Demographic resilience of Anopheles stephensi to synthetic detergent (surfactants) pollution: life-table responses and implications for urban malaria transmission

Environmental contamination of freshwater habitats is increasingly recognized as a factor influencing the ecology of disease vectors. In this study, we used life table-based analyses to examine the effects of three concentrations of sodium dodecylbenzene sulfonate, a detergent/surfactant pollutant (0, 1.5, and 8.5 ppm), on the survival, reproductive output, and transmission potential of Anopheles stephensi under laboratory conditions. Population growth parameters including intrinsic rate of increase ( r m ), finite rate of increase ( λ ), and net reproductive rate ( R 0 ) exhibited treatment-dependent variations, with the 1.5 ppm group generally showing reduced reproductive output, whereas the 8.5 ppm group maintained rates comparable to the control group. Life history traits, including preadult and adult longevity, fecundity, and female-to-male ratios, revealed distinct patterns across treatments, highlighting potential sex-specific sensitivities. Age-stage survival, life expectancy, and reproductive value analyses indicated shifts in population structure and timing of reproductive peaks under pollutant exposure. Modeling of malaria parasite transmission probability suggested that female longevity under all treatment conditions remained sufficient to support the development of multiple Plasmodium species, emphasizing the persistence of transmission potential despite environmental stress. Composite resilience analyses revealed nonlinear and heterogeneous responses, with partial recovery of some biological parameters at higher pollutant concentrations, indicating potential compensatory mechanisms. Collectively, these findings illustrate the sensitivity of vector life history and population dynamics to detergent pollution, and demonstrate the utility of integrated demographic and modeling approaches for assessing environmental impacts on disease vectors. Such assessments provide a framework for monitoring and anticipating ecological and epidemiological outcomes in polluted aquatic systems, highlighting the demographic resilience of An. stephensi to detergent pollution without implying enhanced transmission risk.