283 - Family-level variation and heritability of deltamethrin resistance in a wild-type Culex pipiens population

Abstract: Understanding the genetic and physiological basis of insecticide resistance is critical for improving resistance management and establishing effective of mosquito control programs. In this study, we investigated family-level variation in insecticide susceptibility within a wild-type population of Culex pipiens from Northern California. Using a full-sibling breeding design, we tested multiple families derived from field-collected females to assess variation in susceptibility and to estimate the broad-sense heritability (H²) of the resistance trait. Mosquitoes were exposed to a pyrethroid insecticide using CDC bottle bioassays, and mortality was monitored over time to calculate lethal time estimates (LT₅₀) for each family. Preliminary results reveal considerable phenotypic variation among families, suggesting that resistance has a heritable component. All individuals were preserved following bioassays for downstream metabolomic analyses, which will compare the most resistant and most susceptible families to identify potential biochemical pathways associated with resistance. This study builds on previous work using full-sibling designs to investigate heritable traits in mosquitoes and applies that framework to explore the evolutionary and metabolic underpinnings of insecticide resistance in Culex pipiens.