Date of Graduation
8-2024
Document Type
Thesis
Degree Name
Master of Science in Entomology (MS)
Degree Level
Graduate
Department
Entomology and Plant Pathology
Advisor/Mentor
McDermott, Emily
Committee Member
Kariyat, Rupesh
Second Committee Member
Loftin, Kelly
Third Committee Member
McGregor, Bethany
Keywords
Competence; Culicoides; Insecticide; Sublethal; Vector
Abstract
Culicoides biting midges are common pests around the world of humans, livestock, and wildlife. In addition to nuisance blood feeding, they are also able to transmit pathogens to their hosts like bluetongue virus (BTV) and African horse sickness virus, which can be damaging in terms of both production economics and animal welfare. In order to protect humans and livestock from biting pests like Culicoides, a wide array of interventions is recommended, but chemical insecticides and repellent use are ubiquitous. For a multitude of reasons ranging from natural weathering of applied insecticides to the increase in resistance-associated mutations and behaviors in exposed populations, it is common for insects like Culicoides midges to come into contact with chemicals at concentrations which do not kill them. These sublethal exposures have been shown to cause a variety of changes in vector physiology and behavior, sometimes affecting their ability to transmit the pathogens they carry. The converse is also true: it has been found that arboviral infection can alter vector responses to commonly employed chemicals like permethrin and DEET. To investigate the interactive effects of anthropogenic chemical use and arboviral infection, we studied Culicoides sonorensis in several experimental scenarios. By exposing C. sonorensis midges to sublethal concentrations of insecticide and offering them a BTV-infected bloodmeal, we discovered a potential effect of permethrin on viral dissemination 7 days after infection and a pronounced reduction in blood feeding following permethrin exposure. In a follow-up study, we tested the effects of three insecticides on midge blood feeding and confirmed that sublethal exposure of permethrin can significantly reduce blood feeding in midges for up to 12 hours. Similarly, Fluralaner can reduce blood feeding for up to 6 hours after exposure. In the last experiment, we tested the effects of BTV on C. sonorensis blood feeding behavior and found that infection did not change engorgement rates when midges were exposed to two common repellents: DEET and permethrin.
Citation
Mullins, P. (2024). Interactive Effects Between Bluetongue Virus Infection and Insecticide Exposures in Culicoides sonorensis. Graduate Theses and Dissertations Retrieved from https://scholarworks.uark.edu/etd/5481