Sniffing out snacks: Olfaction based host preferences in Culex pipiens mosquitoes

Abstract

Mosquitoes are important vectors of zoonotic disease transfers and have been implicated in the spread of diseases such as yellow fever, West Nile virus, and Zika. Mosquito preferences for sources of blood meal are, in part, genetically determined. The species Culex pipiens are found across Europe, North Africa, Asia, as well as North America. It has two forms with distinct genetic and ecological backgrounds: pipiens and molestus. The molestus form of Culex pipiens is active throughout the year, lives in man-made underground habitats, and, in European and North African populations, bites mammalian hosts. The pipiens form of Culex pipiens has been shown to diapause in the winter, live aboveground and prefer avian hosts in some populations in the Old World. Populations situated in lower latitude regions of the Old World and in the United States tend to have less discrete host preferences. This study attempted to establish lab-based evidence and confirm the molestus preference for mammalian hosts, specifically for humans over an alternative of quail, and for the pipiens preference of avian hosts over mammalian. The expected preference patterns were not observed in the study. The study also attempted to document blood feeding patterns in the American Culex pipiens complex populations based on blood meal source analysis data found in existing literature. Rather than displaying the decreasing proportion of mammal blood meal sources with increasing distance from the equator observed in aboveground (pipiens) populations from Europe and Africa, no clear pattern in the data was observed in the US, suggesting that the Culex pipiens mosquito population in the United States is different from those observed elsewhere.