Synergistic interaction between a toxicant and food stress is further exacerbated by temperature

• Published in: Environmental pollution (1987) 2024-12, Vol.363 (Pt 1), p.125109, Article 125109
• Main Authors: Shahid, Naeem, Siddique, Ayesha, Liess, Matthias
• Format: Article
• Language: English
• Subjects: Animals; Combined stress; Daphnia - drug effects; Daphnia - physiology; Effect-models; Environmental stressors; Insecticides - toxicity; Nitriles - toxicity; Pesticide-effects; Pyrethrins - toxicity; Stress, Physiological; Synergism; Temperature; Water Pollutants, Chemical - toxicity
• ISSN: 0269-7491; 1873-6424; 1873-6424
• DOI: 10.1016/j.envpol.2024.125109

Global biodiversity is declining at an unprecedented rate in response to multiple environmental stressors. Effective biodiversity management requires deeper understanding of the relevant mechanisms behind such ecological impacts. A key challenge is understanding synergistic interactions between multiple stressors and predicting their combined effects. Here we used Daphnia magna to investigate the interaction between a pyrethroid insecticide esfenvalerate and two non-chemical environmental stressors: elevated temperature and food limitation. We hypothesized that the stressors with different modes of action can act synergistically. Our findings showed additive effects of food limitation and elevated temperature (25 °C, null model effect addition (EA)) with model deviation ratio (MDR) ranging from 0.7 to 0.9. In contrast, we observed strong synergistic interactions between esfenvalerate and food limitation at 20 °C, considerably further amplified at 25 °C. Additionally, for all stress combinations, the synergism intensified over time indicating the latent effects of the pesticide. Consequently, multiple stress substantially reduced the lethal concentration of esfenvalerate by a factor of 19 for the LC50 (0.45–0.024 μg/L) and 130 for the LC10 (0.096–0.00074 μg/L). The stress addition model (SAM) predicted increasing synergistic interactions among stressors with increasing total stress. [Display omitted] •Interaction between one chemical and two non-chemical stressors was studied.•Food limitation and elevated temperature showed additive interactions.•Environmental stressors substantially increase the effects of esfenvalerate.•Multiple stressors induced strong latent synergistic effects.•Combined effects of multiple stressors were predicted by the Stress Addition Model.