QTL determining the time of blood feeding in Culex pipiens (Diptera: Culicidae)

Authors: Hickner, Paul; MORI, AKIO - University Of Notre Dame; RUND, SAMUEL - University Of Notre Dame; SEVERSON, DAVID - University Of Notre Dame

Submitted to: Journal of Medical Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/18/2022
Publication Date: 8/17/2022
Citation: Hickner, P.V., Mori, A., Rund, S., Severson, D. 2022. QTL determining the time of blood feeding in Culex pipiens (Diptera: Culicidae). Journal of Medical Entomology. https://doi.org/10.1093/jme/tjac118.
DOI: https://doi.org/10.1093/jme/tjac118

Interpretive Summary: Mosquitoes are vectors of pathogens causing serious human diseases, such as Plasmodium spp. (malaria), Wuchereria bancrofti (lymphatic filariasis), and viruses causing dengue, Zika, West Nile, chikungunya, and yellow fever. Among the most effective strategies for the prevention of vector-borne diseases are those aimed at reducing human-vector interactions, such as insecticide applications and insecticide-treated bed nets (ITNs). In some areas where ITNs are widely used, behavioral adaptations have resulted in mosquitoes shifting their time of blood feeding to earlier or later in the night when the bed nets are not being employed. Little is known about the genetic basis of these behavioral shifts. We conducted QTL analysis using two strains of Culex pipiens mosquitoes with contrasting blood feeding behaviors, wherein the lab adapted Shasta strain blood feeds at any time of the day or night, while the newly established Trinidad strain feeds only at night. We identified a single region on chromosome 2 associated with the observed variation in feeding times. None of the core clock genes period, timeless, clock, cycle, PAR-domain protein 1, vrille, discs overgrown, cryptochrome 1, or cryptochrome 2 were located within the QTL region. We then monitored locomotor behavior to determine if they differed in their flight activity. The highly nocturnal Trinidad strain showed little daytime activity while the day-feeding Shasta strain was active during the day, suggesting blood feeding behavior and flight activity are physiologically linked.

Technical Abstract: Mosquitoes and other blood feeding arthropods are vectors of pathogens causing serious human diseases, such as Plasmodium spp. (malaria), Wuchereria bancrofti (lymphatic filariasis), Borrelia burgdorferi (Lyme disease), and viruses causing dengue, Zika, West Nile, chikungunya, and yellow fever. Among the most effective strategies for the prevention of vector-borne diseases are those aimed at reducing human-vector interactions, such as insecticide applications and insecticide-treated bed nets (ITNs). In some areas where ITNs are widely used, behavioral adaptations have resulted in mosquitoes shifting their time of blood feeding to earlier or later in the night when the bed nets are not being employed. Little is known about the genetic basis of these behavioral shifts. We conducted QTL analysis using two strains of Culex pipiens (L.) sensu lato with contrasting blood feeding behaviors, wherein the lab adapted Shasta strain blood feeds at any time of the day or night, while the newly established Trinidad strain feeds only at night. We identified a single locus on chromosome 2 associated with the observed variation in feeding times. None of the core clock genes period, timeless, clock, cycle, PAR-domain protein 1, vrille, discs overgrown, cryptochrome 1, or cryptochrome 2 were located within the QTL region. We then monitored locomotor behavior to determine if they differed in their flight activity. The highly nocturnal Trinidad strain showed little daytime activity while the day-feeding Shasta strain was active during the day, suggesting blood feeding behavior and flight activity are physiologically linked.