It may not seem to have a nose, but a mosquito has an extraordinary sense of smell, which gives it the uncanny ability to find and bite us.
Zainulabeuddin Syed, a mosquito biologist with the University of Notre Dame's Eck Institute for Global Health in the US, studies olfaction in mosquitoes and other insects. An understanding of what leads mosquitoes to feed on humans can play an important role in developing more effective mosquito and disease control.
A large part of a mosquito's brain is devoted to smell. Only female mosquitoes feed on blood, which they use to produce eggs. And they find their meals through smell.
Culex mosquitoes, for example - which transmit West Nile virus, an emerging infectious disease, and other life-threatening illnesses - can detect minute concentrations of nonanal, a chemical substance given off by humans. They detect it via receptor neurons on their antennae. Birds, the main hosts of mosquitoes and a prime source of West Nile virus, also emit nonanal.
Syed is also researching the role that plants - and how they smell - play in mosquito behaviour. A deeper understanding of the role of the chemicals produced by plants and how mosquitoes select plants to obtain their energy sources can lead to better control and elimination strategies.
As for mosquito repellent, Syed says DEET (N, N-Diethyl-meta-toluamide) is effective. But rather than mask odours that attract mosquitoes, the insects smell DEET and avoid it.
In many areas of the world, mosquito control is a matter of life and death. In Africa, malaria claims a victim every 30 seconds. A better understanding of the role that smell plays in mosquito behaviour can offer important clues that may lead to new control strategies.
Test your knowledge of mosquitoes here.
1. Which of these diseases is not carried by mosquitoes?
a. Japanese encephalitis
b. Dengue fever
2. The itchy red bumps from mosquito bites are caused by
a. its sharp mouth parts
b. allergic reaction to pollen carried on its legs
c. an allergic reaction to its saliva
3. How many species of mosquito are there?
4. Is there anywhere in the world that's mosquito free?
a. yes, in deserts
b. yes, in the Arctic Circle
c. no, they are everywhere
Answers: 1. c; 2. c; 3. b; 4. a (mosquitoes breed in stagnant water; a desert doesn't have water)