases, raising awareness of Malaria's possible reintroduction. Using machine learning we developed model predictions, under current and future (2050) climate, for the prospective distribution of Anopheles claviger, Anopheles labranchiae, Anopheles multicolor, and Anopheles sergentii implicated or incriminated in Malaria transmission. RESULTS: All modelled species are expected to find suitable habitats and have the potential to become established in the northern and central parts of the country, under present‐day conditions. Distinct changes in the distributions of the four mosquitoes are to be expected under climate change. Even under the most optimistic scenario, all investigated species are likely to acquire new habitats that are now unsuitable, placing further populations in danger. We also observed a northward and altitudinal shift in their distribution towards higher altitudes. CONCLUSION: Climate change is expected to expand the potential range of malaria vectors in Morocco. Our maps and predictions offer a way to intelligently focus efforts on surveillance and control programmes. To reduce the threat of human infection, it is crucial for public health authorities, entomological surveillance teams, and control initiatives to collaborate and intensify their actions, continuously monitoring areas at risk. © 2023 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

In the Anopheles genus, various mosquito species are able to transmit the Plasmodium parasites responsible for malaria, while others are non‐vectors. In an effort to better understand the biology of Anopheles species and to quantify transmission risk in an area, the identification of mosquito species collected in the field is an essential but problematic task. Morphological identification requires expertise and cannot be checked after processing samples in a destructive treatment, while sequencing of numerous samples is costly. Here, we introduce a method of Species identification via Simple Observation Coupled with Capillary Electrophoresis Technology (SOCCET). This molecular technique of species identification is based on precise determination of ITS2 length combined with a simple visual observation, the colour of mosquito hindleg tip. DNA extracted from field‐collected Anopheles mosquitoes was amplified with universal Anopheles ITS2 primers and analysed with a capillary electrophoresis device, which precisely determines the size of the fragments. We defined windows of amplicon sizes combined with fifth hind tarsus colour, which allows discrimination of the major Anopheles species found in our collections. We validated our parameters via Sanger sequencing of ITS2 amplicons. Using the SOCCET method, we characterised the composition of Anopheles populations in five locations of French Guiana, where we detected a total of nine species. Anopheles braziliensis and Anopheles darlingi were detected in four locations each and represented 13 and 67% of our samples, respectively. The SOCCET method can be particularly useful when working with routine sampling sites with a moderate species diversity, that is, when the number of local species is too high to define species‐specific primers but low enough to avoid individual ITS2 sequencing. This tool will be of interest to evaluate local malaria transmission risk and this approach may be further implemented for other mosquito genera. [ABSTRACT FROM AUTHOR]

Dengue represents an increasing public health burden worldwide. In Africa, underreporting and misdiagnosis often mask its true epidemiology, and dengue is likely to be both more widespread than reported data suggest and increasing in incidence and distribution. Wolbachia‐based dengue control is underway in Asia and the Americas but has not to date been deployed in Africa. Due to the genetic heterogeneity of African Aedes aegypti populations and the complexity of the host‐symbiont interactions, characterization of key parameters of Wolbachia‐carrying mosquitoes is paramount for determining the potential of the system as a control tool for dengue in Africa. The wAlbB Wolbachia strain was stably introduced into an African Ae. aegypti population by introgression, and showed high intracellular density in whole bodies and different mosquito tissues; high intracellular density was also maintained following larval rearing at high temperatures. No effect on the adult lifespan induced by Wolbachia presence was detected. Moreover, the ability of this strain to strongly inhibit DENV‐2 dissemination and transmission in the host was also demonstrated in the African background. Our findings suggest the potential of harnessing Wolbachia for dengue control for African populations of Ae. aegypti. [ABSTRACT FROM AUTHOR]

Galicia, located in the northwestern part of Spain, has a great number and variety of aquatic ecosystems where mosquitoes can breed. Despite the sanitary relevance of these insects, studies on mosquito populations in the region are still scarce. The field research was carried out in 48 sampling points (27 continental lagoons, 12 coastal lagoons and 9 temporary ponds) throughout the entire Galician territory. The samples were collected intermittently and seasonally through different water quality monitoring projects between 2001 and 2017. More than 1500 mosquito larvae belonging to 10 species of five genera (Aedes, Anopheles, Coquillettidia, Culex and Culiseta) were identified. Anopheles (Anopheles) maculipennis s.l. Meigen was the most widely distributed species in the study, being especially dominant in rural areas. In contrast, Culex (Culex) pipiens Linnaeus and Culex (Culex) theileri Theobald showed a preference for breeding in urban areas. New contributions to the knowledge about the larval ecology and distribution of these mosquito species are made throughout this study, including information about the tolerance of each species to water parameters (temperature, pH, dissolved oxygen and conductivity). Likewise, the relationship between culicid diversity and the habitat characteristics of the breeding sites (water body type, climate and level of anthropization) is discussed. [ABSTRACT FROM AUTHOR]

Plasmodium sporozoite development in and egress from oocysts in the Anopheles mosquito remains largely enigmatic. In a previously performed high‐throughput knockout screen, the putative subunit 5 of the prefoldin complex (PbPCS5, PBANKA_0920100) was identified as essential for parasite development during mosquito and liver stage development. Here we generated and analyzed a PbPCS5 knockout parasite line during its development in the mosquito. Interestingly, PbPCS5 deletion does not significantly affect oocyst formation but leads to a growth defect resulting in aberrantly shaped sporozoites. Sporozoites produced in the absence of PbPCS5 were thinner, markedly elongated, and did, in most cases, not contain a nucleus. Sporozoites contained fewer subpellicular microtubules, which reached deep into the sporoblast during sporogony where they contacted and indented nuclei. These aberrantly shaped sporozoites did not reach the salivary glands, and we, therefore, conclude that PbPCS5 is essential for sporogony and the life cycle progression of the parasite during its mosquito stage. [ABSTRACT FROM AUTHOR]

Plasmodium parasites, the eukaryotic pathogens that cause malaria, feature three distinct invasive forms tailored to the host environment they must navigate and invade for life cycle progression. One conserved feature of these invasive forms is the micronemes, apically oriented secretory organelles involved in egress, motility, adhesion, and invasion. Here we investigate the role of GPI‐anchored micronemal antigen (GAMA), which shows a micronemal localization in all zoite forms of the rodent‐infecting species Plasmodium berghei. ∆GAMA parasites are severely defective for invasion of the mosquito midgut. Once formed, oocysts develop normally, however, sporozoites are unable to egress and exhibit defective motility. Epitope‐tagging of GAMA revealed tight temporal expression late during sporogony and showed that GAMA is shed during sporozoite gliding motility in a similar manner to circumsporozoite protein. Complementation of P. berghei knockout parasites with full‐length P. falciparum GAMA partially restored infectivity to mosquitoes, indicating conservation of function across Plasmodium species. A suite of parasites with GAMA expressed under the promoters of CTRP, CAP380, and TRAP, further confirmed the involvement of GAMA in midgut infection, motility, and vertebrate infection. These data show GAMA's involvement in sporozoite motility, egress, and invasion, implicating GAMA as a regulator of microneme function. [ABSTRACT FROM AUTHOR]

The mosquito microbiome is critical for host development and plays a major role in many aspects of mosquito biology. While the microbiome is commonly dominated by a small number of genera, there is considerable variation in composition among mosquito species, life stages, and geography. How the host controls and is affected by this variation is unclear. Using microbiome transplant experiments, we asked whether there were differences in transcriptional responses when mosquitoes of different species were used as microbiome donors. We used microbiomes from four different donor species spanning the phylogenetic breadth of the Culicidae, collected either from the laboratory or the field. We found that when recipients received a microbiome from a donor reared in the laboratory, the response was remarkably similar regardless of donor species. However, when the donor had been collected from the field, many more genes were differentially expressed. We also found that while the transplant procedure did have some effect on the host transcriptome, this is likely to have had a limited effect on mosquito fitness. Overall, our results highlight the possibility that variation in mosquito microbiome communities is associated with variability in host–microbiome interactions and further demonstrate the utility of the microbiome transplantation technique for investigating host–microbe interactions in mosquitoes. [ABSTRACT FROM AUTHOR]

The Aedes aegypti (Linnaeus, 1762) mosquito is the main vector of dengue, chikungunya and Zika and is well established today all over the world. The species comprises two forms: the ancestral form found throughout Africa and a global domestic form that spread to the rest of the tropics and subtropics. In Saudi Arabia, A. aegypti has been known in the southwest since 1956, and previous genetic studies clustered A. aegypti from Saudi Arabia with the global domestic form. The purpose of this study was to assess the genetic structure of A. aegypti in Saudi Arabia and determine their geographic origin. Genetic data for 17 microsatellites were collected for A. aegypti ranging from the southwestern highlands of Saudi Arabia on the border of Yemen to the north‐west in Madinah region as well as from Thailand and Uganda populations (as representatives of the ancestral African and global domestic forms, respectively). The low but significant level of genetic structuring in Saudi Arabia was consistent with long‐distance dispersal capability possibly through road connectivity and human activities, that is, passive dispersal. There are two main genetic groupings in Saudi Arabia, one of which clusters with the Ugandan population and the other with the Thailand population with many Saudi Arabian individuals having mixed ancestry. The hypothesis of genetic admixture of the ancestral African and global domestic forms in Saudi Arabia was supported by approximate Bayesian computational analyses. The extent of admixture varied across Saudi Arabia. African ancestry was highest in the highland area of the Jazan region followed by the lowland Jazan and Sahil regions. Conversely, the western (Makkah, Jeddah and Madinah) and Najran populations corresponded to the global domesticated form. Given potential differences between the forms in transmission capability, ecology and behaviour, the findings here should be taken into account in vector control efforts in Saudi Arabia. [ABSTRACT FROM AUTHOR]