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Investigating Seasonal Responses in the Northern House Mosquito, Culex pipiens

Peffers, Caitlin Skye
http://rave.ohiolink.edu/etdc/view?acc_num=osu1619111174458783

Abstract Details

2021, Master of Science, Ohio State University, Entomology.
Diapause, a period of arrested development that allows mosquitoes to survive inhospitable conditions, is triggered by short daylengths in temperate mosquitoes. Different populations of mosquitoes initiate diapause in response to a specific photoperiod, or daylength, resulting in population-specific differences in annual cycles of abundance. The photoperiod that causes approximately 50% of a population to initiate diapause is known as the critical photoperiod (CPP). In the Northern Hemisphere, northern populations of mosquitoes experience lower temperatures earlier in the year and must be triggered into diapause by longer daylengths than southern populations. CPP is genetically based, but also adapts over time responding to the population’s environment. Therefore, CPP has been shown to lengthen 1 hour with an increase of 5 °N latitude or an increase of 122 m altitude, following Bioclimatic Law. While the positive correlation between CPP and latitude/altitude has been established in a few mosquito species, including Aedes albopictus, Ae. triseriatus, Ae. sirennensis and Wyeomyia smithii, we do not know when most other species initiate their seasonal responses. As several of these species transmit important diseases, characterizing the CPP of arthropod vectors could improve existing control by ensuring that surveillance efforts align with the vector’s seasonally active period. Additionally, better understanding when mosquitoes and other vectors initiate diapause can reduce the frequency of chemical applications, thereby ameliorating the negative impacts to nontarget insects. Females of Culex pipiens, the primary vector of West Nile virus, enter an adult reproductive diapause. The methods by which Cx. pipiens measures daylength are still unknown. However, clock genes which provide information on the time of day, may also be responsible for the regulation of diapause. Previous studies have shown that the mRNA of several circadian clock genes continue to oscillate throughout the day in diapausing and nondiapausing mosquitoes, but it is unclear whether their protein products show daily or seasonal changes in abundance. Two circadian transcription factors that are suspected in the regulation of diapause are encoded by the genes cycle (cyc) and Par domain protein1 (Pdp1). In this thesis, I have characterized the CPP of 3 populations of Cx. pipiens from Lexington, KY; Lansing, MI, and a lab colony established from Columbus, OH. I found that in these 3 populations there was no significant correlation between latitude and CPP, which is inconsistent with Bioclimatic Law and has never been previously observed in insects. I also measured the relative protein abundance of CYC and PDP1 throughout the day in the whole bodies and the heads of female Cx. pipiens reared under either long-day, diapause-averting conditions, or short-day, diapause-inducing conditions using Western blotting. I found that in whole bodies there were no significant changes in the abundance of CYC or PDP1 in both long day and short day-reared female mosquitoes. However, both CYC and PDP1 cycled in the heads of long day-reared female mosquitoes, while only PDP1 showed significant differences in abundance in the heads of short-day mosquitoes. These data bring us closer to understanding the timing and regulation of diapause in Cx. pipiens.
Megan Meuti, PhD (Advisor)
Mary Gardiner, PhD (Committee Member)
Peter Piermarini, PhD (Committee Member)
84 p.
Entomology
Diapause; insect seasonality; circadian clock; cycle; pdp1; critical photoperiod

Recommended Citations

Citations

  • Peffers, C. S. (2021). Investigating Seasonal Responses in the Northern House Mosquito, Culex pipiens [Master's thesis, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1619111174458783

    APA Style (7th edition)

  • Peffers, Caitlin. Investigating Seasonal Responses in the Northern House Mosquito, Culex pipiens. 2021. Ohio State University, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1619111174458783.

    MLA Style (8th edition)

  • Peffers, Caitlin. "Investigating Seasonal Responses in the Northern House Mosquito, Culex pipiens." Master's thesis, Ohio State University, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=osu1619111174458783

    Chicago Manual of Style (17th edition)

osu1619111174458783
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