Long-lasting insecticidal nets (LLINs) are widely used in sub-Saharan Africa to reduce the transmission of malaria. Their operational lifespan under field conditions depends on many factors. This article presents some of the factors associated with the decline in LLIN efficacy in urban and rural settings in Kribi, southern Cameroon. This study, conducted in 2019, aimed to evaluate the usage and residual efficacy of the nets against two strains of Anopheles gambiae s.l.: a local strain with an unknown insecticide susceptibility status and a sensitive reference laboratory strain. A total of 540 households were surveyed. LLIN coverage was similar in rural (69.0%) and urban (68.6%) areas. The proportion of children under five years of age using LLINs was comparable in both settings (88.6%: 651/735). PermaNet 2.0 nets were more degraded than other brands in rural areas, while Yorkool nets were more degraded in urban areas. Mortality rates for the Kisumu strain ranged from 21.6% to 99.6% for LLINs that had been washed more than 20 times, and from 0.8% to 76.5% for the wild-type strain. Those washed with bar soap retained their lethal properties better than those washed with harsh detergents. Similarly, nets dried in the shade retained their lethal properties better than nets hung out in the sun. The study population used MILDAs, especially for children. The fiber composition of the nets, the type of detergent used, and exposure to sunlight are factors that influence the insecticidal efficacy of the nets. Les moustiquaires imprégnées d'insecticide à longue durée d'action (MILDA) sont largement utilisées en Afrique subsaharienne pour réduire la transmission du paludisme. Leur durée de vie opérationnelle dans les conditions de terrain dépend de nombreux facteurs. Cet article présente certains de ces facteurs associés à la dégradation de l'efficacité des MILDA en milieu urbain et rural à Kribi au sud du Cameroun. L’étude, réalisée en 2019, visait à évaluer l’utilisation et l'efficacité résiduelle des moustiquaires contre deux souches d'Anopheles gambiae s.l., une souche locale avec un statut de sensibilité aux insecticides inconnu et une souche de laboratoire de référence sensible. Au total, 540 ménages ont été enquêtés. La couverture en MILDA était similaire entre les zones rurale (69,0 %) et urbaine (68,6 %). Le nombre d'enfants de moins de 5 ans utilisant des MILDA (88,6 % : 651/735) était comparable dans les deux contextes. Les moustiquaires PermaNet 2.0 étaient plus dégradées que les autres marques dans la zone rurale, tandis que les moustiquaires Yorkool l’étaient davantage dans la zone urbaine. Les MILDA ayant subi plus de 20 lavages ont induit une mortalité de 21,6 % à 99,6 % pour la souche Kisumu et de 0,8 % à 76,5 % pour la souche sauvage. Celles lavées avec du savon en morceaux ont mieux conservé leurs propriétés létales par rapport à celles lavées avec des détergents corrosifs. De même, celles qui avaient séché à l'ombre avaient davantage conservé leurs propriétés létales que celles étendues au soleil. La population étudiée utilisait les MILDA particulièrement pour les enfants. La nature de fibre de la moustiquaire, les détergents ainsi que la lumière du soleil sont des facteurs qui influent sur l'effet insecticide des moustiquaires.
In the pursuit of novel insecticidal agents, a series of new thieno-[2,3-b]-quinoline derivatives were synthesized via efficient and versatile routes, starting from ethyl 3-aminothieno-[2,3-b]-quinoline-2-carboxylate. The synthesized compounds including hydrazone (8a-c), arylidene (9a-c), and pyrano-[3,2-c]-thieno-[2,3-b]-quinoline (10a-c) derivatives were characterized using FT-IR, NMR, and mass spectrometry. Their insecticidal efficacy was evaluated against both nymph and adult stages of Aphis fabae, with median lethal concentration (LC50) values determined through probit analysis. Compound 10b exhibited the highest potency, with LC50 values of 0.117 mg/L (nymphs) and 0.366 mg/L (adults), approaching the activity of the commercial insecticide acetamiprid. Molecular docking studies against the Aplysia californica acetylcholine-binding protein (AChBP, PDB: 3SQ6), a surrogate for insect nicotinic acetylcholine receptors, revealed strong binding affinities for the pyranothienoquinoline derivatives, particularly 10b (-7.30 kcal/mol), supported by multiple hydrogen bonds and hydrophobic interactions with key residues. These findings underscore the potential of the pyrano-[3,2-c]-thieno-[2,3-b]-quinoline scaffold as a promising candidate for the development of new, target-specific insecticides.
The Neotropical stink bugs Euschistus heros and Diceraeus melacanthus are major pests of soybean and maize in South America, yet current chemical control strategies face widespread resistance, highlighting the urgent need for sustainable alternatives. This study investigates Ficus carica pruning residues as a source of selective botanical insecticides, integrating optimized extraction, phytochemical profiling, bioassays, and molecular modeling. Eight extracts were prepared under varying solvent, temperature, and acidity conditions, and analyzed for total phenolic content (TPC) and the key furanocoumarins psoralen and bergapten. Acidification enhanced overall mass yields, while mild ethanol extraction at room temperature selectively maximized furanocoumarin recovery, yielding psoralen concentrations up to 14.83 mg g-1, which is substantially higher than previously reported in leaves or fruit. Biological evaluation of the optimized ethanolic extract (ERA) revealed strong insecticidal activity, with 86% mortality of E. heros and 40% of D. melacanthus nymphs at 48 h, and a calculated LC50 of 1232 mg L-1 for E. heros. The differential susceptibility between species suggests both metabolic and cuticular factors influence efficacy. Computational docking and phylogenetic analyses suggested a potential mechanistic basis for the observed selectivity: furanocoumarins are predicted to bind hemipteran AChE via a compensatory polar scaffold, whereas binding to Apis mellifera AChE is predicted to be weaker due to lineage-specific differences in aromatic density within the catalytic gorge, potentially explaining the minimal off-target susceptibility. The molecular modeling results characterize these compounds as low-affinity, reversible inhibitors, combining effective pest control with a favorable safety profile for pollinators. The present work demonstrates that valorizing agro-industrial waste from F. carica can yield potent, selective, and environmentally safer insecticidal agents. The integration of extraction optimization, biological evaluation, and molecular modeling provides a robust framework for developing sustainable botanical insecticides, advancing circular economy principles in pest management and offering promising alternatives to synthetic neurotoxins.
The tomato leaf miner, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae), is a major pest causing severe damage to tomato crops worldwide. The present study evaluated the insecticidal efficacy of Cymbopogon nardus (citronella) and Pelargonium graveolens (geranium) essential oils against T. absoluta larvae and their impact on selected biochemical and oxidative stress parameters under laboratory conditions. GC-MS analysis identified citral and related monoterpenes as the major components of citronella oil, while geranium oil was rich in citronellol. Toxicity assays demonstrated dose-dependent larval mortality for both oils, with citronella oil exhibiting slightly higher potency (LC50 = 3.12%; LC90 = 6.37%) than geranium oil (LC50 = 3.88%; LC90 = 7.65%). Biochemical analyses revealed significant reductions in GABA-transaminase activity, total protein, and total lipid contents in treated larvae, indicating disruption of neurotransmission, metabolism, and energy reserves. Furthermore, oxidative stress markers showed decreased total antioxidant capacity and superoxide dismutase activity, together with increased lipid peroxidation, indicating the induction of oxidative stress in treated larvae. These findings demonstrate that both essential oils possess significant insecticidal activity and induce marked biochemical and oxidative stress responses in T. absoluta larvae. Therefore, citronella and geranium essential oils may represent promising eco-friendly botanical insecticides for incorporation into integrated pest management programs for tomato crops.
The development of sustainable high-yield farming practices is crucial to support a growing human population while providing long-term solutions for the environmental impact of intensified agriculture. Nutrient-rich bio-residuals generated through the industrial production of insects hold a high but underexplored potential as an alternative to less sustainable fertilizers. In a two-year field experiment, we show that mustard plants grown in insect-exuviae-amended soil perform as well or even better than plants grown in soil amended with reference organic fertilizers. Improved plant performance was driven by increased plant growth in terms of height and width, a larger number of flowers produced, more interactions with pollinators, and a larger seed production compared to untreated plants. A parallel greenhouse experiment revealed that native root-associated microbial communities in exuviae-amended soil were more species-rich, less variable, and were characterized by several well-known plant-growth-promoting rhizobacteria compared to those found in unamended soil or soil treated with reference fertilizer. Collectively, these findings demonstrate that valorizing insect-based bio-residuals can improve agricultural sustainability while simultaneously supporting a circular economy.
Current global estimates are that 40% of food produced for human consumption is being wasted, amounting to 2.5 billion tonnes of food waste each year. The UN Sustainable Development Goal 12.3 aims to respond to this by 2030. In addition, Aotearoa-New Zealand is equally under pressure to minimise food waste and greenhouse gas emissions and has committed to its own Emissions Reduction Plan to achieve net-zero emissions by 2050. Insect bioconversion has emerged as a promising, novel and sustainable strategy for upcycling large amounts of organic waste into added-value products such as feed for livestock, industrial compounds including biofuel and chitin, and soil amendments/fertilisers for improving soil quality and productivity. This review explores the research landscape and commercial potential of insect bioconversion in Aotearoa-New Zealand, focusing on the black soldier fly (Hermetia illucens L.; BSF)-a tropical species renowned for its efficiency in bioconversion and its nutrient-rich larvae. We examine current research efforts to valorise agricultural and food waste streams in Aotearoa-New Zealand, assess the economic viability and energy requirements of insect bioconversion in temperate climates, compare its environmental footprint against conventional animal feed production, identify key scientific and technological challenges, and discuss regulatory, infrastructural, and market barriers that must be overcome to establish a viable BSF-based bioconversion industry. By highlighting knowledge gaps, this review also aims to inform future research directions and policy frameworks that could support circular bioeconomy transitions in Aotearoa-New Zealand and beyond.
Automated image-based identification of adult insects is increasingly critical to biodiversity monitoring, pest management, and vector surveillance, yet practical deployment remains limited by data scarcity, field variability, and fine-grained taxonomic challenges. We conducted a PRISMA-guided literature review of computer-vision methods for insect classification and identification. A Web of Science Core Collection search (31 August 2024) retrieved 930 records; after deduplication (n = 2) and screening, 230 articles underwent full-text quality assessment using weighted criteria for taxonomy/methods, image capture, computational technique, sample size, and performance evaluation. Of these, 111 high-quality studies met inclusion thresholds. Data were extracted on taxonomic coverage, optical devices and experimental settings, algorithms and pipelines, datasets, and outcome metrics. Deep learning dominated the field; You Only Look Once variants were common for detection and ResNet/EfficientNet/MobileNet for classification; occasional hybrids combined Convolutional Neural Network (CNN) features with traditional classifiers. CNN-based and 1-stage detectors outperformed hand-crafted pipelines; transformers and self-supervised pre-training showed promise with limited labels. Despite strong laboratory performance, generalization to field conditions was hindered by illumination, occlusion, and pose variability. Public datasets were scarce and geographically skewed, limiting reproducibility and equitable benchmarking. Taxonomic coverage concentrated on Lepidoptera, Diptera, Hemiptera, and Coleoptera. We recommend advancing the field through comprehensive reporting beyond overall accuracy, the design of lifecycle-aware and domain-adapted models validated under field conditions, the establishment of diverse benchmarks with standardized imaging protocols, and the development of interpretable architectures suitable for deployment in embedded trapping systems.
The genetic instability of genes transposed into the baculovirus genome by Bacmid technology, often caused by mini-F replicon, raises a crucial challenge for large scale production of recombinant proteins via serial passages in insect cells. To address this problem, we reconstructed Bacmid vector by decoupling the mini-F replicon from Tn7 transposition site. Two Bacmid variants, BacDC1 and BacDC2, were generated through homologous recombination. In BacDC1, the KanR-lacZα-attTn7 cassette remains in its original position while the mini-F replicon is relocated to the chitinase/v-cathepsin loci. Conversely, BacDC2 undergoes the opposite rearrangement. Using the classical Bacmid technology, two genes encoding enhanced green fluorescent protein (eGFP) and nano-luciferase (Nluc) C-terminally tagged spike 1 (S1) protein of porcine epidemic diarrhea virus (PEDV) were cloned as reporters to assess stability. Fluorescence observation analysis indicated that the genetic stability of cloned genes was markedly improved by the Bacmid variant-derived baculoviruses with sustained expression for up to 20 passages, appropriately 2-3 times longer than the wild-type control. Similarly, western blot and luciferase activity analysis demonstrated the S1-Nluc secretion from Sf9 cells infected with the dual expression variants remained stable over 10 passages, whereas the control showed significant expression decline by passage 5. These data suggest that decoupling the mini-F replicon from Tn7 transposition site significantly stabilizes cloned gene expression. The Bacmid variants thus represent promising vectors for industrial recombinant protein production and gene therapy applications.
Insects that pollinate essential crops are frequently exposed to neurotoxic insecticides. Although most pollinators belong to insect lineages that diverged hundreds of millions of years ago, insecticide safety tests focus on a few model bee species. Here, we used comparative whole-brain transcriptomics to test whether sulfoxaflor and clothianidin elicit similar or distinct responses across four phylogenetically diverse pollinators: Bombus terrestris, Osmia bicornis, Lucilia sericata, and Vanessa cardui. Within each species, both insecticides produce broadly similar gene regulatory profiles, with more than 70% of differentially expressed genes shared. By contrast, transcriptional responses differed sharply across species, with no shared genes or pathways consistently disrupted. Unexpectedly, sulfoxaflor, promoted as a "bee-safe" alternative, provokes broader gene regulatory changes in non-bee species than clothianidin, a restricted neonicotinoid. Our findings reveal extensive transcriptional divergence in insecticide responses across pollinators, suggesting that risk assessments would benefit from greater phylogenetic diversity and novel molecular approaches.
Agricultural intensification, driven by increasing food demand, is one of the main drivers of global biodiversity loss. Pesticides, including fungicides, may increase crop yield but pose substantial threats to the environment. However, our current knowledge on the effects of fungicides on biodiversity suffers from less research interest compared to other pesticides and a neglect of insect herbivores. We here investigate the effects of a commercially available, ready-to-use difenoconazole fungicide on a non-target insect, the butterfly Pieris napi, under controlled laboratory conditions. When being fed with fungicide-treated host plants, butterfly larvae showed a strongly reduced survival (15%) compared to controls (60%). Survival in larvae treated with the fungicide plus an insecticide was only 1%. Sublethal effects of the fungicide included prolonged development and reduced adult size. Our results indicate a surprisingly high toxicity of the tested fungicide formulation on P. napi. Based on the available literature, we speculate that triazole fungicides may be in general toxic to Lepidoptera and potentially other herbivorous insects. This study contributes to the growing evidence that fungicides may well be involved in the loss of insect biodiversity in agricultural landscapes at the global scale.
Leishmaniases are infectious diseases whose vectors are female sand flies that depend on the blood of vertebrates for egg maturation. In this study, we investigated the sand fly species and DNA from Leishmania spp. This entomological/epidemiological study was conducted in a rural area in Nova Andradina, Mato Grosso do Sul, Brazil. From March 2019 to February 2020, five modified Falcão light traps were installed at night once a month. The collected insects were separated by sex into pools of 10 specimens. A sample was used for species identification via microscopic analysis, and another sample was used to detect the DNA of Leishmania in females via polymerase chain reaction (PCR). A total of 42,933 insects were collected, 77.6% (n = 33,313) of which were female. A total of 4,993 (11.6%) insects were identified, most were Nyssomyia neivai (n = 4,839; 96.9%). For PCR, 4,130 (9.6%) insects were analyzed, and four pools were positive for Leishmania spp. (with a natural infection rate of 0.1%). When the number of sand flies collected and the climatic variables were correlated, a significant difference was detected when precipitation > 60 mm (p = 0.0314) and relative humidity ≤ 60% (p = 0.0201). The analyzed area is inhabited by one of the main vectors of cutaneous leishmaniasis in Brazil, and we also found that some specimens were infected with Leishmania DNA, which might favor the occurrence of the disease in the region. This information is essential for understanding the dissemination of leishmaniasis and planning actions to prevent in the municipality.
Mosquitoes transmit arboviruses that represent major global public health challenges. Increasing insecticide resistance and absence of effective antiviral therapies underscore the need for novel vector control strategies. Insect-specific viruses have emerged as candidates for biological control, however, the cellular mechanisms underlying their interactions with mosquito hosts remain poorly understood. Here, we examined the immune response of Aedes albopictus U4.4 cells to Kamiti River virus (KRV) infection, an insect-specific flavivirus. Cells were infected with KRV, and transcriptomic and small RNA profiles were analyzed at 24, 48 and 72 h post-infection. KRV infection induced production of virus-derived small interfering RNAs (vsiRNAs) and virus-derived PIWI-interacting RNA (vpiRNAs) from 24 to 72 h. The vsiRNAs predominantly mapped to the 3' untranslated region of the KRV genome, whereas vpiRNAs formed distinct hotspots in regions encoding the NS1, NS3, NS4A/B and NS5 proteins. Transcriptomic analysis revealed upregulation of genes associated with the humoral immune response, including defensin, cecropin, and glutathione S-transferase, and downregulation of Toll-like receptors and ecdysone-induced transcripts at later stages of infection. These gene expression patterns suggest an early activation followed by suppression of key immune signaling pathways. Collectively, the findings indicate that KRV leads to coordinated modulation of antiviral RNAi and host transcriptional responses, consistent with a balanced, commensal-like interaction in mosquito cells.
Reproductive microbiota is known to modulate host immunity, reproductive physiology, and longevity, yet their interactions with host genetics, sex, and mating status remain relatively underexplored in most insects. Some studies suggest that species (and even populations) can vary in the microbial communities associated with their reproductive tissues. Sexually transmitted microbes can also directly influence population growth and reproductive fitness, making them relevant even for applied insect management strategies. The economically relevant, Black Soldier Fly (BSF; Hermetia illucens), is known for its applications in organic waste management and sustainable food production. Despite several papers on the larval gut microbiota, there is no study (to date) that explores the reproductive microbiota of adults. This study characterizes the reproductive microbial communities of eight genetically distinct BSF populations using 16S rRNA gene sequencing. The results revealed striking, sex-specific microbial signatures within reproductive tissues, dynamically shaped by mating. Virgin females harboured diverse and functionally intriguing taxa, including Staphylococcus, Brevibacterium, and Corynebacterium, which likely supported ovarian maturation and reproductive readiness. Remarkably, mating triggered a dramatic shift, with unclassified Enterococcaceae emerging as the dominant taxon in mated females, suggesting selective microbial retention or transmission with potential implications for post-mating longevity. In contrast, although mated males showed enrichment of Rhodococcus_C_375578, their overall microbiota composition remained comparatively stable pre- and post-mating. Most notably, the genetic lineage significantly influenced the magnitude of sex- and mating-related bacterial shifts in reproductive microbiota. These novel findings advance the understanding of the complex dynamics of reproductive microbiota in insects and provide a foundation for optimizing breeding strategies and colony management in commercial BSF production systems.
Approximately 20 years ago, studies conducted in the city of Bouaké revealed a high level of malaria transmission, primarily due to the Anopheles gambiae vector increasing during the rainy season. The National Malaria Control Program implemented control efforts involving the distribution of long-lasting insecticidal nets (LLINs). However, the political and military crisis from 2002 to 2011 caused many residents to leave the city, leaving the natural environment largely undisturbed. The subsequent return of the population to Bouaké necessitated implementing new LLIN-based control programs. New research studies are needed to collect data on malaria transmission parameters. This study is conducted within this context. The objective is to assess vector-borne malaria transmission by determining entomological parameters in the city's three health districts. Investigations were conducted in urban areas during the rainy season from June 10 to 29, 2016, in Bouaké's three health districts (Northwest, Northeast, and South). Mosquitoes were collected from human-biting samples and identified. We examined the feeding behavior of female vectors and estimated the entomological parameters of malaria transmission. We determined the physiological age of the female vectors by dissecting their ovaries and detected mosquitoes infected with Plasmodium falciparum using the ELISA-CSP test. Only the malaria vector species An. gambiae was collected. The species exhibited a tendency toward endophagy and had an average parturition rate exceeding 90% in all districts. Aggressive densities of the species were 3.6, 15.5, and 14.4 bites/ person/night (b/p/n) in the Northwest, Northeast, and South districts, respectively. The infection rates were 4.2%, 2.9%, and 1.9% in the Northwest, Northeast, and South districts, respectively, with entomological inoculation rates of 0.15, 0.45, and 0.22 b/p/n. Malaria transmission occurs in all three districts of Bouaké, with levels twice as high in the Northeast District. This transmission is carried out by the An. gambiae species, which exhibited a tendency toward endophagous feeding at all sites. Des travaux réalisés dans la ville de Bouaké il y a environ 20 ans ont montré un fort niveau de transmission du paludisme essentiellement dû au vecteur Anopheles gambiae, avec une recrudescence manifestée en saison pluvieuse. Des efforts de lutte à travers la distribution de moustiquaires imprégnées d’insecticides à longue durée d’action (MILDA) ont été menés par le Programme national de lutte contre le paludisme. Cependant, la crise politico-militaire de 2002 à 2011 a provoqué un important flux migratoire des habitants de cette ville, laissant le milieu naturel préservé. Le retour des populations à Bouaké a donc nécessité la mise en place de nouveaux programmes de lutte avec l’utilisation des MILDA. De nouvelles études de recherche sont maintenant nécessaires afin de recueillir des données sur les paramètres de transmission du paludisme. La présente étude s’inscrit dans ce contexte. Elle a pour objectif d’évaluer la transmission vectorielle du paludisme à travers la détermination de paramètres entomologiques dans les trois districts sanitaires de la ville de Bouaké. Les investigations ont été menées en milieu urbain pendant la saison pluvieuse, du 10 au 29 juin 2016, dans les trois districts sanitaires de Bouaké (Nord-Ouest, Nord-Est, Sud). Les moustiques ont été collectés par captures sur sujet humain et identifiés. Le comportement trophique des femelles vectrices a été examiné et les paramètres entomologiques de la transmission du paludisme ont été estimés. L’âge physiologique des femelles vectrices a été déterminé après la dissection de leurs ovaires et les moustiques infestés par Plasmodium falciparum ont été détectés par le test ELISA-CSP. An. gambiae a été la seule espèce vectrice du paludisme collectée. Elle a présenté une tendance à l’endophagie et un taux moyen de parturité supérieur à 90 % dans tous les districts. Les densités agressives de l’espèce étaient respectivement de 3,6, 15,5 et 14,4 piqûres/homme/nuit (p/h/n) dans les districts Nord-Ouest, Nord-Est et Sud. Les taux d’infestation étaient en moyenne de 4,2 %, 2,9 % et 1,9 % pour les districts Nord-Ouest, Nord-Est et Sud avec des taux d’inoculation entomologique de 0,15, 0,45 et 0,22 p/h/n respectivement. La transmission du paludisme existe dans les trois districts de la ville de Bouaké avec un niveau deux fois supérieur dans le district Nord-Est. Cette transmission est assurée par l’espèce An. gambiae qui a présenté une tendance à l’endophagie dans tous les sites.
Fructophilic lactic acid bacteria (FLAB) are a group of lactic acid bacteria with unique growth characteristics, that is, poor growth on glucose. Their growth is enhanced in the presence of fructose or external electron acceptors. These organisms inhabit fructose-rich environments such as flowers, fruits, and pollinating insects, particularly honey bees. Apilactobacillus spp. and Fructobacillus spp. are representatives of FLAB, although they belong to phylogenetically distant clades. These organisms commonly possess markedly small genomes with a low number of coding DNA sequences. Furthermore, their genomes are characterized by a markedly reduced number of genes involved in carbohydrate transport and metabolism. Genome reduction in FLAB reflects convergent adaptation to fructose-rich environments rather than general genome streamlining. The two distinct FLAB genera, Fructobacillus and Apilactobacillus, independently lost more than 100 genes in statistically similar orders. In contrast, genes involved in carbohydrate and amino acid metabolism exhibited reversed orders of loss between the two genera. Furthermore, FLAB genomes lack an intact bifunctional alcohol/aldehyde dehydrogenase gene (adhE), which causes their poor growth on glucose. A comparative genomic study suggested the evolutionary process underlying adhE gene decay during adaptation to the fructose-rich environments, including pollinating insects. In conclusion, FLAB represent a unique example of habitat-driven convergent reductive evolution that can be investigated across multiple biological scales - from individual genes to whole genomes - in the diverse LAB group with a wide range of habitats, and partially share the fructophilic evolution with eukaryotic yeasts found in fructose-rich habitats.
Laboratory and field populations of insects can experience a decline in fitness and loss of genetic diversity due to inbreeding depression and genetic drift, respectively. Matings among related individuals and small population size may also influence insect host microbiomes with consequences for fitness. In the dengue vector mosquito, Aedes aegypti, the bacterial microbiome is largely environmentally determined, but recent studies have also revealed host genetic components. We generated a panel of 55 inbred lines from either of two founding outbred populations of Ae. aegypti to test for associations between life history traits, inbreeding, allelic diversity, and microbiome composition using ddRADseq and bacterial 16S rRNA gene sequencing on pools of mosquitoes. Effects of inbreeding were diverse, with severe composite fitness costs in many lines but minimal costs in others despite similar low levels of genetic diversity. We found no strong relationship between major life history traits across inbred lines, suggesting that any costs due to inbreeding were trait specific. Bacterial microbiome analysis of pooled samples from a subset of lines revealed common microbes across lines, with Elizabethkingia, Aeromonas, and Ralstonia being the most abundant. Despite bacterial composition varying widely, there was no clear relationship between microbiome composition and fitness or population origin. However, there were several significant positive correlations between the relative abundance of different microbial taxa across lines. Our results demonstrate diverse impacts of inbreeding on the fitness of mosquito populations but with limited impacts on the microbiome.
Host-plant selection for oviposition strongly influences herbivorous insect population establishment and crop damage, and is largely mediated by plant volatile cues. Silicon dioxide nanoparticles (SiO2NPs) can modify plant-insect interactions, but whether their effects persist across crop generations through soil-mediated legacy effects remains unknown. Here, we investigated whether foliar SiO2NP application generates a soil legacy that reprograms maize volatiles and alters the host-plant preference in the fall armyworm (Spodoptera frugiperda). Maize grown in SiO2NP-conditioned soil showed no significant changes in early growth traits or silicon (Si) accumulation, but received fewer eggs under field and laboratory conditions. Adult and larval choice assays confirmed reduced S. frugiperda host-plant preference. Soil sterilization eliminated this effect, whereas microbial reintroduction rescued the phenotype, indicating that soil microorganisms contribute to the SiO2NP legacy effect. Volatile profiling revealed substantial reprogramming of maize volatile blends, including increased emissions of hexanal, (Z)-β-ionone, dihydroactinidiolide (DAL), 6,10,14-trimethyl-2-pentadecanone (phytone), and (3E,7E)-4,8,12-trimethyltrideca-1,3,7,11-tetraene (TMTT). Hexanal, DAL, and TMTT exhibited concentration-dependent behavioral effects, shifting from attraction at control-level emissions to repellence at the elevated levels found in SiO2NP-conditioned plants. These results demonstrate that foliar SiO2NP application induces a soil legacy effect that disrupts S. frugiperda oviposition by quantitatively reprogramming of maize volatiles, without detectable effects on plant growth. This study reveals a previously unrecognized nano-Si-mediated soil feedback mechanism and provides a basis for developing SiO2NP-based approaches to suppress pest colonization. © 2026 Society of Chemical Industry.
Helicoverpa armigera (Hübner) is able to feed on more than 280 host plants; however, the mechanisms that allow it to persist on such a wide range of hosts may involve transcriptional reprogramming and biochemical alternations which are still not well understood. Therefore, we analyzed the transcriptional responses of salicylic acid (SA)- and jasmonic acid (JA)-mediated signaling pathways in tomato (Solanum lycopersicum L.), which is increasingly used as a model plant system. The SA-related genes PR1a and PAL showed increased expression both locally and systemically at 12, 24, 36, and 48  h post-infestation (HPI). In contrast, the JA-associated transcripts PIN2 and LOX did not show induction and were even suppressed at 48 HPI. An oxidative burst of H2O2 was detected, which subsequently activated antioxidant enzymes such as catalase (CAT) and superoxide dismutase (SOD) at 2, 5, 12, 24, and 48 HPI. The levels of phenolic compounds increased markedly, and the concentration of soluble proteins also showed noticeable changes. Larval weight of H. armigera declined at 3, 5, and 7  days post-infestation (DPI) when plants were treated with exogenous BTH (Benzothiadiazole) and MeJA (Methyl Jasmonate). The 0.25  mM MeJA resulted in a significantly greater reduction compared with 0.5  mM BTH. These findings suggest that activation of the JA pathway is unfavorable for H. armigera, whereas the insect may survive on diverse hosts by promoting SA signaling pathway. H. armigera-mediated defense network was also constructed. Such insights may contribute to the development of safer pest management techniques and insect-resistant crops against polyphagous pests.
The family Amalgaviridae comprises double-stranded RNA viruses with two partially overlapping open reading frames (ORFs), in which the RNA-dependent RNA polymerase is expressed through programmed ribosomal frameshifting. virus 1 (AnloV1), the founding member of the proposed genus "Anlovirus", represents a poorly characterized viral lineage because only a limited number of genome sequences have been reported. Here, we systematically mined publicly available transcriptome datasets and identified 13 AnloV1-like genome sequences from four insect species and one mammalian fecal sample. Pairwise sequence comparisons indicated that these genomes represent nine putative viral species, substantially expanding the diversity of this lineage. Comparative genomic analyses showed that all newly identified viruses possess two overlapping ORFs and a highly conserved UUU_CNN motif at the ORF1/ORF2 overlap, further supporting this sequence as the consensus +1 programmed ribosomal frameshifting motif of the proposed genus "Anlovirus". Phylogenetic analysis recovered a well-supported AnloV1-like clade distinct from the recognized genera of the family Amalgaviridae, providing additional evidence for the proposed genus "Anlovirus". Transcriptome datasets from all four insect species also contained transcripts with high similarity to microsporidian proteins, suggesting that at least some AnloV1-like viruses may infect microsporidian parasites rather than the sampled animals. These findings substantially expand the genomic resources available for AnloV1-like viruses and provide an evolutionary framework that may facilitate the future establishment and classification of the proposed genus "Anlovirus".
Telomeric sequences in the insect infraorder Nepomorpha (Hemiptera: Heteroptera) have previously been characterized only in the basal superfamily Nepoidea, where the canonical arthropod motif (TTAGG)n was confirmed by fluorescence in situ hybridization (FISH). The telomeric repeat composition of the remaining Nepomorpha superfamilies remained unknown. Using TREW, a tool for de novo identification of candidate telomeric sequences from short-read whole-genome sequencing data, we screened 32 publicly available NCBI datasets representing 24 genera and all 13 Nepomorpha families. The method was validated against species with known (TTAGG)n telomeres in Nepoidea, successfully recovering the expected motif. In Corixoidea, (TTAGG)n was uniformly identified as the best candidate for telomeric sequence across all eight species of three families - Corixidae, Diaprepocoridae and Micronectidae. In contrast, derived 10-bp motifs were recovered from the remaining four superfamilies: (TGGTTAGTGA)n and (TGGTTAGTGT)n in Ochteroidea, (TGGATAGGTG)n and (TGGATAGGAG)n in Naucoroidea (including Aphelocheiridae and Potamocoridae), and (TGGATAGGGT)n uniformly across Notonectoidea and Pleoidea. All derived decamers except those from Ochteroidea share the core octamer TGGATAGG. The retention of (TTAGG)n in the two basal superfamilies and the occurrence of derived decamers in more derived clades are congruent with most current phylogenetic hypotheses for Nepomorpha and support independent evolution of 10-bp motifs within the infraorder. The presence of an identical candidate for telomeric sequence - (TGGATAGGGT)n in Notonectoidea and Pleoidea provides additional support for their close phylogenetic relationship and might be a synapomorphy for this clade. These findings extend the known pattern of telomeric diversification within Heteroptera to Nepomorpha and demonstrate the utility of short-read archival data for taxonomic surveys of telomeric composition.