Imidacloprid and chlorpyrifos insecticides impair migratory ability in a seed-eating songbird

Characterization of Neonicotinoid Metabolites by Cytochrome P450-Mediated Metabolism in Poultry

Neonicotinoids, a neuro-effective class of insecticides, are heavily applied in agricultural activities worldwide. Poultry can be exposed to neonicotinoids by several routes, but the knowledge of neonicotinoid's metabolism in poultry and its associated interspecies differences is highly limited. Hence, this study aims to investigate the species differences in metabolite formations, as well as cytochrome P450 (CYP)-dependent metabolism of four major neonicotinoid compounds, acetamiprid, imidacloprid, clothianidin, and thiamethoxam, in poultry. In vitro biotransformation assays using hepatic microsomes of chicken, ducks, geese, quails, and rats were conducted. Metabolites of neonicotinoids were then screened by LC/Q-TOF and quantified by LC/MS/MS. The results revealed an existence of interspecies differences in the formations of N-[(6-chloro-3-pyridyl) methyl] -N-methyl acetamidine (IM-1-5) of acetamiprid and dm-clothianidin of clothianidin between chicken and other species. In addition, the greatest CYP activities in the metabolism of most neonicotinoid substrates, such as acetamiprid to dm-acetamiprid, imidacloprid to hydroxylated-imidacloprid and imidacloprid-olefin, clothianidin to dm-clothianidin, and thiamethoxam to clothianidin, were found in chicken. These results suggested that the CYPs in chicken may have a greater capacity for metabolism of neonicotinoids compared to other poultry. This study further revealed that the maximum intrinsic clearance of dn-imidacloprid and dn-clothianidin in ducks may be superintended by CYP-mediated nitro-reductions of imidacloprid and clothianidin. Further studies employing CYP recombinant enzymes may be required to elucidate the specific CYP isoforms that may be involved in neonicotinoid metabolism in avian species.

Central nervous system disturbances by thiamethoxam in Japanese quail (Coturnix japonica): In vivo, ex vivo, and in silico study

The neurotoxic effects of neonicotinoids (NEOs) have been widely reported in relation to the poisoning of wild birds, yet the underlying molecular mechanism has remained elusive. This study employed Japanese quails (Coturnix japonica) and primary quail embryonic neurons as in vivo and ex vivo models, respectively, to investigate the neurotoxic effects and mechanism of thiamethoxam (TMX), a representative neonicotinoid insecticide, at environmentally relevant concentrations. Following a 28-day exposure to TMX, metabolomic analysis of quail brain revealed TMX-induced changes in glutamatergic, GABA-ergic, and dopaminergic function. Subsequent ex vivo and in silico experimentation revealed that the activation of nicotinic acetylcholine receptors and calcium signaling, induced by clothianidin (CLO), the primary metabolite of TMX, served as upstream events for the alterations in neurotransmitter synthesis, metabolism, release, and uptake. Our findings propose that the disruption of the central nervous system, caused by environmentally significant concentrations of NEOs, may account for the avian poisoning events induced by NEOs.

A brief review on models for birds exposed to chemicals

"A Who's Who of pesticides is therefore of concern to us all. If we are going to live so intimately with these chemicals eating and drinking them, taking them into the very marrow of our bones - we had better know something about their nature and their power."-Rachel Carson, Silent Spring. In her day, Rachel Carson was right: plant protection products (PPP), like all the other chemical substances that humans increasingly release into the environment without further precaution, are among our worst enemies today (Bruhl and Zaller, 2019; Naidu et al., 2021; Tang et al., 2021; Topping et al., 2020). All compartments of the biosphere, air, soil and water, are potential reservoirs within which all species that live there are impaired. Birds are particularly concerned: PPP are recognized as a factor in the decline of their abundance and diversity predominantly in agricultural landscapes. Due to the restrictions on vertebrates testing, in silico-based approaches are an ideal choice alternative given input data are available. This is where the problem lies as we will illustrate in this paper. We performed an extensive literature search covering a long period of time, a wide diversity of bird species, a large range of chemical substances, and as many model types as possible to encompass all our future need to improve environmental risk assessment of chemicals for birds. In the end, we show that poultry species exposed to pesticides are the most studied at the individual level with physiologically based toxicokinetic models. To go beyond, with more species, more chemical types, over several levels of biological organization, we show that observed data are crucially missing (Gilbert, 2011). As a consequence, improving existing models or developing new ones could be like climbing Everest if no additional data can be gathered, especially on chemical effects and toxicodynamic aspects.

Ornamental plants as vectors of pesticide exposure and potential threat to biodiversity and human health

The production of conventional ornamental plants is pesticide-intensive. We investigated whether pesticide active ingredients (AIs) are still present in ornamentals at the time of purchase and assessed their potential ecotoxicity to non-target organisms. We purchased 1000 pot plants and 237 cut flowers of different species from garden centers in Austria and Germany between 2011 and 2021 and analyzed them for up to 646 AIs. Ecotoxicological risks of AIs were assessed by calculating toxic loads for honeybees (Apis mellifera), earthworms (Eisenia fetida), birds (Passer domesticus), and mammals (Rattus norvegicus) based on the LD50 values of the detected AIs. Human health risks of AIs were assessed on the basis of the hazard statements of the Globally Harmonized System. Over the years, a total of 202 AIs were detected in pot plants and 128 AIs in cut flowers. Pesticide residues were found in 94% of pot plants and 97% of cut flowers, with cut flowers containing about twice as many AIs (11.0 ± 6.2 AIs) as pot plants (5.8 ± 4.0 AIs). Fungicides and insecticides were found most frequently. The ecotoxicity assessment showed that 47% of the AIs in pot plants and 63% of the AIs in cut flowers were moderately toxic to the considered non-target organisms. AIs found were mainly toxic to honeybees; their toxicity to earthworms, birds, and mammals was about 105 times lower. Remarkably, 39% of the plants labeled as "bee-friendly" contained AIs that were toxic to bees. More than 40% of pot plants and 72% of cut flowers contained AIs classified as harmful to human health. These results suggest that ornamental plants are vectors for potential pesticide exposure of consumers and non-target organisms in home gardens.

Behavioral Responses of Imidacloprid-Dosed Farmland Birds to a Simulated Predation Risk

Sublethal exposure to imidacloprid and other neonicotinoid insecticides may affect the neurological functions of birds. As such, behavior may be compromised. Here, we tested experimentally the effects of 1 and 6 mg/kg bw of imidacloprid on the antipredator behavioral responses of the red-legged partridge (Alectoris rufa) to simulated predator threats. Sixty-six partridges were challenged in groups or individually to intra- and interspecific alarm calls, to a raptor silhouette (aerial predation risk), and to a fox model (terrestrial predation risk). Antipredator behaviors were recorded as active (escape, active vigilance) and passive (passive vigilance, crouching, and freezing) responses. Latency in response to the stimuli, percentage of individuals who responded, response duration, speed of active responses, and vocalizations were measured. In experiments with partridges in the group, crouching against simulated predation risk lasted less time in birds treated with 6 mg a.i./kg bw than in control birds. In the experiments with individual partridges, passive vigilance against the intraspecific alarm lasted longer in birds treated with 6 mg a.i./kg bw than in control birds. The observed hyperreactivity to the predatory threat after a sublethal imidacloprid exposure can have consequences on survival under field conditions, where predation is a main driver of population dynamics.

Wildlife ecological risk assessment in the 21st century: Promising technologies to assess toxicological effects

Despite advances in toxicity testing and the development of new approach methodologies (NAMs) for hazard assessment, the ecological risk assessment (ERA) framework for terrestrial wildlife (i.e., air-breathing amphibians, reptiles, birds, and mammals) has remained unchanged for decades. While survival, growth, and reproductive endpoints derived from whole-animal toxicity tests are central to hazard assessment, nonstandard measures of biological effects at multiple levels of biological organization (e.g., molecular, cellular, tissue, organ, organism, population, community, ecosystem) have the potential to enhance the relevance of prospective and retrospective wildlife ERAs. Other factors (e.g., indirect effects of contaminants on food supplies and infectious disease processes) are influenced by toxicants at individual, population, and community levels, and need to be factored into chemically based risk assessments to enhance the "eco" component of ERAs. Regulatory and logistical challenges often relegate such nonstandard endpoints and indirect effects to postregistration evaluations of pesticides and industrial chemicals and contaminated site evaluations. While NAMs are being developed, to date, their applications in ERAs focused on wildlife have been limited. No single magic tool or model will address all uncertainties in hazard assessment. Modernizing wildlife ERAs will likely entail combinations of laboratory- and field-derived data at multiple levels of biological organization, knowledge collection solutions (e.g., systematic review, adverse outcome pathway frameworks), and inferential methods that facilitate integrations and risk estimations focused on species, populations, interspecific extrapolations, and ecosystem services modeling, with less dependence on whole-animal data and simple hazard ratios. Integr Environ Assess Manag 2024;20:725-748. © 2023 His Majesty the King in Right of Canada and The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC). Reproduced with the permission of the Minister of Environment and Climate Change Canada. This article has been contributed to by US Government employees and their work is in the public domain in the USA.

Wildlife ecotoxicology of plant protection products: knowns and unknowns about the impacts of currently used pesticides on terrestrial vertebrate biodiversity

Agricultural practices are a major cause of the current loss of biodiversity. Among postwar agricultural intensification practices, the use of plant protection products (PPPs) might be one of the prominent drivers of the loss of wildlife diversity in agroecosystems. A collective scientific assessment was performed upon the request of the French Ministries responsible for the Environment, for Agriculture and for Research to review the impacts of PPPs on biodiversity and ecosystem services based on the scientific literature. While the effects of legacy banned PPPs on ecosystems and the underlying mechanisms are well documented, the impacts of current use pesticides (CUPs) on biodiversity have rarely been reviewed. Here, we provide an overview of the available knowledge related to the impacts of PPPs, including biopesticides, on terrestrial vertebrates (i.e. herptiles, birds including raptors, bats and small and large mammals). We focused essentially on CUPs and on endpoints at the subindividual, individual, population and community levels, which ultimately linked with effects on biodiversity. We address both direct toxic effects and indirect effects related to ecological processes and review the existing knowledge about wildlife exposure to PPPs. The effects of PPPs on ecological functions and ecosystem services are discussed, as are the aggravating or mitigating factors. Finally, a synthesis of knowns and unknowns is provided, and we identify priorities to fill gaps in knowledge and perspectives for research and wildlife conservation.

Discovery of Potential Neonicotinoid Insecticides by an Artificial Intelligence Generative Model and Structure-Based Virtual Screening

The identification of neonicotinoid insecticides bearing novel scaffolds is of great importance for pesticide discovery. Here, artificial intelligence-based tools and virtual screening strategy were integrated to discover potential leads of neonicotinoid insecticides. A deep generative model was successfully constructed using a recurrent neural network combined with transfer learning. The model evaluation showed that the pretrained model could accurately grasp the SMILES grammar of drug-like molecules and generate potential neonicotinoid compounds after transfer learning. The generated molecules were evaluated by hierarchical virtual screening, hits were subjected to a similarity search, and the most similar structures were purchased for the bioassay. Compounds A2 and A5 displayed 52.5 and 50.3% mortality rates against Aphis craccivora at 100 mg/L, respectively. The docking study indicated that these two compounds have similar binding modes to neonicotinoids, which were verified by further molecular dynamics simulations.

The effects of insecticide seed treatments on the parasitism and predation of Myzus persicae (Homoptera: Aphididae) in canola

The green peach aphid, Myzus persicae (Sulzer) (Homoptera: Aphididae), is a major pest of brassica plants, with the ability to transmit > 100 viruses. Although the adoption of Integrated Pest Management is increasing, chemical treatment remains the predominant method used to control M. persicae globally. Insecticide seed treatments, typically with neonicotinoid active ingredients, have become commonplace in canola crops, and are viewed as a "softer" alternative to foliar sprays but may nevertheless impact natural enemies of M. persicae. In this study, the effects of canola seed treatments, containing imidacloprid, thiamethoxam, and a mixture of thiamethoxam + lambda-cyhalothrin, were investigated on the parasitoid wasp, Aphidius colemani Viereck (Hymenoptera: Braconidae) and the green lacewing, Mallada signatus (Schneider) (Neuroptera: Chrysopidae), both important natural enemies of M. persicae. Laboratory trials were undertaken using whole plants, with lethal and sublethal effects assessed by measuring several traits. Compared with untreated plants, more aphid mummies were produced and more A. colemani were reared on plants treated with thiamethoxam + lambda-cyhalothrin and more aphid mummies were produced on imidacloprid plants. Imidacloprid reduced the time A. colemani spent searching for M. persicae and thiamethoxam reduced its cleaning time. However, after A. colemani were removed from treated plants, there were no such effects observed, suggesting these impacts were relatively short-lived. We found no significant effects of seed treatments on M. signatus. These results point to the complexity of ecotoxicology studies involving multiple trophic levels and indicate that seed treatments may have variable impacts on key fitness traits of natural enemies.

Divergent impacts of the neonicotinoid insecticide, clothianidin, on flight performance metrics in two species of migratory butterflies

Long-distance flight is crucial for the survival of migratory insects, and disruptions to their flight capacity can have significant consequences for conservation. In this study, we examined how a widely used insecticide, clothianidin (class: neonicotinoid), impacted the flight performance of two species of migratory butterflies, monarchs (Danaus plexippus) and painted ladies (Vanessa cardui). To do this, we quantified the free-flight energetics and tethered-flight velocity and distance of the two species using flow-through respirometry and flight mill assays. Our findings show differential effects of the pesticide on the two species. For painted ladies, we found that clothianidin exposure reduced average free-flight metabolic rates, but did not affect either average velocity or total distance during tethered flight. Other studies have linked low flight metabolic rates with reduced dispersal capacity, indicating that clothianidin exposure may hinder painted lady flight performance in the wild. Conversely, for monarchs, we saw no significant effect of clothianidin exposure on average free-flight metabolic rates but did observe increases in the average velocity, and for large individuals, total distance achieved by clothianidin-exposed monarchs in tethered flight. This suggests a potential stimulatory response of monarchs to low-dose exposures to clothianidin. These findings indicate that clothianidin exposure has the potential to influence the flight performance of butterflies, but that not all species are impacted in the same way. This highlights the need to be thoughtful when selecting performance assays, as different assays can evaluate fundamentally distinct aspects of physiology, and as such may yield divergent results.

Determinants of spring migration departure dates in a New World sparrow: Weather variables reign supreme

Numerous factors influence the timing of spring migration in birds, yet the relative importance of intrinsic and extrinsic variables on migration initiation remains unclear. To test for interactions among weather, migration distance, parasitism, and physiology in determining spring departure date, we used the Dark-eyed Junco (Junco hyemalis) as a model migratory species known to harbor diverse and common haemosporidian parasites. Prior to spring migration departure from their wintering grounds in Indiana, USA, we quantified the intrinsic variables of fat, body condition (i.e., mass ~ tarsus residuals), physiological stress (i.e., ratio of heterophils to lymphocytes), cellular immunity (i.e., leukocyte composition and total count), migration distance (i.e., distance to the breeding grounds) using stable isotopes of hydrogen from feathers, and haemosporidian parasite intensity. We then attached nanotags to determine the timing of spring migration departure date using the Motus Wildlife Tracking System. We used additive Cox proportional hazard mixed models to test how risk of spring migratory departure was predicted by the combined intrinsic measures, along with meteorological predictors on the evening of departure (i.e., average wind speed and direction, relative humidity, and temperature). Model comparisons found that the best predictor of spring departure date was average nightly wind direction and a principal component combining relative humidity and temperature. Juncos were more likely to depart for spring migration on nights with largely southwestern winds and on warmer and drier evenings (relative to cooler and more humid evenings). Our results indicate that weather conditions at take-off are more critical to departure decisions than the measured physiological and parasitism variables.

The domestic chick as an animal model of autism spectrum disorder: building adaptive social perceptions through prenatally formed predispositions

Equipped with an early social predisposition immediately post-birth, humans typically form associations with mothers and other family members through exposure learning, canalized by a prenatally formed predisposition of visual preference to biological motion, face configuration, and other cues of animacy. If impaired, reduced preferences can lead to social interaction impairments such as autism spectrum disorder (ASD) via misguided canalization. Despite being taxonomically distant, domestic chicks could also follow a homologous developmental trajectory toward adaptive socialization through imprinting, which is guided via predisposed preferences similar to those of humans, thereby suggesting that chicks are a valid animal model of ASD. In addition to the phenotypic similarities in predisposition with human newborns, accumulating evidence on the responsible molecular mechanisms suggests the construct validity of the chick model. Considering the recent progress in the evo-devo studies in vertebrates, we reviewed the advantages and limitations of the chick model of developmental mental diseases in humans.

Monarch Butterflies in Western North America: A Holistic Review of Population Trends, Ecology, Stressors, Resilience and Adaptation

Monarch butterfly populations in western North America suffered a substantial decline, from millions of butterflies overwintering in California in the 1980s to less than 400,000 at the beginning of the 21st century. The introduction of neonicotinoid insecticides in the mid-1990s and their subsequent widespread use appears to be the most likely major factor behind this sudden decline. Habitat loss and unfavorable climates (high temperatures, aridity, and winter storms) have also played important and ongoing roles. These factors kept overwintering populations stable but below 300,000 during 2001-2017. Late winter storm mortality and consequent poor spring reproduction drove winter populations to less than 30,000 butterflies during 2018-2019. Record high temperatures in California during the fall of 2020 appeared to prematurely terminate monarch migration, resulting in the lowest overwintering population (1899) ever recorded. Many migrants formed winter-breeding populations in urban areas. Normal seasonal temperatures in the autumns of 2021 and 2022 enabled overwintering populations to return to around the 300,000 level, characteristic of the previous two decades. Natural enemies (predators, parasitoids, parasites, and pathogens) may be important regional or local drivers at times but they are a consistent and fundamental part of monarch ecology. Human interference (capture, rearing) likely has the least impact on monarch populations. The rearing of monarch caterpillars, particularly by children, is an important human link to nature that has positive ramifications for insect conservation beyond monarch butterflies and should be encouraged.

Behavioral and physiological changes in the passerine Agelaioides badius following the ingestion of coated seeds with imidacloprid in a 30-day experiment

The wide use of neonicotinoid seed treatment represents a hazard for farmland birds that feed on treated seeds. This study aimed to characterize the long-term effects of the neonicotinoid imidacloprid (IMI) in the passerine grayish baywing (Agelaioides badius). The birds were fed ad libitum for 32 days only with seeds treated with 53.1 (Low, 11 % of LD50) and 514 (High, (112 % of LD50) mg IMI/kg seed; these concentrations representing respectively, 1.8 and 17.1 % of 3 g IMI/kg, an average application rate used to treat crop seeds in Argentina. The effects exerted by IMI on birds were evaluated at behavioral, physiological, hematological, genotoxic, and biochemical levels. No differences in food consumption were observed between Control and Low treatments birds, indicating a lack of aversion to treated seeds. High treatment birds only decreased their food consumption by 20 % in the first 3 days of exposure. Birds from High treatment experienced an early loss of body weight, reduction in their mobility, lack of response to threats (i.e., predator call and approaching person), and altered their use of the cage. On the contrary, birds from Low treatment experienced a delay in the onset of effects like reduction in mobility, lack of response to threats, and a tendency to reduce their body weight. At the end of exposure, glutathione S transferase activity in the plasma of treated birds decreased, and cholinesterase activity increased in the liver of treated birds. This study highlights that consumption equivalent to 1.8 % of the daily diet of baywings as IMI-treated seeds, is sufficient to generate behavioral and physiological alterations and death. In the wild, these effects may have ecological consequences, by impairing the survival of birds, representing a risk to farmland bird populations.

Impacts of neonicotinoids on biodiversity: a critical review

Neonicotinoids are the most widely used class of insecticides in the world, but they have raised numerous concerns regarding their effects on biodiversity. Thus, the objective of this work was to do a critical review of the contamination of the environment (soil, water, air, biota) by neonicotinoids (acetamiprid, clothianidin, imidacloprid, thiacloprid, thiamethoxam) and of their impacts on terrestrial and aquatic biodiversity. Neonicotinoids are very frequently detected in soils and in freshwater, and they are also found in the air. They have only been recently monitored in coastal and marine environments, but some studies already reported the presence of imidacloprid and thiamethoxam in transitional or semi-enclosed ecosystems (lagoons, bays, and estuaries). The contamination of the environment leads to the exposure and to the contamination of non-target organisms and to negative effects on biodiversity. Direct impacts of neonicotinoids are mainly reported on terrestrial invertebrates (e.g., pollinators, natural enemies, earthworms) and vertebrates (e.g., birds) and on aquatic invertebrates (e.g., arthropods). Impacts on aquatic vertebrate populations and communities, as well as on microorganisms, are less documented. In addition to their toxicity to directly exposed organisms, neonicotinoid induce indirect effects via trophic cascades as demonstrated in several species (terrestrial and aquatic invertebrates). However, more data are needed to reach firmer conclusions and to get a clearer picture of such indirect effects. Finally, we identified specific knowledge gaps that need to be filled to better understand the effects of neonicotinoids on terrestrial, freshwater, and marine organisms, as well as on ecosystem services associated with these biotas.

Agricultural Use of Insecticides Alters Homeostatic Behaviors and Cognitive Ability in Lymnaea stagnalis

Lymnaea stagnalis is an ecologically important, stress-sensitive, freshwater mollusk that is at risk for exposure to insecticides via agricultural practices. We provide insight into the impact insecticides have on L. stagnalis by comparing specific behaviors including feeding, locomotion, shell regeneration, and cognition between snails collected at two different sites: one contaminated by insecticides and one not. We hypothesized that each of the behaviors would be altered in the insecticide-exposed snails and that similar alterations would be induced when control snails were exposed to the contaminated environment. We found no significant differences in locomotion, feeding, and shell regeneration of insecticide-exposed L. stagnalis compared with nonexposed individuals. Significant changes in feeding and shell repair were observed in nonexposed snails inhabiting insecticide-contaminated pond water. Most importantly, snails maintained and trained in insecticide-contaminated pond water did not form configural learning, but this cognitive deficit was reversed when these snails were maintained in insecticide-free pond water. Our findings conclude that insecticides have a primarily negative impact on this higher form of cognition in L. stagnalis. Environ Toxicol Chem 2023;42:2466-2477. © 2023 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Photo-Induced Super-Hydrophilicity of Nano-Calcite @ Polyester Fabric: Enhanced Solar Photocatalytic Activity against Imidacloprid

The present study is pertinent to photo-induced, hydrophilic, nano-calcite grown onto the mercerized surface of polyester fabric (PF), treated with UV (10-50 min) and visible light (1-5 h) in addition to its photocatalytic application. The wicking method has been employed to select the most hydrophilic sample of fabric upon irradiation. The micrographs obtained by scanning electron microscopy, transmission electron microscopy, and high-resolution transmission electron microscopy indicated the erosions occurring at the surface of nano-calcite after UV light irradiation, maintaining the crystallinity of the photocatalyst. The surface charge has been measured for as-fabricated and irradiated nano-calcite @ PF for the development of high negative zeta potential after UV light irradiation (-24.6 mV). The irradiated nano-calcite @ PF exhibited a significant change in its contact angle, and the wetting property was enhanced to a considerable extent on UV (55.32°) and visible light irradiation (79.00°) in comparison to as-fabricated nano-calcite @ PF (137.54°). The irradiated samples of nano-calcite @ PF delineated the redshift in harvesting of solar spectrum, as revealed by diffuse reflectance spectroscopy comparative spectra. Additionally, the band gap of untreated nano-calcite was found to be 3.5 eV, while UV- and visible light-irradiated PF showed a reduction in band gap up to 2.95 and 3.15 eV upon UV and visible light irradiation. The photocatalytic efficiency of mesoporous nano-calcite was evaluated by photocatalytic degradation of imidacloprid as the probe pollutant. Higher solar photocatalytic degradation of imidacloprid (94.15%) was attained by UV light-irradiated nano-calcite @ PF. The time-resolved photoluminescence study has verified the high photocatalytic activity of UV light-irradiated nano-calcite @ PF for the generation of high concentration of hydroxyl radicals. The highly efficient reusability of a nano-calcite-based solar photocatalytic reactor has been observed for 10 cycles of treatment of imidacloprid bearing wastewater. The enhanced photocatalytic activity of UV light-exposed (20 min), superhydrophilic, nano-calcite @ PF for mineralization of pollutants suggests it to be an efficient solar photocatalyst for environmental applications.

Behavioral and physiological response of the passerine bird Agelaioides badius to seeds coated with imidacloprid

Neonicotinoids are globally used insecticides, and there are increasing evidence on their negative effects on birds. This study is aimed at characterizing the behavioral and physiological effects of the neonicotinoid imidacloprid (IMI) in a songbird. Adults of Agelaioides badius were exposed for 7 days to non-treated peeled millet and to peeled millet treated with nominal concentrations of 75 (IMI1) and 450 (IMI2) mg IMI/kg seed. On days 2 and 6 of the trial, the behavior of each bird was evaluated for 9 min by measuring the time spent on the floor, the perch, or the feeder. Daily millet consumption, initial and final body weight, and physiological, hematological, genotoxic, and biochemical parameters at the end of exposure were also measured. Activity was greatest on the floor, followed by the perch and the feeder. On the second day, birds exposed to IMI1and IMI2 remained mostly on the perch and the feeder, respectively. On the sixth day, a transition occurred to sectors of greater activity, consistent with the disappearance of the intoxication signs: birds from IMI1 and IMI2 increased their time on the floor and the perch, respectively. Control birds always remained most of the time on the floor. IMI2 birds significantly decreased their feed intake by 31% the first 3 days, compared to the other groups, and significantly decreased their body weight at the end of the exposure. From the set of hematological, genotoxic, and biochemical parameters, treated birds exhibited an alteration of glutathione-S-transferase activity (GST) in breast muscle; the minimal effects observed are probably related to the IMI administration regime. These results highlight that the consumption of less than 10% of the bird daily diet as IMI-treated seeds trigger effects at multiple levels that can impair bird survival.

Imidacloprid exposure is detectable in over one third of wild bird samples from diverse Texas ecoregions

Avian decline is occurring globally with neonicotinoid insecticides posed as a potentially contributing factor. Birds can be exposed to neonicotinoids through coated seeds, soil, water, and insects, and experimentally exposed birds show varied adverse effects including mortality and disruption of immune, reproductive, and migration physiology. However, few studies have characterized exposure in wild bird communities over time. We hypothesized that neonicotinoid exposure would vary temporally and based on avian ecological traits. Birds were banded and blood sampled at eight non-agricultural sites across four Texas counties. Plasma from 55 species across 17 avian families was analyzed for the presence of 7 neonicotinoids using high performance liquid chromatography-tandem mass spectrometry. Imidacloprid was detected in 36 % of samples (n = 294); this included quantifiable concentrations (12 %; 10.8-36,131 pg/mL) and concentrations that were below the limit of quantification (25 %). Additionally, two birds were exposed to imidacloprid, acetamiprid (18,971.3 and 6844 pg/mL) and thiacloprid (7022.2 and 17,367 pg/mL), whereas no bird tested positive for clothianidin, dinotefuran, nitenpyram, or thiamethoxam, likely reflecting higher limits of detection for all compounds compared to imidacloprid. Birds sampled in spring and fall had higher incidences of exposure than those sampled in summer or winter. Subadult birds had higher incidences of exposure than adult birds. Among the species for which we tested more than five samples, American robin (Turdus migratorius) and red-winged blackbird (Agelaius phoeniceus) had significantly higher incidences of exposure. We found no relationships between exposure and foraging guild or avian family, suggesting birds with diverse life histories and taxonomies are at risk. Of seven birds resampled over time, six showed neonicotinoid exposure at least once with three showing exposures at multiple time points, indicating continued exposure. This study provides exposure data to inform ecological risk assessment of neonicotinoids and avian conservation efforts.

Main conclusions and perspectives from the collective scientific assessment of the effects of plant protection products on biodiversity and ecosystem services along the land-sea continuum in France and French overseas territories

Preservation of biodiversity and ecosystem services is critical for sustainable development and human well-being. However, an unprecedented erosion of biodiversity is observed and the use of plant protection products (PPP) has been identified as one of its main causes. In this context, at the request of the French Ministries responsible for the Environment, for Agriculture and for Research, a panel of 46 scientific experts ran a nearly 2-year-long (2020-2022) collective scientific assessment (CSA) of international scientific knowledge relating to the impacts of PPP on biodiversity and ecosystem services. The scope of this CSA covered the terrestrial, atmospheric, freshwater, and marine environments (with the exception of groundwater) in their continuity from the site of PPP application to the ocean, in France and French overseas territories, based on international knowledge produced on or transposable to this type of context (climate, PPP used, biodiversity present, etc.). Here, we provide a brief summary of the CSA's main conclusions, which were drawn from about 4500 international publications. Our analysis finds that PPP contaminate all environmental matrices, including biota, and cause direct and indirect ecotoxicological effects that unequivocally contribute to the decline of certain biological groups and alter certain ecosystem functions and services. Levers for action to limit PPP-driven pollution and effects on environmental compartments include local measures from plot to landscape scales and regulatory improvements. However, there are still significant gaps in knowledge regarding environmental contamination by PPPs and its effect on biodiversity and ecosystem functions and services. Perspectives and research needs are proposed to address these gaps.

Neonicotinoid exposure in Tricolored Blackbirds (Agelaius tricolor)

There is increasing awareness of the negative ecological and environmental effects of widespread use of pesticides on the landscape. Spillover or drift of pesticides from agricultural areas has been shown to impact species health, reproduction, and trophic dynamics through both direct and indirect mechanisms. Neonicotinoid insecticides are associated with observed declines of insectivorous and grassland birds, and these environmental pollutants are a significant conservation concern for many species that have experienced past or current population declines. Due to the high efficacy of these modern insecticides in depressing local insect populations, insectivorous birds can be negatively impacted by a pesticide-mediated reduction in food supply. Neonicotinoids may act synergistically with other stressors, such as habitat loss, to exacerbate threats to species or population viability. The Tricolored Blackbird is an insectivorous grassland bird of conservation concern in California, USA. Due to the high association of this species with agricultural habitats, we sought to quantify the amount of neonicotinoid residues in Tricolored Blackbird carcasses as a first step in assessing how this species may be impacted by pesticides. Out of 85 salvaged carcasses sampled (N = 24 adults, N = 3 fledglings, and N = 58 nestlings), only two contained detectable levels of target compounds. These were an adult and one nestling that contained clothianidin residue (40 ppb and 7 ppb, respectively); both of these birds were salvaged from breeding colonies associated with dairy farms in Kern County, California. We suggest that further work is needed to assess neonicotinoid exposure of Tricolored Blackbirds in dairy-associated breeding colonies.

Environmental occurrence, toxicity concerns, and biodegradation of neonicotinoid insecticides

Neonicotinoids (NEOs) are fourth generation pesticides, which emerged after organophosphates, pyrethroids, and carbamates and they are widely used in vegetables, fruits, cotton, rice, and other industrial crops to control insect pests. NEOs are considered ideal substitutes for highly toxic pesticides. Multiple studies have reported NEOs have harmful impacts on non-target biological targets, such as bees, aquatic animals, birds, and mammals. Thus, the remediation of neonicotinoid-sullied environments has gradually become a concern. Microbial degradation is a key natural method for eliminating neonicotinoid insecticides, as biodegradation is an effective, practical, and environmentally friendly strategy for the removal of pesticide residues. To date, several neonicotinoid-degrading strains have been isolated from the environment, including Stenotrophomonas maltophilia, Bacillus thuringiensis, Ensifer meliloti, Pseudomonas stutzeri, Variovorax boronicumulans, and Fusarium sp., and their degradation properties have been investigated. Furthermore, the metabolism and degradation pathways of neonicotinoids have been broadly detailed. Imidacloprid can form 6-chloronicotinic acid via the oxidative cleavage of guanidine residues, and it is then finally converted to non-toxic carbon dioxide. Acetamiprid can also be demethylated to remove cyanoimine (=N-CN) to form a less toxic intermediate metabolite. A few studies have discussed the neonicotinoid toxicity and microbial degradation in contaminated environments. This review is focused on providing an in-depth understanding of neonicotinoid toxicity, microbial degradation, catabolic pathways, and information related to the remediation process of NEOs. Future research directions are also proposed to provide a scientific basis for the risk assessment and removal of these pesticides.

High population prevalence of neonicotinoids in sharp-tailed grouse and greater prairie-chickens across an agricultural gradient during spring and fall

Neonicotinoids have been detected in many species of wild birds; however, few studies have quantified population-level exposure. We examined population-level exposure to 7 neonicotinoids in 2 species that use agricultural areas, sharp-tailed grouse (Tympanuchus phasianellus) and greater prairie-chickens (T. cupido). We sampled fecal pellets at leks in spring and collected livers from hunter-harvested birds in fall along an agricultural gradient throughout their respective ranges in Minnesota, USA. Most sharp-tailed grouse (93 %) and prairie-chicken (80 %) fecal pellets and livers (90 % and 76 %, respectively) had detectable concentrations of ≥1 neonicotinoid, with imidacloprid (IMI) and clothianidin (CLO) most commonly detected. Spring detections of IMI in both species increased with the proportion of a 2-km buffer in cultivation surrounding sampling locations and varied by year. A similar relationship with cultivation was not supported for CLO, which may reflect differences in the availability of seed types treated with IMI and CLO on the soil surface after planting. However, we also detected IMI and CLO from birds sampled in areas of low cultivation. Sharp-tailed grouse and prairie-chickens may select crop fields preferentially to forage, and thus have a higher risk of exposure than would be expected based only on the amount of cultivation. Year was important in models of IMI and CLO in both species and seasons, which likely reflects differences in planting and in the availability of natural foods among years. In contrast, the proportion of surrounding area in cultivation was not supported in models of fall neonicotinoid detections. Fewer crops are planted in the fall in Minnesota and grouse may be exposed through routes other than treated seeds. High detections, even in areas with little cultivation and during seasons with little planting, likely reflect prairie grouse selection of cultivated fields for food, but may also indicate that exposure risk extends beyond sites of application.

Biomarkers of imidacloprid toxicity in Japanese quail, Coturnix coturnix japonica

The in vivo effect of the oral sublethal doses of 3.014 mg kg^-1 of IMI (1/25 LD₅₀) for 1, 7, 14, and 28 days every other day on Japanese quail was investigated. The results revealed that certain biomarkers in the selected tissues of the quail such as acetylcholinesterase (AChE), butyrylcholinesterase (BuChE), aminotransaminases (alanine aminotransferase, ALT, and aspartate aminotransaminase, AST), phosphatases (acid phosphatase, ACP, and alkaline phosphatase, ALP), lactate dehydrogenase (LDH), adenosine-triphosphatase (ATPase), glutathione-S-transferase (GST), lipid peroxidation (LPO), and blood glucose showed significant inductions, while significant reductions in the levels of glutathione-reduced (GSH), deoxyribonucleic acid (DNA), and ribonucleic acid (RNA) were noticed. In this study, the molecular mechanisms of the toxic effects of imidacloprid on quails were elucidated regarding neurotoxicity, hepatotoxicity, oxidative stress, lipid peroxidation, antioxidant activity, and genotoxicity. Because IMI induced alterations in the levels of these biomarkers in Japanese quail; therefore, Japanese quail as a wild avian can be used as a suite bioindicator to detect imidacloprid toxicity.

Feeding on grains containing pesticide residues is detrimental to offspring development through parental effects in grey partridge

Numerous toxicological studies have shown that ingestion of pesticides can induce physiological stress in breeding birds, with adverse consequences on egg laying parameters and offspring quality through parental effects. However, previous studies do not mimic current levels of pesticide residues in typical landscapes, and they do not consider potential cocktail effects of pesticides as they occur in the wild. Herein, we explored whether realistic pesticide exposure affected reproduction parameters and offspring condition through parental effects in Grey partridge. We fed 24 breeding pairs with either seeds from conventional agriculture crops treated with various pesticides during cropping, or organic grains without pesticide residues as controls. The conventional and organic grain diets mimicked food options potentially encountered by wild birds in the field. The results showed that ingesting low pesticide doses over a long period had consequences on reproduction and offspring quality without altering mortality in parents or chicks. Compared with organic pairs, conventional pairs yielded smaller chicks at hatching that had a lower body mass index at 24 days old. Additionally, these chicks displayed lower haematocrit when body mass index was higher. Therefore, ingestion of conventional grains by parents resulted in chronic exposure to pesticide residues, even at low doses, and this had detrimental consequences on offspring. These results demonstrate a sublethal effect of pesticide residues through parental effects. The consequences of parental exposure on chicks might partly explain the decline in wild Grey partridge populations, which raises questions for avian conservation and demography if current agrosystem approaches are continued.

A Pilot Nationwide Survey on the Concentrations of Neonicotinoids and Their Metabolites in Indoor Dust from China: Application for Human Exposure

The present study assessed the residue levels of six parent neonicotinoids (p-NEOs) and four metabolites (m-NEOs) in indoor dust collected from 12 cities of China. Acetamiprid (ACE) and imidacloprid (IMI) were the predominated p-NEOs (detection rates: 98%) with the median values at 4.54 and 7.48 ng/g dry weight (dw), respectively. N-demethyl-acetamiprid (N-dm-ACE) was the most important m-NEO with the median value at 0.69 ng/g dw, while other m-NEOs were rarely detected (detection rates: < 15%). Significant correlation between ACE and thiacloprid (THD) was observed (p < 0.01), indicating their probably concurrent applications. ACE was significantly correlated to N-dm-ACE (p < 0.01), implicating the degradation of ACE in indoor environment. The estimated daily intake (EDI_ing) of NEOs via dust ingestion were far lower than the acceptable daily intake for NEOs. To our knowledge, this study provided a baseline nationwide investigation on the occurrence of NEOs in indoor dust of China.

Insights into the recent advances in nano-bioremediation of pesticides from the contaminated soil

In the present scenario, the uncontrolled and irrational use of pesticides is affecting the environment, agriculture and livelihood worldwide. The excessive application of pesticides for better production of crops and to maintain sufficient food production is leading to cause many serious environmental issues such as soil pollution, water pollution and also affecting the food chain. The efficient management of pesticide use and remediation of pesticide-contaminated soil is one of the most significant challenges to overcome. The efficiency of the current methods of biodegradation of pesticides using different microbes and enzymes depends on the various physical and chemical conditions of the soil and they have certain limitations. Hence, a novel strategy is the need of the hour to safeguard the ecosystem from the serious environmental hazard. In recent years, the application of nanomaterials has drawn attention in many areas due to their unique properties of small size and increased surface area. Nanotechnology is considered to be a promising and effective technology in various bioremediation processes and provides many significant benefits for improving the environmental technologies using nanomaterials with efficient performance. The present article focuses on and discusses the role, application and importance of nano-bioremediation of pesticides and toxic pollutants to explore the potential of nanomaterials in the bioremediation of hazardous compounds from the environment.

Pesticide impacts on avian species with special reference to farmland birds: a review

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.

Assessing availability of European plant protection product data: an example evaluating basic area treated

Besides the benefits of plant protection products (PPPs) for agricultural production, there is an increasing acknowledgement of the associated potential environmental risks. Here, we examine the feasibility of summarizing the extent of PPP usage at the country level, using Ireland as a case study, as well as at the European level. We used the area over which PPPs are applied (basic area) as an example variable that is relevant to initially assess the geographic extent of environmental risk. In Irish agricultural systems, which are primarily grass-based, herbicides fluroxypyr and glyphosate are the most widely applied active substances (ASs) in terms of basic area, followed by the fungicides chlorothalonil and prothioconazole that are closely associated with arable crops. Although all EU countries are subject to Regulation (EC) No 1185/2009, which sets the obligation of PPP usage data reporting at the national level, we only found usable data that met our criteria for Estonia, Germany, Finland, and Spain (4 of 30 countries reviewed). Overall, the most widely applied fungicide and herbicide in terms of basic area were prothioconazole (20%, 7% and 5% of national cultivated areas of Germany, Estonia and Ireland) and glyphosate (11%, 8% and 5% of national cultivated areas of Spain, Estonia and Ireland) respectively, although evaluations using application frequency may result in the observation of different trends. Several recommendations are proposed to tackle current data gaps and deficiencies in accessibility and usability of pesticide usage data across the EU in order to better inform environmental risk assessment and promote evidence-based policymaking.

Predicting the impacts of chemical pollutants on animal groups

Chemical pollution is among the fastest-growing agents of global change. Synthetic chemicals with diverse modes-of-action are being detected in the tissues of wildlife and pervade entire food webs. Although such pollutants can elicit a range of sublethal effects on individual organisms, research on how chemical pollutants affect animal groups is severely lacking. Here we synthesise research from two related, but largely segregated fields - ecotoxicology and behavioural ecology - to examine pathways by which chemical contaminants could disrupt processes that govern the emergence, self-organisation, and collective function of animal groups. Our review provides a roadmap for prioritising the study of chemical pollutants within the context of sociality and highlights important methodological advancements for future research.

A rapid evidence assessment of the potential risk to the environment presented by active ingredients in the UK's most commonly sold companion animal parasiticides

A number of parasiticides are commercially available as companion animal treatments to protect against parasite infestation and are sold in large volumes. These treatments are not intended to enter the wider environment but may be washed off or excreted by treated animals and have ecotoxic impacts. A systematic literature review was conducted to identify the existing evidence for the toxicity of the six most used parasiticides in the UK: imidacloprid, fipronil, fluralaner, afoxolaner, selamectin, and flumethrin. A total of 17,207 published articles were screened, with 690 included in the final evidence synthesis. All parasiticides displayed higher toxicity towards invertebrates than vertebrates, enabling their use as companion animal treatments. Extensive evidence exists of ecotoxicity for imidacloprid and fipronil, but this focuses on exposure via agricultural use and is not representative of environmental exposure that results from use in companion animal treatments, especially in urban greenspace. Little to no evidence exists for the ecotoxicity of the remaining parasiticides. Despite heavy usage, there is currently insufficient evidence to understand the environmental risk posed by these veterinary treatments and further studies are urgently needed to quantify the levels and characterise the routes of environmental exposure, as well as identifying any resulting environmental harm.

Tallgrass prairie wildlife exposure to spray drift from commonly used soybean insecticides in Midwestern USA

Insecticides are widely used in the Midwestern USA to combat soybean aphids (Aphis glycines), a globally important crop pest. Broad-spectrum foliar insecticides such as chlorpyrifos, lambda-cyhalothrin, and bifenthrin (hereafter, "target insecticides") are toxic to wildlife in laboratory settings; however, little information exists regarding drift and deposition of these insecticides in fragmented tallgrass prairie grasslands such as those in Minnesota, USA. To address this information gap, target insecticide spray drift and deposition were measured on passive samplers and arthropods in grasslands adjacent to crop fields in Minnesota. Samples were collected at focal soybean field sites immediately following target insecticide application and at reference corn field sites without target insecticide application. Target insecticides were detected 400 m into grasslands at both focal and reference sites. Residues of chlorpyrifos, an insecticide especially toxic to pollinators and birds, were measured above the contact lethal dose (LD50) for honey bees (Apis mellifera) up to 25 m from field edges in adjacent grasslands. Chlorpyrifos residues on arthropods were below the acute oral LD50 for several common farmland bird species but were above the level shown to impair migratory orientation in white-crowed sparrows (Zonotrichia leucophrys). Deposition of target insecticides on passive samplers was inversely associated with distance from field edge and percent canopy cover of grassland vegetation, and positively associated with samplers placed at mid-canopy compared to ground level. Target insecticide deposition on arthropods had an inverse relationship with vertical vegetation density and was positively associated with maximum height of vegetation. Tallgrass prairie with cover ≥25 m from row crop edges may provide wildlife habitat with lower exposure to foliar application insecticides. Prairie management regimes that increase percent canopy cover and density of vegetation may also reduce exposure of wildlife to these insecticides.

The ubiquity of neonicotinoid contamination: Residues in seabirds with different trophic habits

Neonicotinoids are one of the most diffusely used classes of pesticides whose level of danger toward non-target invertebrate and vertebrate species has raised increasing concern in the last decades. Among vertebrates, birds are particularly susceptible to unintentional neonicotinoid poisoning since they can be exposed through different pathways, including ingestion of dressed seeds, sucking of contaminated pollen, ingestion of sprayed insects, predation on contaminated aquatic and terrestrial preys. In the present study, we investigated the possible exposure of seabirds by measuring the residues of five neonicotinoids (acetamiprid, clothianidin, imidacloprid, thiacloprid and thiamethoxam) in samples of pooled feathers collected from fledglings of the strictly piscivorous Sandwich tern (Thalasseus sandvicensis) and the mixotrophic species Mediterranean gull (Ichthyaetus melanocephalus). At least one neonicotinoid was quantified in all the Mediterranean gull samples (n = 11) and 89% of the analysed Sandwich tern samples (n = 36). The active principles with the highest quantification rates were imidacloprid (100% in Mediterranean gulls and 58% in Sandwich terns) and clothianidin (100% in Mediterranean gulls and 61% in Sandwich terns), while thiacloprid was the less frequently detected pesticide (<20% of samples in both species). Mean concentrations ± standard error for imidacloprid, clothianidin and thiamethoxam were 8.8 ± 1.4, 4.5 ± 0.19 and 0.16 ± 0.02 ng g^-1 for the Mediterranean gull, and 5.8 ± 0.55, 0.60 ± 0.08 and 0.36 ± 0.03 ng g^-1for the Sandwich tern, respectively. Our data evidenced the exposure of seabirds to neonicotinoids and the further need to investigate the extent of neonicotinoid contamination in non-agricultural ecosystems.

Twenty-four hours of Thiamethoxam: In vivo and molecular dynamics simulation study on the toxicokinetic and underlying mechanisms in quails (Coturnix japonica)

Neonicotinoids is the most widely used insecticide, its contamination has led to sustained bird population declines. However, the toxicokinetic and underlying mechanisms of neonicotinoid toxicity in birds are largely unknown. Thiamethoxam (TMX), as a representative neonicotinoid insecticide, is now widely detected in most environmental medium and animal bodies. In this study, 5 mg/kg body weight TMX (potential environmental intake level) were orally administrated to male Japanese quails (Coturnix japonica). We found a rapid absorption, distribution, metabolism and elimination of TMX in quails in a period of 24 h, with the main metabolite, clothianidin (CLO), being extensively distributed and rapidly eliminated from tissues as well. The maximum plasm concentration of CLO was consistent with wild birds. Metabolomics analysis and followed determination of liver enzymes mRNA expression indicated the rapid metabolism was mediated mainly by CYPs and GSTs that involved riboflavin metabolism and glutathione metabolism pathways upon TMX exposure. Molecular dynamic simulation showed the strongest binding interaction in quail CYP2H1-TMX and CYP3A12-CLO complexes among a set of CYPs-substrate. The present study elucidated toxicokinetic and underlying metabolic mechanisms of TMX in quails at environmentally-relevant concentration, the findings would facilitate the understanding of potential risks of TMX and its metabolites to birds.

Detection of imidacloprid and metabolites in Northern Leopard frog (Rana pipiens) brains

Neonicotinoids are a new type of highly water-soluble insecticide used in agricultural practices to eliminate pests. Neonicotinoids bind almost irreversibly to postsynaptic nicotinic acetylcholine receptors in the central nervous system of invertebrates, resulting in overstimulation, paralysis, and death. Imidacloprid, the most commonly used neonicotinoid, is often transported to nearby wetlands through subsurface tile drains and has been identified as a neurotoxin in several aquatic non-target organisms. The aim of the present study was to determine if imidacloprid could cross the blood-brain barrier in adult Northern Leopard frogs (Rana pipiens) following exposure to 0, 0.1, 1, 5, or 10 μg/L for 21 days. Additionally, we quantified the breakdown product of imidacloprid, imidacloprid-olefin, and conducted feeding trials to better understand how imidacloprid affects foraging behavior over time. Exposure groups had 12 to 313 times more imidacloprid in the brain relative to the control and breakdown products showed a dose-response relationship. Moreover, imidacloprid brain concentrations were approximately 14 times higher in the 10 μg/L treatment compared to the water exposure concentration, indicating imidacloprid can bioaccumulate in the amphibian brain. Reaction times to a food stimulus were 1.5 to 3.2 times slower among treatment groups compared to the control. Furthermore, there was a positive relationship between mean response time and log-transformed imidacloprid brain concentration. These results indicate imidacloprid can successfully cross the blood-brain barrier and bioaccumulate in adult amphibians. Our results also provide insights into the relationship between imidacloprid brain concentration and subsequent altered foraging behavior.

Nitroreduction of imidacloprid by the actinomycete Gordonia alkanivorans and the stability and acute toxicity of the nitroso metabolite

The insecticide imidacloprid (IMI), which is used worldwide, pollutes environments and has significant ecotoxicological effects. Microbial metabolism and photolysis are the major pathways of IMI degradation in natural environments. Several studies have reported that the metabolites of IMI nitroreduction are more toxic to some insects and mammals than IMI itself. Thus, environmental degradation of IMI may enhance the ecotoxicity of IMI and have adverse effects on non-target organisms. Here, we report that an actinomycete-Gordonia alkanivorans CGMCC 21704-transforms IMI to a nitroreduction metabolite, nitroso IMI. Resting cells of G. alkanivorans at OD_{600 nm} = 10 transformed 95.7% of 200 mg L^-1 IMI to nitroso IMI in 4 d. Nitroso IMI was stable at pH 4-9. However, it rapidly degraded under sunlight via multiple oxidation, dehalogenation, and oxidative cleavage reactions to form 10 derivatives; the half-life of nitroso IMI in photolysis was 0.41 h, compared with 6.19 h for IMI. Acute toxicity studies showed that the half maximal effective concentration (EC₅₀) values of IMI, nitroso IMI, and its photolytic metabolites toward the planktonic crustacean Daphnia magna for immobilization (exposed to the test compounds for 48 h) were 17.70, 9.38, 8.44 mg L^-1, respectively. The half-life of nitroso IMI in various soils was also examined. The present study reveals that microbial nitroreduction accelerates IMI degradation and the nitroso IMI is easily decomposed by sunlight and in soil. However, nitroso IMI and its photolytic products have higher toxicity toward D. magna than the parent compound IMI, and therefore increase the ecotoxicity of IMI.

Evaluation of ELISA for the analysis of imidacloprid in biological matrices: Cross-reactivities, matrix interferences, and comparison to LC-MS/MS

Imidacloprid is among the most used pesticides worldwide and there are toxicity concerns for nontarget organisms. Accurate and sensitive methods are necessary to quantitate imidacloprid concentrations in biological matrices to better understand their fate and effects. Here we evaluated an enzyme-linked immunosorbent assay (ELISA) kit for the analysis of imidacloprid in biological samples. Following the dosing of Japanese quail (Coturnix japonica) with imidacloprid-treated wheat seeds, plasma, liver, and fecal matter samples were analyzed by ELISA and compared to previous analyses that employed liquid chromatography-tandem mass spectrometry (LC-MS/MS). Imidacloprid metabolites-5-OH-imidacloprid, imidacloprid-olefin, imidacloprid-urea, desnitro-imidacloprid, and 6-chloronicotinic acid-were tested for their cross-reactivity to antibodies within the commercial imidacloprid ELISA kit. The two major metabolites, 5-OH-imidacloprid and imidacloprid-olefin, showed cross-reactivities of 0.93-26 %. ELISA and LC-MS/MS results were positively correlated but there was poor agreement in concentrations: plasma and fecal matter imidacloprid concentrations were higher by ELISA, whereas liver imidacloprid concentrations were higher by LC-MS/MS. Matrix interferences observed in analyses were minimized by the application of matrix-matched calibration curves. ELISA provided an effective screening tool for imidacloprid in these biological matrices, but the presence of cross-reactants confounded results. Confirmation of ELISA results by more selective techniques (e.g., LC-MS/MS) is suggested for complex samples.

Species Traits Drive Long-Term Population Trends of Common Breeding Birds in Northern Italy

Long-term population trends are considerable sources of information to set wildlife conservation priorities and to evaluate the performance of management actions. In addition, trends observed in functional groups (e.g., trophic guilds) can provide the foundation to test specific hypotheses about the drivers of the observed population dynamics. The aims of this study were to assess population trends of breeding birds in Lombardy (N Italy) from 1992 to 2019 and to explore the relationships between trends and species sharing similar ecological and life history traits. Trends were quantified and tested for significance by weighted linear regression models and using yearly population indices (median and 95% confidence interval) predicted through generalized additive models. Results showed that 45% of the species increased, 24% decreased, and 31% showed non-significant trends. Life history traits analyses revealed a general decrease of migrants, of species with short incubation period and of species with high annual fecundity. Ecological traits analyses showed that plant-eaters and species feeding on invertebrates, farmland birds, and ground-nesters declined, while woodland birds increased. Further studies should focus on investigation of the relationship between long-term trends and species traits at large spatial scales, and on quantifying the effects of specific drivers across multiple functional groups.

Using Transcriptomics and Metabolomics to Understand Species Differences in Sensitivity to Chlorpyrifos in Japanese Quail and Double-Crested Cormorant Embryos

Modern 21st-century toxicity testing makes use of omics technologies to address critical questions in toxicology and chemical management. Of interest are questions relating to chemical mechanisms of toxicity, differences in species sensitivity, and translation of molecular effects to observable apical endpoints. Our study addressed these questions by comparing apical outcomes and multiple omics responses in early-life stage exposure studies with Japanese quail (Coturnix japonica) and double-crested cormorant (Phalacrocorax auritus), representing a model and ecological species, respectively. Specifically, we investigated the dose-dependent response of apical outcomes as well as transcriptomics and metabolomics in the liver of each species exposed to chlorpyrifos, a widely used organophosphate pesticide. Our results revealed a clear pattern of dose-dependent disruption of gene expression and metabolic profiles in Japanese quail but not double-crested cormorant at similar chlorpyrifos exposure concentrations. The difference in sensitivity between species was likely due to higher metabolic transformation of chlorpyrifos in Japanese quail compared to double-crested cormorant. The most impacted biological pathways after chlorpyrifos exposure in Japanese quail included hepatic metabolism, oxidative stress, endocrine disruption (steroid and nonsteroid hormones), and metabolic disease (lipid and fatty acid metabolism). Importantly, we show consistent responses across biological scales, suggesting that significant disruption at the level of gene expression and metabolite profiles leads to observable apical responses at the organism level. Our study demonstrates the utility of evaluating effects at multiple biological levels of organization to understand how modern toxicity testing relates to outcomes of regulatory relevance, while also highlighting important, yet poorly understood, species differences in sensitivity to chemical exposure. Environ Toxicol Chem 2021;40:3019-3033. © 2021 SETAC.

Assessing pesticides exposure effects on the reproductive performance of a declining aerial insectivore

In the context of increasing global environmental changes, it has become progressively important to understand the effects of human activity on wildlife populations. Declines in several avian populations have been observed since the 1970s, especially with respect to many farmland and grassland birds, which also include some aerial insectivores. Changes in farming practices referred to as agricultural intensification coincide with these major avian declines. Among those practices, increased pesticide use is hypothesized to be a key driver of avian population declines as it can lead to both toxicological and trophic effects. While numerous laboratory studies report that birds experience acute and chronic effects upon consuming pesticide treated food, little is known about the effects of the exposure to multiple pesticides on wildlife in natural settings. We monitored the breeding activities of Tree Swallows (Tachycineta bicolor) on 40 farms distributed over a gradient of agricultural intensification in southern Québec, Canada, to evaluate the presence of pesticides in their diet and quantify the exposure effects of those compounds on their reproductive performance between 2013 and 2018. We first assessed the presence of 54 active agents (or derivatives) found in pesticides in 2,081 food boluses (insects) delivered to nestlings by parents and documented their spatial distribution within our study area. Second, we assessed the effect of pesticide exposure through food (number of active agents detected and number of contaminated boluses on a given farm for a given year, while controlling for sampling effort) on clutch size as well as hatching and fledging successes and nestling's mass upon fledging. Pesticides were ubiquitous in our study system and nearly half (46%) of food boluses were contaminated by at least one active agent. Yet we found no relationship between our proxies of food contamination by pesticides and Tree Swallow reproductive performance. More studies are needed to better understand the putative role of pesticides in the decline of farmland birds and aerial insectivores as potential sublethal effects of pesticides can carry over to later life stages and impact fitness.

Chlorpyrifos in environment and food: a critical review of detection methods and degradation pathways

Chlorpyrifos (CP) is a class of organophosphorus (OP) pesticides, which find extensive applications as acaricide, insecticide and termiticide. The use of CP has been indicated in environmental contamination and disturbance in the biogeochemical cycles. CP has been reported to be neurotoxic and has a detrimental effect on immunological and psychological health. Therefore, it is necessary to design and develop effective degradation methods for the removal of CP from the environment. In the past few years, physicochemical (advanced oxidation process) and biological treatment approaches have been widely employed for the pesticide removal. However, the byproducts of this process are more toxic than the parent compound and along with an incomplete degradation of CP. This review focuses on the toxicity of CP, the sources of contamination, degradation pathways, physicochemical, biological, and nano-technology based methods employed for the degradation of CP. In addition, consolidated information on various detection methods and materials used for the detection have been provided in this review.

Early life neonicotinoid exposure results in proximal benefits and ultimate carryover effects

Neonicotinoids are insecticides widely used as seed treatments that appear to have multiple negative effects on birds at a diversity of biological scales. Adult birds exposed to a low dose of imidacloprid, one of the most commonly used neonicotinoids, presented reduced fat stores, delayed migration and potentially altered orientation. However, little is known on the effect of imidacloprid on birds growth rate despite studies that have documented disruptive effects of low imidacloprid doses on thyroid gland communication. We performed a \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$2 \times 2$$\end{document}2×2 factorial design experiment in Zebra finches, in which nestling birds were exposed to a very low dose (0.205 mg kg body \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\hbox {mass}^{-1}$$\end{document}mass-1) of imidacloprid combined with food restriction during posthatch development. During the early developmental period, imidacloprid exposure resulted in an improvement of body condition index in treated nestlings relative to controls. Imidacloprid also led to compensatory growth in food restricted nestlings. This early life neonicotinoid exposure also carried over to adult age, with exposed birds showing higher lean mass and basal metabolic rate than controls at ages of 90–800 days. This study presents the first evidence that very low-dose neonicotinoid exposure during early life can permanently alter adult phenotype in birds.

Removal of chlorpyrifos and its hydrolytic metabolite in microcosm-scale constructed wetlands under soda saline-alkaline condition: Mass balance and intensification strategies

Chlorpyrifos (CP) is a typical organophosphorus insecticide, which poses serious threats to the natural environment and human health. Strategies for the fast elimination of CP and its toxic hydrolytic metabolite 3,5,6-trichloro-2(1H)-pyridianol (TCP) in drainage water are urgently needed. The fate of CP and TCP in microcosm-scale subsurface batch constructed wetlands (SSBCWs) was quantified with different macrophyte species under soda saline-alkaline (SSA) condition and effective intensification strategies were developed. The macrophyte species Canna indica outperformed Phragmites australis and Typha orientalis for CP and TCP removal in SSBCWs. Mass balance calculation indicates the fate of CP in SSBCWs was residue in water (≤8%), alkaline hydrolysis (18.93-57.42%), microbial degradation (37.75-61.91%), substrate adsorption (~4-14%), and macrophyte uptake (≤3%). The addition of ferric-carbon (Fe-C) as a substrate amendment in SSBCWs increased the CP removal percentage by 35% and reduced the effluent TCP concentration by ~70% during Day 1-4 on average compared with the unintensified control. Fe-C addition simplified the microbial community diversity, while increasing the relative abundance of Proteobacteria which tolerates the microelectrolytic environment. A single application of liquid microbial agent improved CP removal percentage by 84% and decreased the effluent TCP concentration by two orders of magnitude during Day 1-4. The hydraulic retention time for thorough removal of TCP reduced from over 8 d to 4 d. Although only two dominant microbial genera (i.e., Sphingomonas and Pseudomonas) adapted to the environment with CP and SSA, they accelerated CP and TCP degradation via their own metabolism and co-metabolism with other indigenous microorganisms.

Agrochemical pesticide production, trade, and hazard: Narrowing the information gap in Colombia

Pesticides are a major tool for the intensification of agriculture, and helped to increase food, feed and biofuel production. Yet, there are persistent concerns about the negative effects of pesticides in human health and the environment, particularly in low and middle income countries (LMICs). Given the lack of information on pesticide exposure and hazard, Colombia exemplifies the need to narrow the information gap on pesticide risk in LMICs. We assessed pesticide hazard in Colombia based on the official toxicity categorization, compared it to more integral international standards, and identified main actions to narrow this information gap. Results showed that Colombia has been a relevant regional actor in pesticide production and trade, reaching almost 75 million kilogrammes and liters sold in 2016. Based on acute toxicity for humans, a quarter of the amount of pesticides sales and imports, and a third of the exports in 2016 ranged from moderately to extremenly toxic. The top-selling agrochemicals in 2016 (glyphosate with 14% of the total sales, chlorpyrifos 7.5% and mancozeb 6.9%) are also commonly used in other countries, reflecting a homogenized global industry. Compared to integral international categorizations, we found that for that year 63% of the pesticides sold with slightly acute toxicity are actually considered highly hazardous pesticides (HHP) for humans or the environment, evidencing the need to use a more integral hazard categorization in the country. Narrowing the information gap in pesticide use and associated risks demands a transparent process of knowledge creation and sharing, including funtional information and monitoring systems. This should be part of an integral assessment and regulation that better defines HHP, their production and trade to reduce pesticide risk while informing a transition towards sustainable food systems.

Investigating Acute and Subchronic Effects of Neonicotinoids on Northwestern Salamander Larvae

This research investigated the adverse effects of neonicotinoids on the Northwestern salamander (Ambystoma gracile; NWS) after acute and subchronic exposures during early aquatic life stages via whole organism (i.e., growth, development) and molecular (i.e., gene expression) level endpoints. In a 96-h exposure, NWS larvae were exposed to four imidacloprid concentrations (250, 750, 2250, 6750 µg/L) and a water control treatment, and no effects on survival, body weight, snout-vent length (SVL), and total body length were observed. However, a significant 1.70- and 2.33-fold decrease in thyroid receptor β (TRβ) mRNA expression levels were detected in the larvae exposed to 750 and 2250 µg/L imidacloprid, respectively, compared with the larvae in the water control. In subsequent subchronic experiments, NWS larvae were exposed for 35 days to imidacloprid alone and an equal part mixture of neonicotinoids (imidacloprid, clothianidin, and thiamethoxam (ICT)) at three concentrations (10, 100 and 1000 µg total neonicotinoids/L) and a water control. In these experiments, there were no effects on larval survival, body weight, SVL, and total body length. However, advanced development of larvae in the 100 µg/L imidacloprid treatment was observed compared with the control after 35-day imidacloprid exposure, providing some evidence of disruption of the thyroid endocrine axis at an environmentally relevant concentration. Ultimately, there is a paucity of studies conducted examining the sensitivity of salamanders to pollutants; thus, this study reports novel findings that will contribute to understanding the sensitivity of a Caudate amphibian model to a common environmental pollutant.

A real-world implementation of a nationwide, long-term monitoring program to assess the impact of agrochemicals and agricultural practices on biodiversity

Biodiversity has undergone a major decline throughout recent decades, particularly in farmland. Agricultural practices are recognized to be an important pressure on farmland biodiversity, and pesticides are suspected to be one of the main causes of this decline in biodiversity. As part of the national plan for reduction of pesticides use (Ecophyto), the French ministry of agriculture launched the 500 ENI (nonintended effects) monitoring program in 2012 in order to assess the unintended effects of agricultural practices, including pesticide use, on biodiversity represented by several taxonomic groups of interest for farmers. This long-term program monitors the biodiversity of nontargeted species (earthworms, plants, coleoptera, and birds), together with a wide range of annual data on agricultural practices (crop rotation, soil tillage, weed control, fertilizers, chemical treatments, etc.). Other parameters (e.g., landscape and climatic characteristics) are also integrated as covariates during the analyses. This monitoring program is expected to improve our understanding of the relative contribution of the different drivers of population and community trends. Here, we present the experience of setting up the 500 ENI network for this ambitious and highly complex monitoring program, as well as the type of data it collects. The issue of data quality control and some first results are discussed. With the aim of being useful to readers who would like to set up similar monitoring schemes, we also address some questions that have arisen following the first five years of the implementation phase of the program.

Agricultural pesticides and ectoparasites: potential combined effects on the physiology of a declining aerial insectivore

Agricultural pesticides usage has been increasing globally. These compounds have been developed to disrupt pest species physiology, but because their specificity is limited, they can also have adverse effects on non-target organisms. Recent studies have shown that the damaging toxicological effects of pesticides can be amplified in stressful environments. However, few studies have documented these effects in natural settings where organisms are simultaneously exposed to pesticides and to other environmental stressors such as parasites. In this study, we assessed both pesticide and ectoparasite effects on the physiology of a free-ranging bird. We measured physiological markers including haematocrit, bacteria-killing ability (BKA) and leucocyte counts, as well as exposure to haematophagous Protocalliphora larvae, in tree swallow nestlings (Tachycineta bicolor), a declining aerial insectivore, in southern Québec, Canada, for over 3 years. We found that combined exposure to pesticides and Protocalliphora larvae was negatively related to haematocrit, suggesting possible synergistic effects. However, we found no such relationships with BKA and leucocyte counts, highlighting the complexity of physiological responses to multiple stressors in natural settings. Populations of several aerial insectivores are declining, and although sublethal pesticide effects on physiology are suspected, our results suggest that exposure to other factors, such as parasitism, should also be considered to fully assess these effects, especially because pesticides are increasingly present in the environment.