Culex mosquitoes & insecticides: Resistance and sublethal exposure

Insecticides play a vital role in mitigating mosquito-borne disease outbreaks. However, the continued use of insecticides across sectors has raised concerns regarding selection for insecticide resistance within mosquito populations. West Nile virus is currently the leading cause of mosquito-borne disease in the continental United States and Culex mosquitoes are key components in maintaining its natural cycle. Insecticide resistance has been reported in Culex populations worldwide requiring the development of effective resistance management approaches. This dissertation explores the mechanisms underlying phenotypic resistance, the factors influencing selection for insecticide resistance, and the impacts of sublethal larval exposure on the vectorial capacity of Culex mosquitoes. In Chapter 1, I provide background information detailing the impact of insecticide resistance and the importance of insecticide use in integrated mosquito management. In Chapter 2, I surveyed Culex mosquito populations in Illinois to determine phenotypic resistance, with results indicating variable resistance levels to permethrin and malathion throughout the state. Additionally, I screened the mosquitoes for increases in detoxification enzymes and target site insensitivities. Population differences in rates of knockdown mutations and metabolic mechanisms drive this variation in resistance. In Chapter 3, I conducted a full-sibling study design to examine heritability and environmental effects on resistance. I divided full-sibling families in half between two larval diet treatments and assessed the adults for permethrin resistance. The results show heritable variation in pyrethroid resistance, highlight phenotypic plasticity in field mosquito populations, and indicate that gene-environment interactions drive resistance changes across populations. In Chapter 4, I determined the effects of sublethal exposure on different components of vectorial capacity after exposing larvae to permethrin. The adult mosquitoes were used to assess the probability of daily survival, the extrinsic incubation period of West Nile virus, vector competence, and fecundity at two different temperatures. Collectively, these studies display how insecticide use and presence in the environment can impact mosquito populations and can inform resistance management strategies.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Entomology

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2024

Author dc:creator

• Noel, Kylee Rae

Contributors dc:contributor

• Stone, Chris M
• Allan, Brian F
• Alleyne, Marianne
• Cáceres, Carla E

• Vector
• Mosquito
• Insecticides
• Culex
• Culex Pipiens
• Culex Restuans
• Insecticide Resistance
• Sublethal Exposure
• Heritability
• Genotype By Environment
• Resistance Mechanisms

Statement dc:rights

• Copyright 2024 Kylee Noel

Language dc:language

en, eng

Handle dc:identifier

https://hdl.handle.net/2142/127494

OAI record oai:identifier

https://www.ideals.illinois.edu/oai-pmh?verb=GetRecord&metadataPrefix=etdms&identifier=oai%3Awww.ideals.illinois.edu%3A2142%2F127494