"Molecular and Neural Insights into the Evolution of Mosquito Preference for Human Odor"
Abstract: Researchers investigating the outbreak of an unknown illness along the coast of East Africa in 1952 discovered homes inhabited by a ‘domestic’ form of the mosquito Aedes aegypti. An ancestral ‘forest’ form of the same species was later found breeding in forests, just hundreds of meters away. Although closely related and fully interfertile in the laboratory, the two forms remained distinct in the wild and showed striking divergence in behavior: Domestic females specialized on biting humans, readily entering homes, flying toward human odor, and laying their eggs in water-storage containers indoors. Forest females avoided homes, preferred the odor of non-human animals, and laid their eggs in tree holes outdoors. These behavioral differences translated into marked divergence in capacity to spread human diseases, such as Chikungunya, the unknown illness from 1952, yellow fever, prevalent in Africa and South America since the 16th century, and dengue fever, currently causing sickness in over 300 million people around the world each year. This story illustrates how marked and complex behavioral differences can evolve between closely related populations in nature with profound implications for human health. In my laboratory, we are taking advantage of such evolution to uncover the genetic and neural basis of behaviors that adapt mosquitoes to human hosts. Using the mosquitoes described above as a model, we are working to identify the genetic changes that underlie the innate preference of domestic females for human odor and determine how these changes alter the activity and structure of olfactory circuits to generate distinct behavioral responses.