Year: 2026
Type: preprint
Abstract: ABSTRACT Insecticide toxicity is commonly assessed under standardized conditions, yet susceptibility may depend on the biological state of the organism, its environment, and its recent exposure history. How these factors shape susceptibility at the organismal level remains insufficiently understood. Here, using Drosophila melanogaster , we systematically compared responses to three insecticides with distinct modes of action - acetamiprid, chlorantraniliprole, and deltamethrin. Susceptibility varied substantially with developmental stage, sex, and age, while temperature altered toxicity in a compound-dependent manner, demonstrating that lethal effects are strongly conditioned by biological and environmental context. Susceptibility was also rapidly modified by prior exposure: sublethal pre-exposure to each insecticide reduced lethality upon subsequent challenge with the same compound, with increased tolerance emerging within 24 h. However, exposure conditions that enhanced insecticide tolerance were associated with reduced resistance to heat stress and nutrient starvation, indicating that increased tolerance to an insecticide challenge can coincide with reduced resilience to other environmental stresses. Sublethal exposure also affected reproductive performance: increasing acetamiprid concentrations reduced egg production but surprisingly increased developmental success of the resulting offspring, largely maintaining the number of offspring reaching adulthood. Together, our findings identify rapid, compound-specific, and potentially costly tolerance as an underappreciated consequence of insecticide exposure and establish insecticide susceptibility as a dynamic organismal trait shaped by physiology, environmental conditions, and recent exposure history. These findings highlight the importance of incorporating such sources of variation, together with the broader consequences of sublethal exposure, into pesticide risk assessment.
Language: English
Subfield: Molecular Biology
Domain: Life Sciences
Open Access status: green
OpenAlex ID: W7214631409