35 

 consists of one port (port A) for introduction of the sample and the second port 



(port B) for the introduction of the control or a second comparative sample. The 



sample sizes or media of introduction are limited only by the volume of the ports; 



in this figure, petri dishes are shown. In port A, the petri dish has either been 



inserted after handling or inserted after deposition of a sample consisting of a sole 



compound or mixture of compounds. The dish in port B is a cleaned untreated petri 



dish used as a control. A humidity-controlled stream of air, pure gas, or mixture of 



gases is passed through the ports, over the samples. Any volatiles desorbed from the 



sample will be carried via the gas stream through a trap on each port. The outlet 



of the trap then opens into a enclosed chamber where the mosquitoes are held. The 



enclosed chamber also contains an exhaust to enhance the airstream effect through 



the olfactometer. 



Mosquitoes used in these tests are typically female Ae. aegypti, although not 



limited to this species or gender. Mosquitoes are usually not fed for a period of time 



in order to enhance the response to any attractive compounds. If the volatiles are 



odor cues for the mosquitoes, the mosquitoes will be activated to flight and follow 



upstream into the appropriate trap. Should mosquitoes not be able to directionally 



locate the source of the odor with accuracy but do alight upstream, they will be 



collected in the control port trap. After a specified period (typically 3-5 minutes), 



the experiment is ended and the mosquitoes trapped in each port counted. This 



allows for the percentage of mosquitoes attracted to a specific stimulus to be 



calculated. 



