155 - Why Mosquitoes Bite Me More Than You: How Differences in Human Skin Bacteria Influences Mosquito Host-Seeking Behavior

Every year, mosquito-borne illnesses continue to be amongst the leading cause of death worldwide. Learning how to control mosquito behavior through traps and repellents is critical to reducing these diseases. Body odor varies across individuals and may be the key to understanding why mosquitoes selectively bite some people more often than others. Both human sweat and bacteria living on the skin comprise body odor, the latter creating a volatile blend that mosquitoes use to host seek. Four bacteria have been identified as important in Anopheles gambiae host-seeking behavior: Staphylococcus epidermidis, Brevibacterium epidermidis, Corynebacterium minutissimum, and Pseudomonas aeruginosa. In vitro community models of these bacteria on sweat plates are sufficient to show mosquito attraction in experimental settings. We tested the responses of host-seeking mosquito females to these four bacteria in equal and non-equal ratios identifying high attraction (HA) and low attraction (LA) blends. Using a uniport olfactometer to determine the attraction rates of Aedes aegypti, Aedes albopictus, and Culex quiquefasciatus, we found striking differences in response rates when comparing these species. Our research has expanded on this study to use a two-choice behavioral assay to determine if the mosquitoes prefer one in vitro skin bacterial community over others. We presented Ae. aegypti females with one of three treatment groups: LA vs sweat (no bacteria), HA vs sweat, and HA vs LA. These results have shown us that Ae. aegypti mosquitoes prefer HA communities over LA communities. Additionally, we are utilizing mutant Ae. aegypti females to determine which olfactory receptors mosquitoes use to discriminate between skin bacteria. These studies will allow us to identify which are the most salient odors produced by these bacterial blends. This knowledge will further the development of long-lasting and effective probiotic repellents and attractants to mitigate the spread of mosquito-borne illness.