Mosquitoes' Olfactory Senses are More Active at Night

A new study suggests that mosquitoes are more likely to chomp on human flesh at night. Why, you ask? Because their olfactory senses are more active then and their led by scent. 

According to a study led by Associate Professor Giles Duffield and Assistant Professor Zain Syed of the Department of Biological Sciences at the University of Notre Dame's Eck Institute for Global Health, they found that a major malaria vector in Africa was actually able to detect human host odorants at night better than in the day time.

The study looked at the insect's ability to smell across a 24-hour-day cycle involving proteomic, sensory physiological and behavioral techniques. Researchers found that when examining a family of mosquitoes, sensory proteins involving smell were released throughout the day but more so at night in order to help mosquitoes find blood.

The study notes that it's thought that the mosquitoes antennae and mouth play a crucial role in helping assist the creature's search for food.

Researchers believe this discovery may help provide a way for humans to protect themselves from the disease-carrying insects.

"This was an exciting opportunity to bring many people and techniques together to make some really fascinating findings on the mosquito's ability to smell humans, its host," Samuel Rund, a doctoral candidate in the laboratory of Duffield and a former Eck Institute for Global Health Fellow, who was involved in the study said, via a press release. "Just think, during the day the mosquito is sleeping and doesn't need to smell you. But when the sun goes down, the mosquito's olfactory system becomes extra-sensitive, and she is ready to smell and then bite you."

The study concludes with the following regarding the type of mosquito studied, via the release: "Anopheles gambiae is the primary species that is responsible for the transmission of malaria in sub-Saharan Africa, with approximately 300 million infections and 1 million deaths annually. The fact that these studies were conducted in Anopheles gambiae mosquitoes has important implications for the development of novel insect control methods with the potential to reduce the transmission of malaria parasites and thus the morbidity and mortality associated with malaria disease. This work provides the first comprehensive evidence of the important role of daily rhythms in the sensory biology of Anopheles gambiae and the implications for developing new control methods."

More information regarding the study can be found via the journal Nature.