Reduced stress defence responses contribute to the higher toxicity of a pesticide under warming

Abstract

Of increasing concern is the phenomenon that warming magnifies the negative effects of many toxicants (e.g., organophosphate and carbamate pesticides, and most metals). This synergism

Cross‐protection interactions in insect pests: Implications for pest management in a changing climate

“…For example, Delnat et al 18 used existing levels of chlorpyrifos and projected mean temperature for 2100 under the 4 °C warming scenario to explore the interactive effects between elevated temperature and insecticides on mosquito survival. 18,117,123 Another factor worth considering is the duration of time between the initial and secondary stressor, also known as the recovery period. 50,121 At one extreme, if the initial and secondary stressors overlap or occur immediately after one another, the interactive effects of both stressors may negatively impact an individual's ability to recover, limiting the possibility for crossprotection.…”

“…To identify cross‐protection between stressors, an ideal experimental framework would test the direct effects of each individual stressor along with the combined effect of both stressors. Full factorial designs, where each stressor and corresponding levels are crossed with one another, offer an effective way to achieve this design, by testing for interactions between multiple stressors and assessing their impact on insect performance and survival 116,117 . However, for this design to be effective, statistical contrasts between combined stress treatments and individual stress treatments are required to identify non‐additive effects, including antagonistic interactions associated with cross‐protection.…”

“…Additionally, multi‐stress frameworks can be utilized to identify interactions between stressors (additive versus non‐additive) at the level of gene expression 80,81 . This approach was recently used to identify interactions between chlorpyrifos and high temperatures on patterns of gene expression in Culex pipiens , in which the authors found evidence for interactions (additive versus non‐additive) on expression levels, with antagonistic up‐regulation being the most prevalent among stress genes 117 …”

“…Full factorial designs, where each stressor and corresponding levels are crossed with one another, offer an effective way to achieve this design, by testing for interactions between multiple stressors and assessing their impact on insect performance and survival. 116 , 117 However, for this design to be effective, statistical contrasts between combined stress treatments and individual stress treatments are required to identify non‐additive effects, including antagonistic interactions associated with cross‐protection. Inconsistent comparisons of stressor effects within full‐factorial designs may lead to missed opportunities for identifying non‐additive interactions.…”

“… 80 , 81 This approach was recently used to identify interactions between chlorpyrifos and high temperatures on patterns of gene expression in Culex pipiens , in which the authors found evidence for interactions (additive versus non‐additive) on expression levels, with antagonistic up‐regulation being the most prevalent among stress genes. 117 …”