The overall goal of this research project is to understand the molecular mechanisms by which the circadian clock regulates overwintering dormancy in the Northern house mosquito, Culex pipiens, a mosquito species that transmits many diseases. Mosquitoes become reproductively active during long, summer days, and enter diapause or overwintering dormancy during short, winter days, when they are less active and conserve energy to survive unfavorable environmental conditions. Organisms that live in temperate environments are able to predict and prepare for winter?s arrival by responding to changes in daylength, or photoperiod. Precisely how insects are able to measure daylength is unclear, but the circadian clock, which provides information on the time of day, is hypothesized to be involved because it controls seasonal responses in plants. Understanding how insects are able to convert environmental signals, like daylength, into internal cues, including gene products and metabolites, will provide insights into the regulation of seasonal responses in other insects. This work has the potential to generate novel ways to control insect pests by manipulating seasonal responses to occur at the wrong time of year, thereby improving public health. This project will allow diverse graduate and undergraduate students to fully participate in scientific research, and will provide accessible and engaging educational programming and resources for middle- and high-school students and teachers.
The investigators hypothesize that circadian transcription factors pleiotropically regulate reproductive and overwintering pathways in both a clock- and daylength-dependent manner in insects. The overall research objective is to determine the mechanism by which circadian transcription factors regulate pathways associated with reproduction and overwintering diapause in the Northern house mosquito, Culex pipiens. Chromatin Immunoprecipitation followed by deep sequencing (ChIP-seq) and RNA sequencing in clock-null mutant backgrounds will identify the targets of circadian transcription factors and how they regulate genes associated with different seasonal responses in both long and short photoperiods. Additionally, NMR spectroscopy will reveal daily and seasonal changes in the metabolome of mosquitoes that are associated with reproduction and survival. Combined, the results will show how insects are able to perceive changes in daylength and translate this information into key molecular pathways that regulate different seasonal responses. Photoperiodic diapause has evolved numerous times among insects, where it converged on a few signaling pathways that also regulate metabolism and cell cycle arrest in other animals. Therefore, the results of this study will extend beyond insect diapause research, with potential applications to the study of hibernation, aging, and obesity. In addition to training the next generation of scientific researchers, the PIs will lead entomology field camps and work with K-12 teachers to develop and assess engaging programming with live arthropods, hypothesis-driven lab experiments, and effective educational resources that will be freely provided online.
This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.