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We investigated the impact of sublethal thermal stress on physiological rates of the copepod Paracartia grani , and explored the influence of previous thermal history on this response. The copepods, originally reared at 19 °C, were raised for 23 generations at 22 °C and 25 °C, and posteriorly exposed for 7-d to stress temperature (28 °C). The copepod acclimation capacity was assessed by comparing metabolic balance at 28 °C against their respective rearing temperatures. There was an inverse relationship between rearing temperature and body size and carbon content for the reared copepod lines. Weight-specific rates, except respiration, increased with rearing temperature, whereas per capita rate differences were levelled, partly due to differences in copepod size. Heat stress impact, as weight-specific rate fold-change, appeared inversely related to rearing temperature. Carbon gains were overall sufficient and slightly in excess to account for carbon losses. Gross-growth efficiency across warming scenarios was conserved, emphasizing resilience to environmental change. Our findings underscore the importance of considering the species' thermal history when predicting the response of copepod populations to climate change associated phenomena such as gradual slow ocean warming or heatwave events. • Copepods under multigenerational warming show alike physiological performance. • Vital rates of warm-reared copepods are less impacted by sublethal acute heat stress. • Copepods can maintain their metabolic balance under different thermal scenarios. • Reproductive effort is maintained under chronic warming and heat stress. [ABSTRACT FROM AUTHOR]

Neonicotinoid insecticides are widely used in agriculture and have been linked to various detrimental physiological effects on wild birds. Despite this, the impact of acetamiprid – a less studied member of the neonicotinoid family – on the hypothalamic-pituitary-adrenal axis responsible for the hormonal regulation of the response to stress has rarely been examined in birds. In our study, we explored the effects of acetamiprid on feather levels of corticosterone, the major end product of the HPA, and blood oxidative status of House sparrows (Passer domesticus), following the ingestion of a low, field-realistic dose during two consecutive experiments in 2015 and 2016. We involved 112 birds in each experiment – 56 males and 56 females – that were administered a placebo or a dose of acetamiprid equivalent to 0.5% of the LD 50 of the Zebra finch over the entire duration of the experiments, which lasted approximately three weeks. We measured corticosterone concentrations in feathers grown during an acclimation phase before ingestion and in newly grown feather after the experiment and assessed three oxidative stress markers in the blood. We found no impact of acetamiprid on oxidative stress markers. However, in 2015, male sparrows that ingested acetamiprid exhibited higher corticosterone levels in their feathers compared to those that received a placebo. No such difference was found in females. Interestingly, this effect was not observed in year 2016, which was characterised by less stressful conditions for the birds. These findings offer the first evidence of a potential effect of acetamiprid on corticosterone levels in a songbird, suggesting that ingesting this compound at very low dose may alter the endocrine physiology of the response to stress. • We experimentally investigated sublethal effects of acetamiprid on House sparrows. • Males ingesting acetamiprid showed higher corticosterone levels in feathers in 2015. • We did not find any impact of acetamiprid in 2016 neither in males nor females. • We did not find any effect of acetamiprid on oxidative stress markers in blood. • Findings highlight potential disruption of the stress response by low-dose acetamiprid. [ABSTRACT FROM AUTHOR]

The aphidicidal activity and efficacy of azadirachtin- and oxymatrine-based biopesticides on the cabbage aphid Brevicoryne brassicae (Linnaeus, 1758) (Hemiptera: Aphididae), and their impacts on the main insect predators of this aphid were assessed under laboratory, semi-field, or field conditions. Laboratory results showed that azadirachtin- and oxymatrine-based biopesticides provided high acute toxicity against B. brassicae nymphs and adult females, in a manner dependent on the concentration, developmental stage, and exposure time of insects to residues. Among the insect's developmental stages, B. brassicae nymphs were more susceptible to biopesticides than adult females. In addition to acute toxicity, the biopesticides reduced the number of offspring and the amount of honeydew excreted by B. brassicae adult females. Furthermore, the biopesticides induced a repellent effect on B. brassicae adult females. Despite their high toxicity, in semi-field conditions, the azadirachtin- and oxymatrine-based biopesticides showed low biological persistence [mortality >80% up to 3 and 1 day after spraying (DAS), respectively] in comparison to the synthetic insecticide flupyradifurone (mortality >80% up to 7 DAS), which was used as a positive control. However, in the field, the biopesticides demonstrated high efficacy in controlling the B. brassicae population, with no significant impact on the population levels of different species of lacewings, ladybugs, and syrphids, which are considered the main insect predators of the cabbage aphid in agroecosystems. Therefore, azadirachtin- and oxymatrine-based biopesticides constitute an important management measure for B. brassicae in agroecosystems, including those with an ecological basis where management tools are limited, and effective control tactics must be incorporated. • Azadirachtin- and oxymatrine-based biopesticides induce high acute toxicity against Brevicoryne brassicae. • Azadirachtin and oxymatrine-based biopesticides reduce the number of B. brassicae offspring. • Azadirachtin and oxymatrine-based biopesticides decrease the honeydew excretion by aphid females. • Azadirachtin and oxymatrine-based biopesticides provide low impact on predator insects. [ABSTRACT FROM AUTHOR]

Melipona scutellaris is a Brazilian stingless bee that is important for pollinating wild flora and agriculture crops. Fungicides have been widely used in agriculture, and floral residues can affect forager bees. The goal of our study was to evaluate the effects of sublethal concentrations of pyraclostrobin on the midgut ultrastructure of M. scutellaris forager workers. The bees were collected from three non-parental colonies and kept under laboratory conditions. The bees were orally exposed continuously for five days to pyraclostrobin in syrup at concentrations of 0.125 ng a.i./µL (FG1) and 0.005 ng a.i./µL (FG2). The control bees (CTL) were fed a no-fungicide sucrose solution, and the acetone solvent control bees (CAC) received a sucrose solution containing acetone. At the end of the exposure, the midguts were sampled, fixed in Karnovsky solution, and routinely processed for transmission electron microscopy. Ultrastructural analysis demonstrated that both the fungicide concentrations altered the midgut, such as cytoplasmic vacuolization (more intense in FG1), the presence of an atypical nuclear morphology, and slightly dilated mitochondrial cristae in the bees from the FG1 and FG2 groups (both more intense in FG1). Additionally, there was an alteration in the ultrastructure of the spherocrystals (FG1), which could be the result of cellular metabolism impairment and the excretion of toxic metabolites in the digestive cells as a response to fungicide exposure. The results indicate that ingested pyraclostrobin induced cytotoxic effects in the midgut of native stingless bees. These cellular ultrastructural responses of the midgut are a prelude to a reduced survival rate, as observed in previous studies.

The codling moth Cydia pomonella (Lepidoptera: Tortricidae) is a major invasive pest of pome fruits and walnuts worldwide. Lambda-cyhalothrin (LCT) and abamectin (AM) have been frequently used in C. pomonella control, but control of this pest is very difficult because shortly after hatching, larvae of this insect bore tunnels and hide inside host plant fruit. In this study, a simulated field spray bioassay method was developed against neonate larvae of C. pomonella and concentration-response bioassays were conducted to evaluate the susceptibility of the neonate larvae to LCT and AM. Exposure of neonate larvae to sublethal concentration (LC30) of LCT or AM significantly reduced the survival rate of larvae (4th and 5th instars), lowered the mean weight of larvae and pupae, and decreased the daily maximal number of eggs laid and the total number of eggs laid (fecundity) per female. The sublethal effects, including reduced body mass, mean fecundity and net reproductive rate, extended mean generation time, and shortened oviposition period, were also found in transgenerational offspring. Furthermore, the transgenerational maternal effects were more obvious for AM than LCT, in comparison to the control. Additionally, the estimated population size was decreased by exposure to LC30 of LCT and AM, and the observed reduction of fecundity and population size within and across generations was likely the result of the downregulation of the reproduction-related vitellogenin gene (CpVg) after exposure to LC30 of LCT and AM. These results provide a better understanding of the overall effects of LCT and AM on C. pomonella and the transgenerational effects which should be taken into consideration when using insecticides in order to control C. pomonella.

Pesticide residues have serious environmental impacts on rice-based ecosystems. In rice fields, Chironomus kiiensis and Chironomus javanus provide alternative food sources to predatory natural enemies of rice insect pests, especially when pests are low. Chlorantraniliprole is a substitute for older classes of insecticides and has been used extensively to control rice pests. To determine the ecological risks of chlorantraniliprole in rice fields, we evaluated its toxic effects on certain growth, biochemical and molecular parameters in these two chironomids. The toxicity tests were performed by exposing third-instar larvae to a range of concentrations of chlorantraniliprole. LC50 values at 24 h, 48 h, and 10 days showed that chlorantraniliprole was more toxic to C. javanus than to C. kiiensis. Chlorantraniliprole significantly prolonged the larval growth duration, inhibited pupation and emergence, and decreased egg numbers of C. kiiensis and C. javanus at sublethal dosages (LC10 = 1.50 mg/L and LC25 = 3.00 mg/L for C. kiiensis; LC10 = 0.25 mg/L and LC25 = 0.50 mg/L for C. javanus). Sublethal exposure to chlorantraniliprole significantly decreased the activity of the detoxification enzymes carboxylesterase (CarE) and glutathione S-transferases (GSTs) in both C. kiiensis and C. javanus. Sublethal exposure to chlorantraniliprole also markedly inhibited the activity of the antioxidant enzyme peroxidase (POD) in C. kiiensis and POD and catalase (CAT) in C. javanus. Expression levels of 12 genes revealed that detoxification and antioxidant abilities were affected by sublethal exposures to chlorantraniliprole. There were significant changes in the expression levels of seven genes (CarE6, CYP9AU1, CYP6FV2, GSTo1, GSTs1, GSTd2, and POD) in C. kiiensis and ten genes (CarE6, CYP9AU1, CYP6FV2, GSTo1, GSTs1, GSTd2, GSTu1, GSTu2, CAT, and POD) in C. javanus. These results provide a comprehensive overview of the differences in chlorantraniliprole toxicity to chironomids, indicating that C. javanus is more susceptible and suitable as an indicator for ecological risk assessment in rice ecosystems.

Bemisia tabaci is a threat to agriculture worldwide because of its potential to cause devastating damage to crops. Chlorogenic acid is a bioactive pesticidal phytochemical agent against various insect pests. We here determined the susceptibility of a laboratory strain of B. tabaci to chlorogenic acid and other popular insecticides, and the susceptibility of several field-collected populations to chlorogenic acid. Also, cross-resistance to four common insecticides was measured. Chlorogenic acid had the highest toxicity of all tested insecticides, and all the field-collected populations were susceptible to chlorogenic acid, and little cross-resistance was detected between chlorogenic acid and the other tested insecticides. Furthermore, analysis of enzyme activities and expression of P450 genes in B. tabaci after treatment with LC50 of chlorogenic acid suggested that enhanced P450 activity could be involved in chlorogenic acid detoxification. We subsequently evaluated sublethal effects of chlorogenic acid, and found that treatment with LC25 of chlorogenic acid prolonged duration of two developmental stages, reduced fecundity, and decreased survival rates of treated B. tabaci compared to untreated insects. Overall, these findings demonstrate strong toxicity and significant sublethal effects of chlorogenic acid on B. tabaci, and suggest that overexpression of P450 genes may be associated with chlorogenic acid detoxification. [ABSTRACT FROM AUTHOR]

The lethal and sublethal effects of Roundup (active substance glyphosate herbicide on phantom midge (Chaoborus flavicans, Meigen, 1830) larvae were checked in the range of concentrations from 20 to 2000 µg/L, in the five-day long tests. The herbicide caused the mortality of insects, with the LC50 values ranging from 357.2 to 120.9 µg of glyphosate/L, for one and five days, respectively. The correlation coefficient >0.9 indicated a strong positive correlation between the concentration of Roundup in water and the mortality of C. flavicans. Also, the LT50 values indicate the toxic activity of the herbicide for the larvae. Also, the reaction to mechanical stimuli was disturbed, in a dose-dependent manner. We also observed the altered vertical migration of midges within the water column. The microscopic observations revealed malformations in insects' morphology and anatomy. Among the most prominent changes were: altered body shape and lower density of chromatophores in air sacs. These changes are in tune with the microscopic observations. We conclude that Roundup 360 Plus herbicide may cause significant changes within C. flavicans populations, especially during long exposure. This, in consequence, may lead to a decline in the population of phantom midges, and next, affect the organisms at the other trophic levels. [ABSTRACT FROM AUTHOR]

The present study aimed to evaluate insecticide toxicity to Doru luteipes (Scudder), a major predator of maize pests. Lethal and sublethal effects were assessed on nymphs and adults exposed to the insecticides through contact (maize leaves) and ingestion (prey eggs) routes. Tested insecticides included a biopesticide (Spodoptera frugiperda multiple nucleopolyhedrovirus, SfMNPV), modern (flubendiamide and metaflumizone), and older neurotoxins (imidacloprid + β-cyfluthrin). The imidacloprid/β-cyfluthrin mix was highly toxic (100% mortality) to the predator, regardless of the exposure route and predator stage. Metaflumizone caused mortality higher than 95% and 45% of nymphs and adults. Flubendiamide and SfMNPV were the least toxic insecticides, not differing from the untreated control in any of the assessed endpoints. Adult tibial length did not differ among treatments. Metaflumizone impaired egg consumption by nymphs and walking distance of adult D. luteipes. Overall, the insecticides caused a more pronounced effect on D. luteipes nymphs than on adults and were more toxic by the contact route. From these findings, flubendiamide and SfMNPV are safer for D. luteipes and should head insecticide choice in integrated pest management programs in maize. [ABSTRACT FROM AUTHOR]

Despite extensive work on both insect disease and plant reproduction, there is little research on the intersection of the two. Insect-infecting pathogens could disrupt the pollination process by affecting pollinator population density or traits. Pathogens may also infect insect herbivores and change herbivory, potentially altering resource allocation to plant reproduction. We conducted a meta-analysis to (1) summarize the literature on the effects of pathogens on insect pollinators and herbivores and (2) quantify the extent to which pathogens affect insect traits, with potential repercussions for plant reproduction. We found 39 articles that fit our criteria for inclusion, extracting 218 measures of insect traits for 21 different insect species exposed to 25 different pathogens. We detected a negative effect of pathogen exposure on insect traits, which varied by host function: pathogens had a significant negative effect on insects that were herbivores or carried multiple functions but not on insects that solely functioned as pollinators. Particular pathogen types were heavily studied in certain insect orders, with 7 of 11 viral pathogen studies conducted in Lepidoptera and 5 of 9 fungal pathogen studies conducted in Hymenoptera. Our results suggest that most studies have focused on a small set of host–pathogen pairs. To understand the implications for plant reproduction, future work is needed to directly measure the effects of pathogens on pollinator effectiveness. [ABSTRACT FROM AUTHOR]

Informed and effective management of emerging infectious diseases can be improved by a clear understanding of host–pathogen–environment interactions. Impacts of the seasonal environment on pathogen dynamics and host responses are poorly described in most reptile host–fungal pathogen systems. Here, we describe seasonal patterns of ophidiomycosis, a disease caused by the fungus Ophidiomyces ophidiicola (Oo), in a population of pygmy rattlesnakes, Sistrurus miliarius, in central Florida. We used field observations of gross clinical signs of disease in combination with qPCR on skin swabs to examine the seasonal prevalence of Oo and patterns of clinical presentation in hosts. We monitored thermoregulatory behaviors, ecdysis, and reproductive status in free‐living snakes to examine seasonal associations between infection and host coping responses. Both the prevalence of Oo and clinical signs of disease varied strongly with the season (winter high and summer low). In both seasons, the presence of clinical signs was a strong predictor of the presence of Oo as identified by qPCR on skin swabs (78% probability across seasons). Snakes with clinical signs of disease were more likely to be observed exhibiting thermoregulatory behavior or in ecdysis compared to non‐clinical snakes across seasons. The prevalence of Oo was not significantly different in pregnant snakes compared to other reproductive categories, but pregnant females were less likely to exhibit clinical signs of disease compared to males. Our results highlight strong seasonal patterns in both host clinical signs and Oo prevalence and support the efficacy of using gross clinical signs of disease in combination with qPCR on skin swabs to assess disease dynamics in free‐living snakes. We also identify ecdysis and thermoregulatory behaviors as components of the seasonal disease‐coping response and highlight the need to examine these behaviors as potential drivers of seasonal infection outcomes in reptiles afflicted with fungal pathogens. [ABSTRACT FROM AUTHOR]

Background and Objectives Brevicoryne brassicae is one of the most serious cabbage pests in the world. This pest feeds on the leaves, mostly on the host plant's middle leaves. Despite having many natural enemies, aphids are not entirely controlled by natural enemies due to their rapid reproduction. Applying chemical insecticides is one of the essential methods used to control aphids; using one pesticide to control several pests can reduce the costs and frequency of spraying. In this study, the lethal and sub-lethal effects (LC25) of matrine insecticide with a contact and stomach function on the cabbage aphid, were evaluated under laboratory conditions. Materials and Methods The dipping method was used in bioassay and life table studies against adults of aphid insects. The LC50 value of matrine insecticide for adults of cabbage aphid was 83.33 μl/ml after 24 hours, and LC25 concentration (30.11 l/ml) was used to estimate the sub-lethal effects of matrine on the biological parameters of the cabbage aphid. Experiments were performed on the acephala variety of cabbage. One common method of investigating insecticides' non-lethal effects is demographic toxicology, which uses life table and growth population parameters to evaluate toxicity. Results According to the results, the female lifespan/longevity and fertility affected by sub-lethal concentration were significantly reduced compared to the control (distilled water and citowett). The mean oviposition period of adult aphids decreased from 8.92 days in control to 3.79 days in LC25 concentration of the insecticide. The present study's data also showed that the sublethal concentration also affected the offspring of treated cabbage aphids. Accordingly, the sublethal concentration of matrine reduced the net reproductive rate (R0) from 23.96 nymphs per female in each generation in the control treatment to 3.26 nymphs in LC25. The intrinsic rate of increase (r) in sublethal concentration was recorded as 0.36 (day-1) and in control as 0.1 (day-1). Other parameters, such as finite rate of increase () and gross reproductive rate (GRR), were also significantly lower than the control. The mean generation time (T) of treatment affected by LC25 concentration of matrine increased compared to the control treatment. Discussion Results of the current research in laboratory conditions showed that this insecticide has significant lethal and sublethal effects on the cabbage aphid. Therefore, matrine, as an herbal insecticide, can be considered in the management programs of cabbage aphids. [ABSTRACT FROM AUTHOR]

Neonicotinoid insecticides are among the most widely used agrochemicals globally. Given the critical importance of bees for biodiversity, crop productivity, and human health, recent decades have seen substantial interest in the impacts of neonicotinoids on bees and the pollination services they provide, both among researchers and the public. Social bees (e.g. honey bees, stingless bees, and bumble bees) are especially important for supporting crop productivity, yet significant knowledge gaps remain in understanding the impacts of neonicotinoids on colony health. Here, we review current knowledge on how neonicotinoid exposure affects social bees, including how direct effects on individuals can impact colony performance, as well as the potential roles of colony state and collective behaviour in modulating these effects. We focus in particular on challenging aspects of predicting real-world impacts of neonicotinoids (including stressor interactions, life history, complex routes of exposure, and taxonomic considerations) that have practical relevance for regulatory decisions, and highlight current knowledge gaps. Finally, we provide an overview of emerging issues and methods, and highlight the potential for mutually beneficial outcomes for crop production and biodiversity conservation. [ABSTRACT FROM AUTHOR]

Acrylamide, a synthetic compound, has a wide range of industrial applications that find multiple ways to reach aquatic ecosystem. The median lethal concentration of acrylamide determined using probit analysis in the fish Anabas testudineus was 132 µg L−1 concentration together with altered behavioral patterns. Hematological and antioxidant status was evaluated at a sublethal concentration (one-tenth of LC50-96 h), i.e., 13.2 µg L−1 concentration for 24, 48, 72, and 96 h. A reduction in erythrocytes count, hemoglobin content, and packed cell volume with a significant (P < 0.05) increase in leukocyte counts and differential counts were observed. Erythrocyte indices like mean corpuscular volume (MCV) and mean corpuscular hemoglobin (MCH) increased, whereas the mean corpuscular hemoglobin concentration (MCHC) showed a significant (P < 0.05) decrease when compared with control groups. The activities of superoxide dismutase, catalase, and glutathione reductase in gill tissues showed significant (P < 0.05) reduction, whereas the levels of hydrogen peroxide and lipid peroxidation increased significantly (P < 0.05) indicating oxidative stress. The findings suggest that acrylamide at sublethal concentration caused alteration in hematological parameters and induced oxidative stress in gill tissue of the fish A. testudineus. Hence, restrictions on the use of acrylamide in food and industrial products are recommended since humans are the direct consumer of fish products. [ABSTRACT FROM AUTHOR]

Both the American lobster fishery and salmon aquaculture are important to the economy of Atlantic Canada. Where these industries operate in proximity, research is needed to better understand any interactions and their possible effects. This study explored the effects of azamethiphos on survival and development of larval American lobsters, Homarus americanus, using exposures that reflect concentrations and durations of azamethiphos (anti‐sea lice therapeutant used in salmon aquaculture) that can be found in the environment following treatment. In adult trials, we recorded the survival and behaviour of individuals consecutively exposed to short pulses of low concentrations of azamethiphos for a period of 1 to 4 days. Larvae from all stages (I‐IV) exhibited an immobilization response when exposed to azamethiphos and that the concentration of azamethiphos that results in a 50% increase in immobilization decreases at increasing exposure time and was as low as 2.9 μgL−1 for a 3 h exposure. After exposure, we registered mortality occurring within 5 days and during the moulting window. In the larval trials the concentration required to reduce the acetylcholinesterase (AChE) activity by 50% increased from stages I to III. In the trials conducted with adults, we observed no mortality over 21 days, but did record an increase in aggressive behaviour with an increasing number of exposures. The temporal overlap between the release of larval lobster stages and the use of azamethiphos is important to consider when assessing potential risk. [ABSTRACT FROM AUTHOR]

Exposure to sublethal doses of insecticide may affect biological traits in triatomines. We investigated the effects of toxicological phenotype (pyrethroid resistance status) and exposure to sublethal doses of deltamethrin on two traits of Triatoma infestans Klug (Heteroptera: Reduviidae) using a phenotypic plasticity experimental design. First‐instar nymphs from 14 and 10 full‐sib families from pyrethroid‐susceptible and pyrethroid‐resistant populations, respectively, were used. For the susceptible population, we treated first instars topically with acetone (control) or deltamethrin (treatment) once. For the resistant population, instars were treated once, twice and three times as first, third or fifth‐instar nymphs, respectively. We measured cuticle thickness, wing size and wing shape of 484 emerging adults, and tested for treatment effects using mixed ANOVA and MANOVA models. Toxicological phenotype, exposure to deltamethrin and full‐sib family exerted significant effects on cuticle thickness, wing size and wing shape. Adult triatomines previously treated with deltamethrin developed significantly thicker cuticles than control triatomines only in the resistant population and significantly bigger wings in both populations. Mean cuticle thickness and wing size increased with increasing exposures to deltamethrin. Exposure to sublethal doses of deltamethrin generated morphological modifications that may affect insect survival and flight dispersal, and hence may have evolutionary and epidemiological consequences. [ABSTRACT FROM AUTHOR]

In order to clarify the effects of low doses of chemical insecticides on parasitic natural enemies, the effects of two low doses (LC5 and LC30) of a commonly used insecticide (acetamiprid) and a novel insecticide (afidopyropen) on the parasitic functional response of Lysiphlebia japonica (Ashmead) to Aphis gossypii Glover were determined in the present study. The results showed that the LC50 of A. gossypii to acetamiprid and afidopyropen were 442.6 mg/L and 1.67 mg/L, and the LD50 of L. japonica to these two insecticides were 0.007 μg/cm² and 20.58 μg/cm², respectively. After exposure to sublethal doses of insecticides, the parasitism of L. japonica showed a negative acceleration curve with the density of A. gossypii. The parasitism load of L. japonica increased gradually with the increase of A. gossypii density. The basic structure of the functional response model of L. japonica still conformed to Holling type-Ⅱ, while the parameters of the model had some changes. When A. gossypii density was 20, 40, and 100 individuals per dish, the parasitism of L. japonica was significantly lower than that of the control group except for that of L. japonica treated with LC5 of acetamiprid, which was not significantly different from the control, and the LD30 of acetamiprid had the strongest inhibition on the parasitism of L. japonica. When A. gossypii was exposed to low doses of insecticides, the parasitism time of L. japonica on A. gossypii was significantly prolonged compared to the control. Moreover, the maximum daily predation of L. japonica was significantly lower than that of the control. In addition, the searching efficiency of L. japonica was significantly inhibited by low doses of acetamiprid and afidopyropen. Our results indicated that low doses of acetamiprid and afidopyropen had negative effects on the parasitism of L. japonica, and these results help to protect and utilize natural enemies and guide the scientific and rational use of pesticides in the fields. [ABSTRACT FROM AUTHOR]

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Abstract ​Background Entomopathogenic fungi have low persistence in the field because of UV light, high temperatures and low humidity. Thus, this study's objective was to correlate the persistence of Beauveria bassiana and Metarhizium anisopliae in soybean leaf by measuring the mortality and sub-lethal effects of Helicoverpa armigera (Hubner) (Lepidoptera/Noctuidae). In the 2017–2018 and 2019–2020 soybean seasons, the experiments were conducted on plots subdivided in a completely randomized design. After spraying each plot with the fungal, either B. bassiana or M. anisopliae, leaves were collected hourly for 8 h after application and transferred to the laboratory. The local air temperature was recorded each time. For persistence assessment, the fungal suspension was prepared from the leaf disks; thereafter, 150 µl of the suspension was removed and poured into a plate. After 72 h of inoculation, colony-forming units (CFUs) were counted. For the mortality test, the leaf disks were placed individually in pots and offered to second instar larvae of H. armigera. The surviving larvae were evaluated for sub-lethal effects and biological parameters. Results Beauveria bassiana was more persistent than M. anisopliae, which persisted for 3 h in the first year and 5 h in the second year when temperatures were milder; B. bassiana persisted throughout the evaluation period (8 h). The mortality of H. armigera decreased with an increase in the time since application fungal suspension, presenting a range of 86–30% for B. bassiana and 78–4.2% for M. anisopliae. Conclusion Assessments of sublethal effects showed an inverse correlation between CFUs and parameters such as fertility and weight.

The elevated concentration of hydrogen peroxide (H2O2) due to natural and anthropogenic causes is a significant bane to marine and coastal organisms, as it has a prolonged half-life and can inject across lipid bilayers and interfere with aquatic redox processes. The present assessment aimed to determine the acute effect of H2O2 on larval development of the Mediterranean mussel Mytilus galloprovincialis and to observe the oxidative stress (OS) responses, including genotoxicity and neurotoxicity in the clam Ruditapes philippinarum. Two experiments were performed, in which (a) mussel embryos were exposed to the consecutive dilution (0.0, 0.05, 0.5, 5.0, 50.0 and 500.00 μM) of H2O2 for 48 h and (b) adult clams were exposed to similar concentrations - of this reactive oxygen species (ROS) for 21 days. Incremental H2O2 significantly retarded the growth of mussel larvae; the percentage of malformed larvae increased with increasing toxicant concentration (p < 0.01, and r = 0.884). H2O2 also induced oxidative stress (OS) in clams, indicated by the activation/inactivation of antioxidant enzymes (GST, GPx, and GR) with a significant rise in lipid peroxidation (LPO) in the digestive gland tissues of the clams (p < 0.05). No genotoxicity or neurotoxicity on R. philippinarum were evident after chronic exposure. The battery of responses (organismal and cellular parameters) showed embryotoxicity and sublethal effects on bivalves, which confirmed their suitability for assessing the effect of H2O2 mediated OS responses in the marine environment.

Using insecticides on soybean (Glycine max, L.) may induce lethal and sublethal effects on beneficial fauna associated with soybean cultivation. In Argentina, the application of pesticides in extensive and intensive crops for weed and insect control has increased by more than 400 % over the last 20 years. This study aimed to determine the effect of chlorantraniliprole applied under field conditions on predators and parasitoids associated with Rachiplusia nu (Guenée) (Lepidoptera: Noctuidae). Phytophagous and predatory organisms were recorded in chlorantraniliprole-treated and untreated field plots during the 2014-2015 crop season. R. nu larvae were collected, individually placed in Petri dishes, and reared in a conditioned growth chamber until adult Lepidoptera or parasitoids appeared. Data were analyzed with the generalized linear mixed model. In untreated plots, the parasitoid Copidosoma sp. reduced the R. nu population growth curve below the economic injury level. In chlorantraniliprole-treated fields, differences before and after application were significant (p > 0.05), indicating that the insecticide affected predators (Araneidae, Syrphidae, Hemiptera) and parasitoids (Hymenoptera). Additionally, the Berger-Parker dominance index showed parasitoids were more sensitive to chlorantraniliprole than predators. Future research on selective insecticides with other action modes would be needed to evaluate sublethal effects on natural enemies.

The sublethal effects of pesticide poisoning will have significant negative impacts on the foraging and learning of bees and bumblebees, so it has received widespread attention. However, little is known about the physiological effects of sublethal spinetoram and glyphosate exposure on bumblebees. We continuously exposed Bombus terrestris to sublethal (2.5 mg/L) spinetoram or glyphosate under controlled conditions for 10 days. The superoxide dismutase, glutathione-S-transferase, carboxylesterase, prophenoloxidase, α-amylase and protease activities, and changes in gut microbes were measured to understand the effects of sublethal pesticide exposure on the physiology and gut microbes of bumblebees. Sublethal pesticide exposure to significantly increased superoxide dismutase activity and significantly decreased gut α-amylase activity in bumblebees but had no significant effect on glutathione-S-transferase, carboxylesterase or gut protease activities. In addition, glyphosate increased the activity of prophenoloxidase. Interestingly, we observed that neither of the two pesticides had a significant effect on dominant gut bacteria, but glyphosate significantly altered the structure of the dominant gut fungal community, and reduced the relative abundance of Zygosaccharomyces associated with fat accumulation. These results suggest that sublethal spinetoram and glyphosate do not significantly affect the detoxification system of bumblebees, but may affect bumblebee health by inhibiting energy acquisition. Our results provide information on the sublethal effects of exposure to low concentrations of glyphosate and spinetoram on bumblebees in terms of physiology and gut microbes.

Xanthogaleruca luteola (Mull., 1766) is the major defoliator pest of elm trees in urban area. In this study the effect of lufenuron on some biochemical and biological characteristics was investigated on X. luteola. The LC30 and LC50 of lufenuron were determined on the second instar larvae as 20.22 and 36.65 mg l-1, respectively. Effects of LC30 and LC50 concentrations of lufenuron on some biological parameters showed that lufenuron caused an increase in larval, pre-pupal and pupal developmental periods. Also, none of the female insects that emerged from the treated larvae did not spawn during their life. The LC50 concentration of lufenuron decreased carbohydrate, lipid and protein content and increased glycogen content. But there was not a significant difference in glycogen, and protein contents following the exposure to LC30 concentration. However, glutathione-s-transferase (GST) and esterase activities were significantly increased at LC50. In conclusion, due to lethal and sublethal effect of lufenuron on biochemical and biological traits of X. luteola, it can be recommended for control this pest in IPM program.

Riptortus pedestris (Fabricius, 1775) (Hemiptera: Alydidae) is a major soybean pest in East Asia that can cause soybean staygreen syndrome. To date, no insecticides have been registered for the control of R. pedestris in China, and these insects are primarily controlled in the field through the application of broad-spectrum insecticides including lambda-cyhalothrin (LCT) and emamectin benzoate (EMB). Here, the lethal and sublethal effects of LCT and EMB on R. pedestris were comprehensively evaluated. LCT and EMB were both found to exhibit high levels of toxicity and concentration-dependent repellent effects for R. pedestris. The exposure of third instar nymphs from the F0 generation to LC30 concentrations of LCT and EMB resulted in a significant increase in the duration of nymph development and adult pre-oviposition period (APOP), together with reductions in fifth instar nymph and adult body weight, longevity, oviposition days, fecundity, vitellarium length, lateral oviduct diameter, and vitellogenin (Vg) gene expression as compared to control treatment. Strikingly, these suppressive effects were transmitted to the F1 generation, which similarly experienced the prolongation of preadult development and the preoviposition period (TPOP). Relative to control-treated populations, the F1 generation for these insecticide-treated groups also exhibited significant decreases in population parameter values. Overall, these data offer new insight into the impact that LCT and EMB treatment can have on R. pedestris, providing a valuable foundation for the application of these pesticides in the context of integrated pest management strategies aimed at soybean crop preservation.

The egg parasitoid Trichogramma japonicum (Hymenoptera: Trichogrammatidae) is used for biological control of lepidopteran pests, and it could be used for optimizing Integrated Pest Management (IPM) in rice crop. Chlorantraniliprole is a diamide insecticide broadly applied for pest control in rice cropping systems and it has been generally considered harmless to egg parasitoids. However, the impact of sublethal or low lethal concentrations of chlorantraniliprole on T. japonicum remains unclear. In this context, under laboratory conditions we assessed the acute toxicity of chlorantraniliprole on T. japonicum as well as sublethal effects of a low lethal concentration (LC10) on key biological traits of the parasitoid. In addition, we also evaluated the impact of chlorantraniliprole on the biocontrol service provided by T. japonicum on the pest Chilo suppressalis (Lepidoptera: Crambidae) under field conditions. The LC10 of chlorantraniliprole on adult parasitoids through exposure with residues was 0.110 mg/L, and this LC10 induced hormesis in exposed individuals; locomotory activity, respiratory metabolism and mass reproduction of T. japonicum were enhanced. Under field conditions, chlorantraniliprole led to increased biocontrol service provided by T. japonicum (reduced pest damage). These results can be useful for optimizing further the use of Trichogramma parasitoids into IPM in rice crops. It also hints the importance of carrying out careful risk-assessment of pesticide non-lethal effects under field conditions when developing IPM. [ABSTRACT FROM AUTHOR]

For decades, we have observed a major biodiversity crisis impacting all taxa. Avian species have been particularly well monitored over the long term, documenting their declines. In particular, farmland birds are decreasing worldwide, but the contribution of pesticides to their decline remains controversial. Most studies addressing the effects of agrochemicals are limited to their assessment under controlled laboratory conditions, the determination of lethal dose 50 (LD50) values and testing in a few species, most belonging to Galliformes. They often ignore the high interspecies variability in sensitivity, delayed sublethal effects on the physiology, behaviour and life-history traits of individuals and their consequences at the population and community levels. Most importantly, they have entirely neglected to test for the multiple exposure pathways to which individuals are subjected in the field (cocktail effects). The present review aims to provide a comprehensive overview for ecologists, evolutionary ecologists and conservationists. We aimed to compile the literature on the effects of pesticides on bird physiology, behaviour and life-history traits, collecting evidence from model and wild species and from field and lab experiments to highlight the gaps that remain to be filled. We show how subtle nonlethal exposure might be pernicious, with major consequences for bird populations and communities. We finally propose several prospective guidelines for future studies that may be considered to meet urgent needs. [ABSTRACT FROM AUTHOR]

Bee populations are declining globally due to different environmental stressors, such as pathogens, malnutrition, and agrochemicals. Brazil is the home of hundreds of stingless bee species, some of them now considered endangered, though very little is known about the impact of disease on native bees. In Southern Brazil the endangered stingless bee Melipona quadrifasciata is affected by an annual syndrome that causes sudden death of workers, eventually leading colonies to collapse. Although novel viruses were found in foragers from diseased colonies, none has been consistently implicated in the outbreak. Here we conducted an integrative longitudinal survey on M. quadrifasciata managed colonies, measuring individual- and colony-level traits, to identify the causes behind the syndrome. We found that key genes related to xenobiotic metabolization, nutrition and immune responses are downregulated in foragers from colonies that became diseased two months later. The period that preceded the outbreak was also marked by pronounced forager weight loss as well as behavioural changes. Our findings reveal the syndrome may result from the stingless bee failure to respond to sublethal stressors and disruption of colony dynamics. These results support the proposition that worldwide bee mortality is influenced by a combination of diverse sublethal factors, and increase awareness of the long-term effects of genetic diversity erosion in stingless bee species, which can be enhancing their vulnerability to environmental stressors. [ABSTRACT FROM AUTHOR]

Triazole compounds are among the most widely used fungicides in agroecosystems to protect crops from potential fungal diseases. Triazoles are suspected to have an impact on nontarget species due to their interactions with nonfungal sterol synthesis, and wild birds are likely to be contaminated by triazole fungicides because many of them live in agroecosystems. We experimentally tested whether exposure to environmental concentrations of a triazole could alter key integrative traits (metabolic rates and body condition) of an agroecosystem sentinel species, the house sparrow (Passer domesticus). Wild‐caught adult sparrows were maintained in captivity and exposed (exposed group) or not (control group) for 7 continuous months to tebuconazole through drinking water. The metabolic rates of exposed and control sparrows were then measured at two different temperatures (12 °C and 25 °C), which correspond, respectively, to the thermoregulation and thermoneutrality temperatures of this species. We found that exposed sparrows had lower resting metabolic rates (i.e., measured at thermoneutrality, 25 °C) than controls. However, the thermoregulatory metabolic rates (i.e., measured at 12 °C) did not differ between exposed and control sparrows. Although the body mass and condition were not measured at the beginning of the exposure, sparrows at the time of the metabolic measurements 7 months after the onset of such exposure had a higher body condition than controls, supporting further the idea that tebuconazole affects metabolic functions. Our study demonstrates for the first time that the use of tebuconazole can alter metabolism and could potentially lead to adverse effects in birds. Environ Toxicol Chem 2022;41:2500–2511. © 2022 SETAC [ABSTRACT FROM AUTHOR]

Amblyseius largoensis (Muma) is a predatory mite that occurs naturally in plants infested with the pest mite, Raoiella indica Hirst, and has been reported as a potential predator for the control of R. indica. Since A. largoensis is not available commercially, coconut producers have used products registered for another coconut pest mite (Aceria guerreronis Keifer) against R. indica with the aim of minimizing economic losses caused by this pest. However, it is possible to explore the natural contribution of this predator using control strategies that allow its conservation. Thus, in the present study, the effects of pesticides registered for the coconut crop (azadirachtin, abamectin, chlorfenapyr, and fenpyroximate) on the survival, consumption, oviposition, and feed conversion efficiency of A. largoensis were evaluated to determine the compatibility between acaricides and the predatory mite. The results showed that the acaricides abamectin, fenpyroximate, and chlorfenapyr reduced the survival of A. largoensis females. Abamectin was the only acaricide that reduced predation, oviposition, and the feed conversion efficiency of A. largoensis. Azadirachtin did not affect any of the assessed parameters. These results suggest a potential compatibility A. largoensis with the pesticides azadirachtin, fenpyroximate, and chlorfenapyr. [ABSTRACT FROM AUTHOR]

Bemisia tabaci is a threat to agriculture worldwide because of its potential to cause devastating damage to various crops. β-asarone is a bioactive pesticidal chemical originating from Acorus calamus (or "Sweet Flag") plants, and it displays significant lethal effects against insect pests. In this study, we established a baseline of susceptibility to β-asarone from China and patterns of cross-resistance to other popular insecticides. We found that all the 12 field-collected B. tabaci populations exhibited high susceptibility to β-asarone, and there was no cross-resistance detected for other tested insecticides. We subsequently evaluated the sublethal effects of β-asarone on physiology and biochemistry via LC25 treatment (4.7 mg/L). LC25 of β-asarone resulted in prolonged developmental duration and decreased survival rates in B. tabaci nymphs, pseudopupae, and adults. Significant reductions in oviposition duration, fecundity, and hatchability were also observed. Additionally, the metabolic enzyme activity and expression profiles of selected cytochrome P450 monooxygenase (P450) genes following the LC25 treatment of β-asarone suggest that enhanced detoxification via P450s could be involved in the observed sublethal effects. These findings demonstrate the strong toxicity and significant sublethal effects of β-asarone on B. tabaci and suggest that the induced overexpression of P450 genes could be associated with the response to β-asarone. [ABSTRACT FROM AUTHOR]

Keywords: neonicotinoid; sublethal effects; colony-level behavior; thermoregulation; bee cage study EN neonicotinoid sublethal effects colony-level behavior thermoregulation bee cage study N.PAG N.PAG 11 09/27/22 20220901 NES 220901 1. The focus of this study was the effect of exposure of flonicamid on honey bee colony behavior in a field experiment and on honey bee survivorship and thermoregulation in controlled cage studies, as has been observed with those other pesticides mentioned above. The total adult bee population weight was calculated by subtracting the combined weights of hive components free of bees from the total hive weight with bees recorded at midnight prior to the inspection. [Extracted from the article]

Mass rearing herbivorous insects used as biological control agents requires a steady supply of optimal host plant material. This often necessitates the use of pesticides to minimise infestations and damage from generalist herbivores. Knowing the efficacy persistence of the pesticide is critical to prevent non-target effects on reared agent populations. We determined the amount of time for an abamectin foliar spray to degrade such that there were minimal impacts on the mass rearing of Pseudophilothrips ichini (Hood), a biological control agent for Brazilian peppertree (Schinus terebinthifolia Raddi) in Florida. Abamectin was applied to plants at the label concentration (0.31 ml/L) for controlling mites. Groups of three plants were brought into our quarantine facility 1, 3, 7, 10, and 14 d after application and were then each infested with 40 founding adult thrips. Founding adult survival was not impacted by the delay, i.e. interval between application and thrips infestation, with at least 75% recovered alive regardless of the delay. However, delaying infestation had a significant effect on the number of offspring produced, with, on average, only 50 produced when waiting 1 d, between 250 and 364 for the intermediate wait times, and 688 produced when waiting 14 d. Waiting 14 d after treatment before infesting new plants would achieve optimal colony yields but waiting as little as 7 d may still be a reasonable balance between timely production operations and colony yields. Those developing insect mass rearing programmes should consider all variables specific to their procedures that may impact pesticide persistence. [ABSTRACT FROM AUTHOR]

Ecdysone receptor (EcR) plays important roles in molting, metamorphosis, and reproduction of insects. EcR ortholog and its function in melon aphid Aphis gossypii have not been documented yet. RNA interference (RNAi) is a reverse-genetic approach used to study functional genomics, but recently, it has also shown promise as a novel tool that could be used to control insect pests. In this study, reverse transcription-PCR (RT-PCR), quantitative real-time PCR (qPCR), RNAi, and bioassays were employed to isolate EcR gene and investigate its knock-down effects on aphids. The lethal and sublethal effects were also studied after silencing the EcR gene. The results showed that EcR gene is highly expressed (P < 0.006) in 2nd nymphal stage of A. gossypii while expression was statistically lower in all other developmental stages. Knock-down of EcR gene caused up to 43 and 68% mortality in 2nd instar nymphs after feeding dsEcR for 48 and 72 h, respectively, compared to the control. Moreover, RNAi-induced silencing of EcR gene caused sublethal effects on surviving aphids. Significantly lower longevity (about 42%) and fecundity (about 44.22%) were observed in insects fed with dsEcR solution at their nymphal stage. Analysis of gene expression showed that the mortality rates and the lowered longevity and fecundity were attributable to the down-regulation of EcR gene by RNA interference technology. Taken together, our results demonstrate that EcR is an essential gene for aphid growth and development and could be a potential target gene for the development of an RNAi-based bio-aphicide. [ABSTRACT FROM AUTHOR]

The biological activity of 2 isolates of Spodoptera frugiperda multiple nucleopolyhedrovirus (Sf-YUC and Sf-CHI) obtained from the states of Yucatán and Chiapas, Mexico, on second instar fall armyworm, Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae) from Michoacán State, Mexico, was determined and compared with that of a Nicaraguan isolate (Sf-NIC). Response of third and fourth instar S. frugiperda to the most active isolate, Sf-YUC, also was determined. Sublethal effects caused by this isolate and its intergenerational persistence were evaluated. The most pathogenic isolates on second instar S. frugiperda were Sf-NIC and Sf-YUC. No significant differences were detected in the speed of kill between the Sf-NIC (146 h) and Sf-YUC (149 h) isolates, whereas that of the Sf-CHI (158 h) isolate was slower significantly. The lethal concentration that kills 50% of the insects (LC50) values of the Sf-YUC isolate increased with larval stage from 9.45 × 104 to 1.25 × 106 occlusion bodies per mL. Statistically significant reductions in pupal weight, fecundity, fertility, and adult longevity were associated in individuals derived from third instar (generation F0) treated with 4.8 × 104 occlusion bodies per mL of the Sf-YUC isolate. A viral mortality of 15.83 ± 1.43% in larvae as well as a significant reduction in pupal weight of generation F1 was recorded. In conclusion, the Mexican isolates may prove suitable as the basis for biological insecticides for regional control of S. frugiperda. Sublethal infections that persist between generations could incur developmental costs and decrease reproductive capacity of the host insect. En el presente estudio, se determinó la actividad biológica de dos aislados mexicanos del nucleopolyhedrovirus múltiple de Spodoptera frugiperda (Sf-YUC y Sf-CHI) sobre larvas de segundo instar del gusano cogollero, Spodptera frugiperda (J. E. Smith), y se compararon con un aislado nicaragüense (Sf-NIC). También se determinó la respuesta de tercer y cuarto instar de S. frugiperda al aislado mexicano más activo, Sf-YUC. Finalmente, se evaluaron los efectos subletales causados por este aislado y su persistencia intrageneracional. Los aislados más patogénicos sobre el segundo instar de S. frugiperda fueron Sf-NIC y Sf-YUC. No se detectaron diferencias significativas en la velocidad de muerte entre los aislados Sf-NIC (146 h) y Sf-YUC (149 h), mientras que la del aislado Sf-CHI (158 h) fue significativamente mayor. Los valores de la concentración letal que matan el 50% de los insectos (CL50) se incrementaron con el estado larval desde 9.45 × 104 a 1.25 × 106 cuerpos de oclusión por mL del segundo al cuarto instar. Reducciones estadísticamente significativas en el peso pupal, la fecundidad, la fertilidad y la longevidad de adultos se asociaron con individuos derivados de tercer estadio (generación F0) tratados con 4,8 × 104 cuerpos de oclusión por mL del aislado Sf-YUC. observó una reducción significativa en el peso pupal. En conclusión, los aislados mexicanos pueden ser adecuados como la base de insecticidas biológicos para el control de S. frugiperda. Las infecciones subletales que persisten entre generaciones pueden generar costos de desarrollo y disminuir la capacidad reproductiva del insecto huésped. [ABSTRACT FROM AUTHOR]

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Anticoagulant rodenticides have been detected in many species of wildlife worldwide; yet the origins, exposure pathways, and effects of this exposure are not well understood. Furthermore, to accurately characterize the risks from rodenticide use, information is needed on what proportion of populations are being exposed, what proportion of the exposed individuals are affected, and in what ways. The relationship between anticoagulant rodenticide concentrations found in wildlife and the rate of mortality or illness is the subject of much current research. Residue levels observed in liver and whole body analyses vary, and overlap extensively among apparently healthy asymptomatic individuals and sublethal and lethal cases. Results from laboratory studies also show there can be wide variability in lethal and sublethal effects among and within taxonomic groups. Correlating the sublethal and reproductive effects observed in laboratory studies with realistic exposure scenarios and effects in the wild is needed to improve risk assessments. For species with limited numbers/declining populations, a critical question is whether the rodenticide exposure documented in individual animals inhibit population growth or contribute to population declines by lowering survival and reproductive success. This information is essential to the regulatory agencies that must weigh the risks and benefits of rodenticide uses and identify restrictions that are effective in reducing risks to wildlife. A primary objective of this symposium was to facilitate communication between regulators and researchers. Current research on many of these topics was presented, and was followed by discussions on how to improve our understanding of what factors lead to wildlife exposure and improve our ability to assess the effects of exposure on individuals and populations. A collaborative approach will be developed to design studies that provide regulatory and wildlife management agencies with additional science on which to base their decisions.

Insect populations exist under acute and chronic exposures to lethal and sublethal insecticide concentrations. Among the sublethal effects of insecticides on insects are reductions in life span, development rates, population growth, fertility, fecundity, changes in sex ratio, deformities, changes in behaviour, feeding, searching, and oviposition. These effects may differ depending on the modes of action of insecticides, their doses, and developmental stage of application. This study evaluated the life-history parameters in Musca domestica Linnaeus, 1758 (Diptera:Muscidae) strains that were exposed to two insecticides (fipronil and chlorfenapyr) with different modes of action at sublethal concentrations in each generation up to tenth. Two approaches to each insecticide’s exposure were used in this study, particularly in one approach, only adults M. domestica were exposed to fipronil or chlorfenapyr and in another approach, only larvae were exposed to each insecticide. The susceptibility of adult flies to these insecticides was assessed by resistance ratio based on results of non-choice feeding bioassays. Fipronil exposure at the sublethal concentration in each generation did not affect the susceptibility of adult M. domestica (in the tenth generation) to fipronil. The resistance ratio values revealed tolerance to chlorfenapyr in adults of M. domestica strains that were exposed to this insecticide, independent of the approach used to insecticide exposure. Most of the life-history parameters (such as durations of separate developmental stages, the emergence duration, the adult emergence ratio, the female ratio, and the number of eggs per female per day) of the second, fourth, sixth, eighth, and tenth generations of the insecticide-exposed strains were similar to those of the control strain. At the same time, the sublethal effects of both insecticides fipronil and chlorfenapyr prolonged the larval duration (1.63–2.22 times) and the number of days from egg to adult (1.18–1.39 times) compared to the control strain. Further studies are needed to investigate a possible genetic variability in M. domestica in response to exposure of parental generation to sublethal doses of fipronil and chlorfenapyr.

Clothianidin is a second-generation neonicotinoid insecticide that can effectively prevent piercing-sucking pests, such as white-backed planthopper (WBPH), Sogatella furcifera (Horváth). In this study, the sublethal effects of clothianidin on the biological traits of S. furcifera were evaluated via the age-stage, two-sex life table procedure. Our results exhibited that the female adult longevity, fecundity and hatchability of F0 generation were significantly decreased after LC10 and (or) LC30 of clothianidin exposure compared to the control. Transgenerational effects showed that the pre-adult period, female adult longevity, total longevity, oviposition days (Od), fecundity and mean generation time (T) of F1 generation were significantly decreased in the LC10 and LC30 groups compared to the control. Moreover, the development times of the third- and fifth-instar nymphs, total preoviposition period (TPOP) and doubling time (DT) were significantly shorter in the LC10 group than in the control and LC30 groups. Furthermore, the intrinsic rate of increase (ri) and finite rate of increase (λ) values of the LC10 group were significantly higher than those of the control group. However, there was no significant difference in the male adult longevity, adult preoviposition period (APOP) and net reproductive rate (R0) between the treated groups and the control. Enzyme activity and gene expression results showed that the P450 enzyme activity and mRNA levels of many P450 genes were significantly increased by clothianidin treatment. In addition, the knockdown of CYP4CE3 and CYP6FJ3, which showed the highest inducing levels, by RNA interference (RNAi) dramatically increased the toxicity of clothianidin against S. furcifera. These results indicated that sublethal concentrations of clothianidin showed a stimulatory effect on the development, but it could adversely affect the survival and reproduction of S. furcifera. Additionally, CYP4CE3 and CYP6FJ3 might play an important role in the detoxification and evolution of clothianidin resistance in S. furcifera.

Chrysoperla carnea Stephens (Neuroptera: Chrysopidae) is an important beneficial predator in agriculture, which is easily reared in laboratory. It is widely used in augmentative biological control programs. Research on sublethal effects, aims to reveal the negative and non-lethal impacts of insecticides on pests and provide practical information for forming effective pest control strategies. The lethal and sublethal effects of tebufenozide, clothianidin, and flupyradifurone on the common green lacewing, C. carnea were investigated in laboratory conditions at 25 ± 2°C, 60 ± 5% RH and a photoperiod of 16:8 h. (L:D). The results indicated the oviposition period in insects treated with flupyradifurone (26.62 days) was significantly different from the oviposition period in insects treated with clothianidin (21.90 days) and tebufenozide (21.62 days). Total fecundity in flupyradifurone treatment was significantly higher than the total fecundity in other treatments. The life table experiment of current study showed the values of r in control and the populations treated with LC30 of clothianidin, tebufenozide and flupyradifurone were 0.15, 0.17, 0.14, 0.15 day-1, respectively. The finite rate of increase (λ) was affected with different treatments; and the values varied from 1.19 to 1.16 day-1 for C. carnea adults treated with clothianidin and tebufenozide, respectively. The highest survival rate of C. carnea was observed in control (58 days). Based on the results, it seems flupyradifurone may have less harmful effects on total lifespan, fecundity rate and bio-characteristics of green lacewing population than clothianidin and tebufenozide.

Abstract Passive integrated transponder (PIT) tags allow a range of individual‐level data to be collected passively and have become a commonly used technology in many avian studies. Although the potential adverse effects of PIT tags have been evaluated in several species, explicit investigations of their impacts on small (

Leaf-cutting ants are important pests of agricultural and forest crops. Currently, few insecticides are registered for the control of these insects. Natural bioactive molecules can serve as models for the synthesis of new insecticidal compounds. Such ant killer products must be sustainable and efficient, considering not only lethal effects, but also sublethal effects, which can interfere with behavior and communication between colony members. In this study, we analyzed the toxicity of the monoterpene thymol and its derivatives, as well as the sublethal effects of these compounds on the behavior of the leaf-cutting ant Acromyrmex balzani. These effects were compared with the conventional synthetic insecticide deltamethrin. Although deltamethrin showed higher toxicity (LD50 = 0.87 × 10−5 µg/mg), all other tested compounds increased ant mortality, with thymyl chloroacetate being the most toxic derivative (LD50 = 1.41 µg/mg), followed by thymol (LD50 = 2.23 µg/mg). These three most toxic compounds interfered differentially in the behavior of ants. Thymyl chloroacetate caused increased self-cleaning and reduced allogrooming, which may be related to an attempt to avoid contamination between nestmates. In general, thymol caused greater avoidance among ants, reduced walking speed and caused disorientation in workers. On the other hand, thymyl chloroacetate (LD30) considerably increased the walking speed of the group, without changing the orientation of the individuals. Such changes may interfere with basic activities such as foraging and altering colony cohesion via different mechanisms. Thus, despite the desirable effects of deltamethrin on ant control, this insecticide is highly toxic and should be discontinued soon. Our results show that thymol and its structural modification in thymyl chloroacetate may represent potential ant killers to be used in the management of A. balzani.

Emamectin benzoate is an avermectin bio-insecticide commonly used for managing several insect pests including Spodoptera litura (Fabricius) (Lepidoptera: Noctuidae), a major polyphagous pest of many cultivated crops. The current study was conducted to evaluate the effects of emamectin benzoate on the fitness of S. litura populations exhibiting differential susceptibility to insecticide. The selection process and all the bioassays were carried out using 6-day-old 2nd instar larvae of S. litura. A field-collected population of S. litura was divided into two groups: one selected with emamectin benzoate for eight generations (EB-Sel) and the other kept unexposed (Unsel-Lab) to insecticide in the laboratory. An increase in resistance ratio from 1.71-fold in the F 1 generation to 22.54-fold in the F 8 generation of the EB-Sel population was observed compared to the Unsel-Lab (F 8) population. The EB-Sel and Unsel-Lab populations were treated with their respective lethal and sub-lethal concentrations which resulted in an extended development period, decreased larval survival, and adult emergence along with increased morphological abnormalities in adults. Significant reductions were observed in both male and female longevity, fecundity, egg hatching, net reproductive rate (R 0), intrinsic rate of increase (r m), and finite rate of increase (λ) in EB-Sel and Unsel-Lab populations. Higher concentrations of the insecticide also reduced the relative fitness (R f) of S. litura larvae, with maximum effect at LC 50 of the EB-Sel population where the R f value was 0.32 compared to the Unsel-Lab population. Both populations have been affected by emamectin benzoate exposure, however, the impact was more pronounced in the EB-Sel population indicating fitness costs. Our results suggested the fitness cost linked to emamectin benzoate resistance in S. litura which might favor managing insecticide resistance by reducing the frequency of resistant alleles by removing selection pressure. Consequently, our research provides significant insights to devise better pest management strategies for S. litura. [Display omitted] • Spodoptera litura was collected from fields and exposed to emamectin benzoate for eight generations. • The selection pressure increases resistance ratio in selected population to 22.54-fold compared to unselected population. • The insecticide exposure adversely impacted the life history traits of S. litura. • The relative fitness value of the selected strain was significantly low compared to unselected population. [ABSTRACT FROM AUTHOR]

Neonicotinoid insecticides (NNI) are agonists of insect nicotinic acetylcholine receptors (nAChR) that induce non-elucidate mechanisms of abnormal behavior in insects. In this work, we investigated the effects of sublethal doses of the neonicotinoid thiamethoxam (TMX) on neurochemical and physiological parameters in cockroaches. Sublethal doses of TMX (0.01–10 ng.g−1 body mass) caused significant alterations in most of the neurophysiological parameters evaluated. TMX reduced sustained locomotor activity by 19.9–25.8 %, depending on the dose. Leg grooming activity increased by 124.5 ± 3.4 %, 158.7 ± 3.5 %, 168.3 ± 3.4 %, and 160.4 ± 3.4 % (mean ± SEM) with TMX doses of 0.01, 0.1, 1, and 10 ng.g−1, respectively. Exploratory activity was significantly reduced only at the lowest TMX dose (0.01 ng.g−1) – the time spent immobile increased from 30 % to ∼45 %, whereas none of the doses affected the walking speed. Treatment with TMX (0.01 ng.g−1) markedly reduced the olfactory sensitivity of the cockroaches and also reduced the mechanosensory action potential amplitude, rise time and decay time by 61.2 ± 19 %, 50 ± 4 %, and 76.8 ± 9.5 %, respectively. In semi-isolated heart preparations, TMX caused positive chronotropism (increases of 34.7 ± 15.9 %, 26.8 ± 7.8 %, 43.0 ± 16.5 %, and 19.0 ± 13.7 % for 0.01, 0.1, 1, and 10 ng of TMX, respectively). TMX attenuated the activity of glutathione-S-transferase by 35.1 ± 6.4 % at the highest dose tested (10 ng.g−1). TMX caused alterations in the metal ion content of cockroach brains that varied with the dose tested and the ion examined. These findings indicate that sublethal doses of TMX can interfere with normal neurological function in cockroaches and disrupt brain metal ion homeostasis. [Display omitted] • Thiamethoxam is an agonist of insect nicotinic acetylcholine receptors (nAChR). • Thiamethoxam disrupt the somatosensorial integration in insects. • Thiamethoxam induces functional alterations of insect brain metal ion homeostasis. • These actions adversely affect neuronal pathways involved in insect behavior. [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 LC 10 and LC 25 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. [Display omitted] • β-cyp·EMB exhibited higher toxicity than quinalphos in S. frugiperda. • Different exposure durations and sublethal concentrations of both insecticides affected activities of CarE, GST, MFO, and AChE. • Significant correlations were observed among CarE, GST, MFO, and AChE activities across different exposure durations. [ABSTRACT FROM AUTHOR]

Bees play a crucial role as pollinating insects in both natural and cultivated areas. However, the use of pesticides, such as thiamethoxam, has been identified as a contributing factor compromising bee health. The current risk assessment primarily relies on the model species Apis mellifera , raising concerns about the applicability of these assessments to other bee groups, including stingless bees. In this study, we investigated the acute toxicity of thiamethoxam on the stingless bee Frieseomelitta varia by determining the average lethal concentration (LC 50) and mean lethal time (LT 50). Additionally, we evaluated the enzymatic profile of Acetylcholinesterase (AChE), Carboxylesterase-3 (CaE-3), and Glutathione S-Transferase (GST), in the heads and abdomens of F. varia after exposure to thiamethoxam (LC 50/10). The LC 50 of thiamethoxam was determined to be 0.68 ng ai/μL, and the LT 50 values were 37 days for the control group, 25 days at LC 50/10 , and 27 days at LC 50/100. The thiamethoxam significantly decreased the survival time of F. varia. Furthermore, the enzymatic profile exhibited differences in CaE3 activity within one day in the heads and ten days in the abdomen. GST activity showed differences in the abdomen after one and five days of thiamethoxam exposure. These findings suggests that the abdomen is more affected than the head after oral exposure to thiamethoxam. Our study provides evidence of the toxicity of thiamethoxam at both the cellular and organismal levels, reinforcing the need to include non-Apis species in pollinator risk assessments. and provide solid arguments for bee protection. [Display omitted] • The LC 50 of thiamethoxam for the stingless bee Frieseomelitta varia is 0.68 ng ai/μL. • LC 50/10 and LC 50/100 of thiamethoxam shortened F. varia lifespan by 11 ± 1 days. • Thiamethoxam affected the enzymatic activity of GST in the abdomen of F. varia. • The enzymatic activity in the abdomen is more affected than in the heads of F. varia. [ABSTRACT FROM AUTHOR]

Aphis gossypii Glover is one of the most agriculturally important phloem-feeding economic pests, causing tremendous loss in crop yield annually. The hormesis is an important cause of A. gossypii resistance formation, population resurgence, and re-outbreak. However, whether the hormesises induced by different insecticides interact mutually remain largely unclear. In the study, four-generation A. gossypii experiment found that the 24-h sublethal-dose (LC 20) sulfoxaflor treatment on G0 significantly increased the net reproductive rate (R0) and fecundity of G1 and G2 generation A. gossypii , but it did not significantly affect the fecundity of G3 and G4 individuals. Transcriptomic analyses revealed that the insecticide-induced significant up-regulation of pathways ribosome, energy metabolism, and the DNA replication and reparation might be responsible for the enhancement of fecundity in G1 and G2 A. gossypii. Notably, G0 exposure to LC 20 sulfoxaflor followed by G1 exposure to LC 30 deltamethrin resulted in a stronger reproductive stimulation than sulfoxaflor or deltamethrin exposure alone. Our findings provide valuable reference for optimizing sulfoxaflor application in integrated pest management strategies. [Display omitted] • The sublethal-dose sulfoxaflor increased the fecundity of G1 and G2 A. gossypii. • The ribosome and energy metabolism was vital to the enhancement of fecundity of G1. • The DNA replication and reparation was vital to the enhancement of fecundity of G2. • The hormesises induced by different insecticides has an interaction. [ABSTRACT FROM AUTHOR]

Native and invasive species often occupy similar ecological niches and environments where they face comparable risks from chemical exposure. Sometimes, invasive species are phylogenetically related to native species, e.g. they may come from the same family and have potentially similar sensitivities to environmental stressors due to phylogenetic conservatism and ecological similarity. However, empirical studies that aim to understand the nuanced impacts of chemicals on the full range of closely related species are rare, yet they would help to comprehend patterns of current biodiversity loss and species turnover. Behavioral sublethal endpoints are of increasing ecotoxicological interest. Therefore, we investigated behavioral responses (i.e., change in movement behavior) of the four dominant amphipod species in the Rhine-Main area (central Germany) when exposed to the neonicotinoid thiacloprid. Moreover, beyond species-specific behavioral responses, ecological interactions (e.g. parasitation with Acanthocephala) play a crucial role in shaping behavior, and we have considered these infections in our analysis. Our findings revealed distinct baseline behaviors and species-specific responses to thiacloprid exposure. Notably, Gammarus fossarum exhibited biphasic behavioral changes with hyperactivity at low concentrations that decreased at higher concentrations. Whereas Gammarus pulex , Gammarus roeselii and the invasive species Dikerogammarus villosus , showed no or weaker behavioral responses. This may partly explain why G. fossarum disappears in chemically polluted regions while the other species persist there to a certain degree. But it also shows that potential pre-exposure in the habitat may influence behavioral responses of the other amphipod species, because habituation occurs, and potential hyperactivity would be harmful to individuals in the habitat. The observed responses were further influenced by acanthocephalan parasites, which altered baseline behavior in G. roeselii and enhanced the behavioral response to thiacloprid exposure. Our results underscore the intricate and diverse nature of responses among closely related amphipod species, highlighting their unique vulnerabilities in anthropogenically impacted freshwater ecosystems. [Display omitted] • Short-time neonicotinoid exposure causes behavioral responses in non-target species. • Environmentally relevant concentrations can induce changes in invertebrate behavior. • Different baseline activity of ecological similar crustacean amphipods. • Species respond specifically to thiacloprid exposure. • Acantocephalan infection affects locomotion of intermediate host Gammarus roeselii. [ABSTRACT FROM AUTHOR]