Socioeconomic predictors of knockdown resistance in Aedes albopictus (Diptera: Culicidae)

Knockdown resistance (kdr) in the mosquito Aedes albopictus (Skuse) jeopardizes the effectiveness of insecticidal control. This is a pressing issue given the expanding range of the species and its role as vector to harmful viruses. Effectively preventing the emergence of resistance or removing the conditions that positively select for kdr mutations requires us first to understand how these conditions arise. Here, we investigate the association between wealth and the frequency of kdr in Ae. albopictus populations in Raleigh, North Carolina, USA. We hypothesized that kdr frequency correlates with wealth, measured by total property value. We speculate that wealthier neighborhoods apply chemical insecticides more frequently, leading to higher kdr frequencies. We tested this hypothesis by sampling mosquito populations from 31 different residential blocks across the city and along a property value gradient. We found a high frequency of 39.0% for mutations at locus F1534S of the voltage-gated sodium channel gene (vgsc). Kdr mutations were found at 84% of the blocks we sampled. Our statistical analysis indicates strong evidence for an association between wealth and F1534S frequency. We discuss these and other findings, and what this means for suburban mosquito control going forward.