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Bees play a crucial role as natural pollinators, ensuring the maintenance and stability of the world's biodiversity and agricultural crops. Native bees in neotropical regions belong to the Meliponini tribe, a larger group that differs significantly in behavior and biology from honeybees (e.g., Apis mellifera) and solitary bees (e.g., Osmia spp.). Hence, the exposure and effects of pesticides is also likely to vary among these different species. The aim of this study was to develop an analytical method to determine the presence of the neonicotinoid clothianidin in the Brazilian native stingless bee Tetragonisca angustula (local common name: Jataí). The method used for the chemical analysis involved a QuEChERS technique combined with UHPLC-MS/MS analysis. The developed method was subsequently used to analyze collected field samples. In addition, the acute toxicity of the pesticide to T. angustula was evaluated in a laboratory bioassay evaluating both lethal and sublethal endpoints. The analytical method was successfully developed with detection and quantification limits of 1.55 and 5 μg L -1 , respectively, along with a linear range of 1-5 ng mL -1 . Clothianidin was detected in environmental samples (9.2-32.9 ng g -1 ), and the exposure experiments demonstrated acute oral toxicity to adults of T. angustula, (24 h-LD 50 of 0.16 ng a.i./bee), as well as no significative interference in acetylcholinesterase activity. Considering the obtained toxicity endpoints for T. angustula and those reported in the literature for other bee species, this study revealed that T. angustula is more (lethally) sensitive to clothianidin than other bee species, including those commonly used in environmental risk assessment studies. This thus also supports the call for using native test species in (regional) risk assessment evaluations., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier Ltd.)

The increase in agricultural productivity associated with the emergence and the extensive use of pesticides is undeniable. However, strong evidence indicates that this continuous demand is causing serious environmental impacts and bringing toxic effects to associated biota as pollinating insects. The present work aims the determination of the insecticide abamectin (ABA) and the fungicide difenoconazole (DIF) in strawberry flowers (Fragaria x ananassa DUCH.) and pollen sampled from beehives of the stingless bee Tetragonisca angustula Latreille (Hymenoptera: Apidae) located nearby strawberry fields. For analysis, QuEChERS method was optimized, and the analytical performance of those two pesticides was verified. Then, the method was applied to strawberry flowers and the pollen was sampled during three field campaigns. While abamectin was not detected, the systemic fungicide difenoconazole was determined in almost all flowers and pollen samples, demonstrating the major persistence of this pesticide in investigated matrices. The results were then discussed about the difenoconazole application rate and transport to colonies to estimate a preliminary environmental risk assessment for stingless native bees. All calculations were proceeded considering exposure rates and toxicity data from the literature, adapted from Apis mellifera studies. In this sense, the determination, application, and discussion about risk assessment figure out as an important tool to the knowledge about the preliminary risks of native bees exposed to pesticides., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

A miniaturized QuEChERS extraction method followed by ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) was developed to analyze thiamethoxam and imidacloprid in 0.3 g of lyophilized Africanized honey bees ( Apis mellifera L.). The work aimed to estimate honey bees' exposure to pesticides at the nanogram/gram (ng g -1 ) levels, using small sample and reagent quantities. Low amounts of solvents and salts were employed - 15× less than used in traditional methods. Average recoveries ranged from 64.5% to 99.7%, with repeatability below 20% for samples spiked at 3 and 167 ng g -1 . LOD and LOQ were 0.7, and 3 ng g -1 for both pesticides. Applying the proposed approach, honey bee samples from different apiaries from the State of São Paulo (Brazil) were analyzed. The pesticides were detected in concentrations between 7.0 and 27.0 ng g -1 . Thus, the proposed method can be used as a greener alternative to analyze the two neonicotinoids at trace levels in small quantities of bees, consequently saving chemicals and waste.

To boost crop yield, sugarcane growers are using increasing amounts of pesticides to combat insects and weeds. But residues of these compounds can pollute water resources, such as lakes, rivers and aquifers. The present paper reports the results of a study of water samples from the Feijão River, which is the source of drinking water for the city of São Carlos, São Paulo, Brazil. The samples were evaluated for the presence of four leading pesticides--ametryn, atrazine, diuron and fipronil--used on sugarcane, the dominant culture in the region. The samples were obtained from three points along the river: the headwaters, along the middle course of the river and just before the municipal water intake station. The pesticides were extracted from the water samples by solid-phase extraction (SPE) and then analyzed by liquid chromatography with diode array detection (LC-DAD). The analytical method was validated by traditional methods, obtaining recovery values between 90 and 95%, with precision deviations inferior to 2.56%, correlation coefficients above 0.99 and detection and quantification limits varying from 0.02 to 0.05 mg L(-1) and 0.07 to 0.17 mg L(-1), respectively. No presence of residues of the pesticides was detected in the samples, considering the detection limits of the method employed.

Bees are considered as important providers of ecosystem services, acting via pollination process in crops and native plants, and contributing significantly to the maintenance of biodiversity. However, the decrease of bee's population has been observed worldwide and besides other factors, this collapse is also related to the extensive use of pesticides. In this sense, studies involving the assessment of adverse effects and the uptake of pesticides by bees are of great concern. This work presents an analytical method for the determination of the insecticide abamectin and the fungicide difenoconazole in the stingless bee Melipona scutellaris exposed via oral and topic to endpoints concentrations of active ingredients (a.i.) alone and in commercial formulations and the discussion about its mortality and uptake. For this purpose, QuEChERS (Quick, Easy, Cheap, Efficient, Rugged and Safe) acetate modified method was used for extraction and pesticides were determined by LC-MS/MS. The validation parameters have included: a linear range between 0.01 and 1.00 μg mL−1; and LOD and LOQ of 0.038 and 0.076 μg g−1 for abamectin and difenoconazole, respectively. The uptake of tested pesticides via oral and topic was verified by the accumulation in adult forager bees, mainly when the commercial product was tested. Mortality was observed to be higher in oral exposure than in topic tests for both pesticides. For abamectin in a commercial formulation (a.i.) no differences were observed for oral or topic exposure. On the other hand, for difenoconazole, topic exposure had demonstrated higher accumulation in bees, according to the increase of received dose. Through the results, uptake and the possible consequences of bioaccumulated pesticides are also discussed and can contribute to the knowledge about the risks involving the exposure of bees to these compounds. Image 1 • Optimized and validated method for the determination of abamectin and difenoconazole in bees by LC-MS/MS. • First report involving the native stingless bee M. scutellaris exposed to abamectin, difenoconazole and the binary mixture. • M. scutellaris can uptake abamectin and difenoconazole through the exposure via oral and topic. [ABSTRACT FROM AUTHOR]