Search

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]

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]

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]

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]

Lufenuron, a benzoylurea chitin synthesis inhibitor, is effective against many insect pests. However, the insecticidal activity of lufenuron has not been completely elucidated, nor has its disturbing effect on chitin synthesis genes. In this study, bioassay results demonstrated an outstanding toxicity of lufenuron against Helicoverpa armigera larvae. The treated larvae died from abortive molting and metamorphosis defects, and severe separation of epidermis and subcutaneous tissues was observed. Treatment of 3rd- and 4th-instar larvae with LC 25 lufenuron significantly extended the duration of larval and pupal stage, reduced the rates of pupation and emergence, and adversely affected pupal weight. Besides, lufenuron can severely reduce chitin content in larval integument, and the lufenuron-treated larvae showed reduced trehalose content in their hemolymph. Further analysis using RNA sequencing revealed that five chitin synthesis genes were down-regulated, whereas the expressions of two chitin degradation genes were significantly enhanced. Knockdown of chitin synthase 1 (HaCHS1), uridine diphosphate- N -acetylglucosamine-pyrophosphorylase (HaUAP), phosphoacetyl glucosamine mutase (HaPGM), and glucosamine 6-phosphate N -acetyl-transferase (HaGNPAT) in H. armigera led to significant increase in larval susceptibilities to LC 25 lufenuron by 75.48%, 65.00%, 68.42% and 28.00%, respectively. Our findings therefore revealed the adverse effects of sublethal doses of lufenuron on the development of H. armigera larvae, elucidated the perturbations on chitin metabolism, and proved that the combination of RNAi and lufenuron would improve the control effect of this pest. [Display omitted] • Lufenuron caused adverse impacts on larval development in H. armigera. • Lufenuron treatment caused perturbations on chitin biosynthetic pathways. • Lufenuron reduced chitin in larval integument and trehalose in hemolymph. • RNAi of CHS1 , UAP , PGM , or GNPAT increased the susceptibilities to lufenuron. [ABSTRACT FROM AUTHOR]

As an agricultural pest, the fall armyworm (FAW), Spodoptera frugiperda , poses a severe threat to agriculture in China. Chlorantraniliprole has been widely used to control this pest. In our previous studies, we discovered that LD 10 , LD 20 , and LD 30 chlorantraniliprole promoted encapsulation in the 4th instar larvae of the FAW, with LD 30 chlorantraniliprole having the most significant effect. To further investigate the molecular mechanism underlying the sublethal effects of chlorantraniliprole on encapsulation in the FAW, this study conducted the effects of encapsulation in 4th instar larvae of the FAW exposed to LD 30 chlorantraniliprole. Then, we analyzed the transcriptome of the FAW hemolymph treated with LD 30 chlorantraniliprole and identified genes related to encapsulation using RNAi. Our results showed that the encapsulation in the FAW was enhanced at 6, 12, 18, 24, and 48 h after exposure to LD 30 chlorantraniliprole. Additionally, LD 30 chlorantraniliprole significantly affected the expression of certain immune-related genes, with the heat shock protein 70 family gene SfHSP68.1 showing the most significant upregulation. Subsequent interference with SfHSP68.1 resulted in a significant inhibition of encapsulation in FAW. These findings suggested that LD 30 chlorantraniliprole can promote encapsulation in the FAW by upregulating SfHSP68.1 expression. This study provides valuable insights into the sublethal effects of chlorantraniliprole on encapsulation in the FAW and the interaction between encapsulation and heat shock proteins (HSPs). [Display omitted] • LD 30 chlorantraniliprole promoted the encapsulation in the FAW. • Expression of some related immune genes was induced by LD 30 chlorantraniliprole. • The SfHSP68.1 was the most significantly up-regulatied by LD 30 chlorantraniliprole. • Interfering with SfHSP68.1 reduced encapsulation in the FAW. • Provides valuable evidence for interaction between the encapsulation and HSPs. [ABSTRACT FROM AUTHOR]

The fall armyworm (FAW), Spodoptera frugiperda (J.E. Smith) (Lepidoptera, Noctuidae), is a highly polyphagous invasive pest that damages various crops. Pesticide control is the most common and effective strategy to control FAW. In this study, we evaluated the toxicity of metaflumizone and indoxacarb against third-instar FAW larvae using the insecticide-incorporated artificial diet method under laboratory conditions. Both metaflumizone and indoxacarb exhibited substantial toxicity against FAW, with LC 50 values of 2.43 and 14.66 mg/L at 72 h, respectively. The sublethal effects of metaflumizone and indoxacarb on parental and F1 generation FAW were investigated by exposing third-instar larvae to LC 10 and LC 30 concentrations of these insecticides. Sublethal exposure to these two insecticides significantly shortened adult longevity, extended pupal developmental times and led to reduced pupal weight, pupation rates, and adult fecundity in the treated parental generation and F1 generation at LC 10 or LC 30 concentrations, in comparison to the control group. The larval developmental times were shortened in the parental generation but prolonged in the F1 generation, after being treated with sublethal concentrations of metaflumizone. Furthermore, larvae exposed to LC 10 or LC 30 concentrations of indoxacarb exhibited elevated activity levels of cytochrome P450 monooxygenase and glutathione S-transferase, which coincides with the observed synergistic effect of piperonyl butoxide and diethyl maleate. In conclusion, the high toxicity and negative impact of metaflumizone and indoxacarb on FAW provided significant implications for the rational utilization of insecticides against this pest. [Display omitted] • LC 10 and LC 30 of Met and Ind reduced reproductive parameters of parental FAW. • Sublethal concentrations of Met and Ind affect transgenerational FAW on biological parameters. • LC 10 and LC 30 of Met and Ind potentially affect P450 and GST activities. • CarE activity was slightly affected by LC 10 and LC 30 of Met and Ind. [ABSTRACT FROM AUTHOR]

• The two prevalent citrus coccinellid species engage in intricate Intraguild interactions. • IGI patterns vary influenced by factors such as prey density and quality. • The dynamic nature of IGI may explain changes on their relative dominance. • The dynamic nature of IGI prompts a seasonal niche partitioning. • This phenomenon would contribute to the coexistence of the two coccinellid species. Scymnus interruptus and Scymnus subvillosus (Coleoptera: Coccinellidae) are the most frequent aphid predators in Western Mediterranean citrus agroecosystems. Intraguild predation (IGP) between them would be expected, but how IGP might affect their coexistence and biological control function remains unknown. In this work, we assess the frequency of predator encounters in the field and investigate intraguild predation between these two predators in laboratory settings. Different field prey scenarios derived from the field observations were simulated with the two dominant aphid species in this agroecosystem, Aphis gossypii and Aphis spiraecola. Scymnus subvillosus and S. interruptus engaged in IGP but the magnitude and symmetry varied with the prey species and abundance. At high aphid densities, IGP was symmetric and weak, whereas, at low aphid densities, IGP was strong and very asymmetric, with S. interruptus taking the role of the intraguild predator. The developmental time of S. subvillosus was reduced when competing with S. interruptus at high extraguild prey densities. The adult size of both predators under weak IGP also increased even when the developmental time had been reduced. We predict that high aphid infestations in the spring would benefit S. subvillosus, while the strong and asymmetric IGP at low aphid infestations would hinder its coexistence with S. interruptus. Our results give a theoretical explanation to what is observed in the field: S. subvillosus is typically dominant during the high aphid infestations of the spring, whereas S. interruptus increases in relative dominance during the summer and fall when aphid abundance is much less. [ABSTRACT FROM AUTHOR]

Abstract Populations of stingless bees have declined around the world and pesticides have been indicated as one of the possible causes of this decrease. Spinosad, which is synthesized from the fermentation process produced by the soil actinomycete Saccharopolyspora spinosa , is one of the most used bioinsecticides today. This study aimed to evaluate the possible effects of spinosad (formulation) on survival, general group activity and the processes of autophagy, apoptosis and oxidative stress in two organs (midgut and brain) of workers of Partamona helleri , after 24 h of oral exposure. Workers were orally exposed to different concentrations of spinosad. The concentration (8.16 × 10−3 mg a.i./mL) that led to the mortality of approximately half the number of treated bees was considered LC 50 and was used in behavior, histology and immunofluorescence bioassays. The results revealed that bee survival was substantially reduced with increasing spinosad concentrations. The LC 50 of the bioinsecticide compromised general group activity, caused morphological alterations in the midgut and intensified the processes of autophagy, apoptosis and oxidative stress in this organ. The brain, on the other hand, did not present significant alterations under the tested conditions. The data obtained demonstrate, therefore, that spinosad negatively affects individual survival, general group activity and the midgut epithelium of P. helleri. Highlights • The toxic effect of the bioinsecticide spinosad were investigated on Partamona helleri. • The sublethal effects of spinosad included changes in survival and behavior. • Spinosad also lead to morphological changes in the midgut after acute oral exposition. • Spinosad enhances autophagy, apoptosis and oxidative stress in the midgut. [ABSTRACT FROM AUTHOR]

Abstract Neonicotinoids are the most widely used insecticides in the world. They are preferentially toxic to insects while displaying a low toxicity toward vertebrates, and this selective toxicity has resulted in the rapid and ubiquitous use of these compounds. However, neonicotinoids have been detected in agricultural surface waters and are known to cause adverse effects in non-target aquatic organisms. A wide range of toxicity has been reported for aquatic crustaceans, but most of the studies focus on the acute effects of imidacloprid, and few data are available regarding chronic effects of other neonicotinoids or neonicotinoid replacements (e.g., butenolides). The objective of this study was to assess the acute and chronic toxicity of six neonicotinoids (imidacloprid, thiamethoxam, acetamiprid, clothianidin, thiacloprid, and dinotefuran) and one butenolide (flupyradifurone) to the freshwater amphipod Hyalella azteca. Chronic (28-d), water-only, static-renewal tests were conducted. Survival was assessed weekly, and growth was measured at the end of the exposure. Effects of neonicotinoids varied depending on the compound. Acute (7-d) LC50s were 4.0, 4.7, 60, 68, 230, and 290 μg/L for clothianidin, acetamiprid, dinotefuran, thiacloprid, imidacloprid, and thiamethoxam, respectively. Chronic (28-d) survival and growth were reduced at similar concentrations to acute (7-d) survival for thiamethoxam, acetamiprid, clothianidin, and dinotefuran. However, chronic survival and growth of amphipods exposed to imidacloprid and thiacloprid were reduced at lower concentrations than acute survival, with respective 28-d LC50s of 90 and 44 μg/L, and EC50s of 4 and 3 μg/L. Flupyradifurone was intermediate in toxicity compared to the neonicotinoids: 7-d LC50, 28-d LC50, and 28-d EC50 were 26, 20, and 16 μg/L, respectively. The concentrations of imidacloprid and clothianidin reported for North American surface waters fall within the effect ranges observed in this study, indicating the potential for these compounds to cause adverse effects to indigenous populations of H. azteca. Highlights • Toxicity of neonicotinoid and butenolide insecticides was assessed in Hyalella. • Range in toxicity among compounds and endpoints was 100-fold. • Clothianidin and acetamiprid had the lowest 7-d and 28-d LC50s. • Acetamiprid, clothianidin, thiacloprid, and imidacloprid had the lowest 28-d EC50s. • Flupyradifurone was intermediate in toxicity compared to neonicotinoids. [ABSTRACT FROM AUTHOR]

Abstract The final fate of many drugs is release into the natural aquatic environment. It is necessary to assess the toxicity caused by this situation and the associated concerns for human beings. Zebrafish (Danio rerio) is a common biomodel used to assess toxicity in aquatic environments. The zebrafish embryo toxicity test was selected to evaluate the acute toxicity of several drugs (diphenhydramine, gentamicin, tobramycin, enalapril and lidocaine) due to the lack of such information. Lethal and sublethal effects were detected, and the LC 50 values of the drugs ranged from 11.0 mg/L to 422·102 mg/L. For all of the drugs tested, these values were higher than the concentrations found in the natural environment. Therefore, there was a low environmental toxicological risk. Nevertheless, teratogenic effects were also recorded when embryos of zebrafish were exposed to caffeine (control drug), diphenhydramine and lidocaine at lower concentrations than the respective LC 50 values. Quantitative structure–activity relationship analysis was also performed to analyse these drugs and other chemicals with pharmaceutical uses as well as previous toxicological data in this vertebrate after 48 h of exposure. It is estimated that the partition coefficient, log P, is the main physicochemical property related to the ecotoxicological data and can be used for the development of a mathematical model. Highlights • The FET was selected to evaluate the acute toxicity of several drugs. • Results indicate a low environmental risk (LC 50 > environmental concentration). • The QSAR revealed that Log P is the property that best fits the data. • QSAR analysis improves the correlation when lethal activity is using for classifying. • For Cramer classification, class I chemical group showed the best correlation. [ABSTRACT FROM AUTHOR]

In addition to the acute lethal toxicity, insecticides might affect population dynamics of insect pests by inducing life history trait changes under low concentrations, however, the underlying mechanisms remain not well understood. Here we examined systemic impacts on development and reproduction caused by low concentration exposures to cyantraniliprole in the fall armyworm (FAW), Spodoptera frugiperda, and the putative underlying mechanisms were investigated. The results showed that exposure of third-instar larvae to LC 10 and LC 30 of cyantraniliprole significantly extended larvae duration by 1.46 and 5.41 days, respectively. Treatment with LC 30 of cyantraniliprole significantly decreased the pupae weight and pupation rate as well as the longevity, fecundity and egg hatchability of female adults. Consistently, we found that exposure of FAW to LC 30 cyantraniliprole downregulated the mRNA expression of four ecdysteroid biosynthesis genes including SfNobo , SfShd , SfSpo and SfDib and one ecdysone response gene SfE75 in the larvae as well as the gene encoding vitellogenin (SfVg) in the female adults. We also found that treatment with LC 30 of cyantraniliprole significantly decreased the whole body levels of glucose, trehalose, glycogen and triglyceride in the larvae. Our results indicate that low concentration of cyantraniliprole inhibited FAW development by disruption of ecdysteroid biosynthesis as well as carbohydrate and lipid metabolism, which have applied implications for the control of FAW. [Display omitted] • Low concentrations of cyantraniliprole negatively affected the fitness of S. frugiperda. • LC 30 cyantraniliprole downregulated the mRNA expression of ecdysteroid biosynthesis genes. • LC 30 cyantraniliprole treatment led to disruption of carbohydrate and lipid metabolism. [ABSTRACT FROM AUTHOR]

Abstract Engineered nanomaterials (ENMs) may be functionalised with a surface coating to enhance their properties, but the ecotoxicity of the coatings and how hazard changes with ageing in soil is poorly understood. This study determined the toxic effect of CuO ENMs with different chemical coatings on the earthworm (Eisenia fetida) in fresh soil, and then after one year in aged soil. In both experiments, earthworms were exposed for 14 days to the CuO materials at nominal concentrations of 200 and 1000 mg Cu kg−1 dry weight and compared to CuSO 4. In the fresh soil experiment, CuO-COOH was found to be the most acutely toxic of the nanomaterials (survival, 20 ± 50%), with tenfold increase of total Cu in the earthworms compared to controls. Sodium pump activity was reduced in most CuO ENM treatments, although not in the CuSO 4 control. There was no evidence of glutathione depletion or the induction of superoxide dismutase (SOD) activity in any treatment. Histology showed a mild hypoplasia of mucous cells in the epidermis with some nanomaterials. In the aged soil, the CuO-NH 4 + was the most acutely toxic ENM (survival 45 ± 3%) and Cu accumulation was lower in the earthworms than in the fresh soil study. Depletion of tissue Mn and Zn concentrations were seen in earthworms in aged soil, while no significant effects on sodium pump or total glutathione were observed. Overall, the study showed some coating-dependent differences in ENM toxicity to earthworms which also changed after a year of ageing the soil. Highlights • Earthworms exposed to CuO ENMs of different surface coatings in fresh or aged soil. • Reduced survival, Cu accumulation and osmotic disturbances observed in fresh soil. • Tissue Mn and Zn depletion, but not sodium pump inhibition, observed in aged soils. • No oxidative stress or inflammation pathology in either fresh or aged soil. • Toxicity ranking depended both on the type of coating and soil ageing. [ABSTRACT FROM AUTHOR]

The seven-spotted ladybird beetle, Coccinella septempunctata L., as a dominant predator of aphids, has played a crucial role in integrated pest management (IPM) strategies in agricultural ecosystems. To study the risk of insecticides to C. septempunctata , the neonicotinoid clothianidin was selected for evaluation of its influence on C. septempunctata at lethal and sublethal doses. The LR 50 (application rate causing 50% mortality) in the exposed larvae decreased from 19.94 to 5.91 g a.i. ha −1 , and the daily HQ (hazard quotient) values increased from 3.00 to 10.15, indicating potential intoxication risks. We also determined NOERs (No Observed Effect application Rates) of clothianidin on the total developmental time (10 g a.i. ha −1 ), survival (2.5 g a.i. ha −1 ) and pupation (5 g a.i. ha −1 ). Moreover, clothianidin at a NOER of 2.5 g a.i. ha −1 did not profoundly affect adult emergence, fecundity or egg hatchability. The total effect (E) assessment also showed that clothianidin at 2.5 g a.i. ha −1 was slightly harmful to C. septempunctata . These results suggested that clothianidin would impair C. septempunctata when applied at over 2.5 g a.i. ha −1 in the field. Conservation of this biological control agent in agricultural ecosystems thus requires further measures to decrease the applied dosages of clothianidin. [ABSTRACT FROM AUTHOR]

Mercury (Hg) is a toxic element which has increased in marine environments for more than a century, due largely to anthropogenic activities, and biomagnifies in food chains to harmful levels in some top predators like waterfowl and seabirds. We analysed total mercury (THg) concentrations in blood, brain and muscle tissue from healthy specimens of 13 coastal and pelagic bird species from eastern and northern Canada to provide a baseline on current concentrations, especially for brain concentrations which are highly underrepresented in the literature. We also examined within and among tissues relationships of THg concentrations within individuals. THg concentrations were generally higher in pelagic species and scavenging gulls, when compared to coastal waterfowl. Brain and muscle tissue had similar concentrations of THg in the birds examined, but both of these tissues had lower concentrations that those found in blood. Our results, and that of a previous study, suggest that body condition has a large influence on blood THg concentrations and should be considered when using blood as a sampling medium. Many of the species we examined had tissue THg above levels known to cause deleterious, sublethal effects in some species. [ABSTRACT FROM AUTHOR]

Bacillus thuringiensis var. israelensis (Bti) is presumed to be an environmental friendly agent for the use in either health-related mosquito control or the reduction of nuisance associated with mosquitoes from seasonal wetlands. Amphibians inhabiting these valuable wetlands may be exposed to Bti products several times during their breeding season. Up until now, information regarding effects on the non-targeted group of amphibians has to be considered rather inconsistent. On this account, we evaluated how three repeated exposures to frequently used Bti formulations (VectoBac ® 12AS, VectoBac ® WG) in field-relevant rates affect European common frog ( Rana temporaria ) larvae. In a laboratory approach, we assessed potential effects with regard to enzymatic biomarkers (glutathione-S-transferase (GST), glutathione reductase (GR), acetylcholine esterase (AChE)), development, body condition and survival until the end of metamorphosis. Although survival and time to metamorphosis were not significantly affected, larval development tended to be shortened in the Bti treated water phase. Furthermore, exposure to Bti induced significant increases of GST (37–550%), GR (5–140%) and AChE (38–137%) irrespectively of the applied formulation, indicating detoxification, antioxidant responses as well as an alteration of neuronal activity. GST activity increased twice as much after two repeatedly executed Bti applications within a time period of 6 days. The examination of several biochemical markers is needed to fully evaluate the ecotoxicological risk of Bti for amphibian populations, especially in the context of worldwide amphibian declines. Nevertheless, following the precautionary principle, it may be advisable to implement certain thresholds for application numbers and intervals in order to ensure environmentally friendly mosquito control programs, especially in areas designated for nature conservation. [ABSTRACT FROM AUTHOR]

The fall armyworm, Spodoptera frugiperda , is a notorious polyphagous pest that causes serious economic losses in crucial crops and has invaded Africa and Asia. Lufenuron is widely used for controlling S. frugiperda in China, owing to its high toxicity against this key pest, and less pollution and little impact on natural enemies. In the present study, the sublethal and transgenerational effects of lufenuron on S. frugiperda were investigated to provide in-depth information for the rational use of lufenuron. Results showed that the development time and pupae weight were not significantly affected following exposure of females to LC 10 and LC 25 and male S. frugiperda to the LC 10 of lufenuron. However, LC 25 exposure significantly reduced pupal and total development time and pupae weight of male S. frugiperda. The longevity of S. frugiperda adults was prolonged by lufenuron and the fecundity of S. frugiperda treated with LC 10 of lufenuron was significantly increased by 40% compared to the control. In addition, our study demonstrated that the LC 25 of lufenuron had transgenerational effects on the progeny generation. The development time of female S. frugiperda whose parents were exposed to LC 25 of lufenuron was significantly decreased compared to the control. And then, the expression profiles of Vg , VgR , JHEH , JHE , JHAMT , JHBP , CYP307A1 , CYP306A1 , CYP302A1 and CYP314A1 genes involved in insect reproduction and development were analyzed using Quantitative Real-Time PCR (RT-qPCR). Results showed that Vg , VgR , JHE , JHAMT, and CYP306A1 were significantly upregulated at the LC 10 of lufenuron, which revealed that these upregulated genes might be linked with increased fecundity of S. frugiperda. Taken together, these findings highlighted the importance of sublethal and transgenerational effects under laboratory conditions and these effects may change the population dynamics in the field. Therefore, our study provided valuable information for promoting the rational use of lufenuron for controlling S. frugiperda. [Display omitted] • Sublethal effects of lufenuron on S. frugiperda (F0 and F1) were detected. • The longevity of S. frugiperda adults were prolonged by LC 10 and LC 25. • Lufenuron (LC 10) significantly improved the fecundity of F0 S. frugiperda. • The development time of female offspring (F1) was shortening by lufenuron (LC 25). • Lufenuron (LC 10) increased the expressions of 5 reproductive related genes of F0. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the sublethal effects of thiacloprid on microRNA (miRNA) expression in honeybees (Apis mellifera L.) and the role of a specific miRNA, ame-miR-283–5p, in thiacloprid resistance. The high-throughput small RNA-sequencing was used to analyze global miRNA expression profile changes in honeybees orally exposed to sublethal concentrations of thiacloprid (20 mg/L and 4 mg/L) for 72 h. Thiacloprid at 20 mg/L had no observed adverse effects. In addition, bees were fed with miRNA mimics or inhibitors to increase or decrease ame-miR-283–5p expression, and its effects on P450 gene expression (CYP9Q2 and CYP9Q3) were examined. Thiacloprid susceptibility was also detected. The results showed that treatment with thiacloprid at 20 mg/L and 4 mg/L induced 11 and five differentially expressed miRNAs (DEMs), respectively. Bioinformatic analysis suggested that the DEMs are mainly involved in the regulation of growth and development, metabolism, nerve conduction, and behavior. ame-miR-283–5p was downregulated by both concentrations, which was validated using quantitative real-time reverse transcription PCR analysis. Enhancing ame-miR-283–5p expression significantly inhibited CYP9Q2 mRNA and protein expression, and increased thiacloprid toxicity, while reducing ame-miR-283–5p expression significantly promoted CYP9Q2 expression, and decreased thiacloprid susceptibility. Our study revealed a novel role of miRNAs in insecticide resistance in honeybees. [Display omitted] • Thiacloprid exposure significantly affects microRNA expression in honeybees. • Differentially expressed miRNAs are involved in, e.g. , development and behavior. • ame-miR-283–5p negatively regulates CYP9Q2 expression. • Modulating ame-miR-283–5p expression alters thiacloprid susceptibility. [ABSTRACT FROM AUTHOR]

Prolonged exposure to a disturbance such as a toxicant has the potential to result in rapid evolution to toxicant resistance in many short-lived species such as daphniids. This evolution may allow a population to persist at higher levels of the toxicant than is possible without evolution. Here we apply evolutionary game theory to a Leslie matrix model for a daphniid population to obtain a Darwinian model that couples population dynamics with the dynamics of an evolving trait. We use the Darwinian model to consider how the evolution of resistance to the lethal or sublethal effects of a disturbance may change the population dynamics. In particular, we determine the conditions under which a daphniid population can persist by evolving toxicant resistance. We then consider the implications of this evolution in terms of the use of daphniids as surrogate species. We show for three species of daphniids that evolution of toxicant resistance means that one species may persist while another does not. These results suggest that toxicant studies that do not consider the potential of a species (or its surrogate) to develop toxicant resistance may not accurately predict the long term persistence of the species. [ABSTRACT FROM AUTHOR]

The mirid bug, Apolygus lucorum (Meyer-Dür) has evolved the resistance towards some traditional insecticides, especially pyrethroids and organophosphates. Sulfoxaflor, as a novel insecticide, is used for control of sap-feeding insects, like A. lucorum . Therefore, it is necessary to determine the acute toxicity and the potential sublethal effects of sulfoxaflor in A. lucorum . Here, the LD 50 value of sulfoxaflor against A. lucorum was assayed as 3.347 ng/adult at 48 h via topical application. Besides, the effects of a sublethal dose (LD 15 ) of sulfoxaflor on biological characteristics of A. lucorum were estimated by comparison of the life table parameters. The longevities and fecundity of parent generation did not exhibited significant difference between both control and treatment groups after exposure to LD 15 dose of sulfoxaflor (0.568 ng/adult) for 48-h. However, the parameters reflecting their progeny G1 generation population dynamics, including the intrinsic rate of increase ( ri ), the finite rate of increase ( λ ), the mean generation time ( T ), the net reproductive rate ( R 0 ) and gross reproduction rate (GRR) significantly reduced in the treatment group compared to the control. Furthermore, the expression level of AlVg mRNA significantly decreased by 43.8% in the progeny whose parents were treated with LD 15 dose of sulfoxaflor in comparison with the control transgenerational female adults. These results suggested that sublethal dose of sulfoxaflor adversely affect the development and reproduction of transgenerational A. lucorum . The downregulation of AlVg might have negative impacts on the fecundity of A. lucorum . [ABSTRACT FROM AUTHOR]

Despite the frequent detection of organic ultraviolet-filters (UV-filters) in freshwater sediments, there is a lack of ecotoxicological data undermining a correct risk assessment for these emerging contaminants. The present study assessed the effects of three of the most commonly used UV-filters (benzophenone-3 – BP3; 3-(4-methylbenzylidene)camphor – 4-MBC and octocrylene – OC) on Chironomus riparius life history and biochemical responses. Standard ecotoxicological assays confirmed that all compounds impaired growth of C. riparius larvae and induced developmental effects such as delayed emergence and a reduction of imagoes weight. Concerning the biochemical responses analysed no evidences of oxidative damage in lipids or neurotoxicity (tested assessing acetylcholinesterase activity) were observed for any of the tested compounds. However, 4-MBC exposure induced a decrease in catalase activity and an increase in glutathione- S -transferase activity at 14.13 mg/Kg while OC exposure caused an increase in total glutathione levels at 0.23 and 18.23 mg/Kg. Exposure to all UV-filters tested, increased energy consumption on C. riparius with significant differences above 1.00 mg/Kg for BP3, 0.09 mg/Kg for 4-MBC and 2.13 mg/Kg for OC. These results suggest that environmental relevant concentrations of UV-filters can cause deleterious effects to aquatic benthic species, such as C. riparius, and call for further research concerning effects of organic UV-filters on natural invertebrate communities and ecosystem functioning. [ABSTRACT FROM AUTHOR]

[Display omitted] • Sublethal effects on larval development and movement differed between insecticides. • All insecticides tested synergised Beauveria bassiana but to different degrees. • ß-cyfluthrin was most effective synergist, strongly increasing mortality/conidiogenesis. • Imidacloprid had strong sub-lethal effects, but induced weak synergism. • Spinosad had limited effect on movement and induced moderate synergism. Topical applications of insecticides β-cyfluthrin, imidacloprid, and spinosad in combination with Beauveria bassiana (topical and contact filter paper application) induced synergistic interactions in lesser mealworm larvae, increasing mortality and in some cases numbers of larval cadavers exhibiting conidiogenesis. Reduced concentrations (LC 10 , LC 20 , LC 30) of the insecticides induced sublethal effects in lesser mealworm larvae, inhibiting development (mass, head-capsule width, moulting) after eight days' exposure and movement behaviour (area explored and distance travelled) after 3 h' exposure. The most potent synergist was ß-cyfluthrin, it strongly inhibited larval development and movement while significantly increasing mortality and conidiogenesis in B. bassiana -infected larvae. Imidacloprid also strongly inhibited larval development and movement, but only produced weak short-lived synergistic increases in mortality, with no increase in conidiogenesis. Spinosad induced no effect on development and limited effect on movement, but still induced moderate short-lived synergistic increases in mortality and conidiogenesis. Intoxicated larvae exposed to B. bassiana on filter paper for 3 h showed no synergistic interactions, except when intoxicated by spinosad. [ABSTRACT FROM AUTHOR]

Evaluating the sublethal effects of insecticide is crucial for protecting and utilizing natural enemies. In this study, we determined the sublethal effects of acetamiprid and afidopyropen on Harmonia axyridis (Pallas) and explored the potential molecular mechanisms underlying these effects through transcriptomics analysis. The results showed that sublethal concentrations of acetamiprid significantly reduced the adult fecundity and longevity of F 0 H. axyridis and decreased the survival time and survival rate of the F 1 generation. Sublethal concentrations of afidopyropen prolonged the developmental time of 4th instar larvae in the F 0 generation. Additionally, acetamiprid and afidopyropen treatments significantly decreased the predation of H. axyridis. Furthermore, transcriptome sequencing analysis revealed that several P450 and UGT genes expressed differently when H. axyridis were exposed to sublethal concentrations of acetamiprid and afidopyropen, suggesting that the differential expression of detoxifying genes might be involved in the response and detoxification metabolism of acetamiprid and afidopyropen in H. axyridis. Our findings demonstrate that sublethal concentrations of acetamiprid adversely influences the development and predation of H. axyridis , while afidopyropen has limited effects on H. axyridis. These results are helpful for protecting and utilizing natural enemies and guiding the scientific use of pesticides in the field. [Display omitted] • Acetamiprid has great adverse effects on the development and predation of H. axyridis. • Acetamiprid and afidopyropen treatment reduced the predatory capacity of H. axyridis. • P450 and UGTs contribute to the response of H. axyridis to acetamiprid and afidopyropen. [ABSTRACT FROM AUTHOR]

The stimulation of biological processes by sublethal doses of insecticides or other stressors is known as hormesis. Here, we have evaluated whether exposure to field-relevant or low concentrations of neonicotinoids induce changes in the reproductive capacity of the bulb mite Rhizoglyphus robini (Acari: Acaridae). Among the tested neonicotinoids imidacloprid, thiamethoxam, and dinotefuran, the highest hormetic effect on the reproduction of R. robini occurred 24 h after the 48 h exposure period to imidacloprid at concentrations of 70 and 140 mg a.i./L. Despite the stimulating effects of imidacloprid on mite reproduction, no significant differences were observed in the offspring (F 1) for biological aspects including egg hatch rate, embryonic period and sex ratio, while an increase was found in the duration of development time from egg to adult. Evaluation of the detoxification enzyme activities of treated adults showed that the highest activity of carboxyl/cholinesterases, cytochrome P450s, and glutathione S-transferases was obtained when exposed to 70, 140 and 70 mg a.i./L imidacloprid, immediately after the exposure period, respectively. Also, an increase in the activity of the antioxidant enzyme catalase was observed compared to that of the control. After imidacloprid pretreatment (140 mg a.i./L), the tolerance of adult mites to diazinon was increased about two-fold. This study shows that exposure to imidacloprid can induce hormetic effects on R. robini and could severely complicate its control due to a higher reproduction, enhanced detoxification enzyme activities, and increased tolerance against other pesticides. [Display omitted] • Exposure to imidacloprid, thiamethoxam, and dinotefuran, affected the fecundity in R. robini. • The highest fecundity in R. robini females was observed in matings where only the female was treated with imidacloprid. • Imidacloprid treatment increased the activity of detoxifying enzymes in females of R. robini. • Diazinon toxicity was seriously affected after exposure to a hormetic dose of imidacloprid. [ABSTRACT FROM AUTHOR]

It is well known that sublethal dose of insecticides induces life history trait changes of both target and non-target insect species, however, the underlying mechanisms remain not well understood. In this study, the effects of low concentrations of the anthranilic diamide insecticide chlorantraniliprole on the development and reproduction of the fall armyworm (FAW), Spodoptera frugiperda , were evaluated, and the underlying mechanisms were explored. The results showed that exposure of FAW to LC 10 and LC 30 chlorantraniliprole prolonged the larvae duration, decreased the mean weight of the larvae and pupae, and lowered the pupation rate as well as emergence rate. The fecundity of female adults was also negatively affected by treatment with low concentrations of chlorantraniliprole. Consistently, we found that exposure of FAW to LC 30 chlorantraniliprole downregulated the mRNA expression of juvenile hormone (JH) esterase (SfJHE), leading to the increase of JH titer in larvae. We also found that treatment with low concentrations of chlorantraniliprole suppressed the expression of ribosomal protein S6 kinase1 (SfS6K1) in female adults, resulting in the downregulation of the gene encoding vitellogenin (SfVg). These results provided insights into the mechanisms underlying the effects of low concentrations of insecticides on insect pests, and had applied implications for the control of FAW. [Display omitted] • LC 10 and LC 30 chlorantraniliprole negatively affected the fitness of S. frugiperda. • LC 30 chlorantraniliprole increased the juvenile hormone titer in the larvae. • The mRNA level of SfJHE was downregulated after exposure to LC 30 chlorantraniliprole. • Low concentrations of chlorantraniliprole downregulated SfS6K1 and SfVg. [ABSTRACT FROM AUTHOR]

Animals living in aquatic habitats regularly encounter anthropogenic chemical pollution. Typically, the toxicity of a chemical toxicant is determined by the median lethal concentration (LC 50 ) through a static exposure test. However, LC 50 values and static tests do not provide an accurate representation of exposure to pollutants within natural stream systems. In their native habitats, animals experience exposure as a fluctuating concentration due to turbulent mixing, temporal variations of contamination (seasonal inputs), and contaminant input type (point vs. non-point). Research has shown that turbulent environments produce exposures with a high degree of fluctuation in frequency, duration, and intensity. In order to more effectively evaluate the effects of pollutants, we created a dynamic exposure paradigm, utilizing both flow and substrate within a small mesocosm. A commonly used pharmaceutical, naproxen, was used as the toxicant and female crayfish ( Orconectes virilis ) as the target organism to investigate changes in fighting behavior as a result of dynamic exposure. Crayfish underwent either a 23 h long static or a dynamic exposure to naproxen. Following exposure, the target crayfish and an unexposed size matched opponent underwent a 15 min fight trial. These fight trials were recorded and later analyzed using a standard ethogram. Results indicate that exposure to sublethal concentrations of naproxen, in both static and flowing conditions, negatively impact aggressive behavior. Results also indicate that a dynamic exposure paradigm has a greater negative impact on behavior than a static exposure. Turbulence and habitat structure play important roles in shaping chemical exposure. Future research should incorporate features of dynamic chemical exposure in order to form a more comprehensive image of chemical exposure and predict the resulting sublethal effects from exposure. Possible techniques for assessment include utilizing flow-through experimental set-ups in tandem with behavioral or physiological endpoints as opposed to acute toxicity. Other possibilities of assessment could involve utilizing fine-scale chemical measurements of pollutants to determine the actual concentrations animals encounter during an exposure event. [ABSTRACT FROM AUTHOR]

The toxic effects of older classes of pesticides on natural enemies are typically acute and exposure usually occurs through direct contact with foliar residues. However, older chemistries are being replaced by newer classes of pesticides that can cause sublethal effects in addition to direct mortality. We developed a set of life table response protocols to quantify the effects of multiple routes of exposure to pesticides on individual-level life history parameters of predators and parasitoids. We then integrated the data into population-level endpoint estimates of population growth rates using stage-structured population models. For this study, we evaluated the impacts of five insecticides (cyantraniliprole, chlorantraniliprole, spinetoram, novaluron and lambda-cyhalothrin) and two fungicides (sulfur and a mixture of copper hydroxide and mancozeb) on a generalist insect predator Chrysoperla carnea (Stephens) (Neuroptera: Chrysopidae) and an aphid parasitoid Trioxys pallidus (Haliday) (Hymenoptera: Braconidae). Green lacewings and T . pallidus are key members of the natural enemy community in western USA orchards. The results of these laboratory studies demonstrate that both C . carnea and T . pallidus were negatively affected by cyantraniliprole, spinetoram and lambda-cyhalothrin while only one species was affected by chlorantraniliprole and novaluron ( C . carnea ) or sulfur ( T . pallidus ). The benefits of integrating acute, chronic, and sublethal effects from laboratory bioassays to assess the selectivity of pesticides with respect to natural enemies are discussed. [ABSTRACT FROM AUTHOR]

The evaluation of pesticide side-effects on honeybees is hampered by a lack of colony-level bioassays that not only are sensitive to physiological changes, but also allow predictions about the consequences of exposure for longer-term colony productivity and survival. Here we measured 28 biometrical, biochemical and behavioural indicators in a field study with 63 colonies and 3 apiaries. Colonies were stressed in early summer by feeding them for five days with either the carbamate growth regulator fenoxycarb or the neurotoxic neonicotinoid imidacloprid, or left untreated. Candidate stress indicators were measured 8–64 days later. We determined which of the indicators were influenced by the treatments, and which could be used as predictors in regression analyses of overwintering strength. Among the indicators influenced by fenoxycarb were the amount of brood in colonies as well as the learning performance and 24 h-memory of bees, and the concentration of the brood food component 10HDA in head extracts. Imidacloprid significantly affected honey production, total number of bees and activity of the immune-related enzyme phenoloxidase in forager bee extracts. Indicators predictive of overwintering strength but unrelated to insecticide feeding included vitellogenin titer and glucose oxidase-activity in haemolymph/whole body-extracts of hive bees. Apart from variables that were themselves components of colony strength (numbers of bees/brood cells), the only indicator that was both influenced by an insecticide and predictive of overwintering strength was the concentration of 10HDA in worker bee heads. Our results show that physiological and biochemical bioassays can be used to study effects of insecticides at the colony level and assess the vitality of bee colonies. At the same time, most bioassays evaluated here appear of limited use for predicting pesticide effects on colony overwintering strength, because those that were sensitive to the insecticides were not identical with those that were predictive of colony overwintering. Our study therefore illustrates the difficulties involved in evaluating the economic/ecological significance of pesticide-induced stress in honey bee field studies. [ABSTRACT FROM AUTHOR]

The two-spotted spider mite Tetranychus urticae is a serious pest of many agricultural crops and ornamental plants. The sublethal effects of a new chemical, spinetoram, on T. urticae were investigated by treating adult females and eggs with LC 10 and LC 20 in the laboratory. The data were assessed based on age-stage, two-sex life table analysis. The results showed that T. urticae developmental time from egg to adult was reduced and that fecundity was increased by treatment with LC 10 and LC 20 of spinetoram. The LC 10 and LC 20 of spinetoram also increased the intrinsic and finite rate of increase and the net reproductive rate and reduced the mean generation time, egg duration, and larval duration whether eggs or adult females were treated. These laboratory results suggest that sublethal or lethal doses of spinetoram may cause outbreaks of T. urticae . [ABSTRACT FROM AUTHOR]

Acute toxicity and genotoxicity of the 54.8% 2,4-D-based commercial herbicide DMA® were assayed on Cnesterodon decemmaculatus (Pisces, Poeciliidae). Whereas lethal effect was used as the end point for mortality, frequency of micronuclei (MNs), other nuclear abnormalities and primary DNA damage evaluated by the single cell gel electrophoresis (SCGE) assay were employed as end points for genotoxicity. Mortality studies demonstrated an LC 50 96 h value of 1008 mg/L (range, 929–1070) of 2,4-D. Behavioral changes, e.g., gathering at the bottom of the aquarium, slowness in motion, slow reaction and abnormal swimming were observed. Exposure to 2,4-D within the 252–756 mg/L range increased the frequency of MNs in fish exposed for both 48 and 96 h. Whereas blebbed nuclei were induced in treatments lasting for 48 and 96 h, notched nuclei were only induced in fish exposed for 96 h. Regardless of both concentration and exposure time, 2,4-D did not induce lobed nuclei and binucleated erythrocytes. In addition, we found that exposure to 2,4-D within the 252–756 mg/L range increased the genetic damage index in treatments lasting for either 48 and 96 h. The results represent the first experimental evidence of the lethal and several sublethal effects, including behavioral alterations and two genotoxic properties namely the induction of MNs and primary DNA strand breaks, exerted by 2,4-D on an endemic organism as C. decemmaculatus . [ABSTRACT FROM AUTHOR]

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. LC 50 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 (LC 10 = 1.50 mg/L and LC 25 = 3.00 mg/L for C. kiiensis ; LC 10 = 0.25 mg/L and LC 25 = 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. [Display omitted] • Sublethal effects of chlorantraniliprole were investigated in two chironomids. • Chironomus javanus was more susceptible to chlorantraniliprole than C. kiiensis. • Sublethal chlorantraniliprole exposure prolonged the life cycle of two chironomids. • Chlorantraniliprole inhibited pupation and emergence and decreased the egg number. • Enzyme activity and gene expression were inhibited by chlorantraniliprole. [ABSTRACT FROM AUTHOR]

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 (LC 30) 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 LC 30 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 LC 30 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. [Display omitted] • Developed a simulated field spray bioassay method against neonate larvae of C. pomonella. • Exposure of neonate larvae to sublethal concentrations of insecticides has negative effects on key life history traits and reproduction. • The sublethal effects were found in transgenerational offspring, including reduced weight and fecundity, extended generation time, and shortened oviposition period. • Transgenerational maternal effects were more obvious for abamectin than lambda-cyhalothrin. [ABSTRACT FROM AUTHOR]

Several crops of agronomic interest depend on bees' pollination, and Apis mellifera L (Hymanoptera: Apidae) is the most studied direct pollinator. Nevertheless, the use of pesticides in agricultural environments is common, including fungicides. Studies that seek to evaluate the effects of fungicides on the hypopharyngeal glands of bees, the site of royal jelly synthesis, are lacking. Thus, this work aimed to evaluate the effect of field doses of fungicides (Captan SC® and Zignal®), alone or in mixture, on the hypopharyngeal glands and their subsequent effect on the strength of hives. The evaluations were carried out under field conditions in three hives per treatment. For a period of one month, bee hives received feed containing sugar syrup, pollen and 1.2 mL of Zignal® and 3 mL of Captan SC® in the isolated treatments and 4.2 mL in the mixture. The action of fungicides on the hypopharyngeal glands was determined by transmission electron microscopy analysis in bees 7 and 15 days old, collected in the hives one month after exposure to fungicides. The strength of the hives was evaluated for six months based on the number of frames with adult bees, open and closed brood, and stored food. The results indicate that fungicides promote early degeneration of the rough endoplasmic reticulum and morphological and structural changes in mitochondria. In addition, a reduction in adult population, open and closed breeding and food stock was observed. More pronounced damage occurred when bees were exposed to the mixture of fungicides. Overall, it can be concluded that the presence of fungicides in bee diets promotes harm accentuated over time and compromises the survival of hives. It will be worth estimating the fungicide effects of the queen development and on the colony heath. • Fungicides promote ultrastructural changes in the honey-bee glands. • Degeneration of the rough endoplasmic reticulum in bees caused by fungicides. • Fungicides mixture increase damage in bees. • Long term chronic effects of fungicides on bees. [ABSTRACT FROM AUTHOR]

We recently discovered infections by a microsporidium closely related to Nosema fumiferanae in field populations of the light brown apple moth, Epiphyas postvittana (Walker) (Lepidoptera: Tortricidae), in the San Francisco region of California. E. postvittana originates from Australia and was first detected in California in 2006; therefore, our aim was to identify and determine the origin of the Nosema isolate. We characterized the pathogenicity, transmission pathways, and ultrastructure of this new Nosema isolate. In addition, we sequenced fragments of commonly used genetic markers (ITS, SSU, and RPB1), and examined the phylogenetic relationships between the Nosema isolate and other microsporidian species commonly found in lepidopteran hosts. The pathogenicity of the Nosema isolate was investigated by infecting second instar larvae of E. postvittana . Larval and pupal survivorship were reduced by 7% and 13% respectively, and pupation occurred 1–2 d later in infected individuals than in healthy individuals. Emerging infected females died 5 d earlier than healthy females, and daily fecundity was 22% lower. Hatch rate also was 22% lower for eggs oviposited by infected females. Vertical transmission was confirmed; spores were present in 68% of egg masses and 100% of the surviving larvae from infected females. Ultrastructure images, together with sequences from selected genetic markers, confirmed the Nosema isolate to be a member of the Nosema fumiferanae species complex ( Nosema fumiferanae postvittana subsp. n.). The association of this pathogen with E. postvittana contributes further to the biotic resistance that E. postvittana has experienced since its introduction to California. [ABSTRACT FROM AUTHOR]

A battery of biomarkers was evaluated on Ruditapes philippinarum exposed during 14 days to caffeine, ibuprofen, carbamazepine and novobiocin (0.1, 1, 5, 10, 15, and 50 µg L −1 ). The battery included general stress (lysosomal membrane stability – LMS) analysed in the hemolymph, and biochemical biomarkers analysed in digestive gland tissues including: biomarkers of phase I (etoxyresorufin O-deethylase – EROD, dibenzylfluorescein dealkylase – DBF), phase II (gluthathione-S-transferase – GST), oxidative stress (gluthathione reductase – GR, gluthathione peroxidase – GPX, lipid peroxidation – LPO), neurotoxicity (acetylcholinesterase activity – AChE), and genotoxicity (DNA damage). Pharmaceuticals tested induced the sublethal responses (even at the environmental range 0.1 µg L −1 ). At this low concentration; caffeine, ibuprofen and carbamazepine decreased the LMS significantly compared with controls ( p <0.05). The four compounds induced significantly the detoxification metabolism and oxidative stress ( p <0.05). Neurotoxicity was noticed in clams exposed to caffeine and carbamazepine ( p <0.05). Ibuprofen, carbamazepine and novobiocin produced genotoxic effects ( p <0.05). Results from this research validate the use of biomarkers when assessing the effects of pharmaceuticals within a marine environmental risk assessment framework, using as a laboratory bioassay model the species R. philippinarum. [ABSTRACT FROM AUTHOR]

The effect of the fungicide tebuconazole (0.41, 0.52, 0.71 and 1.14 mg/L) on survival, reproduction and growth of Daphnia magna organisms was monitored using 14 and 21 days exposure tests. A third experiment was performed by exposing D. magna to the fungicide for 14 days followed by 7 days of recovery (14+7). In order to test fungicide effects on D. magna , parameters as survival, mean whole body length, mean total number of neonates per female, mean number of broods per female, mean brood size per female, time to first brood/reproduction and intrinsic rate of natural increase ( r ) were used. Reproduction was seriously affected by tebuconazole. All tebuconazole concentrations tested affected the number of broods per female and day to first brood. At 14-days test, number of neonates per female and body size decreased by concentrations of tebuconazole higher than 0.52 mg/L, whereas at 21-days test both parameters were affected at all the concentrations tested. Survival of the daphnids after 14 days fungicide exposure did not exhibited differences among experimental and control groups. In this experiment r value was reduced (in a 22%) when animals were exposed to concentrations of 0.71 mg/L and 1.14 mg/L. Survival of daphnids exposed during 21 days to 1.14 mg/L declined, and the intrinsic rate of natural increase ( r ) decreased in a 30 % for tebuconazole concentrations higher than 0.41 mg/L. Longevity of daphnids pre-exposed to tebuconazole for 14 days and 7 days in clean water did not show differences from control values and all of them survived the 21 days of the test. However, after 7 days in fungicide free medium animals were unable to restore control values for reproductive parameters and length. The maximum acceptable toxicant concentration (MATC) was calculated using the r values as parameter of evaluation. MATC estimations were 0.61 mg/L and 0.46 mg/L for 14 and 21 days, respectively. Results showed that the number of neonates per female was the highest sensitive parameter to the effects of tebuconazole on D. magna . On the other hand, a recovery period of 7 days in a free toxicant medium would not be longer enough to reestablish normal reproduction parameters in pre-exposed tebuconazole daphnids. [ABSTRACT FROM AUTHOR]

The effects of exposure to a novel synthetic organophosphorus compound, 2-(4-Methoxyphenyl)-5, 6-trimethylene-4H-1, 3, 2-oxathiaphosphorine-2-sulfide (OMTOS) concentrations (Control=0, C 1=0.01, C 2=0.1, C 3=1 and C 4=10 μg/L) were investigated in the clam Ruditapes decussatus . Vitellogenin (Vg)-like protein levels in haemolymph from males and females were investigated. Concentrations of 1 μg/L and 10 μg/L significantly decreased Vg levels in male haemolymph after 7 days, whereas significant variations were only found in females treated with 10 μg/L. On the other hand, superoxide dismutase (SOD), catalase (CAT) and acetylcholinesterase activities (AChE) in whole soft tissue were measured after 2, 4 and 7 days of exposure to the same series of concentrations. After 2 days of exposure, 0.1, 1, and 10 μg/L of OMTOS increased SOD activity significantly, but this decreased with 10 μg/L after 4 and 7 days. No changes in CAT activity were observed after 2 days compared to controls. OMTOS significantly reduced AChE activity after 4 and 7 days in treated clams with the highest concentration 10 μg/L, but it did not induce significant variations at the other concentrations tested. Our study demonstrates that OMTOS alters biochemical parameters in R. decussatus , even at low concentrations, and suggests differing modes of action of the contaminant. Using clams is a powerful tool to provide valuable insights into possible mechanisms of environmental toxicity of novel synthetic organic products both in non-target organisms and the marine ecosystem. Additionally, our results highlight that biomarker responses facilitate elucidation of putative mechanisms of action of OMTOS in non-target species. [ABSTRACT FROM AUTHOR]

Acute lethal and sublethal toxicity of the imidazolinone imazethapyr (IMZT)-based commercial formulation herbicide Pivot H® (10.59% IMZT) was evaluated on Hypsiboas pulchellus tadpoles. Whereas mortality was used as the end point for lethality, frequency of micronuclei (MNs) and other nuclear abnormalities as well as DNA single-strand breaks evaluated by the single cell gel electrophoresis assay were employed to test genotoxicity. Behavioral, growth, developmental, and morphological abnormalities were also employed as sublethal end points. Mortality studies revealed equivalent LC 50 (96 h) values of 1.49 mg/L (confidence limit, 1.09–1.63) and 1.55 mg/L (confidence limit, 1.51–1.60) IMZT for Gosner stage (GS) 25 and GS36, respectively. Behavioral changes, i.e., irregular swimming and immobility, as well as a decreased frequency of keratodonts were observed. The herbicide increased the frequency of MNs in circulating erythrocytes of tadpoles exposed for 48 h to the highest concentration assayed (1.17 mg/L). However, regardless of the concentration of the herbicide assayed, an enhanced frequency of MNs was observed in tadpoles exposed for 96 h. The herbicide was able to induce other nuclear abnormalities, i.e., blebbed and notched nuclei, only when tadpoles were exposed for 96 h. In addition, we observed that exposure to IMZT within the 0.39–1.17 mg/L range increased the genetic damage index in treatments lasting for both 48 and 96 h. This study represents the first evidence of acute lethal and sublethal effects exerted by IMZT on amphibians. Finally, our findings highlight the properties of this herbicide that jeopardize nontarget living species exposed to IMZT. [ABSTRACT FROM AUTHOR]

[Display omitted] • Literature on essential oils (EOs) as effective insecticides and acaricides is steadily growing. • The non-target impact of EOs include lethal and sublethal effects. • We analyzed literature on EO toxicity towards biocontrol agents, pollinators, and soil invertebrates. • The modes of action leading to EO toxicity on non-target species are scarcely studied. • In the final section, a research agenda outlining major challenges in the field is proposed. The control of arthropod pests of agricultural importance is increasingly difficult due to the quick development of resistance in the targeted pest populations coupled to their massive non-target lethal and sublethal effects. This fostered the progressive banning of active ingredients at international and national levels, making pest management challenging. Reliable and environmentally sustainable pest control tools are required. Botanicals, with special reference to plant essential oils (EOs), can represent a broad source of active ingredients to develop effective insecticides and acaricides for agricultural purposes. In this context, our review analyzed the literature currently available about the lethal and sublethal activity of EOs on non-target terrestrial invertebrates in agricultural settings, including biological control agents (predators and parasitoids), pollinators and soil non-target species. Even if EO-based insecticides and acaricides are generally considered safer from a non-target point of view, a number of detrimental effects have been noted on biological control agents, including negative effects on respiration rate, reduced predatory ability and reduced parasitization rates, among others. Examples of sublethal effects experienced by pollinators exposed to EO-based pesticides are the reduction in the movement speed and distance travelled, while the toxicity of EO-based products on soil invertebrates is limited. Of note, the modes of action leading to EO toxicity on non-target species are scarcely studied. Further research on long-term non-target effects of EO-based pesticides in the field is still needed. [ABSTRACT FROM AUTHOR]

Mosquito management programs rely basically on the use of conventional synthetic larvicides. However, frequent applications and misuse of some synthetic insecticides have led to problems related to mosquito resistance development, harmful effects on human health and unacceptable environmental effects on non-target organisms. Recently, a growing number of phytochemicals has been tested as more eco-friendly larvicides against various mosquito species, exerting high efficacy with multiple modes of action. In the laboratory, we investigated for the first time the sublethal effects of oregano oil and its major compound carvacrol, against Aedes albopictus (Asian tiger mosquito) , a mosquito of great medical importance. We determined the effects of short term (24h) exposure of 3rd- 4th larvae to LC 50 concentrations on survival and development of survived larvae until adulthood, as well as on fecundity, fertility, longevity and wing length of emerged adults. Only half of 24h survived larvae from oregano oil and carvacrol treatment finally reached adulthood. Abnormal shapes of dead larvae and pupae, and failed adult emergence were also observed, indicating a potential growth inhibitory activity of the tested materials. No particular effects from exposure to larvicidal LC 50 concentrations were recorded on life cycle parameters of successfully emerged adults. These findings suggest the tested oregano oil and carvacrol as sufficiently effective larvicides against Ae. albopictus at lower than the acutely toxic concentrations, promoting a more eco-friendly and less costly profile for these biopesticides. [Display omitted] • Potential growth inhibitory activity of oregano oil and carvacrol on Ae. albopictus. • Half of survived larvae from oregano oil and carvacrol treatment reached adulthood. • Oregano oil and carvacrol are effective larvicides at lower than the acutely toxic doses. [ABSTRACT FROM AUTHOR]

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 F 0 generation were significantly decreased after LC 10 and (or) LC 30 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 F 1 generation were significantly decreased in the LC 10 and LC 30 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 LC 10 group than in the control and LC 30 groups. Furthermore, the intrinsic rate of increase (r i) and finite rate of increase (λ) values of the LC 10 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 (R 0) 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. [Display omitted] • Sublethal and transgenerational effects of clothianidin on S. furcifera were studied. • Clothianidin exposure decreased the survival and reproduction of S. furcifera. • P450 enzyme activity and gene expression were induced by clothianidin exposure. • CYP4CE3 and CYP6FJ3 might contribute to clothianidin detoxification in S. furcifera. [ABSTRACT FROM AUTHOR]

The ingestion of imidacloprid treated seeds by farmland birds may result in exposure to toxic amounts of this insecticide. Here we report on the effects that the exposure to the recommended application rate and to 20% of that rate may produce on birds feeding on treated seeds. Experimental exposure to imidacloprid treated seeds was performed on red-legged partridges ( Alectoris rufa ) ( n =15 pairs per treatment group: control, 20% or 100% of the recommended application rate) during two periods that corresponded to the autumn (duration of exposure: 25 days) and late winter (10 days) cereal sowing times in Spanish farmlands. We studied effects on the survival, body condition, oxidative stress biomarkers, plasma biochemistry, carotenoid-based coloration, T-cell mediated immune response and reproduction of exposed adult partridges, and on the survival and T-cell immune response of their chicks. The high dose (recommended application rate) killed all partridges, with mortality occurring faster in females than in males. The low dose (20% the recommended application rate) had no effect on mortality, but reduced levels of plasma biochemistry parameters (glucose, magnesium and lactate dehydrogenase), increased blood superoxide dismutase activity, produced changes in carotenoid-based integument coloration, reduced the clutch size, delayed the first egg lay date, increased egg yolk vitamins and carotenoids and depressed T-cell immune response of chicks. Moreover, the analysis of the livers of dead partridges revealed an accumulation of imidacloprid during exposure time. Despite the moratorium on the use of neonicotinoids in the European Union, birds may still be at high risk of poisoning by these pesticides through direct sources of exposure to coated seeds in autumn and winter. [ABSTRACT FROM AUTHOR]

The acute toxicity of fipronil and its sublethal effects on detoxification enzymes (carboxylesterases (CarEs), glutathione S -transferases (GSTs), and 7-ethoxycoumarin O-deethylase (ECOD)) in zebrafish ( Danio rerio ) were investigated. The results indicated that the 24-h LC 50 of fipronil for zebrafish was 220.4 μg/L (95% CI: 173.7–272.4 μg/L). Sublethal concentrations of fipronil did not cause significant changes in CarEs activities. In the liver and muscle tissues, GST activities at the tested concentrations did not significantly differ from those in the control. In the brain and gill tissues, GST activities at a concentration of 4 μg/L were significantly lower than those at a concentration of 2 μg/L. The results suggest that CarEs and GSTs were not suitable biomarkers for fipronil effects in D. rerio . A significant induction in the ECOD activities in the brain, gill, liver, and muscle tissues was observed compared with the control. Moreover, the dose-dependent responses of the ECOD activity were observed after treatment with sublethal concentrations of fipronil in the range of 2–20 μg/L. The results suggested that ECOD could be a suitable biomarker of fipronil effects in D. rerio . [ABSTRACT FROM AUTHOR]

Abstract: Chemical communication is one of the most important ecological phenomena promoting the maintenance of ecosystem dynamics. In predator–prey interactions, mediation signals allow prey to detect their predators and can be crucial in the process of avoiding them. Since organisms in many natural waterbodies are often subjected to anthropogenic stressors, it is hypothesised that low concentrations of xenobiotic compounds can disturb this chemical communication, acting as infodisruptors. This study analyzes whether two anthropogenic pollutants (chromium and an insecticide) interfere in two freshwater predator–prey interactions, by altering the behavioural responses of a cladoceran and a copepod species to a fish chemical cue. The concentrations tested were lower than those considered innocuous under international water quality guidelines, and two types of behaviour were analysed: escape ability and depth selection in an artificial water column. Both species tested demonstrated a higher escape ability when exposed to the cue than when they were not exposed. Xenobiotics modified the responses of the copepod in opposite ways: chromium inhibited this behaviour and the insecticide prompted a higher than expected level of escape ability. The depth selection patterns were different between N. conifer and C. dubia. Fish kairomones did not modify them, however chromium and the insecticide caused important alterations in both cases. Such disruptions would be detrimental to the organisms'' life cycle trajectories, which, in natural systems, would cause longterm damage in trophic structure and in evolutionary processes. [Copyright &y& Elsevier]

Abstract: The current state of knowledge regarding the effect of pesticides on insect immunity is reviewed here. A basic understanding of these interactions is needed for several reasons, including to improve methods for controlling pest insects in agricultural settings, for controlling insect vectors of human diseases, and for reducing mortality in beneficial insects. Bees are particularly vulnerable to sublethal pesticide exposures because they gather nectar and pollen, concentrating environmental toxins in their nests in the process. Pesticides do have effects on immunity. Organophosphates and some botanicals have been found to impact hemocyte number, differentiation, and thus affect phagocytosis. The phenoloxidase cascade and malanization have also been shown to be affected by several insecticides. Many synthetic insecticides increase oxidative stress, and this could have severe impacts on the production of some antimicrobial peptides in insects, but research is needed to determine the actual effects. Pesticides can also affect grooming behaviors, rendering insects more susceptible to disease. Despite laboratory data documenting pesticide/pathogen interactions, little field data is available at the population level. [Copyright &y& Elsevier]

Abstract: Parasitoid wasps are important control agents for a suite of economically important arthropod pests. However, it is well known that hymenoptera in general are highly vulnerable to the effects of chemical pesticides, and so represent an opportunity to better understand the compatibility of biological and chemical control of pests. Closely related species are often used in trials aimed at assessing the effects of different chemical toxicants on hymenoptera. Most of these tests focus on acute toxicity, with few exploring longer-term population outcomes. Here, using a simple mathematical framework, we quantify the relative vulnerability of a suite of parasitoid species to the sublethal effects of a toxicant acting on fecundity. Using an equation that describes a critical extinction threshold, we calculate levels of reduction in fecundity above which parasitoid species important for biological control are driven to local extinction. We apply this framework to four economically important braconid biological control agents (Diachasmimorpha longicaudata, Psyttalia fletcheri, Fopius arisanus, and Diaeretiella rapae), and find that threshold levels vary widely among them. In particular, we find that D. rapae is far more robust to pesticide exposure than the other three species, suggesting that these four species are not interchangeable in terms of risk assessment. Our findings imply that caution should be exercised in assuming species even within the same functional guild may be used as surrogate species for one another. [Copyright &y& Elsevier]

Abstract: Laboratory studies were performed to determine the insecticidal activity of granulovirus against cotton leafworm Spodoptera littoralis (Boisduval) (Lepidoptera: Noctuidae). The S. littoralis granulovirus (SpliGV) was tested against first (L1), third (L3), and fifth (L5) instar larvae fed on alfalfa leaf disks treated with aqueous suspensions of occlusion bodies (OBs). LD50 values were 3.74×104, 6.86×105, and 1.1×107 OB/larva, for L1, L3, and L5, respectively. Median lethal times (LT50s) to similar response levels (mortality rates between 60% and 70%) decreased with increasing larval age (from 27.98 to 15.93days). Sublethal effects were studied for the treatment of third instar larvae at a concentration equivalent to the LC50 (previously determined by bioassay on artificial diet). Larval development time and pupation period were not affected by SpliGV. Significant differences were found in the oviposition period and number of days in which the female laid viable eggs when both sexes derived from treated larvae. Fecundity, spermatophore number and egg viability percentage were not statistically affected, while female longevity increased only when both adults derived from treated larvae. The SpliGV treatment caused morphological alterations in some areas of male reproductive system: width of vas deferens and length of the aedeagus. Histological sections of testes from SpliGV-treated larvae revealed impaired in follicle development and spermatocyte depletion. In 1- and 5-day-old male pupae from larvae treated with SpliGV, there was not visible change in spermatogenesis, but in 9-day-old pupae a reduction was noted in the number of primary and secondary spermatocytes. Treatment increased the number of oocytes in virgin females, but egg production was unaffected in both virgin and mated females. In conclusion, SpliGV treatment failed to cause high mortality rates in S. littoralis larvae, but did prompt deleterious effects on survivors development and reproductive capacity. [Copyright &y& Elsevier]

Relatively little is known about the potential impacts of engineered nanoparticles on aquatic biota. Particularly relevant to aquatic ecosystems are those particles, which display increased solubility either through specialized coatings or through an ability to interact with water column constituents such as natural organic matter (NOM). Previous research has indicated that grazing zooplankton (Daphnia magna) are able to ingest lipid-coated single-walled carbon nanotubes (SWNTs) from the water column during their normal feeding behavior (). Acute mortality was observed only at high concentrations (>5mg/L). In this research NOM was used in place of a surfactant to stabilize suspensions. Water chemistry (ionic strength, hardness, and pH) has been shown to alter the behavior of NOM in natural systems. We hypothesized that these same variables may also affect the toxicity of multi-walled carbon nanotubes (MWNT) stabilized in NOM. The purpose of this research was to examine the potential for sublethal effects to occur following exposure to multi-walled carbon nanotubes suspended in NOM and to determine whether those effects vary with pH alterations. [Copyright &y& Elsevier]

In this study, we examined the chronic waterborne and dietary exposure of silver (Ag) and cadmium (Cd) to the abalone Haliotis diversicolor using various endpoints such as growth and feeding rates, metal body burden, subcellular distribution, and metallothionein (MT) concentration over a period of 7 weeks of exposure. The growth and feeding rates of abalones were inhibited during the early stage of exposure to different extents, but then recovered to nearly the control levels. A large portion of Ag was redistributed to organelles and metal-rich granules from the cellular debris fraction, whereas cellular debris and metallothionein-like protein were the dominant pools for the storage of Cd, which remained comparable during the exposure period. The MT concentrations were significantly elevated (in a dose-dependent manner) within the first 2 weeks of exposure, after which the MT concentrations started to decrease. All these results implied that abalones respond rapidly to metal exposure, but apparently developed subsequent acclimation. [Copyright &y& Elsevier]