Master of Science, The Ohio State University, 2021, 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 throu (open full item for complete abstract)

Committee: Megan Meuti PhD (Advisor); Mary Gardiner PhD (Committee Member); Peter Piermarini PhD (Committee Member) Subjects: Entomology