Introduction Environmental contamination by polycyclic aromatic hydrocarbons (PAHs) has increased in recent decades, intensifying the exposure of organisms in wetland ecosystems. Anthracene, due to its chemical stability and persistence, represents a potential risk to herbivorous insects associated with aquatic vegetation. Methods The toxicity of anthracene to the semi-aquatic grasshopper Cornops aquaticum (Bruner, 1906) was experimentally evaluated under controlled laboratory conditions using Eichhornia crassipes leaf fragments (49 cm 2 ) contaminated with increasing amounts (0.05, 0.10, and 0.20 g). Mortality, survival time, and bioaccumulation parameters, including daily uptake rate, were assessed. Results Anthracene exposure significantly reduced survival, confirming a dose-dependent toxic effect. A non-linear response was observed, with the 0.10 g treatment showing the most pronounced effect, resulting in only 10% survival at the end of the experiment. This pattern may be associated with reduced feeding or avoidance behavior at higher contamination levels. Sex-dependent differences were also identified: females exhibited greater tolerance at lower doses, whereas males showed higher survival at elevated concentrations. Body concentrations ranged from 0 to 4,022 μg g −1 , confirming effective uptake. Survival was more strongly associated with daily exposure rate than with total accumulated concentration, indicating a critical threshold between 450 and 550 μg g −1 day −1 . Discussion These findings demonstrate that exposure dynamics play a key role in anthracene toxicity and highlight Cornops aquaticum as highly sensitive to PAHs. The species shows strong potential as a bioindicator of organic contamination in wetland ecosystems, contributing to improved ecological risk assessment of persistent pollutants.