Thermal sensitivity of Rhinella arenarum tadpole at low concentrations of dimethoate pesticides

• Published in: Comparative biochemistry and physiology. Toxicology & pharmacology 2024-05, Vol.279, p.109884-109884, Article 109884
• Main Authors: Quiroga, Lorena B., Gordillo, Luciana F., Aragon-Traverso, Juan H., Iribas, Francisco J., Sanabria, Eduardo A.
• Format: Article
• Language: English
• Subjects: Argentina; Global warming; Locomotor performance; Monte desert; Thermal extremes
• ISSN: 1532-0456; 1878-1659
• DOI: 10.1016/j.cbpc.2024.109884

One of the main causes of contamination of aquatic environments, which affects biotic communities, is the use of pesticides in agricultural regions. Amphibians are considered good bio-indicators of aquatic pollution, because they are one of the most susceptible groups to pollution. Several studies suggest that both pollution and climate change produce synergistic effects in amphibians which amplify the toxicity afecting survival, and malformations with an increase in temperature. We studied the sensitivity of sublethal concentrations of dimethoate in Rhinella arenarum tadpoles on two fitness related thermal traits including locomotor swimming performance and thermal tolerance limits (CTmax = critical thermal maximum and CTmin = critical thermal minimum). The locomotor performance of R. arenarum tadpoles decreased with increasing sublethal dimethoate concentrations up to ∼60 % at intermediates dimethoate concentration. The tadpoles showed a tendency to decrease their tolerance to high temperatures (CTmax) with increasing dimethoate concentration around ∼0.5 °C, however no significant differences were found among treatments. Similarly, tadpoles showed decreases in their cold resistance (CTmin) with dimethoate concentrations, around 1 °C the high concentrations of dimethoate. The increase of atypical climatic events, such as heat waves may put R. arenarum tadpoles at greater risk when exposed to dimethoate. Our results show that the sublethal concentrations of the dimethoate pesticide may affect the fitness and survival of the larvae of R. arenarum in natural, and seminatural enviroments. [Display omitted] •Thermal extremes of R. arenarum tadpoles were negatively affected by dimethoate.•Sublethal concentration of pesticide affects the maximum locomotor performance.•Dimethoate has a negative effect on locomotion at 35 °C in R. arenarum tadpoles.•TPCs shape could suffer modifications with sublethal concentrations of pesticides.