Age-related changes in female mosquito carbon dioxide detection.

Mosquitoes rely on carbon dioxide (CO2) as a primary component in host-seeking behavior. CO2 is detected by specialized receptor neurons in basiconic sensilla located on the maxillary palps of the mosquito. The sensitivity and specificity of these sensors can be studied using single-cell electrophysiological methods. Such electrophysiological data reveal that certain aspects of the sensitivity of these sensors change during the maturation of adult female Aedes aegypti (L.) (Diptera: Culicidae). Although the mean threshold of response is similar between the ages examined, the overall sensitivity and temporal pattern of discharge of the neurons vary with age. Older females, which are likely to engage in host-seeking behavior, are more responsive to CO2 than very young females that are unlikely to seek hosts. Male mosquitoes did not show a similar pronounced pattern of sensitivity. The implications of such differences are discussed with respect to behavior.