Journal of Medical Entomology

BackgroundAttractive Targeted Sugar Baits (ATSBs) are a promising, environmentally friendly approach for mosquito control, but the direct field application, scalability and long-term effectiveness of ATSBs across diverse mosquito species remain significant challenges. Methodology/Principal FindingsWe assessed the efficacy of a genetically engineered RNA interference (RNAi) yeast strain (Sh.463_56.10R) formulated in three sugar baits, soda (Coca-ColaTM), 10% sucrose, and a commercial mosquito bait (BaitStabTM), on Aedes, Anopheles and Culex mosquitoes. All RNAi yeast bait formulations induced significantly higher mean mortality (87-100%) compared to the control groups (0-9%; P<0.0001), but mosquitoes exhibited a higher feeding preference for RNAi yeast-soda baits, which induced mortality rates of 94-100% (P < 0.0001) recorded across all mosquito species. Additionally, to assess the competitiveness of the RNAi yeast-soda bait to other tropical sugar sources, semi-field choice assays were conducted in Trinidad, West Indies using competing flowering plants and fruits typically found in residential environments. The RNAi yeast-soda ATSB continued to perform well in the presence of competing floral and fruit sugar sources during both Aedes albopictus and Culex quiquefasciatus trials, though the presence of several fruits and flowers did reduce A. aegypti mortality, suggesting that further field testing will be necessary. The residual activity of the Sh.463_56.10R + soda formulation was retained for at least 14 months, with sustained 100% mortality in C. quinquefasciatus and 93-100% mortality in Aedes aegypti, Anopheles gambiae and Anopheles stephensi. The RNAi yeast-soda ATSB also performed well in semi-field studies performed with a prototype soda bottle feeder. Conclusions/SignificanceThis study demonstrates the potential of soda-baited RNAi yeast as a potent, long-lasting, and scalable platform for ATSB-based mosquito control as a component of integrated vector management programs. Author SummaryMosquito-borne diseases continue to affect millions of people worldwide, and current mosquito control methods face challenges such as low public uptake, insecticide resistance and environmental concerns. Here we evaluated a new and environmentally friendly approach to mosquito control using ATSBs. We tested genetically engineered species-specific yeast producing RNAi molecules capable of killing mosquitoes that feed on it. We mixed the yeast with three different sugar baits, including soda (Coca-ColaTM), 10% sucrose, and the commercial mosquito bait BaitStabTM formulation, and evaluated how well they worked against different mosquitoes. The results showed that the RNAi yeast mixed with soda was the most effective, killing up to 100% of mosquitoes in laboratory and outdoor tests. The bait remained effective in the presence of many competing natural tropical fruit and floral sugar sources. Remarkably, the bait, which can be delivered in a soda bottle feeder, stayed active for at least 14 months under simulated field conditions. These findings suggest that soda-based RNAi yeast baits could provide a practical, long-lasting and scalable tool for mosquito control and may help strengthen future strategies to reduce mosquito-borne diseases.

Insecticide spraying is a common strategy for controlling dengue outbreaks, but its effectiveness is compromised by the development of resistance in mosquito populations. In this study, we subjected a strain of Aedes aegypti known for its exceptional ability to develop resistance to controlled permethrin and lambda-cyhalothrin insecticides pressure using two different concentrations. We analyzed resistance mechanisms that are enhanced at each concentration and used RNA sequencing to identify transcripts specifically associated with these exposure levels. Our objective was to uncover the molecular mechanisms triggered by different insecticide concentrations and to distinguish responses between type I and type II pyrethroids, which differ in chemical structure. Our results showed that kdr mutations confer only moderate levels of resistance, as do detoxifying enzymes. For lambda-cyhalothrin, we identified genes involved in the electron transport chain, mitochondrial function, and overall responses to oxidative stress. tRNA transcripts were also upregulated, along with mitochondrial and stress-response transcripts, suggesting a metabolic shift, particularly toward maintaining homeostasis under oxidative stress. These changes point to mechanisms that sustain resistance to this type II insecticide beyond direct detoxification in this population. On the contrary, permethrin induced marked overexpression of cuticle genes, CYP450 genes (especially CYP4), and Odorant Binding Proteins. These expression patterns, together with metabolic enzymes, point to detoxification, reduced penetration, or even sequestration of insecticide, all of which intensify with increasing concentrations. This overregulation of genes suggests an integrated response complemented by classical metabolic detoxification and accompanied by overregulation of mitochondrial complexes. We showed that despite the shared mode of action of the insecticides permethrin and lambda-cyhalothrin, they elicit distinct responses in this Ae. aegypti population. We also showed that the transcriptomic response depends on insecticide concentration and may modulate insecticide tolerance. This article advances understanding of the complexity of pyrethroid resistance in Aedes aegypti and underscores the importance of considering both the insecticide type and the concentration used in vector control programs. Author summaryAedes aegypti mosquitoes transmit dengue and other arboviruses, being a major public health problem in tropical regions like Colombia, where control relies on pyrethroid insecticide spraying. Based on reports of inconsistent results in the field due to different effects of insecticide concentrations, we recreated variable doses by exposing a resistant Colombian Aedes aegypti strain to low (LC25) and high (LC75) concentrations of permethrin (type I) and lambda-cyhalothrin (type II) to identify concentration-dependent resistance mechanisms. Using genetic mutation analysis, enzyme activity assays, and RNA sequencing, we identified the molecular mechanisms these mosquitoes use to survive. Knockdown resistance (kdr) and detoxification enzymes contributed to some extent to resistance but varied by insecticide type and concentration. RNAseq identified that lambda-cyhalothrin upregulated genes for mitochondrial energy production, oxidative stress defense, immune signaling, and transfer RNAs, facilitating homeostasis under chemical stressors. Permethrin instead upregulated genes for cuticle thickening, cytochrome P450 enzymes, and odorant-binding proteins, which are associated with improved penetration barriers, and metabolic breakdown that intensified with higher concentrations. This reveals pyrethroid resistance as complex beyond classic mechanisms, as even low field doses favor stress tolerance or physical defenses to evade sprays. We detected transcripts that improve survival at high concentrations and could be selected in these mosquitoes. Carefully selecting the type of pyrethroid to be used and the dose should be an important factor in vector control. This optimizes current interventions, prolongs their efficacy, and aids researchers in modeling resistance to protect communities.

BackgroundThe malaria transmission potential and the vulnerability of Anopheles mosquitoes to different vector control methods depend, among other factors, on the endophily, endophagy, anthropophagy and survival of each species. Local information on these bionomic parameters is generally unavailable. MethodsTo address this, we estimated species-specific values of these parameters using an augmented version of the global database of bionomics data by Massey et al. (2016). We applied inclusion and exclusion criteria to select eligible studies with relevant experimental designs that minimise bias from collection methods for parous, sac, endophagy, and endophily rates as well as for the resting duration. For the human blood index (HBI), we separated data from indoor and outdoor collections. We fitted hierarchical Bayesian models with levels based on Anopheles taxonomy to estimate these quantities. Based on the estimated bionomics, we quantified the expected vectorial capacity reduction after the introduction of a pyrethroid-pyrrole insecticide-treated net (ITN) for 57 Anopheles species. ResultsWe identified 26 eligible studies for endophagy and 61 for the parous rate, leading to a Bayesian posterior average for the Anopheles genus of 42% (95% credible interval: 18-70) and 55% (32-77) respectively. HBI values widely varied depending on the location of collection, except for some species showing strong anthropophilic behaviours. Resting duration was estimated to be 2.1 days (1.2 - 4.8) at the genus level. Few studies were available to estimate the sac and endophily rates, which prevented us from deriving precise estimates for the whole Anopheles genus. Our estimates of the vectorial capacity reduction following the introduction of a pyrrole-pyrethroid ITN ranged between 48% and 76% across species, highlighting the important differences among mosquito species in vulnerability to vector control interventions. ConclusionThis work demonstrates how data from both Anopheles species complexes and individual species can be leveraged to generate species-specific estimates of bionomic parameters, capturing the local characteristics and behaviour of malaria vectors. The dataset is readily updatable as new data become available. However, more frequent and standardised field surveys are still needed to accurately characterise local vector behaviour.

Tickborne diseases are a significant burden in many parts of the world. In the upper Midwestern United States, Lyme disease is the most common tickborne disease. It is carried by Ixodes scapularis. This vector can also transmit the pathogens causing anaplasmosis, babesiosis, ehrlichiosis, and several more tickborne diseases in this region. There is also concern for other tick species, such as Amblyomma americanum, that are expanding their ranges northward. We launched a citizen science passive tick surveillance program in 2024 to investigate tick species ranges in the upper Midwest, as well as the pathogens carried by I. scapularis. We received over 12,000 ticks in the first two years of this program, primarily from Wisconsin. While we received submissions of adult A. americanum outside of their endemic range, we did not see evidence of establishment in our study area. We measured pathogen prevalence in adult female I. scapularis (n=707) and observed 51% positivity for Borrelia burgdorferi, 9% for Babesia microti, 9% for Anaplasma phagocytophilum, and 3% for Ehrlichia muris eauclairensis. Multiple pathogens were identified in 14% of tested specimens, and significant associations were observed between B. burgdorferi and B. microti, and B. burgdorferi and E. muris eauclairensis. Pathogen prevalences varied across time and geography. Our results can begin to inform risk assessment for tickborne diseases in our region. A non-technical version of this document with interactive maps is available here: https://storymaps.arcgis.com/stories/8008c9d710b5400599f3c6cf88b2c546 Our online data dashboard is available here: redcap.link/TICS

BackgroundAnopheles gambiae sensu lato (s.l.) is the primary vector of malaria in sub-Saharan Africa. Although insecticide-based vector control has been central to prevention, the widespread emergence of insecticide resistance poses a serious biological threat to control efforts. Effective resistance monitoring is essential for sustaining vector control but remains highly limited in malaria-endemic hotspots. Here, we assessed pyrethroid and DDT resistance intensity and the frequency of the L1014F knockdown resistance (kdr) mutation in Anopheles gambiae s.l. populations from Sokoto, north-western Nigeria. MethodologyResistance status and intensity to five insecticides were determined in adult Anopheles reared from larvae collected in 2021 and 2022 using the World Health Organization (WHO) tube test and Centers for Disease Control and Prevention (CDC) bottle bioassay, respectively. A subset of resistant mosquitoes was analyzed using PCR-based diagnostic assays to identify species within the Anopheles gambiae complex and to genotype for the West African kdr mutation (L1014F). ResultsHigh knockdown times (KDT) were observed, with KDT50 ranging from 38 to 91 minutes and KDT95 from 104 to 678 minutes, indicating increased resistance levels across all insecticides. In 2021, resistance was detected to DDT, lambda-cyhalothrin, and permethrin, while susceptibility to alpha-cypermethrin (98%) and suspected resistance to deltamethrin (91%) were recorded. In 2022, a general increase in resistance to all insecticides was observed, with mortality rates ranging from 41% to 81%. High resistance intensity was observed against DDT, while permethrin and alpha-cypermethrin exhibited low resistance intensity in both years, failing to reach 10x the diagnostic dose. Deltamethrin and lambda-cyhalothrin showed low to moderate resistance intensity. The 1014F kdr mutant genotype was widely distributed (68.1%) across species and years. Allele frequencies were higher in An. gambiae s.s. (0.83) than in An. arabiensis (0.71), with significant deviations from Hardy-Weinberg equilibrium (p < 0.05), except for An. gambiae s.s. in 2021 (p = 0.7). ConclusionThese findings reveal a concerning increase in key insecticide resistance among Anopheles populations in Sokoto, underpinned by strong genetic mechanisms. This underscores the urgent need for integrated vector management strategies to sustain effective vector control efforts in the region.

The wMel strain of the insect endosymbiont Wolbachia reduces the potential for Aedes aegypti to transmit mosquito-borne viruses such as dengue (DENV). Field trials that have introgressed wMel into Ae. aegypti populations have shown this approach significantly reduces dengue incidence. In a laboratory setting some wMel-Ae. aegypti develop infectious saliva following a viremic blood meal. Additionally, studies have demonstrated that exposing wMel-Ae. aegypti to heat treatment, particularly during the larval stage, reduces wMel density in key tissues such as the ovaries, midgut and salivary glands. Here we build on these studies, using viremic blood collected from 13 dengue inpatients at the Hospital for Tropical Diseases in Ho Chi Minh City (Viet Nam), to assess how temperature affects the protection afforded to Ae. aegypti by wMel. We found that, compared to wMel-Ae. aegypti reared at 28 {+/-} 4{degrees}C, those reared at 31 {+/-} 4{degrees}C developed infectious saliva more frequently, but the risk of this occurring was still reduced compared to WT mosquitoes reared at the same temperature. Heat treatment reduced the density of wMel in all tissues tested, decreased the magnitude of wMels protection against DENV replication in the head/thorax, and significantly increased the amount of DENV replication in wMel-Ae. aegypti. When comparing cohorts of wMel-Ae. aegypti that did or did not develop infectious saliva, DENV levels in the head/thorax were associated with increased odds of mosquitoes developing infectious saliva, but wMel density was not. Overall, these findings show that elevated rearing temperatures increase the risk of patient-derived DENV breakthrough infections in wMel-Ae. aegypti, potentially due to increased DENV replication in these mosquitoes. This limitation suggests it would be prudent to increase surveillance in regions using wMel for dengue control when daily mean temperatures remain above 30{degrees}C for multiday periods. Author SummaryThe mosquito species Ae. aegypti can be infected with the bacterium Wolbachia (wMel strain), reducing its capacity to transmit viruses like dengue (DENV). Wolbachia is now being used as a biocontrol tool to reduce the burden of dengue in communities. However, some mosquitoes with Wolbachia can still transmit DENV. Here we utilised a natural infection model using dengue patient-derived blood to examine how temperature may increase the risk of DENV transmission occurrence in mosquitoes with wMel. Mosquitoes with wMel were more likely to transmit virus when reared at an average temperature of 31{degrees}C compared to those reared at an average temperature of 28{degrees}C but these mosquitoes still had a lower risk of developing infectious saliva compared to their wMel-free counterparts. Higher temperatures reduced the amount of wMel in mosquito tissues and increased the amount of DENV replicating in the head/thorax. Increasing levels of DENV RNA in these tissues were found to be associated with increased risk of mosquitoes with wMel developing infectious saliva. This finding indicates surveillance is warranted in high temperature settings or during heat waves, to monitor for changes in wMel frequency and DENV infection in Ae. aegypti.

Background: The lifespan of insecticide-treated nets (ITNs) varies widely across settings, reflecting both intrinsic product characteristics and external factors related to use, care, and environment. While the resistance to damage (RD) score captures intrinsic product durability, there is no standardized metric to quantify contextual risks. This study presents a proof of concept for the Risk Index (RI), a composite measure of site-level risk factors for ITN physical durability and survival. Methods: We conducted a secondary analysis of durability monitoring data from 44 sites across 15 countries in sub-Saharan Africa, covering 14 ITN products. The RI was calculated as a weighted composite of 12 indicators spanning net handling, net care attitudes, and use environment. Associations between RI and median ITN survival were assessed using weighted linear regression and multivariable mixed-effects models adjusting for RD score, with country included as a random effect. Results: RI scores ranged from 25.1 to 83.7 across study sites. In bivariable analysis, a 10-point decrease in RI was associated with a 4.0-month increase in median ITN survival (95% CI: 1.7-6.3; p=0.001). In multivariable analysis adjusting for RD, this association remained significant but attenuated to 2.2 months (95% CI: 0.1-4.2; p=0.037). Independently, a 10-point increase in RD score was associated with a 3.5-month increase in survival (95% CI: 1.3-5.7; p=0.001). No interaction was observed between RI and RD. Predicted survival differed by approximately one year between the lowest- and highest-risk settings. Conclusion: The RI provides a standardized measure of contextual risk factors affecting ITN lifespan, independent of ITN product type. When used alongside a product's RD score, the RI enables improved interpretation of expected site-level variation in net performance. This combined framework offers a practical basis for incorporating behavioural and environmental risk into vector control planning and for tailoring ITN strategies to local conditions.

O_LIAlthough ecological research has long focused on the effects of temperature on population growth, arthropod pests are exposed to a wide variety of environmental factors that affect their performance, such as chemical pesticides targeted against them. Moreover, these environmental factors likely do not act in isolation. Identifying the extent to which abiotic factors interact to affect pest population dynamics can strengthen current and future pest management programs. C_LIO_LIHere, we investigated the extent to which temephos, a common pesticide applied to aquatic environments for mosquito control, influences the thermal performance of juvenile survival and development rate, as well as the intrinsic population growth rate, of the invasive mosquito pest, Aedes aegypti. We implemented a response surface experimental design to measure these traits across seven temperatures and five temephos concentrations and fit temperature- and insecticide-dependent performance curves to assess impacts on the overall performance and the thermal optimum, minimum, and maximum. C_LIO_LITemephos exposure profoundly altered the thermal performance of juvenile survival by reducing survival across all temperatures, shrinking the thermal breadth, and shifting the thermal optimum to warmer temperatures. Through this, temephos also altered the thermal performance of population growth primarily by reducing its thermal breadth. C_LIO_LISynthesis and applications: Our findings demonstrate that interactions between temperature and insecticide exposure can fundamentally reshape pest population dynamics, rather than acting as independent stressors. By quantifying this interaction, we showed that temphos is most effective below the pests thermal optimum, suggesting that larvicides may yield the greatest population suppression in cooler regions or during cooler periods of the year. Incorporating such temperature-dependent efficacy into pest management strategies could improve the timing and spatial targeting of control efforts. More broadly, these results highlight the need to integrate anthropogenic stressors with climatic drivers when predicting pest risk and optimizing management under ongoing environmental change. C_LI

Ultra-low volume (ULV) insecticide spraying with deltamethrin as the active ingredient is widely used in mosquito control programs, yet its effectiveness against target mosquitoes and its ecological side effects remain poorly quantified under field conditions in Central Europe. Here, we experimentally evaluated the short-term impact of ground ULV spraying on both mosquito populations and non-target flying insects in Hungary using a paired before-after-control-impact (BACI) design. Mosquitoes were sampled with BG Sentinel traps, while non-target insects were collected using malaise traps. ULV treatment resulted in a significant reduction in mosquito abundance at treated sites, with an average decline of approximately 45%. Native and invasive mosquito species, including Aedes albopictus and Aedes koreicus, showed similar proportional decreases. However, treatment effectiveness varied substantially among sites and was influenced by initial mosquito abundance and wind conditions. In parallel, malaise trap samples revealed a marked decline in non-target flying insects, with reductions exceeding 40% across multiple taxonomic groups, particularly among small- and medium-sized insects, and also when considering pollinator taxa together. Our results indicate that while ULV spraying can temporarily reduce mosquito abundance, it also imposes considerable short-term impacts on non-target insect communities, highlighting trade-offs between vector control and insect conservation within mosquito management programs.

Mosquito-borne diseases such as dengue, chikungunya, and malaria remain major public health challenges in South Asia, particularly in Bangladesh, where mosquito repellents are widely used as primary preventive tools. This study presents a comparative evaluation of commonly used repellent products, including mosquito coils, liquid vaporizers and aerosols, DEET-based creams, and natural formulations, focusing on their efficacy, protection duration, and potential health risks. Efficacy was assessed using controlled laboratory methods, including chamber-based exposure and arm-in-cage tests against Aedes aegypti (Barnard & Xue, n.d.). Safety was evaluated through in vivo toxicological analysis in a rat model, incorporating clinical observations, hematological and biochemical profiling, and histopathological examination. The results indicated an overall mean effectiveness of 85%, with DEET-based creams demonstrating the highest efficacy (95%), while natural repellents showed the lowest (70%). Mosquito coils provided the longest protection duration ([~]10 hours) but were associated with the highest health risk due to combustion-related emissions. Vaporizers and aerosols offered moderate efficacy with moderate health risk. Toxicological findings revealed that coil exposure induced significant respiratory stress, elevated liver enzymes (ALT, AST), increased leukocyte count, and notable lung tissue damage. Vaporizer and aerosol exposure resulted in mild physiological changes, whereas DEET-based and natural repellents showed minimal systemic toxicity. Overall, the study highlights a clear trade-off between efficacy and safety across repellent types. These findings emphasize the need for informed product selection, stronger regulatory control, and the development of safer, cost-effective, and sustainable mosquito repellent technologies for effective vector control in endemic regions.

A field trial was conducted using 10% lambda-cyhalothrin microcapsule suspension to provide a method for killing ticks and preventing diseases in outdoor gatherings of people or temporary resettlement places after disasters. In this study, three field experimental sites were selected, and each experimental site was set up with a test area and a control area. Before pesticide application, the tick density in three test areas and three control areas was surveyed using the flagging method. Subsequently, two methods were used for pesticide spraying: motorized fogging and electric constant-volume spraying (with the pesticide diluted 300 times). The relative density decline rate of ticks was calculated in three test sites on days 1, 7, 14, 21, and 28 after spraying, and all experimental areas achieved good tick-killing effects. Even without prohibiting wild animals, grazing sheep, and dogs (which are often infested with ticks and not treated) from entering the trial sites, spraying 10% lambda-cyhalothrin microcapsule suspension could maintain a tick-free (low-density) state for approximately 3-4 weeks. Our study provides an idea for controlling epidemics through tick elimination during the high incidence period of tick-borne diseases.

Electroantennography (EAG) is a valuable approach for monitoring the sensory responses of insects to insecticidal and repellent molecules and an effective tool for early screening of compounds aimed at controlling and protecting against medically important insect vectors. However, its predictive potential for repellent efficacy in triatomine vectors remains poorly explored. The objective of this study was to evaluate the EAG responses to different xenobiotics as a preliminary selection strategy for compounds with potential repellent action against triatomines. For this purpose, the antennae of adult triatomines subjected to prolonged fasting ([&ge;]30 days) were exposed to repellent molecules. In parallel, repellency bioassays were conducted using a live bait (Gallus gallus) and a newly designed laboratory device to validate the electroantennographic results. EAG recordings showed a significant reduction in olfactory capacity of> 60% in response to the chemical compounds IR3535 and carvone, consistent with the protection times observed in the repellency tests (135.6 {+/-} 43.29 min and 108 {+/-} 26.33 min, respectively). In conclusion, the compounds with the highest repellent activity were clearly discriminated by the insects olfactory system, a finding corroborated by the decrease in electrical signals recorded in the EAG bioassays.

BACKGROUNDThe two-spotted spider mite, Tetranychus urticae Koch, is a major agricultural pest with a rapid propensity for developing acaricide resistance. Bifenazate targets mitochondrial cytochrome b (CYTB). While the G126S mutation is frequently associated with resistance, its independent role remains unclear as it often occurs with other substitutions. This study explores the molecular basis of bifenazate resistance in a Russian laboratory strain derived from a St. Petersburg greenhouse population. RESULTSDisruptive selection with increasing bifenazate concentrations generated resistant and susceptible isofemale lines. AlphaFold2 structural modeling of CYTB indicated that G126S causes a steric clash, leading to conformational destabilization, whereas other reported mutations primarily affect the ligand-binding pocket. Oxford Nanopore sequencing revealed a very low initial frequency of the G126S allele (<1%; 226/35,895 reads) in the unselected population. After one year of stepwise selection (0.00005-0.031% a.i.), the mutant allele frequency surged to 90% (7,272/8,056 reads). No other known resistance-associated mutations were found in the analyzed cytb fragment. CONCLUSIONWe report the first identification of the G126S mutation in a Russian T. urticae population and demonstrate its rapid fixation under bifenazate selection. Within this genetic background, G126S alone appears sufficient to confer high-level resistance, emphasizing the population-specific nature of resistance evolution and the critical need for local monitoring.

Gastropods are a highly diverse and often overlooked taxonomic group of significant ecological and economic importance. Some terrestrial gastropods are critical pests of commercial agriculture and home gardens worldwide. Malacopathogenic nematodes offer an effective biological control method of managing pest slugs and snails as a natural enemy. Pellioditis (syn. Phasmarhabditis) hermaphrodita and Pellioditis (syn. Phasmarhabditis) californica are two species of biocontrol nematodes that have been commercialized, sold as Nemaslug(R) and Nemaslug(R) 2.0 respectively on three continents. Although there is interest in bringing Nemaslug(R) products to the US, they are currently not permitted due to limited knowledge on their North American distribution and effects on non-target and native species. In this study, we investigated the impact of P. hermaphrodita and P. californica on Ariolimax columbianus across two slug-host life stages, in laboratory infectivity assays. The objectives were to 1. determine whether P. hermaphrodita and P. californica nematodes impact survival of A. columbianus, and 2. evaluate whether there are differential effects on survival in juvenile and adult life stages of A. columbianus, in laboratory infectivity trials. We found that P. hermaphrodita caused significant mortality in A. columbianus with 100% mortality observed in both juvenile and adult slug hosts. The P. californica treatment had significant effects on the juvenile A. columbianus group only, with 80% mortality. By contrast, only 16% of unexposed control juveniles and 4% of control adult slugs died during the experiment. These results indicate that P. hermaphrodita and P. californica are lethal to the native, non-target Pacific banana slug (A. columbianus) under laboratory conditions, with mortality differing between juvenile and adult host life stages. Given the ecological importance of A. columbianus, these findings raise concerns for potential non-target effects of P. californica and P. hermaphrodita on terrestrial gastropod communities and emphasize the need for testing biocontrol agents against multiple life stages.

Nature-Based Solutions are increasingly promoted to address current urban challenges. While their potential effects on vector-borne disease risks have been documented, data on Aedes albopictus, a known arbovirus vector, remain limited in France. A previous study showed that urban vegetation moderately increases the abundance of adult mosquitoes of this species, but the monitoring period lasted only six months. Using ovitraps, we monitored Ae. albopictus egg density dynamics over multiple years (2022 to 2024) and analysed its environmental predictors in various urban environments. We included lagged meteorological variables, land cover metrics, and the cumulated egg densities recorded in the previous weeks as environmental predictors. Both parametric (GLMM) and non-parametric (Random Forest) models were fitted to weekly egg counts per trap. Our findings highlight that (i) egg density dynamics were related to how vegetation classes structured the landscape, (ii) growing degree days and cumulated number of eggs recorded in specific lagged time windows were the main contributors to egg density, and (iii) the non-parametric and parametric models performed similarly in terms of prediction accuracy.

Understanding how vector ecology intersects with host behaviour is essential for predicting zoonotic disease risk in tropical ecosystems. We conducted a two-year field study (November 2016-October 2018) in a riverine forest in Sabah, Malaysian Borneo, to characterize mosquito communities and the spatial distribution of potential simian-malaria vectors. Mosquitoes were sampled on 44 nights using CO{square}-baited light traps repeatedly deployed along a 500 m transect at three distances from the river (0, 250, 500 m) and two vertical strata (ground and canopy), yielding 244 trap collections across repeated sampling nights. In total, 9,928 mosquitoes were collected, dominated by Culex spp. (9,079; 91.4%), whereas Anopheles spp. were rare (153; 1.5%); most remaining specimens were unidentified to genus, and species-level identification was limited primarily to Anopheles. Nevertheless, female Anopheles (n=57) were more frequently detected near the river and less commonly at intermediate distance, and tended to be captured more often in ground traps. Zero-inflated negative binomial GLMMs based on the full mosquito dataset indicated significant effects of river distance and height on mosquito abundance, while night-time temperature and humidity showed no detectable effects. The zero-inflated structure of the data further suggested that many zero captures reflected true absence rather than sampling variability. The Anopheles assemblage was dominated by An. balabacensis, and molecular screening of 57 females detected simian Plasmodium DNA in two individuals. Overall, these findings suggest that river-edge habitats may represent localized areas where vectors persist and where primates and human activities overlap, creating repeated opportunities for host-vector contact even when vector densities are low.

Black soldier fly larvae (BSFL) have quickly become one of the most farmed animals in the world. However, little is known about how to monitor stress and welfare in these animals. The difficulty of welfare assessment is compounded by the fact that BSFL live in their feed and prefer darkness. This behaviour makes it challenging to observe potential welfare indicators without inducing stress via disturbing the larvae or moving them into the light. However, acoustic devices may be able to pick up signatures of stress in the population even while they are out of sight, allowing for remote monitoring of animals in natural conditions (in the feed and/or in the dark). Acoustic monitoring of this type has been deployed for the detection of insects in stored grains, suggesting this method holds some promise for assessing insect behavioural signatures. In this study, we aimed to identify general, acoustic signatures of stress in BSFL by recording them during exposure to two stressors (light or shaking) or in a low-stress control condition. Our data suggest there are consistent differences in the acoustic recordings of the non-stressed and stressed conditions that may indicate the animals behaviours shift consistently in response to stress. Ultimately, the data suggest acoustic monitoring may hold promise for larval behaviour and/or welfare assessment and should be further explored in response to a variety of stressors across the larval life stage.

Ectotherm insects growth and development are dictated by temperature and humidity. Conducive habitats and the availability of resources set ideal conditions for insect population growth. Mosquitoes require water, favorable temperature, and blood meal to survive. In this research, we picked a rapidly growing megacity, Ahmedabad, in western India, to explore and establish potential linkages between disease spread and meteorological conditions. Ahmedabad, with a population of over 8 million, is experiencing changes in rain and humidity patterns, pushing the city towards changing vector-borne disease dynamics. We examined dengue cases over ten years, 2012-22, and explored their connections with two prominent climatic variables, temperature and relative humidity. Our findings indicate that stable temperature (25-27.5 {degrees}C) and humidity (> 60%) interaction is a ruling factor in spikes in dengue cases in the city. While stable temperature ranges triggers the dengue cases, RH drives the explosive phases and sustainability of such episodes. Statistically significant increasing trends in temperatures, narrowing down of the day-night temperature ranges, and increasing night temperatures provide more stable temperature regimes in a warming world thereby likely to extend the dengue season beyond the usual monsoon season. Plain Language SummaryDengue incidences have been found to be associated with mosquito population outbreaks. Every year, thousands of lives are lost due to this deadly virus spread by mosquitoes. Particularly in the Indian subcontinent, a large proportion of these cases is associated with the monsoon season and rain patterns. In recent years, there have been abrupt spikes in dengue cases across Indian cities, particularly in western India. To understand this complex interaction of viral proliferation and local environmental conditions, the last ten years of dengue case patterns have been scanned in parallel to the climate data. Our findings suggest that stable temperature windows and humidity levels above certain thresholds trigger a rise in dengue cases. While stable temperature ranges trigger dengue cases, humidity drives such episodes explosive phases and sustainability. Our work pinpoints specific temperature-humidity combinations and suggests that local municipal corporations use them as warning indicators to initiate preventive measures.

Spatial emanators (SE) are a promising complement to existing tools for preventing mosquito transmitted diseases. In 2025, the WHO updated the WHO Guidelines for Malaria to include a conditional recommendation for the indoor use of prequalified SE products in malaria control. Both prequalified, and many other SE products contain the volatile pyrethroid transfluthrin, which shares the same target site as other (contact/solid phase) pyrethroids. Therefore, an assessment of cross resistance is critical to predict effectiveness against mosquitoes with existing pyrethroid resistance. Our results show that resistance to solid phase pyrethroids is correlated with resistance to transfluthrin in Anopheles and Aedes species. Moreover, commonly-selected resistance mechanisms including target site mutations and over-expression of P450 detoxification enzymes can confer resistance to transfluthrin. Furthermore, we show that resistant mosquitoes are less impacted by transfluthrin in terms of flight activation (irritancy) and reduced blood feeding inhibition, with the response correlating with resistance strength. Transfluthrin did not elicit an electroantennography response in Anopheles gambiae and surgically ablating mosquitoes antennae did not result in differences in flight activation upon transfluthrin exposure, suggesting the antennae are not required for transfluthrin to elicit behavioral responses. These results provide new insight regarding the mode of action of transfluthrin and the risk of resistance reducing transfluthrins efficacy in vector control interventions.

Tick-borne diseases are now reported from nearly every county in Illinois, and three vector tick species (Amblyomma americanum, Dermacentor variabilis, and Ixodes scapularis) are of particular concern because these are responsible for most of the tick-borne disease transmission in the state. However, active surveillance is patchy, many counties have little or no sampling, and there is no statewide, quantitative map of relative abundance that can be used to anticipate risk in unsampled areas. To address these gaps, we developed Bayesian hierarchical spatial models to estimate the county-level abundance of these three vector tick species in Illinois. Using active surveillance data from 2019-2022, we modeled county-level abundance as a function of climate, land cover, forest fragmentation, and deer habitat suitability. Spatial dependence was captured using a Besag-York-Mollie 2 (BYM2) prior implemented in INLA, along with spatial 5-fold cross-validation to assess predictive performance. A. americanum showed the highest predicted abundance in southern and central Illinois, D. variabilis was widespread but diffuse, and I. scapularis was concentrated in northern and selected central counties. Together, these models provide the first spatial, statewide, uncertainty-aware assessment of tick abundance in Illinois, highlighting priority counties where surveillance lags disease risk.