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Background: Deltamethrin, as a highly effective and broad‐spectrum insecticide, has been widely used for agricultural pest control such as Aphis gossypii worldwide. Increasing evidence has shown that despite great economic benefits brought by it, deltamethrin has also non‐negligible side effects. However, the potential risks and related molecular mechanisms remain largely unclear. Results: Herein, the life table parameters and transcriptome sequencing analyses of the four successive aphid generations were performed to investigate the hormesis and transgenerational effects of deltamethrin on A. gossypii. The life table analysis showed that although the exposure of G0 aphid to 30% lethal concentration (LC30) deltamethrin significantly reduced the net reproduction rate (R0), intrinsic rate of increase (r), and fecundity of G0, but it significantly enhanced the R0 and fecundity of subsequent two generations (G1 and G2) of A. gossypii. Moreover, transcriptomic analyses showed that the signaling pathways related to posttranscriptional regulation (spliceosome), protein processing, longevity regulating, and cell proliferation (DNA replication, homologous recombination and non‐homologous end‐joining) were significantly up‐regulated in G1 or G2 under LC30 deltamethrin treatment. Additionally, we also found that the deltamethrin–sulfoxaflor rotation of G0 and G1 still induced reproductive stimulation, but the reproductive stimulation induced by insecticides rotation treatment was significantly lower than that in the deltamethrin exposure alone. Conclusion: Our study demonstrates that sublethal concentrations of deltamethrin significantly enhanced the offspring fecundity of cotton aphid. In addition, our study also reveals the transcriptional response mechanism of hormesis‐induced fecundity increase, providing valuable reference for optimizing the application of deltamethrin in integrated pest management. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Spodoptera litura (Fabricius) is a major polyphagous pest of global relevance due to the damage it causes to various crops. Chlorpyrifos (CPF) is generally used by farmers to manage S. litura, however, its widespread use has resulted in the development of insecticide resistance. Therefore, in the present study, a population of S. litura was exposed to CPF for eight generations under laboratory conditions, resulting in a 2.81-fold resistance ratio compared with that of the unselected laboratory population (Unsel-Lab). The exposure of Unsel-Lab and CPF-Sel populations to their respective lethal and sublethal concentrations reduced larval survival, adult emergence, and prolonged development period, and induced morphological deformities in adults. The reproductive and demographic parameters were also significantly lowered in the treated larvae of both populations at higher concentrations. Moreover, hormetic effects on fecundity, next-generation larvae, the net reproductive rate (R0), and relative fitness (Rf) were observed at lower sublethal concentrations of CPF, specifically at the LC5 of Unsel-Lab and the LC10 of the CPF-Sel population. Sublethal exposure to CPF negatively affected the biological and demographic parameters in both populations, although the impact was more prominent in the CPF-Sel population. The relative fitness of the CPF-Sel was also greatly reduced at the LC50 (0.28) compared to that of the Unsel-Lab population. However, only a marginal trade-off of insecticide resistance evolution was observed in the CPF-Sel population in the absence of insecticide selection pressure. These results provide useful information for devising improved pest management strategies for CPF resistance in S. litura. [ABSTRACT FROM AUTHOR]

BACKGROUND: Lepidopteran pest control in agriculture has become heavily dependent on cultivars that express Bacillus thuringiensis (Bt) toxins as 'plant‐incorporated protectants'. However, populations of Spodoptera frugiperda (Smith) in Brazil appear resistant to the Bt traits currently available in commercial soybean cultivars. RESULTS: This study evaluated S. frugiperda life history when feeding on three different Bt soybean cultivars. Cultivars expressing Cry1Ac + Cry1F and Cry1A.105 + Cry2Ab2 + Cry1Ac Bt toxins caused 100% larval mortality in S. frugiperda. Both non‐Bt and Cry1Ac‐expressing soybean induced transgenerational effects that increased the survival of subsequent generations. A Cry1Ac soybean diet reduced the generation time (T) of S. frugiperda relative to non‐Bt soybean, resulting in shorter generation time and more rapid population growth. CONCLUSION: The implications of these results revealed how diet can alter aspects of insect life history and biology, and have important implications for sustainable management of S. frugiperda on soybean. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Bee populations are facing numerous stressors globally, including environmental pollution by trace metals and metalloids. Understanding whether bees can detect and avoid these pollutants in their food is pivotal, as avoidance abilities may mitigate their exposure to xenobiotics. While these pollutants are known to induce sublethal effects in bees, such as disrupting physiological mechanisms, their potential impacts on locomotive abilities, fat metabolism, and reproductive physiology remain poorly understood. In this study, utilising workers of the buff-tailed bumble bee and two prevalent trace metals, namely cadmium and copper, we aimed to address these knowledge gaps for field-realistic concentrations. Our findings reveal that workers did not reject field-realistic concentrations of cadmium and copper in sucrose solutions. Moreover, they did not reject lethal concentrations of cadmium, although they rejected lethal concentrations of copper. Additionally, we observed no significant effects of field-realistic concentrations of these metals on the walking and flying activities of workers, nor on their fat metabolism and reproductive physiology. Overall, our results suggest that bumble bees may not avoid cadmium and copper at environmental concentrations, but ingestion of these metals in natural settings may not adversely affect locomotive abilities, fat metabolism, or reproductive physiology. However, given the conservative nature of our study, we still recommend future research to employ higher concentrations over longer durations to mimic conditions in heavily polluted areas (i.e., mine surrounding). Furthermore, investigations should ascertain whether field-realistic concentrations of metals exert no impact on bee larvae. [ABSTRACT FROM AUTHOR]

The impact of warming on zooxanthellate corals is widespread, from tropical to temperate seas, with its associated mortalities causing global concern. The temperate coral Cladocora caespitosa is the only zooxanthellate coral with reef building capacity in the Mediterranean Sea, a climate change hotspot with warming rates triple the global average. During the past two decades, C. caespitosa populations have suffered severe mortality events associated with marine heatwaves (MHWs). However, with monitoring efforts beginning, at best, in the 2000s, the occurrence of MHWs before that period, as well as the sublethal effects of these events remain poorly understood. Here, we use sclerochronology to reconstruct the histories of past stress events and long‐term sublethal effects on C. caespitosa in three locations along a latitudinal gradient within the NW Mediterranean Sea, each with different environmental conditions. Skeletal extension, density and calcification rates were compared with the in situ seawater temperature of each site to assess their relationship. Furthermore, we assessed the occurrence of skeletal growth anomalies to reconstruct stress events between 1991 and 2021, a period that encompasses the onset and evolution of warming‐related mass mortality events in the NW Mediterranean Sea. Our results reveal a positive association between calcification and temperature, following a latitudinal temperature gradient. However, the evolution of the likelihood distribution of growth rates in the warmest site (Columbretes Islands) since the 1990s indicates a decrease in linear extension and calcification rates during the most recent years. With the increase in the frequency of MHWs and growth anomalies during the last decade, this decline suggests recurrent physiological stress events. These results unravel information on the long‐term impacts of warming on coral growth and highlight the potential of applying sclerochronology to reconstruct the sublethal effects of warming using C. caespitosa. [ABSTRACT FROM AUTHOR]

Insecticides are a mainstay for controlling the invasive pest Drosophila suzukii (Diptera: Drosophilidae), but their use comes with several drawbacks related to the adverse target and non-target impacts at lethal and sublethal concentrations. While pesticide risk assessments generally emphasize the short-term efficacy of chemicals on arthropods pests, the evaluation of long-term effects is generally limited to beneficials. The aim of this study was to (i) assess the baseline toxicity of conventional and organic insecticides on D. suzukii following residual contact exposure, and (ii) evaluate the impact of insecticide field rates (FR) and sublethal (LC10) concentrations on D. suzukii and its pupal parasitoid Trichopria drosophilae (Hymenoptera: Diapriidae). Based on estimated LC50 values, the organophosphates malathion and chlorpyrifos, and the spinosyns spinetoram and spinosad emerged as the most toxic active substances toward D. suzukii, although all tested insecticides did not affect the fertility of treated D. suzukii females when applied at LC10. Cyazypyr, lambda-cyhalothrin and the two aforementioned organophosphates were the most harmful insecticides on T. drosophilae, exhibiting lethal and sublethal effects on wasp survival and fertility. Spinetoram only affected parasitoid survival at FR, while azadirachtin and spinosad reduced the parasitoid's fertility only at LC10. No insecticides affected parasitoid sex-ratio at either tested concentration. These results suggest that insecticides can disrupt the biocontrol service provided by T. drosophilae, even at extremely low concentrations. Understating both target and non-target impact of insecticides is crucial for developing accurate pesticide risk assessments and promoting sustainable D. suzukii management strategies that integrate chemical and biological control methods. [ABSTRACT FROM AUTHOR]

Simple Summary: Drosophila suzukii (Matsumura) (Diptera: Drosophilidae) is an important invasive pest of small soft-skinned fruits globally. The combined application of insecticides and natural enemies can effectively control D. suzukii and reduce chemical insecticide residues. The pupal parasitoid Trichopria drosophilae (Hymenoptera: Diapriidae) has been evaluated as a biological agent of D. suzukii. However, little is known about the toxicity of common insecticides in T. drosophilae. Thus, this study assessed the toxicity of eight common insecticides against D. suzukii in fruit orchards and the effects of semilethal and sublethal doses on T. drosophilae. Emamectin benzoate, spinetoram, lambda-cyhalothrin, abamectin, and sophocarpidine showed high toxicity in adults and larvae of D. suzukii. The toxicities of lambda-cyhalothrin and imidacloprid in T. drosophilae adults were higher than those of the other six insecticides. Exposure to chlorantraniliprole, emamectin benzoate, sophocarpidine, abamectin, azadirachtin, and spinetoram at semilethal and sublethal doses decreased the parasitism of T. drosophilae or eclosion of the next generation. In conclusion, some insecticides at the recommended dose applied for D. suzukii had no effect on the survival of T. drosophilae adults, but insecticide residues can affect T. drosophilae development. The pupal parasitoid Trichopria drosophilae (Hymenoptera: Diapriidae) has been evaluated as a biological agent of Drosophila suzukii. Integrated pest management strategies mostly rely on combined application of multiple insecticides and natural enemies. This study assessed the toxicity of eight common insecticides against D. suzukii in fruit orchards and the effects of semilethal and sublethal doses on T. drosophilae. The eight insecticides had higher toxicities to D. suzukii larvae with lower LC50 values than those for adults. Adults and larvae showed high susceptibility to emamectin benzoate, spinetoram, lambda-cyhalothrin, abamectin, and sophocarpidine. The median lethal doses (LC50) of lambda-cyhalothrin and imidacloprid to T. drosophilae adults were 60.41 mg/L and 100.58 mg/L, higher than the toxicities of the other six insecticides. Applying chlorantraniliprole, emamectin benzoate, sophocarpidine, abamectin, azadirachtin, and spinetoram resulted in low toxicity to D. suzukii pupae. However, the exposure of D. suzukii pupae or larvae to these insecticides at semilethal and sublethal doses decreased the parasitism or eclosion rate of T. drosophilae. These results improve our understanding of the effects of insecticide residues on T. drosophilae development and provide a basis for the combined use of chemical and biological options for managing D. suzukii. [ABSTRACT FROM AUTHOR]

Insulin‐like peptides (ILPs) act as crucial reproductive neuropeptides in insects, regulating insect reproduction through the insulin signaling pathway (ISP). Our previous studies have found that the sublethal concentrations (LC1 and LC10) of lambda‐cyhalothrin (λCy) could induce severe reproductive toxicity in the lacewing, Chrysoperla sinica (Tjeder), but the toxicological mechanism remains unclear. This study discovered that λCy could inhibit CsILP transcription, leading to a decrease in insulin content and downregulation of C. sinica insulin receptor (CsInR) and C. sinica forkhead box O (CsFOXO) expression in ISP. Interference with CsILP expression resulted in downregulation of C. sinica vitellogenin (CsVg) and decreasing fecundity, while exogenous injection of bovine insulin promoted upregulation of CsVg expression and facilitated reproduction in female adults of C. sinica. Meanwhile, interference with FOXO of ILP downstream transcription factor could lead to downregulation of CsVg, hindering ovarian development and resulting in a decrease in egg production. However, exogenous injection of bovine insulin could remedy the effects caused by FOXO interference. In addition, ILP mediates juvenile hormone and 20‐hydroxyecdysone biosynthesis by acting on their synthetic regulatory enzymes and influences the signal transduction of the 2 reproductive endocrine hormones, thereby regulating the reproductive endocrine environment in C. sinica. In conclusion, λCy inhibits CsILP expression, leading to disorder of ISP, leading to the reduced fecundity of C. sinica. [ABSTRACT FROM AUTHOR]

In this study, sublethal effects, toxicity of Bacillus thuringiensis δ-endotoxin (Cry1Ac) on development, reproductive behaviour, and life table characteristics of the tobacco cutworm, Spodoptera litura (S. litura) were assessed by leaf dip bioassay method. The SDS-PAGE of the B.t. endotoxin revealed a single band with 65 kDa size confirmed the presence of activated Cry1Ac protein. The bioassay of Cry1Ac toxin to S. litura was recorded and the LC25, LC50 and LC75 values were 5.78, 22.67 and 88.83 µg/mL, respectively. The results indicated that the biological and life table characters were significantly affected in dose-dependent manner. The influence on life table also revealed higher net reproductive rates (Ro), intrinsic rate of increase (r), finite rate of increase (λ), mean fecundity (F) and lower mean generation time (T) in control (183.8 females/generation, 0.157/day, 1.170/ day, 420.80 eggs/female and 33.05 days, respectively) followed by LC25 (161.9 females/generation, 0.145/day, 1.156/ day, 375.20 eggs/female and 34.25 days, respectively). Similarly, LC50 of Cry1Ac toxin (132 females/generation, 0.123/day, 1.131/ day, 334.00 eggs/female and 39.5 days, respectively). On the contrary, the lower net reproductive rates (Ro), intrinsic rate of increase (r), finite rate of increase (λ), mean fecundity (F) and higher mean generation time (T) were recorded in LC75 of Cry1Ac toxin (103.1 females/generation, 0.100/day, 1.105/day, 313.25 eggs/female and 46.09 days, respectively). Furthermore, the unhealthy larvae with longer developmental time may make them more susceptible to natural enemies and entomopathogens which indeed decrease the population growth and density of S. litura. [ABSTRACT FROM AUTHOR]

Simple Summary: CNAP is a novel anthranilic diamide insecticide and its toxicological profiles pertaining to ladybird beetles remain largely uncharacterized. Through dipping method and topical application, we comprehensively evaluated acute toxicity and sublethal effects of CNAP against Harmonia axyridis, a predacious coccinellid commonly utilized in integrated pest management (IPM). Our outcomes indicated that CNAP was moderately toxic to H. axyridis and most noxious to 1st-instar larvae, with the least LC50 of 86.11 mg/L. When eggs and 1st instars were treated with LC30 CNAP, embryonic, larval and pupal durations all significantly dropped, accompanied by reduced pupal weight and pupation rate. Post sublethal treatments on newly emerged females, reproductive proxies displayed dose-effect responses, with daily spawning and vitellin level substantially diminished and the pre-oviposition period retarded. In addition, sublethal exposure to CNAP profoundly disrupted the antioxidant system of females, as evidenced by an induced hormesis effect at LC10 and impaired enzymatic activities at LC30 over time. Taken together, this study revealed the prospective ecological risk of CNAP and its adverse implications for H. axyridis fitness. As such, the practical compatibility of agrochemicals with biocontrol agents should be well assessed before being embraced into IPM for pest control. Extensive utilization of pesticides and their persistent residues inadvertently pose threats to the effectiveness and fitness of biocontrol agents in agroecosystems. However, these ecological consequences are generally disregarded when executing integrated pest management strategies (IPM). Cyantraniliprole (CNAP) serves as a wide-spectrum diamide insecticide and its sublethal effects have been well characterized on multiple insect pests, whereas its impacts on beneficial natural enemies remain unfathomed. Herein we exposed Harmonia axyridis, a predacious generalist, to lethal and sublethal concentrations of CNAP via dipping treatment (egg stage) and topical applications (1st-instar stage + adult stage). The acute toxicity tests revealed that LC50 of CNAP were 90.11, 86.11 and 240.50 mg/L against embryos, 1st instar nymphs and female adults, respectively, with safety factors ranging from 1.14 to 5.34, suggesting its medium toxicity for H. axyridis and larval stage was the most susceptible. The embryonic, larval and pupal durations of coccinellids ecdysed from CNAP-treated eggs and 1st instars were all elongated under sublethal concentrations, of which LC30 triggered more pronounced and significant retardations relative to control. Besides, exposed coccinellids displayed substantially diminished pupal mass and pupation rate, most notably for insects molted from the 1st-instar stage upon CNAP sublethal treatments. With respect to reproductive performance, LC10 and LC30 of CNAP all significantly suppressed female fecundity, as evidenced by reduced vitellin content, a prolonged pre-oviposition period (POP), mitigated laid eggs and the egg hatching rate. Specifically, there existed positive correlations between vitellin level (Vn) and number of eggs deposited by per female, indicative of CNAP affecting fecundity by regulation of Vn. In addition, the antioxidant system was also profoundly disrupted by CNAP, with compromised POD activity at different concentrations over time and induced hormesis of SOD/CAT activities post LC10 exposure. Activities of SOD and TAC were enhanced to exert protective functions during the first 48 h, while defense collapsed at 72 h following LC30 treatments that depleted all enzymatic activities. We speculated that fitness trade-offs may occur between reproductive capacity and antioxidant defenses to sustain physiological homeostasis in response to CNAP stress. Collectively, this study evaluated the ecological risk of CNAP and unmasked its adverse implications for overall fitness of H. axyridis, which highlighted rational application of agrochemicals to conserve biocontrol agents when implementing IPM strategies for sustainable pest control. [ABSTRACT FROM AUTHOR]

Beneficial microbes induce resistance in plants (MIR), imposing both lethal and sublethal effects on herbivorous insects. We argue that herbivores surviving MIR carry metabolic and immunological imprints of MIR with cascading effects across food webs. We propose that incorporating such cascading effects will strongly enhance the current MIR research framework. [ABSTRACT FROM AUTHOR]

Imidacloprid and other neonicotinoid insecticides severely impact the performance and survival of honey bees and other pollinators. In the present study, we focused on the gene expression profile of newly emerged Apis mellifera queen bees after sublethal imidacloprid treatment during the larval stage. Royal jelly containing 1 ppb imidacloprid was provided to larvae for 3 consecutive days (2–4 days postemergence). Queen larvae treated with imidacloprid showed lower capping and emergence rates (35.5% and 24.22%, respectively) than did control larvae (61.68% and 52.95%, respectively), indicating a high failure rate of queen rearing associated with imidacloprid exposure during the larval stage. The molecular response to imidacloprid treatment was examined next. By comparing the gene expression profiles of imidacloprid‐treated queen larvae and those of control queen larvae using DESeq2, we identified 215 differentially expressed genes, with 105 and 111 up‐ and downregulated genes, respectively. Gene Ontology results indicated that chitin binding– and calcium ion binding–related genes were upregulated, while phototransduction‐ and visual perception–related genes were downregulated. The high mortality rate and altered gene expression profiles suggest that treatment with even 1 ppb imidacloprid can severely impact queen bee survival. Environ Toxicol Chem 2024;43:2232–2242. © 2024 SETAC [ABSTRACT FROM AUTHOR]

We compared the effects of lambda‐cyhalothrin as the pure active ingredient and as a formulated product (Zero®), on the larval stage of the autochthonous species Boana pulchella. We evaluated ecotoxicological endpoints, behavioral and developmental alterations, and the biochemical detoxifying, neurotoxic, and oxidative stress responses, covering a wide concentration range from environmental to high application levels. Both pyrethroid preparations displayed similar ecotoxicity (median lethal concentration of ~0.5 mg/L), with the lethal effect of Zero® being more pronounced than that of the active ingredient. Sublethal behavioral alterations in natatory activity were observed at 1000 times lower concentrations, indicating the ecological hazard of tadpole exposure to this pyrethroid at environmentally relevant concentrations. Biochemical endpoints in B. pulchella larvae showed significant responses to lambda‐cyhalothrin in the ng/L range; these responses were different for the pure or the formulated product, and they were variable at higher concentrations. Principal components analysis confirmed the prevalence of biochemical responses as early endpoints at the lowest lambda‐cyhalothrin concentrations; the Integrated Biomarker Response Index proportionally increased with pyrethroid concentration in a similar way for the pure and the formulated products. We conclude that lambda‐cyhalothrin is of concern from an environmental perspective, with particular emphasis on autochthonous anuran development. The battery of biochemical biomarkers included in our study showed a consistent integrated biomarker response, indicating that this is a potent tool for monitoring impacts on amphibians. Environ Toxicol Chem 2024;43:2134–2144. © 2024 SETAC [ABSTRACT FROM AUTHOR]

The predatory bug Cyrtorhinus lividipennis Reuter (Hemiptera: Miridae) is an important biological control agent for planthoppers, such as Nilaparvata lugens (Stål) (Hemiptera: Delphacidae), and leafhoppers in rice fields (Oryza sativa L., Poaceae). In this study, the sublethal effects of azoxystrobin and difenoconazole, two fungicides extensively used in rice production, on this predatory bug were investigated. The results indicated that exposure to the two fungicides at the third instar had no influence on developmental duration, but difenoconazole resulted in a 25.2% decrease in the lifespan of adult males. When exposed as newly emerged adults, azoxystrobin caused a 33.5% decrease in female longevity. The pre‐oviposition period of azoxystrobin‐treated females mating with azoxystrobin‐treated males was shortened by 44.9%, compared with the control, whereas the pre‐oviposition period of difenoconazole‐treated females mating with control males was lengthened by 32.2% compared with the control group. However, the two fungicides had no effect on fecundity and egg hatchability. Furthermore, the two fungicides did not impact the average consumption of C. lividipennis of N. lugens individuals. They did stimulate the response of C. lividipennis males to rice plants infested by N. lugens in a two‐choice H‐shaped olfactometer test. Also, the predatory capacity of C. lividipennis males was increased after exposure to difenoconazole, whereas the predatory capacity of females was decreased after exposure to the two fungicides. Overall, our results indicated that azoxystrobin and difenoconazole pose no notable risk to C. lividipennis. These findings establish a foundation for the rational and coordinated utilization of fungicides and biological control agents in rice ecosystems. [ABSTRACT FROM AUTHOR]

Background: G1 strain Ganaspis brasiliensis (Ihering) has been recently released in both Europe and America as a biological control agent of the spotted wing drosophila, Drosophila suzukii (Matsumura). In initial phases of classical biological control programs, it becomes imperative to evaluate the susceptibility of parasitoids to insecticides, to identify the best alternatives to adopt in an integrated pest management and organic perspective. In this study, we evaluated lethal and sublethal effects of topical application of five different insecticides classes: neonicotinoids, diamides, pyrethroids, organophosphates and spinosyns. Additionally, we tested residual toxicity in field trials in vineyards and sweet cherry orchards. Results: Adult wasps' susceptibility to different insecticides' classes were consistent between laboratory and field. Spinosad exhibited the highest toxicity, with a median lethal concentration (LC50) of 0.00372 of the maximum field dose, and the highest knock‐down effect in field trials, causing 92.5 ± 5% of mortality at T0. λ‐cyhalothrin showed sublethal effects on both male and female insects' longevity when applied at LC30. In field trials, deltamethrin showed the highest persistence, causing significant parasitoid mortality up to 14 days after treatment. Conversely, cyantraniliprole was the least toxic active ingredient according to both topical and residual bioassays, even though its residues caused mortality up to 7 days after the treatment in the field. Conclusion: Our results indicate that spinosad and λ‐cyhalothrin are highly toxic to G. brasiliensis, making them incompatible with classical biological control programs. Cyantraniliprole exhibited lower toxicity, and may be considered a selective pesticide for the integrated management of D. suzukii. © 2024 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

The melon fruit fly, Zeugodacus cucurbitae, is a major pest of cucurbitaceous fruits. Insecticides are commonly used to control this pest. However, environmental factors can reduce lethal doses to sublethal levels. Additionally, adult flies might only receive sublethal exposure due to limited contact during spraying. This study aimed to determine the sublethal effects of fipronil 5 SC, spinosad 45 SC and malathion 50 EC insecticides on mating and remating performance in Z. cucurbitae. Adults were treated with LC20 of insecticides through topical application and the experiment included four combinations: (1) treated female and treated male (F+M+); (2) treated female and untreated male (F+M-); (3) untreated female and treated male (F-M+); (4) untreated female and untreated male (F-M-). Fipronil treated flies exhibited significantly lower mating percentage (75%-females, 60%-males). However, mating percent in spinosad and malathion was on par with control group. Contrary to this, a significant decrease in remating percentage was noticed in all the insecticide treatments. These findings underscore the adverse effects of sublethal insecticide exposure on reproductive performance in melon fruit fly, which may alter population dynamics and the efficacy of pest management strategies. [ABSTRACT FROM AUTHOR]

Agrochemicals pose significant threats to the survival of bees, yet the physiological impacts of sublethal doses on stingless bees remain poorly understood. This study investigated the effects of acute oral exposure to three commercial formulations of agrochemicals [CuSO4 (leaf fertilizer), glyphosate (herbicide), and spinosad (bioinsecticide)] on antioxidant enzymes, malondialdehyde content (MDA), nitric oxide (NO) levels, and total hemocyte count (THC) in the stingless bee Partamona helleri. Foragers were exposed to lethal concentrations aimed to kill 5% (LC5) of CuSO4 (120 μg mL−1) or spinosad (0.85 μg mL−1) over a 24-h period. Glyphosate-exposed bees received the recommended label concentration (7400 μg mL−1), as they exhibited 100% survival after exposure. Ingestion of CuSO4 or glyphosate-treated diets by bees was reduced. Levels of NO and catalase (CAT) remained unaffected at 0 h or 24 h post-exposure. Superoxide dismutase (SOD) activity was higher at 0 h compared to 24 h, although insignificantly so when compared to the control. Exposure to CuSO4 reduced glutathione S-transferase (GST) activity at 0 h but increased it after 24 h, for both CuSO4 and glyphosate. MDA levels decreased after 0 h exposure to CuSO4 or spinosad but increased after 24 h exposure to all tested agrochemicals. THC showed no difference among glyphosate or spinosad compared to the control or across time. However, CuSO4 exposure significantly increased THC. These findings shed light on the physiological responses of stingless bees to agrochemicals, crucial for understanding their overall health. [ABSTRACT FROM AUTHOR]

As climate change intensifies heatwaves, quantifying associated mortality within ectothermic populations is crucial for effective conservation. Thermal tolerance landscape (TTL) models are useful predictive tools that assume exponentially decreasing survival durations in individuals with increasing temperatures. This assumption has been validated through regression analyses on data from constant temperature experiments, primarily focusing on adult‐stage individuals. However, this approach does not allow for direct model validation with data from dynamic, real‐world heatwave events and overlooks early recruitment stage vulnerabilities.This study aimed to address these gaps using the blue mussel Mytilus, a foundation species forming extensive reefs along temperate coasts, as a model organism. We monitored survival rates of mussels (juveniles and adults) under constant heatwave (CHW) conditions in a laboratory experiment and under dynamic heatwave (DHW) scenarios simulated in an outdoor mesocosm experiment. Post‐heatwaves, we also assessed recruitment rates within the mesocosms. TTL models were parametrised by employing Approximate Bayesian Computation with Sequential Monte Carlo (ABC‐SMC) on each dataset separately.The parameter distributions were similar across both experiments, and the ABC‐SMC model predictions closely matched the observed survival declines, validating these models. In comparison, we found a lower predictive performance when using a Bayesian regression approach. Additionally, our best‐fit model predicted that warming across the non‐fatal DHW regimes would increase sublethal effects on mussels. The observed impact on the recruitment stage was more pronounced, with the recruitment rate following an exponential decay as sublethal effects increased. Our model projected minor (<4%) sublethal effects in adult mussels during the century's five warmest summer temperature regimes, corresponding to 0%–32% declines in recruitment rates.Our research extends the TTL model validation, demonstrates the resilience of subtidal Baltic Mytilus to future extreme heatwaves and offers an approach to predict heatwave‐induced population mortalities, applicable to other species and sensitive systems. Read the free Plain Language Summary for this article on the Journal blog. [ABSTRACT FROM AUTHOR]

Simple Summary: Pollinator bees are often exposed to environmental pollutants such as herbicides and heavy metals during the pollen collection process. Most of the current studies focus on the individual toxic effects of herbicides and heavy metals on bees. However, bees are generally threatened by both heavy metals and herbicides in real environments. Therefore, in this study, the common heavy metal lead and the widely used herbicide glyphosate were selected for joint toxicity analysis. We assessed the combined acute toxicities of heavy metal lead and herbicide with respect to Apis cerana cerana and found that they have a synergistic effect. Feeding the bees this mixture severely impaired their ability to learn and remember and thus their ability to feed. In the long term, enzyme activity and gene expression in bees were also affected. This study helps reveal the interaction of lead and glyphosate and provides a basis for the study of multiple environmental pollutants. Glyphosate (GY) is the most widely used herbicide in agriculture worldwide. Lead is a common heavy metal in the natural environment. Honeybees, as pollinators, are exposed to these pollutants. So far, few reports have evaluated the toxic effects of GY mixed with heavy metals on honeybees (Apis cerana cerana). This study found that the acute toxicity of lead (LC50 = 1083 mg/L) is much greater than that of GY (LC50 = 4764 mg/L) at 96 h. The acute toxicities of the mixed substances were as follows: LC50 = 621 mg/L of lead and LC50 = 946 mg/L of GY. The combination of lead and GY was more toxic than either of the individual substances alone. Compared to the individual toxicity, combined treatment significantly affected the bees' learning and cognitive abilities and changed the relative expression of genes related to immune defense and detoxification metabolism in A. c. cerana. The combination of lead and GY seriously affected the behavior and physiology of the studied honeybees. This study provides basic data for further research on the combined effects of GY and heavy metals on bee health. It also serves as a reference for effective colony protection. [ABSTRACT FROM AUTHOR]

To date, studies of the impacts of climate warming on individuals and populations have mostly focused on mortality and thermal tolerance. In contrast, much less is known about the consequences of sublethal effects, which are more challenging to detect, particularly in wild species with cryptic life histories. This necessitates the development of molecular tools to identify their signatures. In a split‐clutch field experiment, we relocated clutches of wild, nesting loggerhead sea turtles (Caretta caretta) to an in situ hatchery. Eggs were then split into two sub‐clutches and incubated under shallow or deep conditions, with those in the shallow treatment experiencing significantly higher temperatures in otherwise natural conditions. Although no difference in hatching success was observed between treatments, hatchlings from the shallow, warmer treatment had different length–mass relationships and were weaker at locomotion tests than their siblings incubated in the deep, cooler treatment. To characterise the molecular signatures of these thermal effects, we performed whole genome bisulfite sequencing on blood samples collected upon emergence. We identified 287 differentially methylated sites between hatchlings from different treatments, including on genes with neurodevelopmental, cytoskeletal, and lipid metabolism functions. Taken together, our results show that higher incubation temperatures induce sublethal effects in hatchlings, which are reflected in their DNA methylation status at identified sites. These sites could be used as biomarkers of thermal stress, especially if they are retained across life stages. Overall, this study suggests that global warming reduces hatchling fitness, which has implications for dispersal capacity and ultimately a population's adaptive potential. Conservation efforts for these endangered species and similar climate‐threatened taxa will therefore benefit from strategies for monitoring and mitigating exposure to temperatures that induce sublethal effects. [ABSTRACT FROM AUTHOR]

Chagas disease is considered one of the most important human parasitosis in the United States. This disease is mainly transmitted by insects of the subfamily Triatominae. The chemical vector control is the main tool for reducing the incidence of the disease. However, the presence of triatomines after pyrethroids spraying has been reported in some regions, as in the case of Triatoma infestans in Argentina and Bolivia. The presence of insects can be explained by the colonization from neighbouring areas, the reduction of insecticide dose to sublethal levels due to environmental factors, and/or by the evolution of insecticide resistance. In the last two scenarios, a proportion of the insects is not killed by insecticide and gives rise to residual populations. This article focuses on the toxicological processes associated with these scenarios in triatomines. Sublethal doses may have different effects on insect biology, that is, sublethal effects, which may contribute to the control. In addition, for insect disease vectors, sublethal doses could have negative effects on disease transmission. The study of sublethal effects in triatomines has focused primarily on the sequence of symptoms associated with nervous intoxication. However, the effects of sublethal doses on excretion, reproduction and morphology have also been studied. Rhodnius prolixus and T. infestans and pyrethroids insecticides were the triatomine species and insecticides, respectively, mainly studied. Insecticide resistance is an evolutionary phenomenon in which the insecticide acts as a selective force, concentrating on the insect population's pre‐existing traits that confer resistance. This leads to a reduction in the susceptibility to the insecticide, which was previously effective in controlling this species. The evolution of resistance in triatomines received little attention before the 2000s, but after the detection of the first focus of resistance associated with chemical control failures in T. infestans from Argentina in 2002, the study of resistance increased remarkably. A significant number of works have studied the geographical distribution, the resistance mechanisms, the biological modifications associated with resistance, the environmental influences and the genetic of T. infestans resistant to pyrethroid insecticides. Currently, studies of insecticide resistance are gradually being extended to other areas and other species. The aim of this article was to review the knowledge on both phenomena (sublethal effects and insecticide resistance) in triatomines. For a better understanding of this article, some concepts and processes related to insect‐insecticide interactions, individual and population toxicology and evolutionary biology are briefly reviewed. Finally, possible future lines of research in triatomine toxicology are discussed. [ABSTRACT FROM AUTHOR]

The pulse beetle is a primary pest of mung bean (Vigna radiata L.), causing heavy losses during storage. Conventional control of pulse beetle with insecticides has led to various challenges. This study sought safer alternatives by exploring the efficacy of hexane extracts derived from seeds of Azadirachta indica and Trachyspermum ammi, Curcuma longa rhizomes, Allium sativum bulbs, Citrullus colocynthis fruits, and Caralluma tuberculata stems against pulse beetle. Each plant extract was tested at six concentrations of 0.5%, 1.0%, 1.5%, 2.0%, 2.5%, and 3.0% w/v, under the constant laboratory conditions of the Gomal University, Dera Ismail Khan, Khyber Pakhtunkhwa, Pakistan. The hexane extracts prepared from A. sativum and C. longa at 3% concentration exhibited significant efficacy, resulting in mortality rates of 99.20% and 94.40% of adult beetles, respectively. Furthermore, mung bean grains treated with the A. sativum extracts at the maximum concentration (3%) demonstrated minimum egg deposition (2.20 per grains-20), prolonged time to adult emergence (25.10 days), minimum progeny emergence (33.40), lowest infestation (5.47%), minimum weight loss (4.39%), and shortest adult life span (8.70 days). The hexane plant extracts prepared from A. sativum and C. longa powders at higher concentrations (2.5% and 3.0%) can benefit the safer management of pulse beetles. [ABSTRACT FROM AUTHOR]

Continued use and development of new insecticides are seen as a necessary part of modern agriculture, but insecticides, even at sublethal levels, may also affect beneficial non‐target species, such as pollinators, predators, and parasitic wasps. Here, we studied sublethal effects of four insecticides – acetamiprid, dimethoate, flupyradifurone, and sulfoxaflor – all targeting cholinergic neurons in insects, on sexual communication and olfactory host finding in the parasitic wasp Lariophagus distinguendus (Förster) (Hymenoptera: Pteromalidae). We found that all four insecticides reduced, at least at one of the tested sublethal doses, pheromone‐mediated courtship behaviour (wing fanning) in males and the mating frequency of treated wasps. Treated females no longer preferred host‐associated kairomones. This suggests that the olfactory sense of the wasps is hampered by sublethal insecticide doses. The lowest bioactive doses tested in the bioassays were 0.021 ng for sulfoxaflor and 0.105 ng for acetamiprid, dimethoate, and flupyradifurone. These low amounts are field realistic and might be taken up by the wasps, e.g., by feeding contaminated plant nectar. Exposure to these compounds likely compromises the important ecosystem service provided by parasitic wasps as natural enemies in terrestrial ecosystems. [ABSTRACT FROM AUTHOR]

The tobacco whitefly, Bemisia tabaci MEAM1, is a destructive pest that damages plants by sucking plant juice and transmitting viruses. B. tabaci insecticide resistance contributes to population resurgence, and new insecticides are continually needed. Flonicamid and afidopyropen are selective pesticides with high insecticidal activity against piercing–sucking pests and safety to non-target species. We determined the toxicity of flonicamid and afidopyropen to B. tabaci, investigated the sublethal effects on life parameters, and studied physiological responses to them. Flonicamid and afidopyropen were highly toxic to B. tabaci, with LC50 values of 12.795 mg/L (afidopyropen) and 25.359 mg/L (flonicamid) to nymphs and 4.711 mg/L (afidopyropen) and 11.050 mg/L (flonicamid) to adults. Sublethal concentrations (LC10 and LC20) reduced the longevity and fecundity of the B. tabaci F0 generation. Transgenerational effects were caused by exposure to sublethal concentrations of flonicamid and afidopyropen. Nymph mortality increased, development was delayed, fecundity decreased, and adult longevity was shortened. Population parameters such as the intrinsic rate of growth (r), net reproductive rate (R0), and finite rate of growth (λ) were significantly decreased compared to the control. The activity of detoxifying enzymes, such as GSTs and P450, were induced by flonicamid and afidopyropen at 72 h, while CarE was inhibited. The expression levels of eleven P450 genes and four GST genes were significantly higher than in the control. In conclusion, flonicamid and afidopyropen have excellent acute toxicity and continuous control effects on B. tabaci. Higher GST and P450 activities and gene expression levels may play important roles in the detoxification metabolic process. [ABSTRACT FROM AUTHOR]

Though far less obvious than direct effects (clinical disease or mortality), the indirect influences of pathogens are difficult to estimate but may hold fitness consequences. Here, we disentangle the directional relationships between infection and energetic reserves, evaluating the hypotheses that energetic reserves influence infection status of the host and that infection elicits costs to energetic reserves. Using repeated measures of fat reserves and infection status in individual bighorn sheep (Ovis canadensis) in the Greater Yellowstone Ecosystem, we documented that fat influenced ability to clear pathogens (Mycoplasma ovipneumoniae) and infection with respiratory pathogens was costly to fat reserves. Costs of infection approached, and in some instances exceeded, costs of rearing offspring to independence in terms of reductions to fat reserves. Fat influenced probability of clearing pathogens, pregnancy and over-winter survival; from an energetic perspective, an animal could survive for up to 23 days on the amount of fat that was lost to high levels of infection. Cost of pathogens may amplify trade-offs between reproduction and survival. In the absence of an active outbreak, the influence of resident pathogens often is overlooked. Nevertheless, the energetic burden of pathogens likely has consequences for fitness and population dynamics, especially when food resources are insufficient. [ABSTRACT FROM AUTHOR]

Simple Summary: Aphis gossypii Glover is an economically important sap-sucking insect pest that causes severe damage worldwide. The flonicamid has been widely used for controlling sap-sucking insect pests, but its intergenerational sublethal effects on key demographic parameters of A. gossypii have not been fully studied. The age-stage, two-sex life table analysis was conducted to investigate the sublethal effects of flonicamid on the biological parameters of adult A. gossypii (F0) and its subsequent intergenerational effects on the offspring (F1 generation). The results showed that the sublethal concentrations of flonicamid significantly decreased the longevity, fecundity, and reproductive days of F0 A. gossypii. Moreover, flonicamid induced intergenerational sublethal effects on the subsequent progeny generation (F1) by impacting the key biological and demographic parameters of A. gossypii. Taken together, these results demonstrated that sublethal concentrations of flonicamid negatively affect the demographic parameters of A. gossypii, resulting in the suppression of population growth. Flonicamid is a novel systemic insecticide widely used against aphids. However, the intergenerational sublethal effects of flonicamid on cotton aphid, Aphis gossypii, have not been fully studied. This study aimed to evaluate the sublethal effects of flonicamid on the biological parameters of adult A. gossypii (F0) and its subsequent intergenerational effects on the offspring (F1 generation) through age-stage, two-sex life table analysis. The results of the bioassays indicate that flonicamid exhibits significant toxicity toward adult A. gossypii, as evidenced by an LC50 value of 0.372 mg L−1 after a 48-h exposure period. The longevity, fecundity, and reproductive days of adult cotton aphids (F0) were significantly decreased when treated with the sublethal concentrations of flonicamid. The pre-adult stage exhibited an increase, whereas the adult longevity, total longevity, and fecundity experienced a notable decrease in F1 aphids after the exposure of F0 aphids to sublethal concentrations of flonicamid. Furthermore, the key demographic parameters, including r, λ, R0, and RPd, showed a significant decrease, while the total pre-reproductive period (TPRP) experienced a significant increase in the F1 generation. Collectively, our findings indicate that sublethal concentrations of flonicamid impact the demographic parameters of A. gossypii, resulting in suppression of population growth. This study presents comprehensive information on the overall impact of flonicamid on A. gossypii, which could potentially aid in managing this major pest. [ABSTRACT FROM AUTHOR]

Simple Summary: Management strategies targeting invasive pests of agricultural crops have relied heavily on the application of synthetic insecticides. However, sustainable pest management approaches and tools are being effectively implemented. The use of microbials, botanicals, and other natural-based substances alone or in combination with natural enemies is a promising approach. In this context, in the laboratory, we studied the potential synergistic or antagonistic effects in pest control of various biopesticides with Ganaspis kimorum and Necremnus tutae, two major parasitoids of the spotted wing Drosophila and the South American tomato pinworm, respectively. Drosophila suzukii and Tuta absoluta are successful biological invaders of agroecosystems. Their integrated pest management (IPM) programs involve the release and/or conservation of natural enemies. Among these, Ganaspis kimorum is a major Asian parasitoid of D. suzukii and has been introduced as a classical biological control agent of this pest in Europe and North America, while Necremnus tutae is a key fortuitous parasitoid of T. absoluta in the Mediterranean region. Bioinsecticides represent key alternatives to chemicals for controlling both pests. This study investigated the potential compatibility of both parasitoids with Beauveria bassiana, Bacillus thuringiensis, garlic essential oil (EO), and spinosad, in comparison to two synthetic insecticides, cyantraniliprole and chlorantraniliprole. The results showed that combining each of the tested insecticides with G. kimorum slightly increased pest mortality compared to the insecticide alone. Necremnus tutae had a significant additive effect on host mortality when combined with insecticides. Beauveria bassiana and B. thuringiensis were most compatible with both parasitoid species. Both garlic EO and chlorantraniliprole impaired the survival of immature N. tutae and showed sublethal toxicity on the reproductive and non-reproductive behaviors of N. tutae. Spinosad exhibited high acute toxicity on both juvenile and adult parasitoids of both species. Overall, these findings provide useful insights into insecticide selectivity toward two key parasitoids and offer new knowledge on the potential of combining natural enemies and bioinsecticides for optimized IPM. [ABSTRACT FROM AUTHOR]

BACKGROUND: Mating is an essential factor that governs the size of insect populations that reproduce sexually. The extensive application of insecticides has both lethal and sublethal effects on the physiology and mating behavior of insect natural enemies. The predatory bug Cyrtorhinus lividipennis is a natural enemy of planthopper and leafhopper populations in the rice ecosystem. Unfortunately, the effects of insecticides on the mating behavior of C. lividipennis are not well‐understood. RESULTS: The mating behavior of C. livdipennis consisted of mounting, antennal touch and mating attempts, genital insertion, adjustment of posture, and separation of the mating pair. Approximately 82.5% of the C. lividipennis mating pairs displayed their first mating at 12–36 h postemergence. Mating activity occurred throughout a 24‐h period, with peak activity at 12:00–14:00 h, and the mean duration of mating was 48.75 min. Sublethal exposure to imidacloprid increased mating latency. Compared with the controls, the duration of courtship, pre‐mating and adjusting posture for males treated with imidacloprid were prolonged. The duration of mating for females treated with imidacloprid was prolonged relative to untreated controls. The fecundity and daily spawning capacity of females treated with imidacloprid were higher than the untreated controls. CONCLUSION: Our results provide insight into the mating process of C. lividipennis. Imidacloprid prolonged the duration of mating, which may explain the enhanced reproductive output in C. lividipennis females treated with imidacloprid. These findings will be useful in both rearing C. lividipennis and deploying this natural enemy in rice fields. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

The aboveground oligolectic bee, Heriades truncorum, is a particularly good model for studying the impact of pesticides on sexual communication, since some aspects of its mating behavior have previously been described. We have tested (1) the interference of the pesticide flupyradifurone on male precopulatory behavior and male mating partner preferences, (2) the way that the pesticide interferes in male quality assessment by the female, and (3) the effects of the pesticide on the chemical compounds in the female cuticle. We exposed bees of both sexes to a sublethal concentration of flupyradifurone. Various behaviors were registered in a mating arena with two females (one unexposed and one exposed) and one male (either unexposed or exposed). Unexposed males were quicker to attempt to mate. Treatment also impacted precopulatory behavior and male quality assessment by females. Males approached unexposed females more quickly than insecticide‐exposed ones. Females exposed to insecticide produced lower amounts of some cuticular hydrocarbons (sex pheromone candidates) and appeared less choosy than unexposed females. Our findings suggest that insecticide exposure affects sexual communication, playing a role both in male preference and in male quality assessment by the female. [ABSTRACT FROM AUTHOR]

Spodoptera litura Fabricius (Lepidoptera: Noctuidae) is a deleterious agricultural pest worldwide. Field populations of S. litura manifest resistance to almost all conventional insecticides and it is imperative looking for novel biorational insecticides to control this pest. In this regard, this study bioassayed some promising biorational insecticides including botanical, microbial and non-conventional synthetic insecticidal formulations against 3rd instar larvae of S. litura. Bioassay with botanical formulations showed a significant toxicity of oil and extract formulations of neem (Azadirachta indica) causing 70-77% larval mortality in 72 h observation and exhibiting minimum medial lethal concentration (LC50) and time (LT50) values (i.e. 12.32 and 38.01 ppm and 16.67 and 11.68 days, respectively). Among microbial formulations tested, S. litura-nuclear polyhedrosis virus (NPV) and Bacillus thuringiensis kurstaki appeared as the most effective microbial treatments exhibiting minimum LC50 (3.78 × 10³ OB mL-1 and 1.22 × 107 spores mL-1, respectively) and LT50 (3.83 and 3.71 days, respectively) values. While flubendiamide, chlorantraniliprole and spinetoram exerted most significant lethal and sublethal effects on S. litura with minimum LT50 values (i.e. 19.58, 30.78 and 26.25 h, respectively). Larval development time was significantly prolonged by both half and one-fourth doses of flubendiamide and chlorantraniliprole (19.51 and 19.63 days and 17.77 and 17.20 days, respectively), while pupal duration prolonged for spinetoram and lufenuron. Similarly, significant suppression of adult lifespan was exhibited by flubendiamide (11.83 and 11.85 days) and chlorfenapyr (12.28 and 12.06 days). Overall study results advocate further consideration of these aforesaid biorational insecticides against S. litura infestations. However, assessment of their compatibility with each other and with other IPM strategies both under lab and field conditions constitutes future perspectives of this work. [ABSTRACT FROM AUTHOR]

Increasingly frequent and severe bleaching events driven by climate change are decreasing coral populations worldwide. Recovery of these populations relies on reproduction by the survivors of such events including local and upstream larval sources. Yet, corals that survive bleaching may be impaired by sublethal effects that suppress reproduction, reducing larval input to reefs, and consequently impeding recovery. We investigated the impact of the 2020 mass-bleaching event on Acropora millepora reproduction on inshore, turbid reefs in Woppaburra sea Country (the Keppel Islands), to improve our understanding of the effects of bleaching on coral populations. A. millepora experienced high bleaching incidence but low mortality across the island group during this event and thus constituted an ideal population to investigate potential sublethal effects on reproductive output. Six months after the heat wave, and just prior to spawning, we collected, decalcified, and dissected samples from 94 tagged A. millepora colonies with a known 2020 bleaching response, to investigate the relationships between stress severity and reproduction. Despite having regained their pigmentation, we detected a significant reduction in fecundity in colonies that had bleached severely. Considering the impact of the bleaching event on the coral population sampled (i.e., mortality, bleaching severity and colony size), coupled with reductions in fecundity, we estimated a total decrease in population-level reproductive output of 21%. These results suggest that reduced reproductive output may impact recovery of coral populations following bleaching and should be considered alongside traditional estimates of coral mortality. [ABSTRACT FROM AUTHOR]

Beta-cypermethrin is a commonly used insecticide for controlling major agricultural pests as Helicoverpa armigera in crop fields. This study investigated the sublethal effect of beta-cypermethrin on the mating physiology of H. armigera. The results demonstrated that the sublethal exposure to beta-cypermethrin significantly decreased sex pheromone production, hindered female ability to attract males and reduced the proportion of successful matings. Further investigations revealed that trehalose content in the sex pheromone glands (PGs) significantly decreased following sublethal beta-cypermethrin treatment, leading to a subsequent decrease of acetyl-CoA content within the PGs. Furthermore, such exposure caused a significant decrease in mRNA expression levels of the trehalose transporter, calcineurin (CaN), acetyl CoA carboxylase (ACC), protein kinase A (PKA), pheromone biosynthesis-activating neuropeptide receptor (PBANR), Δ11-desaturase (DES) and fatty acid reductase 2 (FAR2), as well as a decrease in the enzyme activities of membranebound trehalase, ACC, CaN and PKA. Sublethal exposure lowered the expression levels of pheromone binding protein 1, pheromone binding protein 2 and odorant receptor 13 in males, suggesting decreased male recognition capabilities. Altogether, sublethal exposure to beta-cypermethrin resulted in a decrease in the precursor material (trehalose, acetyl-CoA) and enzyme activities involved in sex pheromone biosynthesis, This, in turn, led to reduced pheromone production and female attractiveness, as well as diminished male detection abilities, ultimately resulted in a lowered likelihood of successful mating. This study enhances knowledge on how sublethal pesticide exposure affects pest biology and their mechanisms of action, providing a basis for including such impact in pest management strategies. [ABSTRACT FROM AUTHOR]

The integration of untargeted lipidomics approaches in ecotoxicology has emerged as a strategy to enhance the comprehensiveness of environmental risk assessment. Although current toxicity tests with soil microarthropods focus on species performance, that is, growth, reproduction, and survival, understanding the mechanisms of toxicity across all levels of biological organization, from molecule to community is essential for informed decision‐making. Our study focused on the impacts of sublethal concentrations of the insecticide teflubenzuron on the springtail Folsomia candida. Untargeted lipidomics was applied to link changes in growth, reproduction, and the overall stress response with lipid profile changes over various exposure durations. The accumulation of teflubenzuron in organisms exposed to the highest test concentration (0.035 mg a.s. kg–1 soil dry wt) significantly impacted reproductive output without compromising growth. The results suggested a resource allocation shift from reproduction to size maintenance. This hypothesis was supported by lipid shifts on day 7, at which point reductions in triacylglycerol and diacylglycerol content corresponded with decreased offspring production on day 21. The hypermetabolism of fatty acids and N‐acylethanolamines on days 2 and 7 of exposure indicated oxidative stress and inflammation in the animals in response to teflubenzuron bioaccumulation, as measured using high‐performance liquid chromatography–tandem mass spectrometry. Overall, the changes in lipid profiles in comparison with phenotypic adverse outcomes highlight the potential of lipid analysis as an early‐warning tool for reproductive disturbances caused by pesticides in F. candida. Environ Toxicol Chem 2024;43:1149–1160. © 2024 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC. [ABSTRACT FROM AUTHOR]

The fall armyworm (FAW), Spodoptera frugiperda Smith (Lepidoptera: Noctuidae), poses a significant threat to food security, necessitating effective management strategies. While chemical control remains a primary approach, understanding the toxicity and detoxification mechanisms of different insecticides is crucial. In this study, we conducted leaf-dipping bioassays to assess the toxicity of quinalphos and beta-cypermethrin·emamectin benzoate (β-cyp·EMB) on S. frugiperda larvae. Additionally, we assessed the response of alterations in CarE, GST, MFO, and AChE activities to sublethal concentrations of these insecticides over various treatment durations. Results indicated that β-cyp·EMB exhibited higher toxicity than quinalphos in S. frugiperda. Interestingly, the highest activities of GST, CarE, MFO, and AChE were observed at 6 h exposure to LC10 and LC25 of β-cyp·EMB, surpassing equivalent sublethal concentrations of quinalphos. Subsequently, GST and CarE activities exposure to β-cyp·EMB steadily decreased, while MFO and AChE activities exposure to both insecticides was initially decreased then increased. Conversely, two sublethal concentrations of quinalphos notably enhanced GST activity across all exposure durations, with significantly higher than β-cyp·EMB at 12–48 h. Similarly, CarE activity was also increased at various durations. Our research has exhibited significant alterations in enzyme activities exposure to both concentration and duration. Furthermore, Pearson correlation analysis showed significant correlations among these enzyme activities at different treatment durations. These findings contribute to a better understanding of detoxification mechanisms across different insecticides, providing valuable insights for the rational management of S. frugiperda populations.

In agricultural environments, bees are routinely exposed to combinations of pesticides. For the most part, exposure to these pesticide mixtures does not result in acute lethal effects, but we know very little about potential sublethal effects and their consequences on reproductive success and population dynamics. In this study, we orally exposed newly emerged females of the solitary bee Osmia cornuta to environmentally-relevant levels of acetamiprid (a cyano-substituted neonicotinoid insecticide) singly and in combination with tebuconazole (a sterol-biosynthesis inhibitor (SBI) fungicide). The amount of feeding solution consumed during the exposure phase was lowest in bees exposed to the pesticide mixture. Following exposure, females were individually marked and released into oilseed rape field cages to monitor their nesting performance and assess their reproductive success. The nesting performance and reproductive success of bees exposed to the fungicide or the insecticide alone were similar to those of control bees and resulted in a 1.3–1.7 net population increases. By contrast, bees exposed to the pesticide mixture showed lower establishment, shortened nesting period, and reduced fecundity. Together, these effects led to a 0.5–0.6 population decrease. Female establishment and shortened nesting period were the main population bottlenecks. We found no effects of the pesticide mixture on nest provisioning rate, offspring body weight or sex ratio. Our study shows how sublethal pesticide exposure may affect several components of bee reproductive success and, ultimately, population growth. Our results calls for a rethinking of pollinator risk assessment schemes, which should target not only single compounds but also combinations of compounds likely to co-occur in agricultural environments.

The red palm weevil (RPW), Rhynchophorus ferrugineus (Olivier) (Coleoptera: Dryophthoridae), is a destructive and voracious pest of palm species worldwide. Due to environmental and regulatory concerns, ecologically safe alternatives to synthetic chemical insecticides are needed to manage this cryptic insect species. Entomopathogenic fungi have the potential to manage this pest. The scope of management and effectiveness can be improved by direct control or horizontal transmission of entomopathogenic fungal isolates. We tested in the laboratory the virulence and pathogenicity of fifteen different entomopathogenic fungal isolates belonging to the following species: Beauveria bassiana, Metarhizium anisopliae, Beauveria brongniartii and Purpureocillium lilacinum. All fungal isolates were found virulent against larvae (14.9 ± 1.06 to 81.5 ± 1.48% mortality) and adults (5.6 ± 1.12 to 51.7 ± 1.51% mortality) at 12 d post-treatment. From a screening bioassay, five M. anisopliae (WG-08, WG-09) and B. bassiana (WG-23, WG-24, WG-25) isolates were tested for their concentration response mortality against larvae and adults after 7, 14 and 21 days (d) of treatment. Mortality was found positively correlated with concentration and time. At 21 d of treatment, WG-23 and WG-25 1 × 108 conidia/mL resulted in 100% mortality against larvae while only WG-25 1 × 109 conidia/mL caused 100% mortality of adults. Along with mortality, all the potential isolates have strong ovicidal effects that reduced 81.49% at 1 × 108 conidia/mL. The horizontal transmission bioassay indicated that the infected adults transmitted the disease to healthy individuals. Horizontal transmission of fungi from infected to non-infected adults not only caused significant mortality but also had a serious sublethal impact on insect development and fitness including reduced number of eggs/d fecundity, egg viability and neonate survival. Isolate WG-25 reduced oviposition (0.5 eggs/d), fecundity (11.7 eggs/female), egg viability (11.6%) along with larval survival 25.9% when infected male mated with normal female. In semi-field trials, all fungal isolates reduced survival of larvae found inside the palms and ultimately reduced infestations over a period of two months. The results of this study indicate that entomopathogenic fungi should be further tested for sustainable and efficient control of RPW in date palm production systems. [ABSTRACT FROM AUTHOR]

BACKGROUND: The stingless bee, Trigona spinipes, is an important pollinator of numerous native and cultivated plants. Trigona spinipes populations can be negatively impacted by insecticides commonly used for pest control in crops. However, this species has been neglected in toxicological studies. Here we observed the effects of seven insecticides on the survival of bees that had fed directly on insecticide‐contaminated food sources or received insecticides via trophallactic exchanges between nestmates. The effects of insecticides on flight behavior were also determined for the compounds considered to be of low toxicity. RESULTS: Imidacloprid, spinosad and malathion were categorized as highly toxic to T. spinipes, whereas lambda‐cyhalothrin, methomyl and chlorfenapyr were of medium to low toxicity and interfered with two aspects of flight behavior evaluated here. Chlorantraniliprole was the only insecticide tested here that had no significant effect on T. spinipes survival, although it did interfere with one aspect of flight capacity. A single bee that had ingested malathion, spinosad or imidacloprid, could contaminate three, four and nineteen other bees, respectively via trophallaxis, resulting in the death of the recipients. CONCLUSION: This is the first study to evaluate the ecotoxicology of a range of insecticides that not only negatively affected T. spinipes survival, but also interfered with flight capacity, a very important aspect of pollination behavior. The toxicity of the insecticides was observed following direct ingestion and also via trophallactic exchanges between nestmates, highlighting the possibility of lethal effects of these insecticides spreading throughout the colony, reducing the survival of non‐foraging individuals. © 2023 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

In agroecosystems, insects contend with chemical insecticides often encountered at sublethal concentrations. Insects' exposure to these mild stresses may induce hormetic effects, which has consequences for managing insect pests. In this study, we used an electrical penetration graph (EPG) technique to investigate the feeding behavior and an age-stage, two-sex life table approach to estimate the sublethal effects of thiamethoxam on greenbug, Schizaphis graminum. The LC5 and LC10 of thiamethoxam significantly decreased longevity and fecundity of directly exposed adult aphids (F0). However, the adult longevity, fecundity, and reproductive days (RPd)—indicating the number of days in which the females produce offspring – in the progeny generation (F1) exhibited significant increase when parental aphids (F0) were treated with LC5 of the active ingredient. Subsequently, key demographic parameters such as intrinsic rate of increase (r) and net reproductive rate (R0) significantly increased at LC5 treatment. EPG recordings showed that total durations of non-probing (Np), intercellular stylet pathway (C), and salivary secretion into the sieve element (E1) were significantly increased, while mean duration of probing (Pr) and total duration of phloem sap ingestion and concurrent salivation (E2) were decreased in F0 adults exposed to LC5 and LC10. Interestingly, in the F1 generation, total duration of Np was significantly decreased while total duration of E2 was increased in LC5 treatment. Taken together, our results showed that an LC5 of thiamethoxam induces intergenerational hormetic effects on the demographic parameters and feeding behavior of F1 individuals of S. graminum. These findings have important implications on chemical control against S. graminum and highlight the need for a deeper understanding of the ecological consequences of such exposures within pest management strategies across the agricultural landscapes. [ABSTRACT FROM AUTHOR]

Heatwaves are increasing in frequency and intensity due to climate change, pushing animals beyond physiological limits. While most studies focus on survival limits, sublethal effects on fertility tend to occur below lethal thresholds, and consequently can be as important for population viability. Typically, male fertility is more heat-sensitive than female fertility, yet direct comparisons are limited. Here, we measured the effect of experimental heatwaves on tsetse flies, Glossina pallidipes, disease vectors and unusual live-bearing insects of sub-Saharan Africa. We exposed males or females to a 3-day heatwave peaking at 36, 38 or 40°C for 2 h, and a 25°C control, monitoring mortality and reproduction over six weeks. For a heatwave peaking at 40°C, mortality was 100%, while a 38°C peak resulted in only 8% acute mortality. Females exposed to the 38°C heatwave experienced a one-week delay in producing offspring, whereas no such delay occurred in males. Over six weeks, heatwaves resulted in equivalent fertility loss in both sexes. Combined with mortality, this lead to a 10% population decline over six weeks compared to the control. Furthermore, parental heatwave exposure gave rise to a female-biased offspring sex ratio. Ultimately, thermal limits of both survival and fertility should be considered when assessing climate change vulnerability. [ABSTRACT FROM AUTHOR]

Plant-borne secondary metabolites are attracting high interest for their potential use in agricultural applications, with special reference to the control of arthropod pests. In the present work, the structural elucidation of glycosylated diterpenoid carboxyatractyloside (2) isolated from the roots of Chamaeleon gummifer Cass. (Asteraceae) is reported by means of spectroscopic and spectrometric techniques. Complete identification occurred thanks to one- and two-dimensional NMR experiments, assigning the single protons and carbons, and the stereochemistry by the NOESY correlations. Carboxyatractyloside (2), together with two ent-kaurenes atractyloside (1) and atractyligenin (3), extracted from the roots of C. gummifer, have been tested for their acaricidal and oviposition inhibition activity against the two-spotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae) Notably, compounds 1–3 were toxic to T. urticae, leading to significant mortality, oviposition inhibition, reduced hatchability of eggs, and natality inhibition. However, at the lowest dose (12.5 µg cm−2) compound 2 was the most effective, leading to mortality > 60% after 5 days exposure, inhibiting oviposition by > 70% and egg hatching by 33%; it also reduced natality by 80%. Overall, these compounds represent valuable candidates to develop novel acaricides for crop protection. Further research on how to develop stable formulations for field use, as well as on non-target effects of these compounds on pollinators and mite biocontrol agents, is ongoing. [ABSTRACT FROM AUTHOR]