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Use of genetically engineered plants that express insecticidal Cry proteins derived from Bacillus thuringiensis (Bt) have been proven efficacious for managing lepidopteran pests. However, in some cases herbivores that are not targeted by the Bt trait have increased in importance. It has been suggested that reduced caterpillar damage to Bt crops could lead to decreased levels of induced plant defensive compounds which might benefit other non‐target herbivores. Here we investigated the potential effect of reduced damage by larvae of Mythimna separata on aphid populations in Bt corn. We compared the performance of Rhopalosiphum maidis feeding on non‐Bt corn plants that had been infested by M. separata larvae or were uninfested. The results showed that caterpillar‐infested corn plants significantly reduced the fitness of R. maidis leading to a prolonged nymphal development time, reduced adult longevity and fecundity compared to uninfested plants. Consequently, the population growth rate of corn aphids feeding on caterpillar‐infested corn plants was significantly lower than on uninfested plants. As expected, the aphids performed significantly better on Lepidoptera‐resistant Bt corn than on non‐Bt corn when plants were infested with M. separata, since the caterpillars caused very little damage to the Bt plants. The current findings indicate that reduced M. separata infestation could benefit aphid development in Bt corn. Bt corn has the potential to be commercialized in China in the near future and aphids and other non‐target pests should be monitored in the farming fields. [ABSTRACT FROM AUTHOR]

• The application of gene drives is a powerful new tool to control insect populations. • Concerns exists regarding the environmental consequences of gene drive applications. • Experience in assessing risks of control methods using living organisms exists. • We do not envisage any unforeseen novel risks with the use of gene drive organisms. • Existing frameworks can assist the risk assessment of insects carrying gene drives. The application of (synthetic) gene drives is a powerful tool to control populations of insects that are agricultural pests, vectors of diseases, or a threat to biodiversity potentially leading to the local or global eradication of a species. The potential use of gene drive organisms has triggered a heated discussion regarding their environmental impacts and regulatory oversight. However, experience exists in assessing the environmental impacts of a number of established agricultural pest control methods that require the release of living organisms, that provide high levels of area-wide control and that might be irreversible. This includes classical biological control, the sterile insect technique, the incompatible insect technique that is based on the cytoplasmic incompatibility caused by Wolbachia endosymbionts, and genetically modified insects containing self-limiting traits. The different technologies are described, the regulatory practice and experience is summarized and pathways through which these control technologies could harm valued ecosystem services are presented. With a focus on the application of gene drives in agriculture, using the invasive Drosophila suzukii (Diptera: Drosophilidae) as a case study we then discuss to what extent the existing frameworks could assist the risk assessment of insects carrying gene drives. We suggest that drawing on existing practices, experiences and legislative frameworks will provide a pragmatic and proportionate approach to evaluate the environmental risks of novel solutions based on gene drive technologies. [ABSTRACT FROM AUTHOR]

BACKGROUND One concern with the adoption of RNAi‐based genetically engineered (GE) crops is the potential harm to valued non‐target organisms. Species of Coccinellidae (Coleoptera) are important natural enemies and might be exposed to the insecticidal dsRNA produced by the plant. To assess their susceptibility to dietary RNAi, we fed Adalia bipunctata and Coccinella septempunctata with a dsRNA designed to target the vATPase A of the western corn rootworm, Diabrotica virgifera virgifera (Dvv dsRNA). Specific dsRNAs designed to target the vATPase A of the two ladybird beetle species served as positive controls. RESULTS: Our results revealed that both species were sensitive to dietary RNAi when ingesting their own dsRNAs, with C. septempunctata being more sensitive than A. bipunctata. Dvv dsRNA also adversely affected the two ladybird beetles as indicated by a significantly (but marginally) prolonged developmental time for A. bipunctata and a significantly reduced survival rate for C. septempunctata. These results, however, were obtained at Dvv dsRNA concentrations that were orders of magnitude higher than expected to occur in the field. Gene expression analyses confirmed the bioactivity of the dsRNA treatments and the results from the feeding bioassays. These results are consistent with the bioinformatics analyses, which revealed a higher number of 21‐nucleotide‐long matches, a requirement for effective RNAi, of the Dvv dsRNA with the vATPase A of C. septempunctata (34 matches) than with that of A. bipunctata (six matches). CONCLUSION: Feeding bioassays revealed that two ladybird species are responsive to dietary RNAi. The two species, however, differed in their sensitivity. © 2019 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Highlights • Insecticidal Bt crops were grown on more than 100 million hectares in 2017. • Risk assessment considers exposure and toxicity of natural enemies to Bt proteins. • Bt proteins appear not to harm natural enemies. • Reduced insecticide use in Bt crops can enhance the conservation of natural enemies. • Bt technology represents a powerful tool for IPM. Abstract Genetically engineered (GE) crops producing insecticidal proteins from Bacillus thuringiensis (Bt) (mainly Cry proteins) have become a major control tactic for a number of key lepidopteran and coleopteran pests, mainly in maize, cotton, and soybean. As with any management tactic, there is concern that using GE crops might cause adverse effects on valued non-target species, including arthropod predators and parasitoids that contribute to biological control. Such potential risks are addressed prior to the commercial release of any new GE plant. Over the past 20+ years, extensive experience and insight have been gained through laboratory and field-based studies of the non-target effects of crops producing Cry proteins. Overall, the vast majority of studies demonstrates that the insecticidal proteins deployed today cause no unintended adverse effects to natural enemies. Furthermore, when Bt crops replace synthetic chemical insecticides for target pest control, this creates an environment supportive of the conservation of natural enemies. As part of an overall integrated pest management (IPM) strategy, Bt crops can contribute to more effective biological control of both target and non-target pests. The growing use of insecticidal seed treatments in major field crops (Bt or not) may dampen the positive gains realized through reductions in foliar and soil insecticides. Nonetheless, Bt technology represents a powerful tool for IPM. [ABSTRACT FROM AUTHOR]

Abstract The transgenic rice line T1C-19 provides high resistance to lepidopteran pests because of the synthesis of the Bacillus thuringiensis (Bt) insecticidal protein Cry1C. It thus shows good prospect for commercial planting in China. Species of Cladocera, an order of aquatic arthropods commonly found in aquatic ecosystems such as rice paddies, might be exposed to the insecticidal protein released from Bt -transgenic rice-straw residues. For the study reported herein, we used Daphnia magna (water flea) as a representative of Cladocera to evaluate whether aquatic arthropods are adversely affected when exposed to Bt rice-straw leachates. We exposed D. magna to M4 medium containing various volume percentages of medium that had been incubated with T1C-19 rice straw or rice straw from its non-transformed near-isoline Minghui 63 (MH63) for 21 days. Compared with pure M4 medium (control), the fitness and developmental and reproduction parameters of D. magna decreased significantly when exposed to rice-straw leachates; conversely, no significant differences between the T1C-19 and MH63 rice-straw leachate treatments were observed, indicating that the Bt rice straw leachate did not adversely affect this non-target species. Highlights • Rice-straw leachate affects water quality and different life-table parameters of Daphnia magna. • D. magna is not affected by rice-straw leachate from Bt rice expressing Cry1C when compared to its corresponding non-Bt rice. • Catalase activity in D. magna exposed to rice-straw leachate was significantly higher than that of blank control. [ABSTRACT FROM AUTHOR]

BACKGROUND: Legumes have been genetically engineered to express α‐amylase inhibitor 1 (αAI‐1) from common bean in their seeds. Whereas the genetically modified (GM) seeds are immune to multiple bruchid pest species, the cosmopolitan bruchid Acanthoscelides obtectus is tolerant to αAI‐1 and their larvae develop normally inside the seeds. Hymenopteran bruchid parasitoids, the most important natural enemies of bruchids, might thus be exposed to αAI‐1 when attacking A. obtectus larvae developing inside GM seeds. Exposure might reduce parasitoid fitness, resulting in a decline in the natural control of A. obtectus, and thus promote the spread of this pest. We investigated the impact of the presence of αAI‐1 in legume seeds on parasitoid fitness in tritrophic experiments with αAI‐1 GM or non‐GM chickpea seeds, A. obtectus, and three parasitoid species. Additionally, we investigated the exposure of parasitoids to αAI‐1 using a fourth, highly sensitive parasitoid species. RESULTS: Parasitoid fitness was not affected when A. obtectus was used in GM chickpea seeds as hosts, and this lack of effects was probably attributable to the fact that exposure of the parasitoids to αAI‐1 was negligible. CONCLUSION: We conclude that the release of GM chickpeas containing αAI‐1 should not harm this important group of non‐target insects. © 2018 Society of Chemical Industry Bruchid parasitoids (in the picture: Heterospilus prosopidis) are not adversely affected by transgenic chickpeas producing the α‐amylase inhibitor αAI‐1 from the common bean for bruchid resistance. [ABSTRACT FROM AUTHOR]

Abstract: BACKGROUND: Honeydew is a sugar‐rich excretion produced by sap‐feeding Sternorrhyncha and is an important source of carbohydrates for natural enemies, especially for parasitoids. Honeydew derived from genetically modified (GM) crops can contain amounts of the transgene product. Thus, it is a possible route of exposure for natural enemies feeding on honeydew. In the present study, the potential effects of Nilaparvata lugens honeydew derived from Cry1C and Cry2A rice on different life‐table parameters and parasitism dynamics of the egg parasitoid Anagrus nilaparvatae were evaluated under laboratory and field conditions. Furthermore, the Bacillus thuringiensis (Bt) levels and the sugar and amino acid composition of honeydew were analyzed. RESULTS: Results indicated that A. nilaparvatae was exposed to Bt proteins by feeding on N. lugens honeydew produced from Bt rice. However, honeydew derived from the tested Cry1C and Cry2A rice lines did not affect the development, longevity, emergence rate and fecundity of A. nilaparvatae. Also, the parasitism dynamics in the field remained unaffected. In addition, the sugar and amino acid composition of N. lugens honeydew was not significantly altered for the tested Bt rice lines compared with the parental non‐Bt plant. CONCLUSION: The quality of honeydew derived from the tested Bt rice lines as a food resource for natural enemies was maintained. © 2018 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Assessing the potential effects of insect-resistant genetically engineered (GE) plants on collembolans is important because these common soil arthropods may be exposed to insecticidal proteins produced in GE plants by ingestion of plant residues, crop pollen, or root exudates. Laboratory studies were conducted to evaluate the potential effects of two Bacillus thuringiensis (Bt)-rice lines expressing Cry1C and Cry2A in pollen and leaves and of their non-Bt conventional isolines on the fitness of the collembolan Folsomia candida and on the activities of its antioxidant-related enzymes, superoxide dismutase and peroxidase, and of its detoxification-related enzymes, glutathione reductase and glutathione S-transferase. Survival, development, reproduction, and the intrinsic rate of increase (rm) were not significantly reduced when F. candida fed on the Bt rice pollen or leaf powder than on the non-Bt rice materials; these parameters, however, were significantly reduced when F. candida fed on non-Bt rice pollen or non-Bt leaf-based diets containing the protease inhibitor E-64 at 75 μg/g. The activities of the antioxidantrelated and detoxification-related enzymes in F. candida were not significantly affected when F. candida fed on the Bt rice materials, but were significantly increased when F. candida fed on the non-Bt rice materials containing E-64. The results demonstrate that Cry1C and Cry2A are not toxic to F. candida, and also indicate the absence of unintended effects on the collembolan caused by any change in plant tissue nutritional composition due to foreign gene transformation. [ABSTRACT FROM AUTHOR]

Cry1C is a Bacillus thuringiensis ( Bt ) insecticidal protein and it can be produced by transgenic rice lines developed in China. Cladocera species are common aquatic arthropods that may be exposed to insecticidal proteins produced in Bt -transgenic plants through ingestion of pollen or crop residues in water. As the cladoceran Daphnia magna plays an important role in the aquatic food chain, it is important to assess the possible effects of Bt crops to this species. To evaluate the safety of the Cry1C protein for D. magna , individuals were exposed to different concentrations of purified Cry1C protein in M4 medium for 21 days. Potassium dichromate (K 2 Cr 2 O 7 ), a known toxicant to D. magna , was added to M4 medium as a positive control treatment, and pure M4 medium was used as a negative control. Our results show that developmental, reproductive, and biochemical parameters of D. magna were not significantly different between Cry1C and negative control treatments but were significantly inhibited by the positive control. We thus conclude that D. magna is insensitive to Cry1C. [ABSTRACT FROM AUTHOR]

The potential risks that genetically modified plants may pose to non-target organisms and the ecosystem services they contribute to are assessed as part of pre-market risk assessments. This paper reviews the early tier studies testing the hypothesis whether exposure to plant-produced Cry34/35Ab1 proteins as a result of cultivation of maize 59122 is harmful to valued non-target organisms, in particular Arthropoda and Annelida. The available studies were assessed for their scientific quality by considering a set of criteria determining their relevance and reliability. As a case-study, this exercise revealed that when not all quality criteria are met, weighing the robustness of the study and its relevance for risk assessment is not obvious. Applying a worst-case expected environmental concentration of bioactive toxins equivalent to that present in the transgenic crop, confirming exposure of the test species to the test substance, and the use of a negative control were identified as minimum criteria to be met to guarantee sufficiently reliable data. This exercise stresses the importance of conducting studies meeting certain quality standards as this minimises the probability of erroneous or inconclusive results and increases confidence in the results and adds certainty to the conclusions drawn. [ABSTRACT FROM AUTHOR]

A concern with Bt-transgenic insect-resistant plants is their potential to harm non-target organisms. Early studies reported that Cry1Ab-producing Bt maize and purified Cry1Ab harmed larvae of the green lacewing, Chrysoperla carnea. Although these effects could not be confirmed in subsequent studies, some authors still refer to them as evidence that Bt maize harms beneficial species. We provide a comprehensive review of the studies evaluating the effects of Bt (Cry1Ab) maize on C. carnea. The evidence indicates that this important predator is not affected by Bt maize or by the produced Cry1Ab protein. We discuss how conceptual models can assist environmental risk assessments, and we emphasize the importance of robust and reproducible studies. [ABSTRACT FROM AUTHOR]

The effects of insect-resistant genetically engineered rice producing Cry1C protein derived from Bacillus thuringiensis (Bt) on Chrysoperla sinica (Tjeder) (Neuroptera: Chrysopidae) were assessed in laboratory bioassays. Survival and development of C. sinica larvae were not adversely affected when the larvae were fed a diet containing purified Cry1C protein at 200 µg/g fresh weight, representing a worst-case exposure scenario; in contrast, C. sinica larvae were adversely affected when the diet contained avidin or potassium arsenate. Life table parameters of C. sinica adults did not differ when the adults were fed with Bt or non-Bt rice pollen together with a 2-M sucrose solution. Life table parameters of C. sinica adults also did not differ when the adults were fed an artificial diet with or without purified Cry1C protein at a nominal concentration that was approximately 20 times higher than that in rice pollen; in contrast, C. sinica adults were adversely affected when the diet contained potassium arsenate. In all bioassays with lacewings, the bioactivity and stability of the Cry1C protein in the diet and Cry1C protein uptake by the lacewings were confirmed by enzyme-linked immunosorbent assay (ELISA) and by bioassays with a Cry1C-sensitive lepidopteran. These results demonstrate that neither larvae nor adults of C. sinica are sensitive to Cry1C protein at concentrations higher than those encountered in the field, demonstrating that the growing of Bt rice producing Cry1C protein is unlikely to pose a risk to C. sinica. Environ Toxicol Chem 2014;33:1391-1397. © 2014 SETAC [ABSTRACT FROM AUTHOR]

Abstract: Bt maize varieties expressing the insecticidal protein Cry3Bb1 against larvae of the Western corn rootworm (Diabrotica virgifera virgifera; Coleoptera: Chrysomelidae) may harm non-target beetles due to the spectrum of activity of the protein. We have conducted studies to assess the prey-mediated effects of Cry3Bb1-expressing Bt maize (event MON88017) on the ladybird beetle Stethorus punctillum (Coleoptera: Coccinellidae). This species specifically consumes spider mites that are known to contain high amounts of Bt toxin when feeding on Bt maize. The developmental and reproduction life-history parameters did not differ for spider mites, Tetranychus urticae (Acari: Tetranychidae), fed Bt maize or non-Bt maize. Similarly, larval survival and development, adult survival, and adult dry weight did not differ for S. punctillum fed with spider mites reared on Bt or non-Bt maize for over 2months. Female beetles that were fed T. urticae from Bt maize had a shorter pre-oviposition period, increased fecundity, and increased fertility relative to females fed spider mites from non-Bt maize. The reasons for these effects are unclear but may be due to unidentified differences in plant characteristics. T. urticae contained 56% of the Cry3Bb1 concentration in Bt maize leaves. Beetle larvae and adults that had consumed Bt maize-fed spider mites contained toxin concentrations that were six and 20 times lower, respectively, than Cry3Bb1 levels in their spider mite prey. Thus, the toxin was diluted at higher trophic levels. The results indicate that S. punctillum is not harmed by feeding on spider mites containing Cry3Bb1. Consequently, detrimental effects on this predator when preying in Cry3Bb1-expressing Bt maize fields are unlikely. [Copyright &y& Elsevier]

Abstract: Based on the finding that Galanthus nivalis agglutinin (GNA) has direct negative effects on larvae of Chrysoperla carnea, laboratory experiments were conducted to investigate its toxicity to the adults. While the ingestion of GNA dissolved in an artificial diet did not affect adult longevity, there were concentration-dependent negative effects on the pre-oviposition period, daily fecundity and total fecundity (number of eggs laid). When GNA was ingested by larvae of C. carnea, it caused a significant extension of larval development time. Adults that had emerged from GNA-fed larvae did not differ from those that developed from control larvae in terms of adult fresh weight, pre-oviposition period and daily or total fecundity. However, fertility (proportion of hatching eggs) was significantly decreased in adults raised from GNA-treated larvae. Western blots revealed that GNA ingested by larvae of C. carnea was partly transferred to the adult stage and was subsequently excreted or digested within a few days. Our toxicity studies (Tier-1 tests) clearly established a hazard of GNA to adult C. carnea when administered to larvae or adults at high concentrations. Implications of these toxicity data for the non-target risk assessment of GNA-expressing transgenic crops are discussed. [Copyright &y& Elsevier]

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Previous studies reported adverse effects of genetically engineered maize that produces insecticidal Cry proteins from Bacillus thuringiensis (Bt) on the water flea Daphnia magna. In the current study, effects of flour, leaves, or pollen from stacked Bt maize that contains six Bt proteins (SmartStax) in two plant backgrounds on life table parameters of D. magna were investigated. Adverse effects were observed for Bt maize flour, originating from different production fields and years, but not for leaves or pollen, produced from plants grown concurrently in a glasshouse. Because leaves contained eight to ten times more Cry protein than flour, the effects of the flour were probably not caused by the Cry proteins, but by compositional differences between the plant backgrounds. Furthermore, considering the natural range of variation in the response of D. magna to conventional maize lines, the observed effects of Bt maize flour were unlikely to be of biological relevance. Our study demonstrates how Cry protein effects can be separated from plant background effects in non-target studies using Bt plant material as the test substance and how detected effects can be judged for their biological relevance. [Display omitted] • Daphnia magna was fed SmartStax maize with six Bacillus thuringiensis Cry toxins. • Two different plant backgrounds with the same stacked Bt trait were used. • Adverse effects were observed for Bt maize flour, but not for leaves or pollen. • Plant background differences and not the Cry toxins likely caused the effects. • Separating Bt effects from plant background effects is important in risk assessment. [ABSTRACT FROM AUTHOR]

Winter wheat expressing the sucrose transporter HvSUT1 from barley (HOSUT) has an increased yield potential. Genetic engineering should improve cultivars without increasing susceptibility to biotic stresses or causing negative impacts on ecosystem services. We studied the effects of HOSUT wheat on cereal aphids that feed on the sugar-rich phloem sap. Three HOSUT winter wheat lines, their conventional parental cultivar Certo, and three conventional cultivars were used. Clip cage experiments in the greenhouse showed no differences in life-table parameters of Rhopalosiphum padi and Sitobion avenae (Hemiptera: Aphididae) on transgenic lines compared to Certo, except higher fecundity of S.avenae on one HOSUT line. Population development of both aphid species over three weeks on caged flowering tillers did not reveal differences between the HOSUT lines and Certo. When aphids were monitored in a Swiss field study over two years, no differences between HOSUT lines and Certo were observed. We conclude that HOSUT wheat did not have consistent effects on aphids compared to the parental cultivar and measured parameters were generally in the range observed for the conventional winter wheat cultivars. Thus, HOSUT wheat is unlikely to suffer from increased aphid damage. [ABSTRACT FROM AUTHOR]

The rapid adoption of genetically engineered (GE) plants that express insecticidal Cry proteins derived from Bacillus thuringiensis (Bt) has raised concerns about their potential impact on non-target organisms. This includes the possibility that non-target herbivores develop into pests. Although studies have now reported increased populations of non-target herbivores in Bt cotton, the underlying mechanisms are not fully understood. We propose that lack of herbivore-induced secondary metabolites in Bt cotton represents a mechanism that benefits non-target herbivores. We show that, because of effective suppression of Bt-sensitive lepidopteran herbivores, Bt cotton contains reduced levels of induced terpenoids. We also show that changes in the overall level of these defensive secondary metabolites are associated with improved performance of a Bt-insensitive herbivore, the cotton aphid, under glasshouse conditions. These effects, however, were not as clearly evident under field conditions as aphid populations were not correlated with the amount of terpenoids measured in the plants. Nevertheless, increased aphid numbers were visible in Bt cotton compared with non-Bt cotton on some sampling dates. Identification of this mechanism increases our understanding of how insect-resistant crops impact herbivore communities and helps underpin the sustainable use of GE varieties. [ABSTRACT FROM AUTHOR]

Abstract: Adults of Chrysoperla sinica Tjeder are prevalent pollen feeders in rice fields in China. They are therefore exposed to insecticidal proteins when foraging insect-resistant genetically engineered rice pollen containing Bacillus thuringiensis (Bt) proteins. Laboratory bioassays were conducted to evaluate the potential impacts of Cry2Aa-expressing transgenic rice (T2A-1) pollen on fitness of adult C. sinica. Survival, pre-oviposition period, fecundity and adult dry weight did not differ between lacewings that had consumed Bt or non-Bt rice pollen. To ensure lacewing adults were not sensitive to Cry2Aa protein independent from the plant background and to add certainty to the toxicity assessment, C. sinica adults were fed with an artificial diet containing Cry2Aa protein at an approximately 10 times higher concentration than in rice pollen. Artificial diet containing potassium arsenate (PA) was included as a positive control. No difference was detected for any of the life-table parameters tested between Cry2Aa-containing and pure diet. In contrast, the pre-oviposition, fecundity and dry weight of C. sinica were significantly adversely affected by feeding on PA-containing diet. In both bioassays, the uptake of Cry protein by adult C. sinica and the bioactivity of Cry protein in the food sources were confirmed by ELISA measurements and sensitive insect bioassays, respectively. These results indicate that adults of C. sinica are not affected by Cry2Aa-expressing rice pollen and are not sensitive to Cry2Aa protein at concentrations exceeding the levels in pollen, thus demonstrating that growing Bt rice expressing Cry2Aa protein will pose a negligible risk to adult C. sinica. [Copyright &y& Elsevier]

Abstract: Plants genetically modified to express Galanthus nivalis agglutinin (GNA) have been found to confer partial resistance to homopteran pests. Laboratory experiments were conducted to investigate direct effects of GNA on larvae of three species of aphid predators that differ in their feeding and digestive physiology, i.e. Chrysoperla carnea, Adalia bipunctata and Coccinella septempunctata. Longevity of all three predator species was directly affected by GNA, when they were fed a sucrose solution containing 1% GNA. However, a difference in sensitivity towards GNA was observed when comparing the first and last larval stage of the three species. In vitro studies revealed that gut enzymes from none of the three species were able to break down GNA. In vivo feed-chase studies demonstrated accumulation of GNA in the larvae. After the larvae had been transferred to a diet devoid of GNA, the protein stayed present in the body of C. carnea, but decreased over time in both ladybirds. Binding studies showed that GNA binds to glycoproteins that can be found in the guts of larvae of all three predator species. Immunoassay by Western blotting of haemolymph samples only occasionally showed the presence of GNA. Fluorescence microscopy confirmed GNA accumulation in the midgut of C. carnea larvae. Implications of these findings for non-target risk assessment of GNA-transgenic crops are discussed. [Copyright &y& Elsevier]