Females of the Northern house mosquito, Culex pipiens, enter a hibernation-like state called diapause in response to a decrease in absolute day length and environmental temperature. Diapausing female mosquitoes adjust their feeding patterns, exhibiting a preference for sugar-rich sources like nectar rather than human or animal blood, thereby reducing the transmission of diseases, such as West Nile virus. During diapause, females of Cx. pipiens upregulate a protein referred to as Major Royal Jelly Protein 1 (MRJP1). This protein is highly abundant in royal jelly, a substance produced by honey bees, Apis mellifera, that is fed to future queens throughout larval development and stimulates their longevity and reproduction. We investigated how supplementing the diets of both diapausing and nondiapausing females of Cx. pipiens with royal jelly affects diapause status, protein content, and longevity. We reared mosquitoes under both short-day, diapause-inducing, and long-day, diapause-averting conditions and allowed females to feed on either sugar water (control treatment) or royal jelly (experimental treatment). Furthermore, we knocked down MRJP1 using RNA Interference (RNAi) and determined the effect on diapause status and longevity. Once females were one week old, we measured their primary egg follicle lengths and fat content to assess their diapause status, as short egg follicles and an increase in fat content indicate that the females are in diapause. We found that feeding royal jelly to females significantly reduced egg follicle length in non-diapausing females, suggesting that these females entered a diapause-like state. Additionally, RNAi directed against MRJP1 significantly increased egg follicle length of diapausing females, suggesting that these females averted diapause. I hypothesize that supplementing the diet of female mosquitoes with royal jelly will increase mosquito lifespan, while knocking down MRJP1 with RNAi will decrease lifespan. These findings could lead to novel developments to prevent mosquitoes from biting humans and animals and thereby prevent disease transmission.