Artificial light at night (ALAN) changes seasonal responses in mosquitoes

Research Poster
Lydia Fyie
Mary Gardiner, Megan Meuti
Department of Entomology

Cities experience a wide range of environmental impacts, one of which is light pollution caused by artificial light at night (ALAN). ALAN has been shown to impact insect physiology, behavior, and ecology, but the effects on seasonal responses have not been extensively investigated. The West Nile virus vector, Culex pipiens, is abundant in cities. Female mosquitoes enter a state of developmental arrest, or reproductive diapause, when exposed to short days in order to survive the winter. While in diapause females halt reproductive development and do not engage in host seeking behaviors, and instead increase fat reserves. In contrast, long days inhibit females from entering diapause and stimulate reproductive development and bloodfeeding. The goal of this study is to determine if ALAN interferes with mosquito perception of day length, thus altering the timing of diapause initiation; we hypothesize that mosquitoes exposed to environmentally-relevant levels of ALAN will be less likely to enter diapause and more likely to bite than those that are not exposed to ALAN. We tested this hypothesis by rearing mosquitoes in diapause-inducing short day conditions with either dim ALAN or no added ALAN. Under both conditions, we measured three markers of diapause: egg follicle size, fat content, and propensity to bloodfeed. ALAN-exposed females exhibited increased egg follicle size, decreased fat content, and were more likely to bloodfeed, suggesting that some females averted diapause. These results indicate that city residents may be at risk of mosquito bites and disease transmission for longer than their rural counterparts.