Transgenic Bacillus thuringiensis (Bt) maize has broad prospects for application in China. Before commercialization, it is necessary to assess possible ecological impacts, including impacts on non-target arthropods (NTAs) in the field. In the present study, transgenic Bt maize expressing cry1Ab/2Aj and its corresponding non-transformed near isoline were planted under the same environmental and agricultural conditions, and arthropods in the field were collected during the three main growth stages of maize. In a one year trial, the results showed the composition of NTA communities in the transgenic and control maize fields were similar. There were no significant differences for community-level parameters of species richness (S), Shannon–Wiener diversity index (H′), evenness index (J) and Simpson’s dominant concentration (C) between the two types of maize fields. Likewise, a Bray–Curtis dissimilarity and distance analysis showed that Cry1Ab/2Aj toxin exposure did not increase community dissimilarities between Bt and non-Bt maize plots and that the structure of the NTAs community was similar on the two maize varieties. Furthermore, planting of the transgenic cry1Ab/2Aj maize did not affect the density or composition of non-target decomposers, herbivores, predators, parasitoids and pollinator guilds. In summary, our results showed that planting of Bt maize producing Cry1Ab/Cry2Aj proteins do not adversely affect population dynamics and diversity of NTAs.

While transgenic Bacillus thuringiensis (Bt) maize provides pest resistance and a reduced application of chemical pesticides, a comprehensive environmental risk assessment is mandatory before its field release. This research determined the concentrations of Bt protein in plant tissue and in arthropods under field conditions in Gongzhuling City, northeastern China, to provide guidance for the selection of indicator species for non-target risk assessment studies. Bt maize expressing Cry1Ab/2Aj and non-transformed near-isoline were grown under identical environmental and agricultural conditions. Cry1Ab/2Aj was detected in plant tissues and arthropods collected from Bt maize plots during pre-flowering, flowering, and post-flowering. The expression of Cry1Ab/2Aj varied across growth stages and maize tissues, as well as in the collected arthropods at the three growth stages. Therefore, representative species should be chosen to cover the whole growing season and to represent different habitats and ecological functions. Dalbulus maidis (Hemiptera: Cicadellidae), Rhopalosiphum padi (Hemiptera: Aphididae), Heteronychus arator (Coleoptera: Scarabaeidae), and Somaticus angulatus (Coleoptera: Tenebrionidae) are suitable non-target herbivores. Propylea japonica (Coleoptera: Coccinellidae), Paederus fuscipes (Coleoptera: Staphylinidae), Chrysoperla nipponensis (Neuroptera: Chrysopidae), and spiders are suggested predators. Apis cerana and Apis mellifera ligustica (both Hymenoptera: Apidae) represent pollinators and Folsomia candida (Collembola: Isotomidae) decomposers.

Spodoptera frugiperda (J.E. Smith) is a highly significant agricultural pest that poses a threat to crop production worldwide. It is polyphagous, has a strong migratory ability, and is difficult to control, which makes it a threat not only to crops but also to woody plants. However, research on its adaptability to woody plants is limited. This study compares the feeding adaptations (survival rate, pupation time, pupation rate, weight, length, and daily food consumption), protective enzyme activities, and feeding preferences of S. frugiperda on leaves of six economically important tree species (Areca catechu L., Aquilaria sinensis (Lour.) Spreng, Cocos nucifera L., Camellia oleifera Abel, Dalbergia odorifera T. Chen, and Hevea brasiliensis (Willd. ex A. Juss.) Müll. Arg.), with Zea mays L. used as a control treatment. The results indicate that S. frugiperda did not survive when fed with A. catechu, C. oleifera, and D. odorifera. A. catechu had similar survival rates (83.33%), pupation (86.67%), weight, and length data compared to the maize control. C. nucifera had lower survival rates (46.67%) but no significant differences in pupation (76.67%), weight, and length data of S. frugiperda. H. brasiliensis exhibited significantly lower survival (50.00%) and pupation rates (46.67%) compared to maize. However, there was no significant difference in weight and length data, and its preference index was higher among the six tree species treatments. Therefore, A. sinensis is a vulnerable tree with a high risk, while H. brasiliensis and C. nucifera showed varying degrees of susceptibility. A. catechu, C. oleifera, and D. odorifera were found to be unsuitable hosts for S. frugiperda. In conclusion, this study extensively explores the feeding effects of S. frugiperda on six economically important tree species. It provides insights into the feeding preferences of the pest, thereby informing the potential threat posed by S. frugiperda to economically important trees. It helps to prevent further damage from S. frugiperda and provides a reference for agriculture and forestry to develop effective joint prevention and control measures.

Human‐driven landscape change, particularly urbanization, is reshaping pollinator communities, yet the functional traits that mediate species persistence remain poorly understood. Dietary specialization is commonly used to predict species vulnerability. However, conventional measures based on taxonomic plant host breadth may not reflect pollinators' actual nutritional needs, especially in cities where exotic and native plants coexist. Because insects cannot synthesize sterols de novo, they must obtain these essential lipids from their diet, making sterol requirements a critical and overlooked axis for understanding pollinator persistence. Here, we analysed 22 sterols in 274 pollen provision samples and 1267 bee individuals from four common wild bee species, ranging from specialists to generalists, sampled following urban intensity gradients across five European cities. We reveal that regardless of host–plant specialization levels, all species relied on a shared set of four abundant sterols, commonly found in plant pollen, suggesting that sterol generalization may contribute to their urban persistence. Nonetheless, the full sterol profiles, both composition and concentration, varied between the bees' bodies and their pollen provisions, as well as across species and cities. This suggests that wild bees do not simply mirror their diet, but rather assimilate sterols in a species‐specific manner. The most specialized bee, Chelostoma florisomne , showed more uniform sterol use and was often absent in highly urbanized areas, possibly due to frequent mowing of its main host, Ranunculus flowers. These findings underscore the limitations of using solely on plant host composition in pollen for predicting pollinator responses to urban intensity and highlight the importance of nutritional needs, such as sterols, in shaping ecological niches and guiding conservation strategies. Read the free Plain Language Summary for this article on the Journal blog.

Introduction: The environmental safety of genetically engineered (GE) crops expressing insecticidal proteins remains debated, partly because observed biological effects are often difficult to distinguish from natural variation in plant genetic background. Methods: Here, we conducted a 21-day chronic feeding experiment to assess the effects of two Bt maize lines expressing three insecticidal proteins on the aquatic model organism Daphnia magna . Individuals were exposed to four ecologically relevant maize materials (pollen, leaves, flour, and straw leachate), alongside near-isogenic non-engineered controls and eight conventional maize varieties used to establish a natural variation baseline. Results: Protein concentrations varied substantially among tissues and between maize lines. However, life-table responses of D. magna , including survival, reproduction, and growth, were more strongly influenced by plant genetic background than by the presence of insecticidal proteins. Importantly, nearly all response values observed under exposure to Bt maize fell within the natural variation range defined by conventional varieties. Discussion: These results indicate that the tested maize lines do not cause biologically meaningful effects beyond the variability inherent to conventional crops. More broadly, this study demonstrates that incorporating natural variation baselines provides a robust and generalizable framework for distinguishing trait-related effects from background variability, thereby improving the scientific basis of environmental risk assessment for GE crops.