Publication Type

Journal Article

Journal Name

Nature

Publication Date

6-2-2011

Abstract

Carbon dioxide (CO2) present in exhaled air is the most important sensory cue for female blood-feeding mosquitoes, causing activation of long-distance host-seeking flight, navigation towards the vertebrate host 1 and, in the case of Aedes aegypti, increased sensitivity to skin odours2. The CO2 detection machinery is therefore an ideal target to disrupt host seeking. Here we use electrophysiological assays to identify a volatile odorant that causes an unusual, ultra-prolonged activation of CO2-detecting neurons in three major disease-transmitting mosquitoes: Anopheles gambiae, Culex quinquefasciatus and A. aegypti. Importantly, ultra-prolonged activation of these neurons severely compromises their ability subsequently to detect CO2 for several minutes. We also identify odours that strongly inhibit CO2-sensitive neurons as candidates for use in disruption of host-seeking behaviour, as well as an odour that evokes CO2-like activity and thus has potential use as a lure in trapping devices. Analysis of responses to panels of structurally related odours across the three mosquitoes and Drosophila, which have related CO 2-receptor proteins, reveals a pattern of inhibition that is often conserved. We use video tracking in wind-tunnel experiments to demonstrate that the novel ultra-prolonged activators can completely disrupt CO 2-mediated activation as well as source-finding behaviour in Aedes mosquitoes, even after the odour is no longer present. Lastly, semi-field studies demonstrate that use of ultra-prolonged activators disrupts CO 2-mediated hut entry behaviour of Culex mosquitoes. The three classes of CO2-response-modifying odours offer powerful instruments for developing new generations of insect repellents and lures, which even in small quantities can interfere with the ability of mosquitoes to seek humans. © 2011 Macmillan Publishers Limited. All rights reserved.

PubMed ID

21637258

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