Pyrethroid Insecticides Research Articles

Cypermethrin induces apoptosis, autophagy and inflammation via ERS-ROS-NF-κB axis in hepatocytes of carp (Cyprinus carpio)

Cypermethrin (CYP, IUPAC name: [cyano-(3-phenoxyphenyl)methyl] 3-(2,2-dichloroethenyl)-2,2-dimethylcyclopropane-1-carboxylate) is a pyrethroid insecticide that poses a threat to the health of humans and aquatic animals due to its widespread use and environmental contamination. However, the mechanism of CYP on apoptosis, autophagy and inflammation in hepatocytes of carp (Cyprinus carpio) is unknown. We hypothesized that CYP caused damage to hepatocytes through the endoplasmic reticulum stress (ERS) pathway, CCK-8 was used to detect the toxic effects of different doses of CYP on hepatocytes, and finally low (L, 10 μM), medium (M, 40 μM), and high (H, 80 μM) doses of CYP was selected to construct the model. ROS staining, oxidative stress-related indices (MDA, CAT, T-AOC, SOD), AO/EB staining, MDC staining, and the expression levels of related genes were detected using qRT-PCR and western blot. Our results showed that CYP exposure resulted in an increase in ROS production, an increase in MDA content, and a decrease in the activity of CAT, SOD, and T-AOC in hepatocytes; the proportion of apoptotic, necrotic, and autophagic cells increased significantly in a dose-dependent manner. We also found that CYP exposure increased the expression levels of endoplasmic reticulum-related genes (GRP78, PERK, IRE-1, ATF-6 and CHOP), apoptosis (Bcl-2, Bax, Caspase-3, Caspase-9 and Cyt-c) and autophagy-related genes (LC3b, Beclin1 and P62) also showed dose-dependent changes, and the expression levels of inflammation-related genes (NF-κB, TNF-α, IL-1β, IL-6) were also significantly elevated. Thus, we demonstrated that CYP exposure caused apoptosis, autophagy and inflammation in hepatocytes via ERS-ROS-NF-κB axis. This research contributes to our understanding of the molecular mechanisms underlying CYP-induced damage in hepatocytes of carp (Cyprinus carpio).

Assessing the potential of biopesticides to control the cabbage stem flea beetle Psylliodes chrysocephala.

Cabbage stem flea beetle (CSFB) is an economically important pest of oilseed rape crops in Europe that was effectively controlled by neonicotinoid insecticide seed treatments until they were banned by the European Union in 2013. Since then, CSFB has been a difficult pest to control effectively, in part due to many populations having developed resistance to pyrethroids, the only authorized insecticides used to control this pest in many countries. Alternative solutions are therefore necessary, such as biopesticides. We tested an entomopathogenic fungus, three entomopathogenic bacteria isolates, two fatty acids and azadirachtin against CSFB adults under laboratory conditions. We also tested the efficacy of the pyrethroid insecticide lambda-cyhalothrin. Fatty acids were effective, with up to 100% CSFB mortality after 24 h. The entomopathogenic fungus Beauveria bassiana resulted in up to 56% mortality 14 days after treatment. Entomopathogenic bacteria formulations and azadirachtin were not effective (<50% and <40% mortality, respectively). Results from a bioassay using lambda-cyhalothrin indicated that the CSFB used in this study were resistant to this insecticide. Entomopathogenic fungi and fatty acids could potentially be used to control CSFB as part of an integrated pest management programme. This study is the first to investigate the efficacy of different biopesticides to control CSFB under laboratory conditions. As such, these biopesticides require further testing to optimise the formulation and application methods, and to assess the impact on nontarget organisms. Finally, efficacy under field conditions must be determined to understand the influence of environmental variables. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Microbial detoxification of bifenthrin insecticide by selected fungal strains and optimizing conditions using response surface methodology for agricultural sustainability.

Bifenthrin is a type I broad spectrum pyrethroid insecticide widely employed in urban and agricultural settings with little knowledge about its biodegradation. Bifenthrin was subjected to a 35 days incubation period in which it was degraded by five fungal strains named as Aspergillus niger, Aspergillus flavus, Aspergillus fumigatus, Penicillium chrysogenum, and Lasiodiplodia theobromae. Penicillium chrysogenum was found to be extremely effective in degrading bifenthrin up to 85%. Furthermore, response surface methodology (RSM) with Box-Behnken design is applied to optimize the degradation conditions with varying pH, temperature (°C), and incubation time (days). The p value < 0.05 in the response surface design and analysis of variance showed the significance of the reaction parameters. The ideal conditions for Penicillium chrysogenum to break down bifenthrin (10 mgL-1) were found to be 30 °C, pH 7, and a 24 days incubation period. In eutrophic conditions and a glucose-rich media, this fungus co-metabolized bifenthrin. By hydrolytically cleaving the carboxyl ester bond, the Penicillium chrysogenum breaks down bifenthrin, as shown by the chromatogram of four metabolites from GCMS. The biodegradation of bifenthrin by strain Penicillium chrysogenum and its use in agronomic situations are now well understood as per the findings of this study.

Analysis of the α-CYPERMETHRIN biodegradation by Klebsiella pneumoniae YH43

Cypermethrin (CYP) is an insecticide pyrethroid used in the agriculture for its broad-spectrum activity. However, recent studies have shown the accumulation of CYP in soil, and water and a high toxicity against different species, including humans. On the other hand, the use of bacteria in bioremediation represents an eco-friendly alternative for the removal of different xenobiotics. In this study, the aim was to isolate and identify bacteria from agricultural soils to determine their ability to tolerate and biodegrade CYP. Additionally, some metabolites of the CYP biodegradation were detected by ultra-performance liquid chromatography with mass spectrometry (UPLC-MS). Klebsiella pneumoniae YH43 isolate used CYP as a carbon source, degrading 87.55 % at a concentration of 100 mg/L. α-cyano-3-phenoxybenzyl alcohol and cis,trans-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane carboxylate were identified as the main metabolites in the pathway of the CYP biodegradation. These results suggest that K. pneumoniae YH43 has the potential to be used in the bioremediation of contaminated soils with CYP.

A Survey on Ambrosia Beetle (Coleoptera: Curculionidae) Problems in Ornamental and Pecan Industries in Georgia

Abstract The ambrosia beetles, mainly Xylosandrus crassiusculus (Motschulsky) (Coleoptera: Curculionidae: Scolytinae), are serious pests of young trees in the ornamental industry and pecan orchards as infested trees develop branch dieback with occasional tree mortality. Surveys were conducted in the ornamental industry in 2020 and 2021 and the pecan industry in 2020 because clientele perspective on the extent of damage, phenology, monitoring, management, and loss related to the ambrosia beetle was unclear. Of 35 and 40 ornamental industry respondents, 68% and 82% indicated problems with this pest in 2020 and 2021, respectively. Of 66 pecan industry respondents, 52% reported beetle problems in 2020. About 85% of ornamental and 58% of pecan respondents indicated that 1–10 trees were attacked by ambrosia beetles and 1–30 or more trees were culled annually. The beetle problem persists throughout the growing season but appears greater during the spring than in other periods. About 73% of respondents indicated that current monitoring tools helped them with management decisions; however, a proportion did not use recommended monitoring tools but instead relied on visual signs to determine attacks on trees. In the 2020 surveys, only 37% of ornamental respondents and 43% of the pecan respondents used insecticide sprays, whereas in the 2021 survey, 71% of the ornamental clientele (mostly nurseries) sprayed pyrethroid insecticides for ambrosia beetle management. In 2020 surveys, about 48% and 56% of ornamental and pecan respondents, respectively, spent &amp;lt;$500 USD for ambrosia beetle management.

The Effect of the Pyrethroid Pesticide Fenpropathrin on the Cardiac Performance of Zebrafish and the Potential Mechanism of Toxicity.

Fenpropathrin, a pyrethroid insecticide, has been widely used for many years in agricultural fields. It works by disturbing the voltage-gated sodium channel, leading to paralysis and the death of the target animal. While past studies have focused on neurodegeneration following fenpropathrin poisoning in humans, relatively few pieces of research have examined its effect on other peripheral organs. This study successfully investigated the potential toxicity of fenpropathrin on the cardiovascular system using zebrafish as an animal model. Zebrafish larvae exposed to varying doses of fenpropathrin underwent an evaluation of cardiac physiology by measuring the heart rate, stroke volume, cardiac output, and shortening fraction. The blood flow velocity and the dorsal aorta diameter were also measured to assess the impact of fenpropathrin exposure on the vascular system. Furthermore, molecular docking was performed to evaluate the pesticide binding affinity to various proteins associated with the cardiovascular system, revealing the potential mechanism of the fenpropathrin cardiotoxic effect. The findings demonstrated a significant dose-dependent increase in the heart rate stroke volume, cardiac output, shortening fraction, and ejection fraction of zebrafish larvae after 24 h of acute treatment with fenpropathrin. Additionally, zebrafish treated at a concentration of 1 ppm exhibited significantly larger blood vessels in diameter and an increased blood flow velocity compared to the control group. According to molecular docking, fenpropathrin showed a high affinity for various voltage-gated sodium channels like scn1lab, cacna1sb, and clcn3. Finally, from the results, we found that fenpropathrin caused cardiomegaly, which may have been induced by the voltage-gated sodium channel disruption. This study highlights the significant disruption of fenpropathrin in the cardiovascular system and emphasizes the need for further research on the health implications of this pesticide.

The voltage-gated sodium channel, para, limits Anopheles coluzzii vector competence in a microbiota dependent manner

The voltage-gated sodium channel, para, is a target of DDT and pyrethroid class insecticides. Single nucleotide mutations in para, called knockdown resistant or kdr, which contribute to resistance against DDT and pyrethroid insecticides, have been correlated with increased susceptibility of Anopheles to the human malaria parasite Plasmodium falciparum. However, a direct role of para activity on Plasmodium infection has not yet been established. Here, using RNA-mediated silencing, we provide in vivo direct evidence for the requirement of wild-type (wt) para function for insecticide activity of deltamethrin. Depletion of wt para, which is susceptible to insecticide, causes deltamethrin tolerance, indicating that insecticide-resistant kdr alleles are likely phenocopies of loss of para function. We then show that normal para activity in An. coluzzii limits Plasmodium infection prevalence for both P. falciparum and P. berghei. A transcriptomic analysis revealed that para activity does not modulate the expression of immune genes. However, loss of para function led to enteric dysbiosis with a significant increase in the total bacterial abundance, and we show that para function limiting Plasmodium infection is microbiota dependent. In the context of the bidirectional “enteric microbiota-brain” axis studied in mammals, these results pave the way for studying whether the activity of the nervous system could control Anopheles vector competence.

Deltamethrin and transfluthrin select for distinct transcriptomic responses in the malaria vector Anopheles gambiae

BackgroundThe widespread use of pyrethroid insecticides in Africa has led to the development of strong resistance in Anopheles mosquitoes. Introducing new active ingredients can contribute to overcome this phenomenon and ensure the effectiveness of vector control strategies. Transfluthrin is a polyfluorinated pyrethroid whose structural conformation was thought to prevent its metabolism by cytochrome P450 monooxygenases in malaria vectors, thus representing a potential alternative for managing P450-mediated resistance occurring in the field. In this study, a controlled selection was used to compare the dynamics of resistance between transfluthrin and the widely used pyrethroid deltamethrin in the mosquito Anopheles gambiae. Then, the associated molecular mechanisms were investigated using target-site mutation genotyping and RNA-seq.MethodsA field-derived line of An. gambiae carrying resistance alleles at low frequencies was used as starting material for a controlled selection experiment. Adult females were selected across 33 generations with deltamethrin or transfluthrin, resulting in three distinct lines: the Delta-R line (selected with deltamethrin), the Transflu-R line (selected with transfluthrin) and the Tiassale-S line (maintained without selection). Deltamethrin and transfluthrin resistance levels were monitored in each selected line throughout the selection process, as well as the frequency of the L1014F kdr mutation. At generation 17, cross-resistance to other public health insecticides was investigated and transcriptomes were sequenced to compare gene transcription variations and polymorphisms associated with adaptation to each insecticide.ResultsA rapid increase in resistance to deltamethrin and transfluthrin was observed throughout the selection process in each selected line in association with an increased frequency of the L1014F kdr mutation. Transcriptomic data support a broader response to transfluthrin selection as compared to deltamethrin selection. For instance, multiple detoxification enzymes and cuticle proteins were specifically over-transcribed in the Transflu-R line including the known pyrethroid metabolizers CYP6M2, CYP9K1 and CYP6AA1 together with other genes previously associated with resistance in An. gambiae.ConclusionThis study confirms that recurrent exposure of adult mosquitoes to pyrethroids in a public health context can rapidly select for various resistance mechanisms. In particular, it indicates that in addition to target site mutations, the polyfluorinated pyrethroid transfluthrin can select for a broad metabolic response, which includes some P450s previously associated to resistance to classical pyrethroids. This unexpected finding highlights the need for an in-depth study on the adaptive response of mosquitoes to newly introduced active ingredients in order to effectively guide and support decision-making programmes in malaria control.

A single-fluorophore-based self-calibrating supramolecular sensor for the fast and ratiometric detection of permethrin

Permethrin (PMT) is a broad-spectrum synthetic pyrethroid insecticide widely used for treatment of insects in agriculture. Yet the massive use of PMT comes at the cost of its residue ubiquitous in the environment thereby causing a significant risk to human health. Therefore, development of an analytical method for accurate detection of PMT at the point-of-care is of great importance. In this study, we report a novel single-fluorophore-based supramolecular sensor with dual emissions as ratiometric output signals, successfully realizing the fast detection of PMT with the self-calibrating feature. This sensor exhibited several advantages for PMT detection, such as fast response, high sensitivity, high specificity, and excellent anti-interference property. Notably, this sensor could be used for on-site monitoring of PMT residues on the food surface without the help of complicated testing facilities. To our best knowledge, this is the first promising fluorescent method for the fast and ratiometric determination of PMT.

The copepod Eurytemora affinis as a relevant species to assess estuarine sediment toxicity: Effects on gene expression and swimming behavior

Compared to freshwater ecosystems, the health status of estuarine waters remains little studied despite their importance for many species. They represent a zone of interest for Human settlements that make them the final sink of pollution in both the water column and sediment. Once in sediments, pollutants could represent a threat to benthic as well as pelagic estuarine species through resuspension events. In the Seine estuary, the copepod Eurytemora affinis has been previously presented as a relevant species to assess resuspended sediment contamination through fitness-related effects at the individual level. The aim of the present study was to use E. affinis copepods to assess estuarine sediment-derived elutriates toxicity at environmental concentrations of particles using a molecular (i.e. transcriptomics) and a behavioral approach. Two sites along the Seine estuary were sampled. The analysis of sediments reveals that both sites have the same granulometric composition and close contamination profiles with the detection of PCBs, PAHs and pyrethroid insecticides. The transcriptomic analysis reveals that exposure to elutriates from both sites triggers the dysregulation of genes involved in biological function as defense response, immunity, ecdysone pathway or neurotoxicity with 66% and 36% of shared genes at the highest concentration for Tancarville and Fatouville. This analysis also reveals a higher count of dysregulated genes in the Fatouville site compared to the Tancarville (271 vs 148) despite their close contamination profile. These results emphasize the molecular approach sensitivity to assess environmental matrix toxicity with E. affinis. The analysis of the swimming behavior of E. affinis did not highlight significant effects after elutriate exposure. However, our strategy to assess E. affinis swimming behavior allows the discrimination of basal swimming behavior i.e. dark/light velocity changes and strong thigmotaxis behavior. Thus, it represents a promising standardized tool to assess copepods swimming behavior in ecotoxicological studies.

Exploring the binding mechanism and adverse toxic effects of degradation metabolites of pyrethroid insecticides to human serum albumin: Multi-spectroscopy, calorimetric and molecular docking approaches.

Pyrethroid insecticides (PIs), a class of structurally similar non-persistent organic pollutants, can be degraded and metabolized to more toxic, and longer half-life products. In this study, the binding interaction mechanisms between human serum albumin (HSA) and the main degradation metabolites of PIs, 3-phenoxybenzoic acid (3-PBA) and 4-fluoro-3-phenoxybenzoic acid (4-F-3-PBA), were studied by theoretical simulation and experimental verification. Steady state fluorescence spectra showed that the fluorescence quenching mechanism was static. According to the binding constant, 4-F-3-PBA (1.53×105Lmol-1) was bound more strongly to HSA than 3-PBA (1.42×105Lmol-1) in subdomain ⅡA (site I). It was found by isothermal titration calorimetry that the metabolites and HSA spontaneously combined mainly through hydrogen bond and van der Waals interaction. Ultraviolet absorption spectra and circular dichroism spectra showed that the metabolites caused slight changes in the microenvironment and conformation of HSA. The above results were proved by molecular docking. The toxicity properties of the metabolites were further analyzed by software, and 4-F-3-PBA was found to be more toxic than 3-PBA. Considering the high exposure level of these metabolites in food, the environment and human body, it is necessary to further explore the toxicity of PIs metabolites.

New insights into Microalgal astaxanthin's effect on Lambda-cyhalothrin-induced lymphocytes immunotoxicity in Cyprinus carpio: Involving miRNA-194-5p-FoxO1-mediated-mitophagy and pyroptosis

Lambda-cyhalothrin (LC), a pyrethroid insecticide widely used in agriculture, causes immunotoxicity to aquatic organisms in the aquatic environment. Microalgal astaxanthin (MA) is a natural carotenoid that enhances viability of a variety of fish. To investigate the immunotoxicity of LC and the improvement effect of MA in lymphocytes (Cyprinus carpio), lymphocytes were treated with LC (80 M) and/or MA (50 M) for 24 h. Firstly, CCK8 combined with PI staining results showed that MA significantly attenuated the LC-induced lymphocyte death rate. Secondly, LC exposure resulted in excessively damaged mitochondrial and mtROS, diminished mitochondrial membrane potential and ATP content, which could be improved by MA. Thirdly, MA upregulated the levels of mitophagy-related regulatory factors (Beclin1, LC3, ATG5, Tom20 and Lamp2) induced by LC. Importantly, MA decreased the levels of pyroptosis-related genes treated with LC, including NLRP3, Cas-4, GSDMD and active Cas-1. Further study indicated that LC treatment caused excessive miRNA-194-5p and reduced levels of FoxO1, PINK1 and Parkin, which was inhibited by MA treatment. Overall, we concluded that MA could enhance damaged mitochondrial elimination by promoting the miRNA-194-5p-FoxO1-PINK1/Parkin-mitophagy in lymphocytes, which reduced mtROS accumulation and alleviated pyroptosis. It offers insights into the importance of MA application in aquaculture as well as the defense of farmed fish against agrobiological hazards in fish under LC.

Deltamethrin Toxicity: Impacts on Non-Target Organisms and the Environment

Deltamethrin is a synthetic pyrethroid insecticide widely used for controlling pests in agriculture and public health programs. However, its toxicity towards non-target organisms, including humans, has raised concerns over its safe use. This review paper aims to summarize the current knowledge of deltamethrin toxicity, including its mechanism of action, acute and chronic toxicity, genotoxicity, and ecotoxicity. The findings suggest that deltamethrin can cause acute toxicity in humans and animals, leading to symptoms such as convulsions, respiratory distress, and even death. Chronic exposure to deltamethrin has been associated with various adverse health effects, including neurotoxicity, reproductive toxicity, and carcinogenicity. Furthermore, deltamethrin has been shown to have toxic effects on non-target organisms, such as bees and aquatic organisms, which can have significant ecological consequences. Therefore, there is a need to regulate and monitor the use of deltamethrin to ensure its safe use and protect the environment and human health.

P21-02: Developmental neurotoxicity of pyrethroid insecticides in cultured human neuroblastoma cells

P21-02: Developmental neurotoxicity of pyrethroid insecticides in cultured human neuroblastoma cells

Mutations of voltage-gated sodium channel contribute to pyrethroid resistance in Panonychus citri.

Insecticide resistance in Panonychus citri is a major obstacle to mite control in citrus orchards. Pyrethroid insecticides are continually used to control mites in China, although resistance to pyrethroids has evolved in some populations. Here, the resistance to the pyrethroid fenpropathrin was investigated and 7 out of 8 field-collected populations of P.citri exhibited a high level of resistance, ranging from 171-fold to 15391-fold higher than the susceptible (SS) comparison strain. Three voltage-gated sodium channel (VGSC) mutations were identified in the tested populations: L1031V, F1747L, and F1751I. Amplicon sequencing was used to evaluate the frequency of these mutations in the 19 field populations. L1031V and F1751I were present in all populations at frequencies of 11.6%-82.1% and 0.5%-31.8%, respectively, whereas the F1747L mutation was only present in 12 populations from Chongqing, Sichuan, Guangxi, and Yunnan provinces. Introduction of these mutations singly or in combination into transgenic flies significantly increased their resistance to fenpropathrin and these flies also exhibited reduced mortality after exposure to the pyrethroids permethrin and β-cypermethrin. Panonychus citri VGSC homology modeling and ligand docking indicate that F1747 and F1751 form direct binding contacts with pyrethroids, which are lost with mutation, whereas L1031 mutation may diminish pyrethroid effects through an allosteric mechanism. Overall, the results provide molecular markers for monitoring pest resistance to pyrethroids and offer new insights into the basis of pyrethroid actions on sodium channels.

High efficacy of chlorfenapyr-based net Interceptor® G2 against pyrethroid-resistant malaria vectors from Cameroon

BackgroundThe increasing reports of resistance to pyrethroid insecticides associated with reduced efficacy of pyrethroid-only interventions highlight the urgency of introducing new non-pyrethroid-only control tools. Here, we investigated the performance of piperonyl-butoxide (PBO)-pyrethroid [Permanet 3.0 (P3.0)] and dual active ingredients (AI) nets [Interceptor G2 (IG2): containing pyrethroids and chlorfenapyr and Royal Guard (RG): containing pyrethroids and pyriproxyfen] compared to pyrethroid-only net Royal Sentry (RS) against pyrethroid-resistant malaria vectors in Cameroon.MethodsThe efficacy of these tools was firstly evaluated on Anopheles gambiae s.l. and Anopheles funestus s.l. from Gounougou, Mibellon, Mangoum, Nkolondom, and Elende using cone/tunnel assays. In addition, experimental hut trials (EHT) were performed to evaluate the performance of unwashed and 20 times washed nets in semi-field conditions. Furthermore, pyrethroid-resistant markers were genotyped in dead vs alive, blood-fed vs unfed mosquitoes after exposure to the nets to evaluate the impact of these markers on net performance. The XLSTAT software was used to calculate the various entomological outcomes and the Chi-square test was used to compare the efficacy of various nets. The odds ratio and Fisher exact test were then used to establish the statistical significance of any association between insecticide resistance markers and bed net efficacy.ResultsInterceptor G2 was the most effective net against wild pyrethroid-resistant An. funestus followed by Permanet 3.0. In EHT, this net induced up to 87.8% mortality [95% confidence interval (CI): 83.5–92.1%) and 55.6% (95% CI: 48.5–62.7%) after 20 washes whilst unwashed pyrethroid-only net (Royal Sentry) killed just 18.2% (95% CI: 13.4–22.9%) of host-seeking An. funestus. The unwashed Permanet 3.0 killed up to 53.8% (95% CI: 44.3–63.4%) of field-resistant mosquitoes and 47.2% (95% CI: 37.7–56.7%) when washed 20 times, and the Royal Guard 13.2% (95% CI: 9.0–17.3%) for unwashed net and 8.5% (95% CI: 5.7–11.4%) for the 20 washed net. Interceptor G2, Permanet 3.0, and Royal Guard provided better personal protection (blood-feeding inhibition 66.2%, 77.8%, and 92.8%, respectively) compared to pyrethroid-only net Royal Sentry (8.4%). Interestingly, a negative association was found between kdrw and the chlorfenapyr-based net Interceptor G2 (χ2 = 138; P < 0.0001) with homozygote-resistant mosquitoes predominantly found in the dead ones.ConclusionsThe high mortality recorded with Interceptor G2 against pyrethroid-resistant malaria vectors in this study provides first semi-field evidence of high efficacy against these major malaria vectors in Cameroon encouraging the implementation of this novel net for malaria control in the country. However, the performance of this net should be established in other locations and on other major malaria vectors before implementation at a large scale.Graphical

Significant 24 h recovery and survival of Culex mosquitoes exposed to pyrethroid insecticides using the CDC bottle bioassay

Significant 24 h recovery and survival of Culex mosquitoes exposed to pyrethroid insecticides using the CDC bottle bioassay

Sensitivity of non-target groups of invertebrates to cypermethrin

Agrogenic pollution with pyrethroid insecticides has been impacting the structure of populations of terrestrial invertebrates, causing decline in their taxonomic diversity and tolerance to critical values of environmental factors. In a laboratory experiment, we evaluated the sensitivity of 46 non-target invertebrate species to cypermethrin. In most examined species, we observed correlation between the body parameters (length and weight of body) and tolerance to this insecticide. We determined that the greater body size of the invertebrates, the better their tolerance to cypermethrin. Differences in LD50 were the highest for groups of invertebrates with the body weight of 1.0–3.9 mg (1.9 ± 0.5 g/ha) and 16.0–63.9 mg (16.4 ± 3.2 g/ha). We observed a relashionship between the trophic specialization and sensitivity to the insecticide in phytophages and zoophages. Average LD50 values for phytophages were 2.1 ± 0.5 g/ha, much lower than for zoophages – 15.6 ± 3.3 g/ha. Among zoophages, the greatest tolerance to cypermethrin was demonstrated by ground beetles Carabus coriaceus L., Pterostichus niger (Schall.), P. melanarius (Ill.), Pseudoophonus rufipes (De Geer), and earwigs Forficula auricularia L. Analysis of various taxonomic groups of insects revealed the parameter to be 24.00 ± 4.66 for Carabidae, 8.60 ± 2.72 for Formicidae, and 0.23 ± 0.08 for Staphylinidae. Among the taxonomic groups we studied, the most sensitive to cypermethrin (LD50 = 0.002–0.99 g/ha) were Philonthus decorus (0.0029), Ph. rectangulus (0.0035), Ophonus rufibarbis (0.121), Oxytelus sculptus (0.124), Myrmica ruginodis (0.39), Aleochara lanuginosa (0.49), Carabus granulatus (0.51), Oxythyrea funesta (0.52), Tachinus signatus (0.55), Cixiidae sp. (0.56), Lygus pratensis (0.56), Carabus convexus (0.71), and C. hortensis (0.83). Lower sensitivity to cypermethrin (LD50 = 1.00–9.99 g/ha) was seen in Lasius fuliginosus (1.05), Pyrrhocoris apterus (1.28), Chortippus sp. 2 (1.96), Rhyparochromus phoeniceus (2.24), Phosphuga atrata (2.25), Chironomus plumosus (2.58), Labia minor (2.86), Graphosoma italicum (2.86), Hister fenestus (3.39), Cylindroiulus truncorum (3.61), Opilio saxatilis (3.71), Chortippus sp. 1 (3.94), Epaphius secalis (4.54), Lasius niger (4.77), Silpha carinata (4.84), Aphodius foetens (4.94), Porcellio laevis (5.68), Coreus marginatus (6.50), Leistus ferrugineus (7.39), and Lasius alienus (9.73). The most tolerant to cypermethrin (LD50 = 10.00–108.00 g/ha) were Calathus fuscipes (12.14), Limodromus assimilis (12.22), Trochosa terricola (12.55), Lithobius forficatus (13.98), Calathus ambiguus (20.85), Nebria brevicollis (23.20), Ponera coarctata (27.04), Megaphyllum sp. (29.01), Pseudoophonus rufipes (41.75), Pterostichus melanarius (45.78), P. niger (58.29), Forficula auricularia (80.57), and Carabus coriaceus (107.71). The differences we found in tolerance to cypermethrin ranged 100,000 times. This evidences the necessity of further research of taxonomic differences in tolerance of invertebrates to cypermethrin.

Multiple Pyrethroid Resistance in Urban Male and Female An. gambiae s.l Populations in Ilorin Nigeria: Implications for Swarm Spraying and Toxic Sugar Bait Malaria Vector Control

Background: Male mosquito control through swarm spraying and Attractive Toxic Sugar Baits (ATSB) have been identified as potential strategies to complement the regular but insufficient female mosquito-based insecticide-treated net (ITN) approach. However, the effectiveness of these control strategies relies on under-standing the insecticide susceptibility status of the targeted male and female mosquito populations. Therefore, this study aimed to assess the insecticide susceptibility status of male and female An. gambiae s.l. Popu-lations in urban Ilorin, Nigeria. Methods: Using WHO kits and protocol, adult male and female mosquitoes reared from the same larval col-lections from different sites were exposed separately to permethrin, deltamethrin, and alphacypermethrin insecticides. Joint insecticide susceptibility tests, involving exposures of equal numbers of male and female mosquitoes to each insecticide, were also conducted in anticipation of joint insecticide exposure on the field. Exposed mosquitoes were identified to species level. Results: Higher kdt50s (52.5-641.3mins) and lower mortalities (permethrin 39-62%, deltamethrin 57-68%, alphacypermethrin 44-60%), indicating higher levels of resistance, were observed for the females compared to the male (22.1-42.2 mins, 60-94%) mosquitoes. The percentage mortalities of males (71-94%) were sig-nificantly (P ≤ 0.043) higher than those of the jointly exposed females (39-62%). However, separately ex-posed male mosquito mortalities (60-81%) were not significantly (P ≥ 0.067) higher than the females (55-68%). All the male mosquito populations were resistant to permethrin (75-94% mortality), deltamethrin (60-82%), and alphacypermethrin (74-86%) insecticides after joint and separate exposures. Resistant male and female mosquitoes were identified predominantly as An. arabiensis (74-84%). Conclusion: Multiple pyrethroid insecticide resistance detected in the male and female mosquito populations indicates the potential ineffectiveness of pyrethroid-based swarm spraying, pyrethroid ATSB and ITNs in the study location

Cypermethrin induces endoplasmic reticulum stress and autophagy, leads to testicular dysfunction

Cypermethrin is a pyrethroid insecticide that is used to control insects and protect crops. However, pesticide residues and their possible toxicity to non-target animals such as mammals are concerning. Although cypermethrin reduces testosterone levels, the molecular mechanisms involved, particularly those regarding endoplasmic reticulum (ER) stress and autophagy regulation, have not yet been fully elucidated. In this study, we demonstrated testicular toxicity of cypermethrin in mouse Leydig (TM3) and Sertoli (TM4) cells. Cypermethrin suppresses TM3 and TM4 cell proliferation and induces apoptosis. Moreover, it interrupted calcium homeostasis in intracellular organelles and dissipated mitochondrial membrane polarization in mouse testicular cells. Moreover, we verified the accumulation of Sqstm1/p62 protein in the mitochondria of cypermethrin-treated TM3 and TM4 cells. Furthermore, we confirmed that cypermethrin activated autophagy and the ER stress pathway in a time-dependent manner in both cell types. Finally, we determined that cypermethrin downregulated testicular function-related genes, steroidogenesis, and spermatogenesis in mouse testis cells. Therefore, we conclude that cypermethrin regulates autophagy and ER stress, leading to testicular dysfunction.