Ecotoxicology最新文献

The yellow fever mosquito, Aedes aegypti L., known for transmitting viruses causing yellow fever, dengue, chikungunya, and Zika fever, presents a substantial risk to global human health. The development of insecticide resistance in disease vectors has become a significant problem in Ae. aegypti. Monitoring insecticide resistance is essential for resistance management in Ae. aegypti. This study involved the collection of Ae. aegypti populations from four important cotton-growing regions in southern Punjab, Pakistan, for resistance monitoring over a two-year period (2021-2022). This study also assessed the impact of insecticide resistance on biological parameters of Ae. aegypti. Moderate-to-high levels of resistance were observed against all the tested insecticides viz., chlorpyrifos, chlorfenapyr, deltamethrin, flonicamid, spirotetramat, and spinetoram. However, compared to the Lab-susceptible population, higher levels of resistance to buprofezin (59.03-84.40) and imidacloprid (68.49-100.01) were found in all populations. This high resistance can be attributed to increased use of these two insecticides in cotton fields, as compared to other insecticides. In the lab-susceptible population, higher values for the intrinsic rate of increase (r) and the net reproductive rate (R₀) i.e., 0.20 per day and 23.24 offspring/female were observed, respectively. This was also validated by population projection data where more than 2.5-fold adults (1,020,361.80 individuals) were calculated in the Lab-susceptible population as compared to the most resistant populations. Sublethal exposure to insecticides may induce physiological or biochemical changes in organisms, subsequently influencing the biological traits. Resistance monitoring provides essential guidance before launching a successful chemical-based vector management program.

Agricultural insecticide usage presents a complex challenge, particularly when addressing hidden targets such as concealed pest species. Typically, insecticide spraying targets either the host plant or the soil substrate, reaching the target when the pests move or feed, yet their vulnerability when concealed remains low. This study delves into the often-obscure effects of insecticides on hidden herbivore species, focusing specifically on the diamide insecticide chlorantraniliprole and its impact on the concealed insect herbivore, the coffee leaf miner Leucoptera coffeella (Guérin-Mèneville & Perrottet) (Lepidoptera: Lyonetidae). We document the progressive effects of chlorantraniliprole from egg-laying through the insect's development and reproductive output. By examining egg-laying preferences, development, survival, respiration rate, leaf consumption, and polysaccharide and protein accumulation, alongside fecundity, in two field-collected leaf miner populations, we elucidate chlorantraniliprole's broader effects. While the insecticide did not alter the leaf miner's egg-laying preferences, one population exhibited higher larval survival, indicating chlorantraniliprole resistance. This chlorantraniliprole-resistant population displayed a lower respiration rate-indicative of reduced stress-and higher leaf consumption, accompanied by increased sugar and protein accumulation. Although this population showed lower adult longevity, it exhibited higher fecundity. These findings highlight the multifaceted impacts of insecticides, extending beyond survival to affect development, fecundity, and potential fitness. Variations in response among insect populations suggest that resistant insects may outperform susceptible ones even under sublethal exposure, with significant implications for management strategies and future outbreaks.

The use of pesticides has notably increased in recent years globally. However, sensitive organisms exposed to these environmental pollutants, such as amphibians, may experience adverse effects. The insecticide imidacloprid (IM) and the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) are two pesticides commonly used in Colombia, but their toxic impacts on tropical anurans remain poorly understood. In this study, we tested the acute toxic effects of IM and 2,4-D on the survival, total length, and burst swimming speed of tadpoles from two anuran species. Under laboratory conditions, the tadpoles of Boana platanera and Engystomops pustulosus were independently exposed to each pesticide for 96 h. We found that the tadpoles of E. pustulosus were more sensitive to both IM and 2,4-D than those of B. platanera. However, the LC₅₀ values were higher than the reported field concentrations for these pesticides. IM led to a reduction in the total length of B. platanera tadpoles and induced total immobility in surviving individuals of both species. In contrast, the herbicide 2,4-D did not affect the total length or the swimming speed of tadpoles from the two species. In conclusion, based on the results and the reported field concentrations, IM and 2,4-D are not lethal to the studied anurans. Nevertheless, it is important to consider that IM caused strong negative sublethal effects on tadpoles, which could compromise their survival in the future. Finally, we also found that the insecticide IM showed notably greater toxicity to the tested species than did the herbicide 2,4-D.

Pesticides often exist as complex mixtures in soil environments, yet the toxicity of these combinations has not been thoroughly investigated. In light of this, the current study aimed to assess the enzymatic activity and gene expression responses in the earthworm Eisenia fetida when exposed to a mixture of beta-cypermethrin (BCY) and triadimefon (TRI). The findings revealed that co-exposure to BCY and TRI triggered acute synergistic toxicity in E. fetida, emphasizing the potential risk they pose to soil health. Significant elevations in MDA, Cu/Zn-SOD, and CAT levels were observed across most individual and combined treatments. Additionally, the expression of crt was notably upregulated under most exposure conditions, while the expression levels of tctp and sod were significantly downregulated. These changes suggested the occurrence of oxidative stress and potential carcinogenic effects upon exposure to BCY, TRI, and their combination. Notably, the activities of CAT, caspase-9, and CarE, along with the transcriptional levels of mt, displayed more pronounced variations in response to the pesticide mixture compared to individual exposures. These results indicated that the combined exposure to BCY and TRI intensified oxidative stress, promoted cellular apoptosis, and disrupted detoxification processes more than exposure to either chemical alone. Molecular docking results showed that these two pesticides could interact with CAT, SOD, and GST. These data provided critical insights into the biochemical and molecular toxicity caused by BCY and TRI on E. fetida, offering a deeper understanding of the ecological risks posed by chemical mixtures to soil organisms. This study shed light on the toxicological implications of BCY and TRI co-occurrence and underscored the importance of evaluating the environmental impact of pesticide mixtures to safeguard soil ecosystems.

Hydroelectric reservoirs favor mercury contamination in biota, but the contamination in cascade reservoirs is not yet clear. We investigated total mercury (THg) contamination in fish in four cascade reservoirs in the Brazilian Amazon between August 2022 and April 2023. Overall, downstream predatory fish showed higher mercury concentrations than those upstream. Mercury concentrations in predatory fish collected upstream increased in the reservoirs along the river. Downstream, these concentrations were consistently high, with no variation between reservoirs. Non-predatory fish did not exhibit a clear spatial trend in mercury concentrations. Considering that the synergistic effect of cascade reservoirs was evident in predatory fish, and that the species Serrasalmus rhombeus is widely distributed and important for regional fishing, we suggest it as a target species for future studies on thi issue in the region.

As the global population continues to grow, the use of pesticides to increase food production is projected to escalate. Pesticides are critical in plant protection, offering a powerful defense against fungal diseases such as apple scab, leaf spot, sclerotinia rot, damping off, sheath blight, and root rot, which threaten crops like cereals, corn, cotton, soybean, sugarcane, tuberous vegetables, and ornamentals. Succinate Dehydrogenase Inhibitor (SDHI) fungicides represent a novel class essential for controlling fungal pathogens and bolstering food security. However, the impact of SDHIs on non-target organisms, including freshwater and terrestrial invertebrates, crustaceans, and oligochaetes, remains insufficiently understood. Empirical studies indicate that SDHIs can induce mortality, mitochondrial dysfunction, oxidative stress, and developmental delays in non-target organims. Additionally, the environmental persistence of these compounds raises concerns about their potential for ecological disruption. The effects of SDHIs on pollinating species and the possible transgenerational transmission of harmful effects warrant further investigation. Comprehensive transcriptomic analyses are necessary to elucidate the molecular disturbances and adverse outcome pathways triggered by SDHIs. Furthermore, there are emerging concerns about the endocrine-disrupting potential of SDHIs in aquatic organisms. For the first time, this review aims to synthesize existing knowledge on the ecotoxicological impacts of SDHIs on non-target organisms and identify critical research directions to address the ecological challenges posed by their use.

Many contaminants from scattered sources constantly endanger streams that flow through heavily inhabited areas, commercial districts, and industrial hubs. The responses of transplanted mussels in streams in active biomonitoring programs will reflect the dynamics of environmental stream conditions. This study evaluated the untargeted metabolomic and proteomic responses and free radical scavenging activities of transplanted mussels Sinanodonta woodiana in the Winongo Stream at three stations (S1, S2, S3) representing different pollution levels: low (S1), high (S2), and moderate (S3). The investigation examined untargeted metabolomic and proteomic responses in the gills and 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) activities in the gills, mantle, and digestive glands. Metabolomic analysis revealed a clear separation between mussel responses from the three stations after 28 days of exposure, with specific metabolites responding to different pollution levels. Proteomic analysis identified β-Actin protein in all stations. The β-Actin protein sequence of unexposed mussels had coverage of 17%, and increased to 23% at S1 on day 28 and 34% at S2 and S3 on day 28. All tissues showed increased DPPH and ABTS activities from day 3 to day 28, mainly in stations S2 and S3. These findings underscore the impact of pollution levels on the metabolomic and proteomic responses of S. woodiana and the importance of these discoveries as early indicators (biomarkers) of long-term aquatic environmental problems. In the face of current environmental challenges, this research raises concerns about the health of water bodies. It underscores the importance of developing robust, standardized, and dependable analytical techniques for monitoring the health of aquatic environments.

Stingless bees are important pollinators in tropical regions, but their survival and behavior have been impacted by various factors, including exposure to insecticides. Here, we evaluated the lethal and sublethal effects of commercial formulations of two widely used insecticides, flupyradifurone (FPF formulation), and cyantraniliprole (CY formulation), on Melipona beecheii and Nannotrigona perilampoides. The study involved oral exposure of bees to insecticides, calculation of the lethal concentration (LC₅₀) and the lethal time (LT₅₀), and evaluation of walking and flight take-off activities. The LC₅₀ values showed that the largest bee, M. beecheii, was more sensitive than N. perilampoides to both insecticides and that the FPF formulation had faster lethal effects in both species (N. perilampoides, 9.6 h; M. beecheii, 5 h) compared to the effects of the CY formulation (N. perilampoides, 17 h; M. beecheii, 24.7 h). Sublethal concentrations (LC_50/10 and LC_50/100) of both insecticides affected walking and flight take-off activities. After 6-24 h of exposure, both FPF and CY formulations significantly reduced the mean walking speed of N. perilampoides (0.962-1.402 cm/s) and M. beecheii (2.026-2.589 cm/s) compared to the control groups (N. perilampoides: 1.648-1.941 cm/s; M. beecheii: 2.759-3.471 cm/s). Additionally, the FPF and the CY formulation impaired individual flight take-off in both species. This study provides the first comprehensive evaluation of the lethal and sublethal effects of flupyradifurone and cyantraniliprole on M. beecheii and N. perilampoides, offering valuable information for future research on insecticide toxicity in stingless bees.

Mussels are filter-feeding animals with a sedentary lifestyle and thus, they were accepted as good bioindicator animals to investigate environmental pollution. In this study, freshwater mussels (Unio tigridis) were exposed to cadmium (0, 30, 90, 270 µg Cd/L) for up to 21 days. Then, the responses of several biomarkers belonging to the antioxidant, osmoregulation and nervous systems, as well as the energy reserves of mussels were investigated. The animals were fed on laboratory-cultured algae (Chlorella vulgaris) during the experiments. Data showed that the exposure conditions did not cause mussel mortality within 21 days, though the levels of all biomarkers altered significantly (p < 0.05) compared to controls. Cadmium exposures significantly altered the activities of antioxidant enzymes in the digestive glands. Similarly, malondialdehyde (MDA) levels in the digestive glands significantly increased after cadmium exposures. Likewise, acetylcholinesterase (AChE) activity and Ca-ATPase activity in the muscle significantly decreased. There were decreases in Na-ATPase and increases in Mg-ATPase activities in the gill. The total energy reserves of mussels significantly decreased, especially at the higher cadmium concentrations. This study showed that environmentally relevant cadmium concentrations could alter the levels of biomarkers belonging to different metabolic systems, emphasizing their possible usage in evaluating metal contamination.

Spodoptera litura (Lepidoptera: Noctuidae) is one of the most destructive insect pests. Insecticides remain the principal management tool to control this pest. However, indiscriminate use of insecticides has resulted in the development of resistance to a variety of insecticides in S. litura. Cypermethrin, a synthetic pyrethroid, is commonly used in pest management. In addition to the mortality produced by cypermethrin, S. litura may suffer a range of sublethal consequences when exposed to low or sublethal levels. This study investigates the effect of cypermethrin exposure on nutritional physiology, digestive, detoxifying, and antioxidant enzymes of lab-selected susceptible (Unsel-Lab) and resistant (CYP-Sel) populations of S. litura. Our findings demonstrated that cypermethrin exposure has a considerable impact on the nutritional physiology of S. litura, as revealed by altered nutrient assimilation and utilization, alongside varying responses in digestive enzymes. In the CYP-Sel population, activity levels of key digestive enzymes- α-amylase, α-glucosidase, ß-glucosidase, α-galactosidase, ß-galactosidase, lipases, and proteases- decreased by 69.30, 81.40, 49.18, 86.36, 73.94, 70.50, and 72.34%, respectively, compared to the control of Unsel-Lab population. Furthermore, detoxification enzymes including mixed-function oxidase (by 1.87 times), glutathione-S-transferase (by 1.71 times), and esterases (by 2.86 times) showed considerably increased activity in CYP-Sel population as compared to Unsel-Lab population, indicating an adaptive response to detoxification processes. Antioxidant enzyme activity, including SOD (increased by 19.66%) and CAT (decreased by 26.19%), changed significantly, indicating oxidative stress caused by cypermethrin. The study gives useful information for developing pest management strategies that reduce the unexpected impacts of chemical exposure.