An update of the Worldwide Integrated Assessment (WIA) on systemic insecticides

Residual distribution and risk assessment of neonicotinoids in urban green space soils of the pearl river delta, South China: A socioeconomic analysis

Urban green spaces are the soil component in cities that interacts most closely with humans. This study investigated the residues of seven neonicotinoids (NEOs) in soils from urban green spaces within the Pearl River Delta (PRD) region and analyzed the correlation between the residue characteristics and the region's economic development. Notably, we introduced the Nemerow Index method, a comprehensive approach, to quantify the overall pollution level of NEOs in the soil of urban park green spaces and utilized this to assess the cumulative exposure probability risks for different populations in this scenario. We found that: (1) The soil of urban park green spaces exhibited varying degrees of NEOs contamination (Σ7NEOs: N.D.-137.31; 6.25 μg/kg), with imidacloprid and clothianidin constituting the highest proportions (89.46 % and 83.60 %); (2) The residual levels of NEOs in Children's Park were significantly higher than those in community parks within Guangzhou, with an average value of 13.30 μg/kg compared to 3.30 μg/kg; (3) The residual characteristics of NEOs exhibited a positive correlation with regional economic development; specifically, the per capita GDP well correlated with IMIRPF, a summation of seven NEOs in imidacloprid equivalents via relative potency factors (R2 =0.86). Regions with higher economic development typically exhibited elevated IMIRPF levels; (4) The fitted cumulative probability distributions for average daily exposure doses revealed that children's exposure was an order of magnitude higher than adults'. Despite this, the exposure risks for both groups remained within acceptable limits.

Sex-specific alterations in adaptive responses of Chironomus columbiensis triggered by imidacloprid chronic and acute sublethal exposures

The use of imidacloprid is a common pest control practice in the Neotropical region. However, the imidacloprid unintended sublethal effects on Neotropical aquatic non-target arthropods and undesirable consequences for aquatic environments remain unclear. Here, we assessed the susceptibility of Chironomus columbiensis (Diptera: Chironomidae) larvae to the neonicotinoid imidacloprid and evaluated whether sublethal exposure types would trigger sex-dependent adaptive responses (e.g., emergence, body mass, reproduction, wing morphology). We conducted a concentration-mortality curve (96 h of exposure) and established chronic and acute sublethal exposure bioassays. While chronic sublethal exposures consisted of exposing individuals during their entire larval and pupal stages, the acute sublethal exposures represented a single short duration (24 h) exposure episode during either the first or fourth larval instar. Our results revealed that chronic sublethal exposure reduced the body mass of males, while acute sublethal exposures during the first instar resulted in heavier males than those that were not exposed to imidacloprid. Chronic exposure also reduced the reproduction of males and females, while the acute sublethal exposure only affected the reproduction of individuals that were imidacloprid-exposed on their later larval instar. Chronic and acute sublethal exposures did differentially affect the wing properties of C. columbiensis males (e.g., increased size when chronically exposed and highly asymmetric wings when acutely exposed in early larval phase) and females (e.g., highly asymmetric wings when chronically and acutely exposed). Collectively, our findings demonstrated that imidacloprid can cause unintended sublethal effects on C. columbiensis, and those effects are dependent on sex, exposure type, and developmental stage.

Detection and Concentration of Neonicotinoids and Other Pesticides in Honey from Honey Bee Colonies Located in Regions That Differ in Agricultural Practices: Implications for Human and Bee Health

This is a preliminary study conducted to analyze the presence and concentration of pesticides in honey obtained from honey bee colonies located in two regions with managed ecosystems that differ in the intensity and technification of agricultural practices. Fourteen pesticides at variable concentrations were detected in 63% of the samples analyzed. The pesticides most frequently found at higher concentrations were insecticides (neonicotinoids, followed by organophosphates), herbicides, and fungicides. The number, frequency, and concentration of pesticides were higher in samples collected from hives located where intensive and highly-technified agriculture is practiced. Forty-three percent of the samples from that zone had residues of imidacloprid, compared with only 13% of the samples from the less-technified zone. Furthermore, 87.5% of those samples had imidacloprid concentrations that were above sublethal doses for honey bees (>0.25 ng/g) but that are not considered hazardous to human health by the European Commission. The results of this study suggest that honey can be used as a bioindicator of environmental contamination by pesticides, which highlights the need to continue monitoring contaminants in this product to determine the risks of pesticide impacts on pollinator health, on ecosystems, and on their potential implications to human health and other non-target organisms.

RNAi in Piezodorus guildinii (Hemiptera: Pentatomidae): Transcriptome Assembly for the Development of Pest Control Strategies

Red-banded stink bug Piezodorus guildinii (P. guildinii) has been described as the most damaging stink bug regarding soybean crops, leading to seed injury, low germination percentages, and foliar retention, at low population densities. In recent years, RNA interference (RNAi), a conserved eukaryote silencing mechanism has been explored to develop species-selective pesticides. In this work, we evaluated RNAi in P. guildinii to develop new pest-control strategies. For this, we assembled and annotated a P. guildinii transcriptome from a pool of all developmental stages. Analysis of this transcriptome led to the identification of 56 genes related to the silencing process encompassing siRNA, miRNA, and piRNA pathways. To evaluate the functionality of RNAi machinery, P. guildinii adults were injected with 28 ng/mg of body weight of double stranded RNA (dsRNA) targeting vATPase A. A mortality of 35 and 51.6% was observed after 7 and 14 days, respectively, and a downregulation of vATPase A gene of 84% 72 h post-injection. In addition, Dicer-2 and Argonaute-2 genes, core RNAi proteins, were upregulated 1.8-fold 48 h after injection. These findings showed for the first time that RNAi is functional in P. guildinii and the silencing of essential genes has a significant effect in adult viability. Taken together, the work reported here shows that RNAi could be an interesting approach for the development of red-banded stink bug control strategies.

Pesticide Toxicity Footprints of Australian Dietary Choices

Pesticides are widely used in food production, yet the potential harm associated with their emission into the environment is rarely considered in the context of sustainable diets. In this study, a life cycle assessment was used to quantify the freshwater ecotoxicity, human toxicity carcinogenic effects, and human toxicity noncarcinogenic effects associated with pesticide use in relation to 9341 individual Australian adult daily diets. The three environmental indicators were also combined into a pesticide toxicity footprint, and a diet quality score was applied to each diet. Energy-dense and nutrient-poor discretionary foods, fruits, and protein-rich foods were the sources of most of the dietary pesticide impacts. Problematically, a dietary shift toward recommended diets was found to increase the pesticide toxicity footprint compared to the current average diet. Using a quadrant analysis, a recommended diet was identified with a 38% lower pesticide toxicity footprint. This was achieved mainly through a reduction in the discretionary food intake and by limiting the choice of fresh fruits. As the latter contradicts dietary recommendations to eat a variety of fruits of different types and colors, we concluded that dietary change may not be the best approach to lowering the environmental impacts of pesticides in the food system. Instead, targeted action in the horticultural industry may be more effective. Consumers might encourage this transition by supporting growers that reduce pesticide use and apply less environmentally harmful active ingredients.

Pollinator conservation requires a stronger and broader application of the precautionary principle

The accumulating scientific evidence on global insect and pollinator decline is fuelling calls for pollinator conservation policies. A broad range of regulating and incentivising policies is undoubtedly needed to address the diverse threats to pollinator abundance and diversity, but implementing policies and regulations is beset by socio-political challenges. Lessons could be learned from the past and current applications of concepts central to biodiversity conservation. Given the uncertainties and data gaps, the concept of the Precautionary Principle (PP) is particularly important. The PP means that when it is scientifically plausible that human activities may lead to morally unacceptable harm, actions shall be taken to avoid or diminish that harm: uncertainty should not be an excuse to delay action. This paper reviews the role of the PP in pollinator conservation. The current research front is fragmented: the PP is briefly mentioned as relevant in literature on biodiversity conservation because of the scientific uncertainties regarding insect decline and their diverse drivers. A separate strand of literature contains studies on specific cases where the PP has played a role in the regulation of specific threats to pollinators: systemic insecticides and global trade in bees. Although limited to two significant threats to pollinator abundance and diversity, these studies provide important lessons on the challenges of implementing precautionary pollinator conservation policies and underline socio-political aspects of the 'human-dimensions' of pollinator conservation. Specifically, they highlight that ambiguity is a greater challenge than scientific uncertainty, which may be heightened when policies are intended to regulate specific economic sectors. We suggest that more attention should be paid to the discrepancy between the PP as formally included in policies or regulations and its inadequate implementation (too little too late) in a context of scientific uncertainty and societal conflict.