Neonicotinoids and phenylpyrazoles are classes of neurotoxic insecticides which are able to bind at different ligand sites of neural receptors, leading to the deregulation of insect neural activity and hence resulting in death. The misuse or indiscriminate use of these chemicals is directly associated with several toxicological effects in biota and at different trophic levels. Based on this premise, the aim of the present study was to evaluate and compare the genotoxic capacity of different concentrations of thiamethoxam (TMX), acetamiprid (ACP), imidacloprid (IMI) and fipronil (FP) through the Micronucleus Test in Tradescantia pallida (Trad-MCN).
View Article and Find Full Text PDFChemosphere
September 2018
Melipona scutellaris Latreille, 1811 (Hymenoptera, Apidae) is a pollinator of various native and cultivated plants. Because of the expansion of agriculture and the need to ensure pest control, the use of insecticides such as fipronil (FP) has increased. This study aimed to evaluate the effects of sublethal doses of FP insecticide on M.
View Article and Find Full Text PDFChemosphere
November 2017
Thiamethoxam (TMX) belongs to a class of neuro-active insecticides referred as neonicotinoids, while actara (AC) is one of the most popular TMX-based products in Brazil. The aim of this study was to evaluate the mutagenic, recombinogenic and carcinogenic potential of TMX and AC insecticides. The mutagenic and recombinogenic effect of TMX and AC were evaluated in vivo by the Somatic Mutation and Recombination Test (SMART) while carcinogenic effects were evaluated through the Test for Detection of Epithelial Tumor Clones (wts test), both in somatic cells of Drosophila melanogaster.
View Article and Find Full Text PDFUnder laboratory conditions, the effects of thiamethoxam were investigated in larvae, pupae and emerging honey bees after exposure at larval stages with different concentrations in the food (0.00001 ng/μL, 0.001 ng/μL and 1.
View Article and Find Full Text PDFThis study used the pearl cichlid Geophagus brasiliensis as a bioindicator to survey the health of the aquatic environment on four sites (P1, P2, P3 and P4) of the Mumbuca stream located at Monte Carmelo/MG, Brazil. The selection of different sites was made with reference to the gradient of urban activity and via physicochemical and biological evaluation of water quality and genotoxicity. The water quality index was classified as 'good' for P1 and P4, regular in P2 and 'poor' for P3.
View Article and Find Full Text PDFMultiple stressors, such as chemicals and pathogens, are likely to be detrimental for the health and lifespan of Apis mellifera, a bee species frequently exposed to both factors in the field and inside hives. The main objective of the present study was to evaluate comparatively the health of Carniolan and Africanized honey bees (AHB) co-exposed to thiamethoxam and Nosema ceranae (N. ceranae) spores.
View Article and Find Full Text PDFSeveral investigations have revealed the toxic effects that neonicotinoids can have on Apis mellifera, while few studies have evaluated the impact of these insecticides can have on the larval stage of the honeybee. From the lethal concentration (LC50) of thiamethoxam for the larvae of the Africanized honeybee, we evaluated the sublethal effects of this insecticide on morphology of the brain. After determine the LC50 (14.
View Article and Find Full Text PDFThe stingless bee Scaptotrigona postica is an important pollinator of native and cultivated plants in Brazil. Among the factors affecting the survival of these insects is the indiscriminate use of insecticides, including the neonicotinoid imidacloprid. This work determined the toxicity of imidacloprid as the topical median lethal dose (LD50) and the oral median lethal concentration (LC50) as tools for assessing the effects of this insecticide.
View Article and Find Full Text PDFThe development of agricultural activities coincides with the increased use of pesticides to control pests, which can also be harmful to nontarget insects such as bees. Thus, the goal of this work was assess the toxic effects of thiamethoxam on newly emerged worker bees of Apis mellifera (africanized honeybee-AHB). Initially, we determined that the lethal concentration 50 (LC50 ) of thiamethoxam was 4.
View Article and Find Full Text PDFFipronil is an insecticide widely used to control a great number of pests, thus the aim of this study was to determine the lethal dose and lethal concentration (LD(50) and LC(50)) of this insecticide to the stingless bees Scaptotrigona postica Latreille, 1807. The LD(50) and LC(50) values obtained after 24 h of exposition were of 0.54 ng a.
View Article and Find Full Text PDFFor a better evaluation of the model using Apis mellifera in toxicology studies with insecticides, the oral acute toxicity of the insecticide fipronil against the stingless bee Melipona scutellaris was determined. The results showed that fipronil was highly toxic to M. scutellaris, with a calculated LC(50) (48 h) value of 0.
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