Culex mosquitoes & insecticides: Resistance and sublethal exposure

Noel, Kylee Rae

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

Description

Title

Culex mosquitoes & insecticides: Resistance and sublethal exposure

Author(s)

Noel, Kylee Rae

Issue Date

2024-12-04

Director of Research (if dissertation) or Advisor (if thesis)

Stone, Chris M

Doctoral Committee Chair(s)

Stone, Chris M

Committee Member(s)

• Allan, Brian F
• Alleyne, Marianne
• Cáceres, Carla E

Department of Study

Entomology

Discipline

Entomology

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

Ph.D.

Degree Level

Dissertation

Keyword(s)

• vector
• mosquito
• insecticides
• Culex
• Culex pipiens
• Culex restuans
• insecticide resistance
• sublethal exposure
• heritability
• genotype by environment
• resistance mechanisms

Abstract

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.

Graduation Semester

2024-12

Type of Resource

Thesis

Handle URL

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

Copyright and License Information

Copyright 2024 Kylee Noel

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